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MG Midget and Sprite Technical - coolant leaking

After cranking engine to get the oil pressure up prior to trying to start for first time i have coolant seaping out of the back left hand cylinder head bolt . Engine nevr run since rebuild by PO dose this bolt pass through the water passage or dose it appear the cylinder head gasket has not been fitted corectly.
mark (1977 1500 Midget) Preston Lancs

Something wrong there. The head should be held by studs, at least some of which do go into water passages, but should be installed with sealant in the block. Right next to the LHR stud is the oil passage to the rockers, so a gasket failure here will put oil in the water jackets, and possibly vice versa.

FRM
FR Millmore

Some muppet has burst through into the water jacket, possibly by helicoiling.

You'll need to remove the head, pull the stud and refit with a sealant and a new HG.

FRM is correct in his assertion about the rocker feed gallery.
Deborah Evans

It would appear to be a capilery action as some coolant has come up the stud over night looks like its head off then.
mark (1977 1500 Midget) Preston Lancs

Keep in mind that the fact of the coolant coming up the stud does not necessarily mean it starts at the stud bottom threads. It could be coming from any water passage in the area, and leaking by the gasket to the stud.

Did anybody retorque the head before resuscitating the car? Head gaskets settle over time, and you don't even know that it was torqued correctly in the first place. I'd try that before dismantling; I've saved a few that were leaking.

Also, I always replace the made-of-cheese head nuts with MGB head nuts, and use thick hardened washers. Check that there is clearance between the front/rear rocker pillars and the nuts when doing this. It sometimes needs a bit more clearance with the thicker nuts/washers, but the pillars are soft and you can do it with a pocketknife if need be.

FRM
FR Millmore

I checked torque loading before refitting engine and checked this stud since it seems to be coming up the thread and seaping out round the top of the nut.
mark (1977 1500 Midget) Preston Lancs

taken head off there dose not appear to be anything obvious the weeping stud had been helicoiled but dose not seem to go into the water passage replaced with hylamor on thread just in case only thing that looks odd is the washers under the head bolts they seem a bit thin and have gone missed shaped see pic wondering if that affected the torque loading and let some coolant reach the stud

mark (1977 1500 Midget) Preston Lancs

pics of head

mark (1977 1500 Midget) Preston Lancs

pic of block

mark (1977 1500 Midget) Preston Lancs

Yes, the washers are garbage and greatly alter the torque effects, just like the horrid nuts (which are frequently stripped, often just after you get the engine all together - if they feel "gummy" when you torque them -THROW THEM AWAY). Don't EVER use a washer that looks like that! All the washers on the TR top end are trash, like the nuts.
Also, if the stud is just slightly less engaged than OE, you may be running up against the end of the threads. Made worse if head or block has been surfaced.
ALWAYS check that the nut can screw down tight against the head with NO washer fitted, then fit the washer. Use the 1/8" thick MGB heavy duty washers or other thick ^ hardened washers, and the MGB/Aseries tall head nuts as I said above. Severely surfaced heads/blocks may require more washers; normal ones can be used as spacers UNDER the hardened one if necessary.
You can see that there is a water passage right next to that stud, as well as the drain to the tappet chest and the rocker oil feed passage; the head was simply not bolted down.

FRM
FR Millmore

FRM is quite correct in his assertion about the 'monkey metal' washers and nuts.

ALWAYS use hardened washers else you will NEVER be able to set the head stud torque correctly!


However, over the last few years it has become apparent to me that the head studs supplied for the Triumph 4-pot, WHOEVER the supplier, are also 'monkey metal'.


Personally I always use ARP studs on all my Triumph engine builds.




It looks like the head wasn't torqued down properly, but I'd still have that stud out to check whether someone has burst into the waterway.


Also, when refitting the studs, do them up hand tight no more.
Deborah Evans

Out of curiosity what are the holes next to number 1 and 4 cylnders it dose not seem to go anywhere?
mark (1977 1500 Midget) Preston Lancs

This thread was discussed between 03/08/2011 and 05/08/2011

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