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MG Midget and Sprite General - 3 issues before I drive Brakes, valves, surging

Defintaly Driving tomarrow...but I got 3 small issues I need help with

Easiest to Hardest

1st. Brake Light sensor wire connection....

There are 2 wires from the brake sensor and 2 wires that light up the brakes in the harness by the wiper motor ....Does it matter if those wires are crossed...or are they pos./neg specific? Im guessing one wire brakes one rear light and the other wire does the other side.


2nd...With the 1.5:1 high lift roller tipped rockers, I have a bad valve slap sound, (Valve is to loose when it warms up) I had them adjusted to .18 but today I re-torqued the head, set the valve gap to .17...it only makes the slap sound when its warmed up....perhaps Adjust them to .16 when they are warm instead of over night cold....OR is that Clapping sound normal for high lift rockers. Further insight help please. AND NO its not the lifters hitting the unside of the valve cover,,,I ground that out 2 days ago and painted the inside...no marks

3rd Carb Surging...Ive been playing with this all day, the carbs are surging at idle, the range is around 500 rpm....steady and takes about 10 sec. to run its cycle...any ideas?

Prop...Im in love with my car
Prop

About the surging...I just had a thought...Im using the HS4 floats in both carbs...maybe they are dropping down to far in the float bowl...I know there are no air leaks aroud the manifold and what not sucking air

it may well be I need richer needles

what if I retarded the timing and richend and reduced the idle? just thinking out loud would that help with the surging

Prop
Prop

2nd problem sounds normal. Your cam supplier would have specified correct clearance so stick to that and enjoy the rattle. It's just your engine's way of saying "I'm very expensive".
Ignore problems 1-3 until you return from your drive (with Nos 6-9).
Mike Allen

Thanks Mike,

On the clackity valve sound its only one valve...Just not sure which one or how to find it. But Im thinking your right...some clakity noise is better then NO clakety noise.

I cant avoid issue #1, the brake senor wires....I have to have rear brake lights or else with my recent luck someone would slam right into the rear of me...I guess I can hook up just one pairing of the wires and see what happens...just dont want another loom fire at this stage.

its an aftermarket sensor that had 2 black wires already installed...its one of those pressure senor deals...you hit the brakes, the pressure activates the sensor, and lights up the rear brake lights Like I said Im not sure if the 2 wires comming out of the cars harness is pos an the other Neg.

Prop
Prop

According to my wiring diagam, the two wires to the brake light switch are 1. green which goes back to the fuse box and green/purple that goes to both brake lights. soooo both would be + wires. i can only conclude that it wouldn't matter which way the switch is connected.
Chris Edwards

Thanks chris

That is correct I have a green and a green/purple coming out of the harness...71 midget

thanks for the FYI...ill hook them up tomarrow with fire extingisher in hand LOl

Prop
Prop

The engine is going - GET IN IT AND DRIVE...!

ALL other problems WILL sort themselves out in time, and, to be honest, it will be easier to assess them when you're actually in the car and driving it.

WHY are you planning on taking the car OFF the road again soon to replace the suspension by the way? It is with great reluctance that I dare ask the question of why didn't you do it while it had no engine in it ... but, it sounds like your kingpins might be out of line or something just as easy and simple as that (if I can do it, you can!), it's a VERY QUICK job to do, so, there's no excuses now really ........ if you don't get it driving, don't forget, I'll be on the same continent as you soon ... and I WILL come down and kick your ass into next year :)

Rach - patience was never my strong point!
rachmacb

Sorry rach,

Only 15 months till midget 50, and a ton of work till then...lots and lots of mod work. I doulbt there will be much driving till then.

reason for not taking on other projects, its hard to maintain focas for one when there is numurous things going on but mainly just to many other projects outside of the midget that had to have my atten. and a brutal winter.

But Ill be driving today...hopefully by noon.

Prop
Prop

Prop,

I thought you sorted out the brake light switch issue with David Leib last fall. It's just a switch. It connects the two wires together so it doesn't matter which wire goes on which terminal. One of the wires is hot all the time (or at least when the key is on). The other goes to the brake lights. The switch connects the hot line to the brake lights.

I don't know what is causing the engine to surge, but trying to work around it by making the timing wrong and then adjusting the carbs wrong is not the way to fix it.

To see which valve is ticking, run it with the valve cover off and feed a feeler gauge in between the roller and the valve stem. When you stick it in the one making the noise, the noise will stop assuming that it is the valve lash causing the noise.

When you did your dry build, if you found that your valves are very close to the pistons, you might not want to use a full 0.018 feeler gauge for this. Maybe something like a 0.010 would do.

Charley
C R Huff

that engine will not be run in by the time Midget50 on both continents is history at this rate

Prop put a wire on each terminal on the brake light switch (any wire of the two)

drive the dam*ed car

much of the surging will disappear as the engine realises it is no longer a statue
bill sdgpm

Prop
Most cam grinders give valve clearance specs as a running clearance - meaning what they should be hot
If I were you I would get it up to temp and then adjust them -- Hot cheers Willy
WilliamRevit

Thanks Willy,

Sorry I never got back to this thread,,,,turns out it wassnt a loose valve...but a rocker (STILL) hitting the valve cover, it seem even though slighttly as to not make a mark, still makes lots of noise.

Im taking a bit of a break from the midget hopefully be back on it in a couple of weeks ... life is just to much in the way right now.

Prop
Prop

Prop,
Put a relay on your brake light system, so you are only using the brake switch to 'turn on' the relay, all the power for the lights is then 'switched' by the relay.

Best Regards,

Howie (still building)
Howard Wright

Prop,
If you didn't use rocker pedestal shims the noise could be the underside of one of the rockers catching on the top edge of a valve spring collar. It may be difficult to see - it would put a mark on the underside of the offending rocker and you might need to remove the rockers to see it clearly.

Guy
Guy Weller

Guy,

Great point to remember...Luckly my noise went away the moment I pulled the valve cover with the engine running,,,Thats how I knew I needed to do more grinding...I think that issue is solved

Howie,

Thats a great idea...hopefully this year the car will get a fresh new wire over haul...But I did get my brake lights working

Prop
Prop

This thread was discussed between 05/04/2010 and 11/04/2010

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