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MG Midget and Sprite General - Nasty photo of props BLOWN HEAD GASKET...ouch!!!

Wow,.. Thank god its just a blown Head gasket, ITS CLY #4 With some leaking into #3

I cant understand what happened, or rather why it happened, I really cant imagine this damaged is the result of driving 100+ mph for up to a minute...

The missing chunk is about 3/8th inch wide and was also eatting into the metal below the composit

Also... the HG didnt stick to the metal...it was just laying in there

any ideas what could have caused this...im stumped

In case the photo didnt turn out... a big chunk of the composite is missing from the water hole to the #4 cly. and its actually eatting into the metal core of the HG... it blew out the inside of the firing ring

any advice to avoid a repeat of this photo

BTW.... the piston does NOT touch the head gasket, its does not extend beyound the top of the deck at full TDC

thanks

Prop

Prop

looking at the water hole... im wondering if it just got under the edge of the gasket comming out of the water hole

Perhaps shome kind of copper tubes screwed into the water jacket hole so the water by passes the gasket and flows into the head and cant seep under the gasket edges

Just a thought Ive had for awhile

Prop
Prop

Never saw one go like that.
Looks like the gasket was overhanging the head, and squished out of the joint.
Did you do your own head mods?

More pics!
Closer of this area, especially just above the blown section.
Other side of damaged area.
Pics around other chambers, both sides of gasket.
Wipe off the head and block, but no scrubbing. Pics of both.

Was it a Payen gasket?
What sort of crap did you use on the gasket?
What was your tightening procedure finally?
What was your retorque procedure?

FRM
FR Millmore

Ill post some pics tomarrow

Head was torqued cold...with arp specs with arp lube it was torqued dec 31, before 1st run, retorqued 100 miles, then at 300...aka just before wisconsin...i would have done at 500...but that would have been during the drive up...which never happened

Its a payen composite, (BK450) so i used nothing on it, but it never sealed/melted...not sure why...mating surfaces are clean when assembled...

Ive never seen anything like that as well...but i dony see many HG, im wondering if it could be a defect... The bottom side looked fine

Could this really have happened in the course of just a few minutes or was there a build up to this

There was no other damage from what ive seen... Well a small burn mark on the intake valve face from the water burning....

Oh wow.... Just a flash thought, i wonder if the intake valve was hitting the edge of the gasket...ill look into that tomarrow


Thanks FRM

Prop
Prop

Prop
Several things spring to mind
-you had trouble locating the HG
-you did your own head work (how close to the HG did you go)
-you torque like a lunatic! (realy just torque cold and then if you must retorque once when it has been through a heat cycle)

So I'd say HG was not clamped properly due to locating problems and head work and over eager torque procedure made it worse
Onno Könemann

What is the bore size?
Dave O'Neill2

I have seen a head gasket blow between 2 cylinders before and then burn the block below as if you had used a burning torch. On those occassions the mixture was extremely weak and pinking had occured which caused the trouble. I suspect yours is something similar.

I agree with David what is the size of your bores????
Bob Turbo Midget England

That fire ring is mighty close to the edge of the bores!

And is this the engine that you were having trouble with the piston rising above the block deck? How did you resolve that?

It's odd that the edge of the gasket has peeled into the bore with no distortion of the composite material behind. Normally they blow outwards, away from the cylinder. You can clearly see on yours where the fire ring has been dragged, or pushed, off the clean cut edge of the composite gasket just on the nearer edge of the break.

Might you have damaged the edge of the gasket when fitting it perhaps?
Guy

And is that a raised ridge on the fire ring? Top of foto where the arrow on the piston is pointing.
Alex G Matla

"BTW.... the piston does NOT touch the head gasket, its does not extend beyound the top of the deck at full TDC"

and

"is this the engine that you were having trouble with the piston rising above the block deck? How did you resolve that?"

A thought on working tolerances... the piston may not go above the deck when gently cranking it by hand but when the engine is doing 7000rpm the piston/conrod has such a speed and therefore momentum as it flys up and down the bore that it exerts quite a force on the con rod that it stretches it slightly.

Just a thought to throw into the pot!

Malcolm
Malcolm Le Chevalier

And is that rust around the top of next cylinder?
Gary & Gaps

And have you "cleaned" piston #4 relative to #3?

What's that stuff in the dish of #3, that's not in #4?
Lawrence Slater

Two things here Prop--
First, the gasket appears to be in the wrong spot , too far to the left in the picture and not lining up with anything there much, the flame ring just above where the damage is there doesn't look as though it's been compressed at all much - maybee a dodgey gasket
Also, personaly - I have had quite a few of that style gasket blow on MGB's -- I feel that little support plate between the cylinders causes a lot of trouble, It's an extra thickness in the gasket and I've had quite a few blow just where the plate finishes and I guess there is a little less pressure on the rest of the gasket just there
I'd be looking for a multi shim type gasket if it were mine Cheers Willy
William Revit

Just had a cruise on the net--
Aptfast over your way list a copper/steel composite gasket -- Part no. CHG-A $32-
I use their big bore MGB gaskets and they are a real nice gasket I give em a light spray of VHT coppercote gasket cement just to stop coolant weepage
You don't have to bother retorqueing as they bolt down rock solid and don't move at all.-
Works for me Willy
William Revit

Thanks guys

Its bored over .060 to create a 1330cc

On the head work all i did was port the inside arond the valve guilds , remove the sand cast ridge and smooth all the port grit off the walls

At the machine shop i had the bigger stainless steel rimflow knock off valves installed...mini cooper sized from 1969, converted to 11 stud, resurfaced, and hardened seats installed and brass bullet guilds made for hi lift roller rockers

I did have issues with locating the head gasket because the stud holes are bigger dia at the out side edge of the cly head then at the center of the head... I used aluminme tape on the studs to fill the gap and take the play out of the gap between the hg and the stud
Prop

A BIG concern...

The HG just lays there... Its not melted or stuck in anyway to the 2 mating surfaces of the deck or the head

I thought the payen composite was supposed to melt, adhere or glue its self to the mating surface

Am i wrong on this thought, or was i supposed to add glue or do something to the composit to make it melt into place

With the hole gaps in the HG vs the size of the arp studs...about 1/32 of an inch

I dont understand what actually holds the HG in place...thats why i used aluminum tape on the studs as gap filler last year

Is there a possiablity that payen composites come in 2 sizes... 948 to 1275 and 1380... I thought it was a one size fits all HG, i remember we talked about this a year ago and decided it was

Prop
Prop

I see what it is.
The gasket failed on the cutting edge of two circles, one is the head and two the bore. The gasket fire ring was crushed there. See pic.
In the lower left side of the picture (prop's) direct opposite of the missing piece you can see a little brown discoloring.

Alex G Matla

Wow alex

How the heck do i correct for that.

Btw ... I forgot to mention ... The brown is rust..i blew this on sunday annd didnt pull till tues day...the #4 cly was filled and the #3 had minor amounts of water...which looks like the water flowed thur the ring between the top composite annd the metal core....

yeah crazy talk i know,i just cant see any other way the water got to #3 and was so minimal

Prop
Prop

Looking at the fire ring of #3, it has the same raised edge, staring at the insert.
Can you post a pic of the whole gasket?
Alex G Matla

Yeah...it will take me a bit of time

Prop
Prop

Are these black payen h'gaskets marked TOP?

Did you fit it the correct way up? :

Also. Now you've told us it's +60, it explains why there appears to be so little metal between the cylinder bores.

It doesn't look like there is much for the fire rings to sit on/be compressed between.

Can you post another pic from higher up, so the whole block with gasket in place can be seen?

Edit, alex beat me to it. :)
Lawrence Slater

Alex

I cant get the whole HG in view and show any kind of detail

But your correct there is minor....edge catchimg for lack of a better word...the other 3 holes look great...ill post a better pic of 4 that shows the off set.edging
Prop

Prop

Prop.

We can download the pic you post and zoom in. So can you post the whole thing?
Lawrence Slater

Or take two, one left one right. Right?
Alex G Matla

I think i know where your going

Ive got some great photos from this morning and ill do a 1/2 and 1/2 of the gasket...

It will take about 1/2 hour to transfer from phone to computer and resize....yeah i need a better photoshop program...to many steps
Prop

Don't you have Microsof Picture manager? Quite handy for resizing.
Alex G Matla

My block is bored to 73.5mm (1380) and supports the HG better!
It was bore specificly with the payen HG as a template so the bores are centered on the gasket.

The gasket does not stick and this works fine it seals though the compression from the headstuds.

I never needed to retorque a black payen HG.

The payen HG has 2 tighter holes that locate it on the headstuds.
If yours does not then either the HG is wrong or you studs are to thin.

things to do now
-get new plack payen HG
-try it on the block with stud to locate

If it is lose around the stud try it with the old std ones
If it is tight but not centered on the bores the machine shop screwed up (or you did not specify).
Onno Könemann

I totally agree with Onno this engine does NOT look like a SMALL plus 50 thou bore, it looks to me more like a 1400 that has not been offset?

All the gaskets I have ever fitted to A Series engines have located perfectly as described by Onno

What I would like to know is why Prop can come up with problems with an A series engine that have never happened before in some 50 odd years!!!!!!!!!!!!!!!!1
Robert (Bob) Midget Turbo

Prop, where's my damned pictures?
Everybody is flying blind here.

First, it appears to me that this is cyl #1.

There is a lot of flat surface on the head between that water hole and the combustion chamber in that area, so even the most incompetent of head work should not have led to the situation Alex proposes. So long as the gasket does not overhang the bore, the only place the chamber edge would possibly be a problem is right between the cylinders; even there it would be incompetent work, not necessity - but that is not the fail point.

Yes, the gasket should have a resin coating that melts and bonds the gasket. I've never been able to get a Payen gasket off in one piece if it was installed on a properly clean and dry deck. As a painter, Prop should be able to see if there is a resin coating on the new gasket. It is a satin/low gloss finish soft coating that can be marked with a fingernail.

I recall a lot of talk re rust and such while the engine was apart. If antirust stuff had soaked into the cast iron and not been cleaned correctly, it would account for the gasket not sticking.

The clearance on the head studs should not be a problem, it is normal. IF the gasket overhangs the bores then it IS a problem, but that is fixed by using a big bore gasket, not by messing with shimming the stud holes.

In the pic so far supplied, the copper grommetted water hole at 10:30 seems to be way out of line with the hole in the head. I do not have a gasket, but on several heads I just looked at, the gasket marks are well centered on the hole in the head. This MAY be an indication that the gasket was/is faulty.

Again in this pic, the fire ring appears to be asymmetric to the bore, narrow at the blown section and wide 180 across. Additionally, there seems to be an anomaly in the fire ring just anticlockwise from the blown section. Might be an optical delusion.

Prop's retorque is pretty much what I do, though I do the post start ones hot. No failures ever in 50 years.

FRM
FR Millmore

Scratch my comment on the cylinder, I was looking at a dead! Dumb!
Lot of activity since I started writing.

FRM
FR Millmore

the fire ring appears to be asymmetric to the bore, narrow at the blown section and wide 180 across.

That's what I meant to illustrate.
Alex G Matla

Alex is right
And it is either caused by no proper location on the studs (yes FRM it should!!!)
Or a major c#ck up at the machine shop.

And a big bore HG???
On a 1380 you just use a normal payen HG....

If the block is bored wrong (don't think so still don't thrust the studs) you could have a solid copper HG made up to match the crookedness and have many happy miles (easy as the HG is reusable)
Cheaper than a new block
Onno Könemann

alright... god I hate this laptop... it gets slower by the year

Im still processing the HG pic

but these should give better clues

cly head

Prop

photo give me a minuteI got to find the file
Prop

Wow what happened to the valve?!
the rest of the head looks fine
Onno Könemann

okay agian

On this you can see... that whats left of the gasket it just wipes off

#4 is to the right

Prop

Gasket please Prop
Alex G Matla

and the last photo for a few min till I can gt the HG photo processed

well ill retry in few minutes... the BBS is now down and cant take photos
Prop

No it isn't, just tested it. :^P

Alex G Matla

agian...maybe

Im waiting on the laptop to process the HG photos

Prop

and head gasket photos

this is the rear 2 cly

Prop

and hear is the front 2


down agian..try agia in a minute
Prop

ahem, actually no 4 is to the left.
Tarquin

ahem, actually no 4 is to the left.
Tarquin

and the front 2

front is to the left

Prop

your correct tarqin.. some how the photo got reversed in the photoshop program

sorry about that

I have Got to get a new computer with updated software...this is ridiculas.. Im not sure how I survived Before my smartphone
Prop

I still think it is odd that the broken bit of the fire ring appears to have blown inwards rather than outwards towards the waterway.
Guy

Prop,

Couple of points,

The block appears to be coated in some sort of lube - antirust etc ? - should be totally clean no wonder it didn't stick - I would give it all a good clean with celly thinners and a good wet/dry rubbing etc prior to reassembly.

A Payen gasket normally has two of the bolt holes as a tighter size to the studs and the others bigger to give location - never needed ali tape etc.

I would ignore special thread lubes and just torque it down as the manual.

As others have said the gasket should not oversail the bore - check when new one arrives.

Best of luck.

R.
richard boobier

Don't forget to do an oil change as well.

I once lost a crank bearing shortly after changing a blown head gasket and found traces of coolant/anti-freeze on the bearings.
Dave O'Neill2

Its WD 40...i sprayed down before i took the pics to avoid corrosion....i did it to the head as well

Here is what im thinking and a couple friends are backing me

I found my emergancy back up payen AF470 gasket...it was installed and torqued but never fired

I placed it on the deck...and there is no room for error..iy fits exactly on the edge of the holes but dosnt go over...there is enough play in the 2 side holes where the studs fit to push it over the edge of the cyc holes

So here is what happened... I never got the engine hot enough and long enough for the resin to melt to the head and deck...when i raced the engine the other dayto over 100 mph there was just enough movement in the head to shove the gasket..and whola bang goes the HG

The guy i talked to said the fireing ring was damaged 1st that led to the hole in the black composite

So i need to make sure the HG is applied perfectly then torqued down then ran really hot for along time for the resin to melt and bond to the head and deck

So any advice as to how hot and how long to run at temp.
Prop

Basicaly this head gasket can never move, once it does the HG is toast....

That sounds like fun

Any body got a recommendation for a HG thats a bit bigger but the firing ring a little skinnier...that might be a better option
Prop

I'm in the dark here, but I can't help thinking that shimming up the stud with tape to "locate" the gasket hasn't had something to do with it?
Matt1275Bucks

I did it to keep the gasket from moving around....namely while installing the head.... It was advice i got from several here about a year ago


Prop

My memory of the advice at the time was that it was NOT to do it? Could be wrong though! I have to say my thoughts are like Matts, but I am in no way (at all!) an expert.
Andrew F

Prop
As I recal the advice from this side of the pond (the side where the aseries is not the exeption but the standard) was not to tape but to get a proper headstud and gasket combo that would locate it properly!!!!

Do not use tape but check the gasket and studs!!
Just these should locate it properly.
If they don't you have a problem that should not be solved with tape
Onno Könemann

Do not use tape.

I don't know anyone else who has ever felt the need to do it.
Dave O'Neill2

"I never got the engine hot enough and long enough for the resin to melt to the head and deck"

I seem to remember a thread here about how this engine was running too hot and you had to keep stopping to let it cool down, to the extent that you had to drive overnight to keep it cooled enough to run and in the end you abandoned your trip.

Or was that the other Prop who posts here sometimes?
Guy

Prop,
just a thought but are you sure all your waterways in the head and block are completely clear?. If there was a weakness in the gasket where it has blown or some other additional interference from piston or valve could a build up of water pressure from a blockage be sufficient to cause the breach?
I'd buy a new correct sized standard gasket, clean off the head and block, take the tape off your studs, torque it down as suggested here and go out and actually put some miles on the car without revving the nuts off it and see what happens. If it blows again you know you have a bigger problem, if not don't worry, just build up the mileage and the revs. Please do it this weekend though and get the Midget back on the road otherwise we'll still be arguing about it in another 3 years!
Matt1275Bucks

I reckon that hg was doomed before you put it on. I don't see anything there that would account for the way it blew.

If it was weak and damaged at that spot, and you simply didn't notice when you fitted it, then the normal course of events could well have resulted in the fire ring being pushed inwards by the hot water pressure.

Add to that the problem you had previously with the overheating, and I reckon it all adds up.

I agree with Matt.

Fit another standard hg. Ditch the tape, and do a bog standard install.

Run it up to "normal" operation temp. Retorque, and then drive it at medium rev's/normal temp for a few hundred miles. Then I'd leave it alone and see how it gets on for a while.

BUT, I'd pull that inlet valve on #4 and have a look see at it's seat; just in case.


AND PS. clean all the crap of both surfaces with solvent, AND change the oil.
Lawrence Slater

Lawrence, do you think the coolant pressure could get that high?
I don't think so personally.
Alex G Matla

Lawerance

Im having the valve looked at this morning and the head vacume checked to make sure the seat is okay....thanks for the reminder

You guys are making no sence

I asked if the payen HG comes in other sizes...everyone said its a one size fits all....now your telling me to get the standard size head gasket....which is it guys ???

For the 5th time... The lubercant on the head and deck is wd 40, to prevent corrosion....its temporary...i sprayed it on after i pulled the head....it will be washed off when assemblied

Yes...the engine got hot really hot during the summer...but appearntly not hot enough for very long as the resin never melted and sealed to the head....thats why i am asking how hot and for how long before the resin melts and seals


Is there a better HG then the payen BK450 black composite i should try that fits better and seals with vht copper HG sealer that you guys can recommend...i only know of payen

Prop
Prop

Alex, if the gasket was faulty, the pressure 15lbs might have been enough to blow the gasket?

As has been remarked earlier, it's blown in, --water in the bore --, rather than out.

Once the fire ring was in the hot bore area, that would account for the condition of it I reckon.

Noted Prop was clean before wd40. :)

As for the melting, I haven't used a black payen yet, but the silver looking composite ones I used in the past, have not always been "stuck to the head either.

Hot enough would be normal running temp for as long as it takes.

How long that is, unless Payen describe this, I guess the only way you know is to fit one, and take it apart again to look.

But it seems reasonable to assume that if the gasket surface is designed to melt and seal, then it should happen as soon as it's at normal running temp.

Your bore size is 60+, so is that oversize enough to require a special hg? I guess you have to measure your HG and compare it to the bores.
Lawrence Slater

Nah, 15lbs hardly more than 1 bar, couldn't bent steel like that. Doesn't matter.

But! I have 73mm (1360cc's) and use a BK450, no problems at all.
Built my engine about the same time as prop but I've done 12000 Mls by now. Had to fit new pistons after some 1000 mls though. But that's another story.
Alex G Matla

Mine too is 1330 (strapped main bearing) and I don't know what gasket I have but used ARP bolts. Torqued to their suggested settings. Aprox 11:1 compression with cheap AE pistons. I wouldn't recommend this but it was run in for 200 miles then absolutely thrashed on a track day at the 200 mile mark. By thrashed i mean foot flat down as fast as I could get the car to go including changing down from 5th to 2nd at the hairpin at the end of a 1 mile straight. Retorqued at 500 miles and thrashed ever since. Am I just lucky (stupid) or is there method in this madness.
Gary & Gaps

I've used that gasket for a few years now and although I've had it go once I don't think thats bad considering the revs and abuse it gets. Plus it was between 2 and 3 and no gasket damage. I've put a new one on every rebuild (obviously!) and I've never had any location problems or done anything other than normal torque and one retorque.

One thing have noticed is that there is a slightly sticky resin surface on the gasket so I make sure I don't touch it and hold it by the edges. The head and block I clean and then wipe with MEK or similar just before fitting. My car has standard 9 studs, it's 11:1 cr and I rev it to 7500.

On removing the head the gasket always comes off easily leaving nothing behind but what I can only describe as a laquer type film which I presume is the sticky resin that has set with heat. Did you see anything like that when you took yours apart? Are you POSITIVE it was a Payen gasket?

The water pressure thing is something I have had problems with but that was blowing water pump gaskets. I don't exactly agree that the pressure is only 15psi very near to the pump - not sure but you are dealing with fluid and air pressure in that system so who knows what it does!! (Anyone?!!) I fitted a larger water pump pulley to slow the pump slightly as it's not really designed to be running at such high revs.

From what I read earlier (as usual with a Prop thread there is always lots to read!) I got the impression you were doing a sustained 100mph plus with not many miles on the engine. Was that wise?!

Anyway, hope it all goes back together ok and you get a few more miles out of it next time!
John Payne


prop

Have a look at the Calver web page - he talks about this offset problem- hope the link works as I'm on a dodgy dongle connection.
Seems likely that your gasket oversailed the bore-
I would try the new gasket taking care to check no oversailing.
If it does oversail you have an offset bore problem and other than the measures he mentions it might be worth a try to 'modify' the gasket around the two locating studs to get a fit to give clearance around the bores.

My view only - others may well disagree !

Best of luck.

R.



http://www.calverst.com/articles/Eng-Engine%20-%20Over-boring%20blocks%20for%2073%2073.5%20or%2074mm%20diameter%20pistons.htm
richard boobier

Here's a working link for "Cylinder head - Torque down and head gasket problems"

http://www.calverst.com/cc110f.htm

From there you can click to other very interesting articles.
I've always liked his no-nonsense approach to tuning.
Alex G Matla

O.K so the link was no good

Go to keith calvers site as Alex's link, go to 'calvers corner' and on the left hand side menu he lists 'engine' then over bore problems -about half way up.

R.
richard boobier

If you copy/paste that link into a new browser window, it will work.

-:G:-
Gryf Ketcherside

My suspicion is that the use of aluminium tape on some studs actually had the opposite of the desired effect. It may have been nicely centred on those studs, but with the rebore and fairly fine tollerance the tape may have forced the gasket to go off-centre in relation to the bores. Either that or it was a faulty (or damaged) head gasket at the outset.

I think it is great that Prop is prepared to try these "alternative" ideas, using his engine as a test-bed and being prepared to accept and learn from it when the idea fails.

As for coolant pressure, I doubt that the pump would cause any significant pressure increase above the system designed pressure if 15 lbs psi. They work on volume of fluid moved rather than be creating a pressure jet!. But getting into the microscale I believe that localised superheating of the water may well occur, possibly causing micro bubbles of superheated steam at high pressure. Especially if water circulation is not as good as it might be, as for instance is reputed to happen around cylinder #4 when the heater tap is closed.
Guy

Yes, forgot to mention the aluminium tape. Never heard of that and not something I'd try! Surely if the ARP studs were the same dia as standard they should locate the gasket fine. Mine have always been a snug fit over the studs with no movement. I know the threads must be the same but is the plain area of the studs the same dia as the original ones?

Going back to coolant pressure when you think of the cylinder pressure being 200psi or so when cranking - what's it going to be at 7000rpm??!! I can't see the water pressure overcoming that! Then again I suppose during the 4 stroke cycle its at a negative pressure in there as well.

Prop, have you put a straight edge along the line of the edge of the bores to check they are all in line? I'm thinking if one or more has been bored slightly offset to the rest. Who knows but the more you check the better.
John Payne

If i dont use ally tape on the studs...how do i keep the gasket in place....its just laying there..non sealed...with lots of play around the head gasket holes...

.without something to hold the head into place... Its going to move around....or am i missing something

There is no issue with the bores...

As i stated earlier i found a slightly used AF470 payne gasket and it fits perfectly on the deck with no overhang into the cly....but it has no room for error...if it moves slightly...ill have over hang

So bore issues are off the table

I need to know how to make the HG stick to both the head and the deck without moving.

Prop

Prop

Ill certianly do that john...straight edge...but as i said...there is nothing wrong with the bores...the HG fits fine...it just has no room for shift

P
Prop

Tomarrow ill shoot a video of what im trying to convey and post it to youtube... Cause you guys just are not getting it


Sorry for being so short... Im just so tired its been a LOng day...and its still got hourS to go

Thanks guys

Prop
Prop

Prop have you not read any of the comments!!!!!

The HG should be located securely by the studs!
If it is not so something is wrong.
Get an other HG and try it with your fancy studs.
If that does not work try it with old std studs.

You are missing the point if you do not calmly check these points first.
Report back when you have checked.
Onno Könemann

Prop,

As others have pointed out the gasket should be accurately located because two of the head stud holes are a smaller diameter. These fit closely to the standard head studs without the need for aluminium tape.

I have just checked an unused spare Payne gasket. The smaller diameter holes are one next to #1, on the pushrod side ofthe engine, and one between #3 and #4 on the spark plug side. These two holes should be sufficient to properly hold the gasket and prevent it "walking", even if the resin doesn't melt and stick down to the block.

Unless of course, your ARP studs are skinny?
Guy


prop,


I have checked a new set of ARP studs on a new composite gasket - two of the head stud holes are a good fit in the gasket the rest are oversized - this is how it should be.

Hence the gasket is automatically centred where it needs to be - it cannot move around.

READ the Calver link page I posted - he is expaining the same thing.

If the gasket then oversails when positivily located by the studs the bores are offset.

Try with the new gasket and report back.

Have a good kip and try again with a clear head.

R.


richard boobier

Uk to US translation...

Kip = sleep
Dave O'Neill2

Guys....I HAVE TRIED A USED PAYEN GASKET...IT FITS....BUT HAS NO ROOM FOR ERROR...AKA NO OVER HANG....BUT NO ROOM FOR SLIP.

THE 2 holes in the HG that center has a small amount of play...AKA SLIPPAGE....meaning ...if it moves.. the HG is toast it will blow

This gap in the HG to stud is about 1/32 of an inch


This is were the core of my issue lies...how do i keep the HG from moving

If the resin isnt melting... Can i wash the resin off and apply VHT cooper HG sealer...that stuff works great.

Prop
Prop

Prop
Read our comments again until it sinks in!!!
The gasket will be located securly with just the studs in the 2 smaler holes!!!!!!!!

Get a new gasket and try this.

If you don't you will not properly solve this problem
Onno Könemann

Can only repeat the above. I've used the BK450 on road engines and my 1380cc race. Always a tight fit around 2 of the studs so needs careful installation. Once down on the block, no "slippage" at all. If you have enough movement so as to allow the gasket to oversail the bore, then something is wrong.
John Collinson

Surely Prop is saying that he doesn't have a tight a fit round those two studs as others do, correct?

Prop, can you post 2 pics, both with the studs loosely in place and with the head gasket on. First pic with the gasket waggled to the left, next pic with it waggled to the right. That will show how much it is supposed to be moving about.
Tarquin

Is this an ARP headstud? Looks different to the other one.

F Pollock

Prop, assuming that you have understood what is being said about the 2 locating holes in the gasket, then it must follow that either you are using thinner studs than normal, or the gasket you are using is a poor quality "copy" of unknown origin.

Are all of the stud holes in the gasket the same size, or are the two I mentioned earlier of a smaller diameter? (even if still loose on their respective studs). On the gasket I have the holes are 0.430", and the two locating ones 0.385"

I do think that trying to fix more than the two location points by wrapping foil around the studs is likely to set up stresses in the gasket and lead to distortion, possibly forcing the larger bore holes out of shape.

Incidentally, on checking my Payen gasket I find that the cylinder bore holes in the gasket are not true circles! Measured across the head width they are 2.905" (+-0.005) and measured along the length of the head they are 2.860" A consistant difference. Not sure if this is manufacturing tollerance for the gasket, or intentional to match cylinders which wear more on the thrust side than fore - and -aft. Except that wear wouldn't extend to the top of the block would it?
Guy

Prop
You might have missed this--

Posted 16 November 2011 at 13:44:11 UK time
William Revit, Tasmania, Australia

Just had a cruise on the net--
Aptfast over your way list a copper/steel composite gasket -- Part no. CHG-A $32-
I use their big bore MGB gaskets and they are a real nice gasket I give em a light spray of VHT coppercote gasket cement just to stop coolant weepage
You don't have to bother retorqueing as they bolt down rock solid and don't move at all.-
Works for me Willy

I probably suggested using metal tape as a way of locating the gasket last time as I use it quite a lot.
Never ever had a problem with it, It's very usefull IF the gasket isn't locating nice and tight on the studs
Willy
William Revit

I think Alex might have nailed it with the link he gave. PROP have a read. http://www.calverst.com/cc110f.htm

Note this pratically describes Props problem to a T.

I've cut and pasted from the site.

Cylinder head - Torque down and head gasket problems

OVER torquing.

"Why? The main reason (there are several) is because over-torquing will almost certainly distort the gasket to the point where failure is likely to occur. The most likely areas are the fire-rings that seal the head face (chambers) to block face (bores) off. Particularly between the bores where the steel fillet inserts are in non-copper/composite gaskets, and where modified heads have been a little over-zealously ‘relieved’ around the gasket fire-ring line. Especially between the centre two exhaust valves.


What happens here is the excessive torque clamps the fire-ring down so hard it forms a sharp edge that either splits, or gets burnt away by combustion chamber temperatures. Or in the case of the steel-fillet insert type; it twists the fillets out of place. In either case this then blows combustion pressure passed the gasket, pressurising the water jacket. The engine then over-heats or forces water out the front joint between head and block."


"this then blows combustion pressure passed the gasket, pressurising the water jacket."


Clearly if this occured on props engine, it would account for the fire ring being blow into the bore, where it was destroyed.
Lawrence Slater

Actually I should also say that Richard gave the link to carver. Great site, I hadn't seen that before so thanks.
Lawrence Slater

Lawerance

Thank you...

With the butt sucking day i had yesterday i had not gotten the chance to read calvers artical...that really discribes the issue to a tee and makes perfect scence

With the arp studs they do torque down more then stock...perhaps if i back off the arp spec by 5 psi...that might take that possiability out of play

I just looked up the torque specs for ARP...

60 psi with 30w motor oil...which would be compareable procedure to stock head studs ...but 40 psi with there special lube which measures out to the same clamping force on the studs

So perhaps if i torque to 35 psi with arp special thread lube
that would be the same as 48 psi ARP on 30w motor oil,

Im not sure what stock non-arp head bolt torque spec is...i want to say its around 50 psi

Does my line of thinking make any scence or have any validity

Thank you lawerance

Prop
Prop

Hey willy

Thank you.... I have another payen arriving today or monday...if this one fails, ill certianly take your suggestion and try yours from apt fast.

Prop
Prop

"butt sucking" ?

Prop, I hope your talking about cigarette butts, and not the other variety.

Whilst both might induce ill health, I suspect the tobbaco kind would be the more pleasant pastime. lol.
Lawrence Slater

Lol...it was just a bad day...

ive never actually did any butt sucking...but im sure butt sucking would almost have been about as bad as my day was yeaterday


Prop
Prop

Hey lawerance,

I just heard back from the machine shop...it didnt pass a vac test..so the valve is leaking...they havent pulled it yet...so itheter a burnt seat and they said possable even a bent valve from the water rushing in and rapid cooling the valve stem...ever hear of any thing like that.

What do i look for or how do i tell if the surface of the head has been damaged at the spot where the gasket blew...they want to resurface the head...fine if it needs it... But id like to know there is damage before i go shaving 5000 off the surface

Prop

Prop

No I've never had that, but from that calver site link, that guy seems to be aware of it.

so if that's the case, the gasket, which may or may not have been weak/faulty to begin with, blew because it was torqued too much. That induced pressure into the water jacket, sent a blast of very heated water into the bore, and that explains your cloud of steam out of the exhaust, and the mark on the face of the valve.

Can't see how it would have bent the valve though. Although I guess the relative temperature difference between the valve stem and the water, prior to, and after the sudden ingress of water, might cause the bend in the stem.

Maybe the leak, if it is the inlet valve in question, might have been there anyway, or might be a litle bit of crud on the seat. You'll know when you see it.

Straight edge the head. It looks good to me in a picture. I wouldn't skim it unless certain.

Lawrence Slater

I got some insight on the payen gasket from the tech dept of my supplier

1. The cly compression is to high...im running about 200 psi and the payen gasket maxes out at no more then 200 psi

2. The resin is as i suspected very thin... There advice to customers is to spray copper coat on both sides of he HG, but a thin amount to promote adhision... But dont do to much or it wont seal

3. HG have variations in the batches to batches and runs to runs...something to do with how the machine is set up...kind of like a printing press, its not uncommon for the stud holes to be bigger or smaller...even out of place by a fraction .... That makes me oh so freaken happy...i could just butt suck a tr6

His advice is i need a differant head gasket...aka a cooper core composit like willy was advising

He didnt have an opinion on culvers artical... He thought id should stay with arp specs as im cranking out alot of compression...that would be a bad idea

So if the valve is bad... I wont have it fixed now till after thanks giving... So that sucks...so im really hoping its just th seat...what is that 15 sec. With the seat grinder

Prop
Prop

Well, all the experts say it can't but....

My pistons are popping a little above deck...
My BK450, torqued only once, is holding up fine...
My 12G1805 head gives an above average compression...
My inlet valve is 39mm and I can't get my thumbnail between in and ex valve...
My radiator needs shrouding when it gets a little colder or my engine won't get warm...
My rev counter stops at 7k, which isn't enough...

Now I will probably blow up my engine because I typed this...
Alex G Matla

1- BS
2- BS
3- BS

Several people with 1380's and scarry high compression use the BK450 and report no problems.

And again I must advise prop to KISS

Keep
It
Simple
Stupid
Onno Könemann

Onno, do you really think he will?!! He might KISS something - by the sounds of it the back end of a TR6.

John Payne

So you belive that if it didnt work the last 2 times...keep doing the exact same thing...

Any idea how many times ill have to repeat before it takes hold ???

Prop
Prop

Prop, I used to use a Payen copper head gasket before the BK450. It was ok and never gave me any probs - I think it was an AF460. I'll go and check.
John Payne

Yep, here it is:

http://www.minispares.com/Product.aspx?ty=pb&pid=37368&title=

It's got a slightly bigger compressed volume than the BK450 so will lower the CR slightly. Might be worth trying something different.
John Payne

Agree with our european contingent

Absolute and utter boll0cks!

Prop when you do something wrong why do you always try and find a scape goat other than yourself!!

Hundreds of Payen headgaskets have been used successfully yet guess what?

Yep Prop gets one that is sub standard and craps his engine!

Staggering absolutely staggering.

Shakes head in total disbelief!!!
Robert (Bob) Midget Turbo

Aye, I agree with those who point out that Prop is overthinking (or underunderstanding) the problem. I use the AF 460 on my racer, bored .045" over, with zero problems (the 460 has a compressed thickness thinner by about .030" than the 450, check one! Vizard is wrong on this). Just drop the gasket in place, drop on the head, torque in stage with lube to no more than 51 ft/lbs (with a verified torque wrench) and Bob's yer uncle. No spray, no glue. By the way, the 450, if properly installed and the engine is running well, does not glue itself into place with heat. It lifts off cleanly after use, which one of the joys of using them. so, as other have advised, KISS and refrain from unnecessary 'fixes' such as the tape on the studs.
MC MacQueen

I m done...nothing left to say

Prop
Prop

Prop has left the thread.
This time we've done it, he's had enough.

Good luck prop, on reassembling your head and many happy miles to come.
Alex G Matla

Nah, don't give up Prop, fight back. :)

Anyway, just out of interest. Fergus pointed out one of your head studs being plain top, and the adjacent one being drill point. If they stretch differently might this have unbalanced the clamping load at cylinders 3/4?
Lawrence Slater

lol. Alex, do you have esp?

I've noticed that on numerous occasions, you just beat people to the post. :)
Lawrence Slater

Prop,

You said "...they want to resurface the head...fine if it needs it..."

Remember, piston height needs to be reconsidered. If I remember correctly we had a discussion about that in your earlier post - I think you said then that the pistons were 0.004" above the deck. If you shave 0.005 of the deck that becomes 0.009".

If you do shave I would remeasure piston height (on all 4) prior to removing any metal. I admit I remained sceptical of your 0.004" given one of your photos in the earlier post.

Gee, I (and probably others) learn heaps from the discussions you generate Prop so, for all the frustration you must at times feel, please remember that. Somebody has to be out at the edge and, for the moment, that is you.

Sage advice here in all posts. Particularly KISS.

I wish you luck with all of it.

Regards
Roger
Roger T

Hey Roger
Don't confuse him

If the pistons are .004" out the top , it doesn't make any difference how much you take off the head , the pistons will always be .004" out the top.

Taking .005 off the head isn't going to alter anything except a minimal increase in compression,
It would be worth about a third of one cc
Willy
William Revit

Willy and Prop (with apologies)

Oops and bu**er, Willy you are absolutely correct and I misinterpreted Prop's post. Prop was speaking about the head so the issue is compression not piston height.

The rest of my sentiments are still intended though.

Frankly I have been amazed at the man's audacity from the outset, but equally impressed with the strength of the support offered to him from the Midget fraternity through the saga. I suspect all of you feel much the same way.

I have long admired the strength of the family, and sense of humour, on this particular BBS.

Slinking into the background (but well intentioned!!!)

Regards
Roger
Roger T

Update...

I FOUND the reason for the HG failure

Im not sure why i didnt think or see it before...

In a word....Detentation, remember back a couple weeks i was talking about my pertronix chip was failing, and i converted back to points....but was having some issues dialing the carbs in...and finally put a light to the marks and the timming was 26 degrees at 1000 rpm then adjusted i back to 10 degrees and everything fell into place....thats when the HG blew, i remember looking at the vac gauge and thinking...wow that showing a blown HG..but it all but disappeared when everything was fine tuned ....it was just 10 mintes later that i took my fateful drive...seperated by 2 weeks

But definate signs of dentation on the head. A small burn spot on the little curve section between the valves....so im 97% sure thats where the HG blow out came from....it was most likely damaged while driving then blew out after my 100 mph drive

So im going to have my 3&4 cly valves & seats re faced hopfully thats all..the shop wanys to do all the valves because there leaking and a resurface...but i think i threw them a curve ball... I didnt scre the plugs in all the way and i think thas the source of the leakage...ill check them today with a mity vac

On the resurface...im going to polish the surface up nd have another look at the area where the blow out occured...i cant see any damage discoloration..or even a clean spot...nor can i fill and flaws in the metal with my finger...so with HG costing $20 and only taking 3 hours to remove and install plus tune in....im going to risk it and NOT resurface...provided after polishing the surface there in no evident sign of damage.

So thats the plan...maybe monday at the earlist i can be up and running.

On my pistons... I had them shaved and are now .020 below the deck at tdc...this made the CR 9.25

So head gasket will be installed as last time


Prop

Prop
Prop

Hey Prop,

That might be the reason, but doesn't really explain the nature of the way the hg blew "inwards".

To check your seats for leaking, just invert the head and with the plugs in - tight- fill the chambers with petrol. Leave and see if any drain through the valves. If still full after an hour, no leaks. Any that do leak will be very obvious as the petrol level will drop.
Lawrence Slater

Sounds plausible, go for it prop!
Alex G Matla

Prop
good luck
If you are happy then that is fien with me

Have fun ignoring the real problems and drive it
Onno Könemann

I was going to do the petrol trick...but time is short today...so i got a piece of plexi and some double stick tape and just pull vac thur the spark plug hole...easy and fast...hopefully in another hour just leaving the barber now

Prop
Prop

Prop you haven't got time for a hair cut, just fix the Midget. lol.
Lawrence Slater

Well the award to me again then look at post 7 :) my first post!! LOL

However I will not claim the golden ball just yet as if it were pinking and detonation then why have none of the pistons picked up (Semi seized) in the bores?
Robert (Bob) Midget Turbo

And also after a night in bedddy byes and further consideration.

Why is there no signs of detonation on the pistons? why did the engine not overheat?
Why weren't dinosaurs on Noahs ark?

All very simple questions that deserve an answer?

After further study of Prop's photograph the only conclusion that can be considered IMO is that this gasket has suffered mechanical damage during instalation and the marks on the block are simply as a result of the engine running without a sealed gasket in that area. Why?

Where was the infamous tape applied? did the tape prevent the cylinder head from being clamped down evenly/correctly?
Bob Turbo Midget England

I'm still somewhat interested to know if the suspect ARP rod that F Pollock pointed at is normal.

I have pretty much the same setup as Prop's (1330cc, Payen Gasket, ARP studs) and haven't had a problem locating the gasket.
OrangeSpyderMan

Yup,Come on Prop, fess up, that's at least three of us asking about the odd man out head stud in your pictures. :)



Lawrence Slater

Roger
Come back mate ,there's no need to apologise, it's all good . I feel this is far from over
Bob
The metal tape is wound around a headstud at each end of the engine to increase the diameter of the stud to match the hole size in the headgasket to locate the gasket nicely - IF NEEDED Most gaskets don't need it, but there are a few out there that are a sloppy fit on the studs It's important to check that the head will slide down over the tape without catching on it though.
Willy
William Revit

Willy

If the gasket needs tape, then the gasket is wrong.
Dave O'Neill2

Hi Willy

Whilst I have never seen a head gasket that has needed to have any massaging to get it located correctly (I agreee with Dave on this issue) I will for the time being give you the benefit of the doubt that one day that may happen.

However I can't believe that you gave Prop such advice!!!??? You have hit the nail on the head if someone without too much ability did such a thing then the only outcome would be that tape would foul the holes in the cylinder head and would tend to bunch up under the head and prevent it from seating correctly.

Did you make him totally aware of that at the time?

Equally we tend to get people on these boards who maybe one minute come on the BBS with a clapped out old Midget, only to find a year or so later they suddenly become overnight experts who suddenly know everything about every MG model built and give (misunderstood)information to other new easily mislead individuals.

I believe we should take great care what information we give out and to whom it is given, I think this maybe a typical case unfortunately.
Robert (Bob) Midget Turbo

Yepp robert...you called the detenation

I became aware of the big holes in the gasket ...no one advised me of it, and was trying to compensate for it, and willy gave the much needed advice

The head bolts do appear to be differant... They are 2 replacement head studs that ARP sent me...i got over sealous with a grinder on 2 of them trying to get the studs to sit lower in the block because the HG was locating on there threads there is a hex hole in them...just not as defined as the others

Prop
Prop

Hi Prop,

If I read you right, a couple of the studs were too long so you ground off the top, and that's why they appear to be different?

I can't see the detonation marks in those pictures, and if this was the cause, why only on 3/4? If the timing was that far advanced as to damage the valve faces, surely it would be visible on the piston crowns too, and on all four cylinders.

I still think the fault was localised to the particular place where the gasket failed. I.e. it was a bad gasket in the first place, or as has been suggested, could you have damaged it when fitting it, without realising you had?
Lawrence Slater

No ...i took the extra off the bottom of the stud...the top of the stud is not showing up in the photo...

Im just guessing no damage to piston tops because there dished...i dont know...i havent had a chance to really look at the pistons yet...but is but its seen easy to see on the head on the curve section between the valves
Prop

Right. Is it possible that ARP sent you the wrong two studs? Why are they not the same as the others?

I've never used ARP studs, so maybe how they look is irrelevent.

But I always thought that plain top and drill point studs were rated differently. If this is not the case, then I've learnt something new. :)
Lawrence Slater

You had to grind studs to fit them to the block? What was the problem?

As Lawrence says, did you grind the top off - why? the fitting instructions are relatively simple for those ARP studs, and I don't see what grinding the top off would do.

I can't believe that ARP sent you 2 studs that were too long, unless in the 11-studedness of it all, something got mixed up. I have only 9, so I don't know what the other 2 look like (one is a bolt, isn't it?)

I'll admit to being little more than a rubber-neck bypasser on this thread, but I'll give 2 excuses (you can judge the worthiness or not) :

- I have what sounds like a very similar setup (as mentioned previously)
- I'm a novice that was toying with my (first) engine rebuild (albeit with a more experienced colleague)
OrangeSpyderMan

Lawrence,

The ARP studs I have, have a hex drive countersunk into the top for threading them into block (i.e to suit allen key)and ARP stamped into the top also.

No I don't understand what Props talking about either and why needed shortening etc.

R.
richard boobier

"the top of the stud is not showing up in the photo"

Erm. Are you sure? The top of all my ARP studs has the hex in it and is, well, facing upwards...
OrangeSpyderMan

Prop didn't grind the top off. He ground the bottom because they weren't screwing into the block far enough.
Dave O'Neill2

Dave,

The query asked is in one of Props pics it shows the studs and one did not look like an ARP type (head markings missing ?)- was it an odd one ?

R.
richard boobier

Thanks Richard, I hadn't realised that was a hex.

Tell you what, if nothing else, Prop is going to make another double century with this one soon. :)
Lawrence Slater

Perhaps, just perhaps, Prop put the ARP studs in upside down. Might explain why the threaded bit was too long and needed to be ground down.

I presume that what Prop is saying is that he shortened all of them, but overdid it on two, and had to get two replacement ones.
Guy

Guy,

Not possible ? as threads are different.

The block thread is course and quite short thread length on the ARP's about 15mm - I wouldnt want to shorten - worth checking it has not pulled if shortened very much.

R.
richard boobier

Richard,
I knew the block thread was short, which is why I thought Prop would find the threaded section was too long if inserted the wrong way up. I had forgotten about the different thread! Of course it would be a coarse thread into CI. Should have known that!
Guy

Hahaha....wow, this is boardering stand up comedy

I ground off just a small amout off the bottom of the arp studs...there was a small amount of thread showing abovr the deck that would not allow proper locating of the Head gasket....aka ALOT of play....so i ground them off at the bottom to push all the thread nto the block

They all have hex indents...but they didnt show up in the pic...not sure why...shadow, grease, dirt...??? I dont know whythe hex is hidden from view in the photo.

Prop
Prop

Prop,

I have been confused before and it is happening again. I may not be alone this time. You have made a number of statements regarding head studs but I'm not sure you have addressed some of the questions asked about them.

Can you tell me, of the 11 studs (correct number?) you have put in the block for the rebuild, are they:

1 all ARP studs from a single order/shipment? or

2 are they all ARP studs from 2 or more orders/shipments? or

3 are they a mix of ARP studs and non-ARP studs? If this is the case:

3a questions 1 and 2 above re the ARP studs, and,

3b what type/origin are the non ARP studs in the block now?

Also

The two studs supposed to anchor the HG, are they ARP?

If so, can you please do some actual measurements?

1 what is their stem diameter, and

2 what was the stem diameter of the original studs in those two locations, the ones you replaced with the ARP studs?

How do those measurements compare to the ones given by Guy in his post on 18 November?


Willy, thanks. Teach me to think a bit deeper first.

Regards
Roger
Roger T

Hahaha...

Your good roger...all studs are ARP, 2 studs are replacements which are ARP...

Sorry i just dont have the time to measure them but they are all the same

Prop
Prop

Tired of staring at these pics!

I think that in pic 1 showing the failure, there is no sign of the fire ring being crimped over the edge of the composite; the exposed surface of the composite is unmarked. Also, I still think the fire ring looks asymmetric, wider on the side away from the failure and narrow where the fail is. The pics 5 & 6 showing the HG also look like there is more space between the fire rings of 3 % 4 than 1 & 2. Better and well lit pics or measurements of fire ring might help.
So the gasket was defective or damaged, with the fire ring being either out of position, unsupported by the composite, and sticking out over the bore, or in position but still unsupported by the composite, possibly from incorrect cutting of the hole in the fiber.
In either case, the fire ring would be unclamped because there was no composite under the crimp, and therefore no pressure on it, and no material behind it for support. This would let the ring flap about in the breeze, and get very hot, which would cause it to turn onto the shredded mess we see.

This could well result in the red hot shards causing autoignition of the incoming charge as the inlet valve opened, which might account for the mark on the valve. The valve may also have gotten bits of debris (fire ring) embedded in the seat, which would also cause a hot spot. To answer Bob, this would not progress to detonation,since the mixture is uncompressed at valve opening, and pressure cannot rise (required for detonation) until the cylinders are filled and the valves closed. The fire would be short lived and local, extinguished by the cold incoming charge as the valve opened more. The mark on the valve might also be a result of the coolant spray hitting the hot valve, but I doubt it. Once water started spraying in, it would cool the shreds, which would again prevent detonation.

Tedious attempts to get info out of the Payen/Felpro website indicate that the gasket resin coat is "designed for clean release", so apparently it is not meant to glue itself down. The Payen or similar gaskets used to stick such that you could lift the car by the head with all the bolts out, and it was always a PITA to scrape the shredded gaskets off, so this is either new tech (some modern HG are teflon coated) or the gaskets I met in the past were not Payen. In truth, since I've never had a HG failure on an engine I put together, it's hard to say what gaskets were in the ones that I replaced for HG failures - some were black fiber. I always hated the fiber gaskets because they were such a pain, and preferred the copper composite ones, and used those on any engine I expected to dismantle.
I would still not apply any alien sealants, just clean it up and install gasket as supplied.

I agree with everybody else, that the gasket probably locates just fine. I see no sign of gasket overhanging the bore, and the studs appear to be the same 3/8 as the OE ones.
Since Prop will worry about it, he can put the gasket in the position he's happy with and use a toothpick to put a small gob of RTV around a stud or two, in the gasket hole only. Let it cure before putting the head on. The head or gasket will not move once it is bolted down.

I am a bit concerned that the gasket just does not look like it was compressed fully, which may be an artifact of the photography. Hardly seems possible with those fancy studs etc., unless the torque wrench is seriously screwed. Another point is that there are marks on the block that look like what you get when water runs under the gasket. The prime time for this is when the engine cools after first start, if it is not retorqued when hot. And before anybody says anything, I do retorque hot and even Payen gaskets DO move at that time.

If all else fails, MiniSpares has an MLS HG for about $150, or special for Prop, just ditch the HG and paint the head with RhinoLiner.

FRM
FR Millmore

I think the gasket was damaged either before or during installation. I suspect that the critical bit of the fire ring was broken or at least coming away from the composite before the head went on. May have just got damaged from too much assembly and disassembly when Prop was trial fitting and getting his taped studs sorted. I would just reassemble with an new gasket, torque and re-torque accuratly after the first run and see how it fares. Over-analysing can cause more "bright ideas" than just folowing established practice and getting on with it.


If you feel you must use tape to fine-tune the gasket position on the studs then ONLY use it on the two studs that Payen designed as the datum points. Using on any or additional other studs could just pull the gasket in too many directions at once, and distort the fire rings. And be mighty carefull that the tape doesn't ridge up and prevent the head from clamping. And finally, don't over torque those head studs. Most of the compression sealing is done by those narrow fire rings. If you overtighten they just go flat, distort and fail to do their job properly and you then transfer and "dilute" the clamping action over the whole of the composite gasket instead of it being focused where it matters, around the chambers and oil feeds.
Guy

I agree with FR.

The fire ring was hanging in bore, for whatever reason, and would have definitely been glowing hot at some points. Just as excess carbon deposits can get hot enough to cause detonation.

As regards the clamping of the gasket.

Look as this cut of props earlier picture.

You can clearly see the triangle embossed on the gasket.

Enlarge and you can see the light reflected in one side that shows a distinct angle from the horizontal. If the hg had been sqeezed enough, I would expect to see it completely flattened.

Lawrence Slater

Lawrence, Not sure about that (squeezing out the Payen logo, that is) At least not on a relatively new gasket. I think the logo would get flattened out over time but maybe not on a relatively new gasket.

The greatest clamping pressure on the fire rings is achieved with the correct head torque at a point before the fire rings get sqashed flat and the clamping force is then dissipated over the larger composite gasket area. At this point the pressure on the fire rings is much reduced (Pressure = force/unit area, remember?)
Its a fine point but the best sealing is when the fire ring takes most of the pressure, with the composite part of the gasket tight enough to properly seal the waterways, and supply back up support to keep the critiical rings in the right locations. Of course foreign objects (bits of stud tape, for example) that get caught in the composite gasket will take pressure off the fire ring parts, reducing their effeciency as a combustion seal.
Guy

Dave/Bob
I agree 100% that there has to be a fault with the gasket if it doesn't locate properly-
The advice I gave Prop to use metal tape was a semi last resort to get him going with what he had at the time
Hopefully his next gasket will be a better fit and he can reassemble without having to use cheats-
He was well aware that he had to do a dummy fit up to make sure the excess tape went up the studholes without a problem and he did that.
I'm really starting to think the gasket he had was a dud,When you look at that first pic in this thread, the gasket just doesn't appear to go close to lining up with anything there really-
It's all very interesting, and I hope Prop posts a pic of his new gasket sitting in place to compare.

Cheers Guys Willy
William Revit

Aside from all the science, remember that in 50 years BMC screwed together someting like 10 million A - Series engines, and if you collected all the headgaskets up - and piled them up one on top of another, that's the equivalent of 26 Empire State Buildings. For some reason they didn't mess about with bits of tape or glue.
F Pollock

From Prop's post on 17th,

"I found my emergancy back up payen AF470 gasket...it was installed and torqued but never fired

I placed it on the deck...and there is no room for error..iy fits exactly on the edge of the holes but dosnt go over...there is enough play in the 2 side holes where the studs fit to push it over the edge of the cyc holes"

If I'm interpreting that correctly then our Prop has TWO dud Payen head gaskets????

Really probable??

Regards

Roger
Roger T

And just to add to that. I know it's considered unwise in the extreme, but I have reused, several times over, the head studs in both of my 1275 engines.

When I got my 1300GT head, I used it as a guide, and outside in the road in london, I drilled and tapped my block to take the extra stud and bolt for it.

I reused the original studs I had, and drove that for well over 90 thousand miles without blowing the hg.

Maybe the gaskets today are just simply crap compared to yesterday, or maybe we all forget that this is really a basic engine and getting too technical with it can be self defeating.

As someone said earlier Keep it simple S.
Lawrence Slater

I still want to know what the stud diameters are.

I'm not refuting any of the views above. Though I don't understand that if a firering overhangs one cylinder sufficiently to be damaged, that the same type of damage is not evident to some extent on all four firerings/cylinders.

I learn't a long time ago that NOTHING substitutes for precise (read verified) knowledge. I acknowledge prop may well be correct when he says that all the studs are the same, however:

1 he also maintains that two Payen gaskets he has do not tight-fit on the two location holes/studs, and

2 the length of the ARP stud block threadings was incorrect on at least some of the ARP studs (first set or replacement two, I don't know which) which makes me wonder if the ones he was sent (either first set or replacement two) are in fact for this application, and

3 without measuring the stud diameters he is confident to back his eye that they are all the same diameter.

Prop may well be right but I call that 'assuming' as distinct from 'verifying'.

I would want to verify against specs in order to be able to remove the possibility from future consideration.

Frankly, given all that I have heard about ARP studs from these BBS, I am amazed that they would produce head studs with proud block threading. Having used Payen head gaskets I would be disappointed in the extreme if their production standards have slipped to the point that a single purchaser can wind up with two 'bad' examples. I suppose that also raises the need to in fact confirm that the HGs are genuine Payen rather than alternatives deemed to be 'of that type'.

Sorry for the 'earbashing' (local topical humour)

Regards
Roger
Roger T

I think that's all fair enough Roger.

The only real fact so far, is that the HG blew.

Everything else posted here -( perhaps with the exception of Props' own posts, which may have mixed the facts and confused us), --is supposition.

Let there be light. :)
Lawrence Slater

so with the teams retiring to the pavilion for tea, it's Prop standng on 149, not out.
MC MacQueen

ho ho ho :)
Lawrence Slater

Unbelievable

A guy from the states with a jock name cracking a joke about cricket!!! LOL

Whatever next?

FRM
I was being synical, according to one of Props speculative thoughts the engine had detonated itself due to the timing being incorrect! I was merely pointing out that had that been the case then the pistons would have become plasticky the rings would have picked up in the bores and more importantly the engine would have severely overheated! all of which did not happen so it is safe to say detonation DID NOT cause this problem!

I am convinced this head was NOT sat down correctly on the gasket for whatever reason!

With that in mind Prop do yourself and all of us a favour.

It will take approximately 4 hours for you to fit your spare gasket, use your old studs, and torque your head down onto your engine. Set the timing correctly and take it for a run!
Robert (Bob) Midget Turbo

"so with the teams retiring to the pavilion for tea, it's Prop standng on 149, not out." (brilliant)

But perhaps, just perhaps, the 'bowling' is starting to get on top!
Roger T

Thats three views of the world we share Laurance. Dylan and Cuban boots the others. I looked so 'cool' in those boots too!!
Roger T

Roger.
I've still got a pair of low cubans lol. One thing about being older is that you dont give a monkeys about following fashion anymore. You please yourself. Well I always did anyway.

That's pretty much what Prop does with his car from what I can tell, and all power to his elbow too. :) It might wind others up, but he's outside the box and having fun from what I can tell. lol

Roger pop over to the diverted " Im RICH... I JUST WON THE LOTTRY...so go suck it !" Thread, and throw in a few mystery songs.

Lawrence Slater

Prop,
Try a Cometic C4148-040 - especially since you have won the lottery - good quality gaskets though.

David
d brenchley

No word from Prop recently. He must have been caught out, leg before gasket, so to speak.
MC MacQueen

Maybe with all this torque, he got bored. :)
Lawrence Slater

Hey guys....update...

the machine shop is behind and wont get to my head till next week....im getting all valves reseated and ground...they were all leaking on avg about 2.0 inches per min and having it resurfaced and replacing the 2 exhaust valves that got wet and they where slightly bent as a result

He said they cant be bent back into shape....the bend was minimal can barly see it in the hand crank... Ow straight do the valves have to be

Prop
Prop

I think I was right the first time then. The black hole midget is so named because of the all the money that disappears into it.

You'll make 200 on this too soon Prop. :)
Lawrence Slater

Lawerance,

Your exactly correct and one of several reasons i named it the black hole ...with the gravitional pull, not even cash is safe in your wallet from 100 feet away

I hope not...but i fear this could reach the X2 mark...hard to belive all i wanted to do was show some pics and gloat about how fast i was driving at 100 plus mph. q: )

.
Prop

ha ha. Well next time you do that Prop, strap a vid cam to the bonnet(hood) so we can all see the clouds of steam emerge. Actually I suppose the cam should face the back end to capture the exhaust. :)
Lawrence Slater

Lawrence, check this; http://youtu.be/l2PUdvl9z3Q
Alex G Matla

Speechless. LOL. I was about to ask who that nutter was, and then when the vid finished, the title was shown as Propaper43. Hillarious.

Don't you love those near empty roads?

And how come it was only doing about 60/70? Bit slow wasn't it?

I mean it's not as if he had his hands full holding a camera or anything :)

Lawrence Slater

Hahaha....guilty as charged ...thats me, the 1st run of the new engine...on dec 31, 2010...

I wish i had spent an extra 10 minites tuning in the carbs a little better


I still love that 1st part when i almost ripped the bottom of the car out


Yeah... Im a little depressed...i was wanting to bring the car to st louis for the holiday...so maybe for christmas....im just hoping to get the head back around the 1st of dec at this point

Prop
Prop

Prop,
your views to camera are just classic

those roads seem a bit too straight for a Midget do you have ones nearby where you need to turn the steering wheel, use the clutch, gears and brakes?
Nigel Atkins

And what happened to the bonnet? Did it bounce off in the first few frames?

Is there a law against driving without your bonnet strapped on? lol
Lawrence Slater

Haha..

I drove it that way for a few days so i could watch if anything went wrong

I dont think its illeagel to drive without a bonnet..im not.completely certian....but its certianly not appericated by the jack boots


J
Prop

Your one crazy horse Prop. lol
Lawrence Slater

They are actually building a statue to CRAZY HORSE.The top of a mountain is slowly being cut up to represent CRAZY HORSE.
Google it and see what's up.
darnoc31

Brilliant.

http://www.google.co.uk/search?q=crazy+horse+memorial&hl=en&prmd=imvns&tbm=isch&tbo=u&source=univ&sa=X&ei=JebQTubdFoGy8QPL56TbDQ&ved=0CFgQsAQ&biw=1024&bih=614

They should have done it on Mount rushmore. I reckon the old guy has a right. :)

Hope that doesn't wrankle with anyone. :)
Lawrence Slater

What's the latest Prop? Head back on yet?
Lawrence Slater

I checked with the shop today...still sitting on the shelf where i left it last week
Prop

This thread was discussed between 16/11/2011 and 29/11/2011

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