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MG Midget and Sprite Technical - head gasket, timing or engine damage?

I had a 'mare in France in the summer. . . midget 1500 head gasket went, broke down shipped back (40 of recovery cover got it shipped back, we flew back after a weeks holiday and they even paid for a night in paris for me n the missus) but I digress

in the process of breaking down, I put water into where it shouldn't (some where just behind the water filler bit)and it ended up in the cylinders. . . . when I got home, I undid the spark plugs and turned the engine over, water p1ssed out. . . . all good!!!

when I took the plugs out one of the helicoils came out with the spark plug. . . I had a difficult job of getting a replacement coil back in but I mananged it and the car was running again on all four cylinders!!!

It now feels a bit like it is missing on a cylinder (but I am pretty sure it isn't. . . definitely not the one where I had the trouble with the helicoil and all of the others are working too)

Here is the question. . . . what is it making the engine not work as smooth as it did pre-head gasket going, the car ran smooth when I had it had broken down so I think the water may have damaged the inners of the engine (until it boiled up) and . . . . what would be your idea as to the order I check things. . . . i am gonna have to take the head off anyway so?. . .any ideas?

is the engine broken due to water damage?

Has the timing gone out with me messing around 9had to take the belt off, loosen the alterantor etc and broggle around a bit to get the spark plug helicoil back in. . is it just that the head gasket needs sorting first? ideas?
d j kirk

"""Has the timing gone out with me messing around 9had to take the belt off, loosen the alterantor etc ""

The belt I assume you are refering too is simply the alternator belt

The timing is as follows

Cam shaft timing (Chain drive)
Ignition timing (Distributor)

These are not modern cars with belt driven camshafts. :)
Robert (Bob) Midget Turbo

If you started it with water in one or more of the cilinders you might have a bent con rod. Compression wil be lower in that cilinder.
Alex G Matla

Can you clarify what you've done so far, you say the head gasket failed, what was done to repair this? Was the HG replaced? If not I would suggest that's still your issue, another possibility is a burnt valve. Either of these will be very evident once you remove the head.

Bob
R.A Davis

I learnt a trick last week which is so amazingly simple and yet conclusive I cannot fathom how I have managed not to come across this before in 50+ years of messing with cars.

If you suspect HGF. Fill the radiator, put the cap on and run the car up to normal operating temp. Switch off, remove the spark plugs and leave overnight. If the HG is faulty water will be forced by the radiator pressure into one or more cylinders as the engine cools. In the morning, lay a piece of kitchen roll paper or card over the head so that it covers the spark plug holes. Spin the engine just a few revolutions, 5 is plenty, on the starter motor. Your paper towel will now show wet patches if there is HGF and you can see exactly which cylinders are effected.

Handy if you suspect HGF but no water is appearing outside the engine block. Or if you are loosing water and are not sure if it is due to HGF.

No doubt others have heard of this but it was new to me! And so obvious too!
Guy


Good tip Guy, hope I shan't, have to use it.

Dave
Dave Barrow

Omg guy

That is great.... I so hope i can remember that the next time i suspect a hgf....that is great

Thanks for sharing

Prop
Prop

Hi Guy,

Do you mind if I reprint that in the magazine?

Gary
Gary & Gaps

Hi Gary,
Yes of course you can use it. But I was waiting for a string of replies saying it was common knowledge, or how it wouldn't tell you anything or some such! If you want it for MASC it might be better if I rewrite it and clarify a bit.

Attached photo illustrates how unmistakable the result of the technique can be.

Guy


Guy

The problem is Guy that any comments about such things can often be thought of as critisism.
However I know you too well so perhaps you will allow me to comment.

Like every technique for dianosing problems the skilled operator may use a whole host of indicators and tools. Each "tool" may or may not indicate a problem.

For example most people will know that a more traditional method of observation may well be looking for "mayonaise" on the dipstick. Equally a further test might be to "sniff" the water header tank for combustables using a co monitor as used by testing stations.

All these techniques and alot more can be used as tools to determine failure, however the important thing is that like all other diagnostics none are fool proof and it is a combination of tools that are used by the skilled artisan to determine problems.

This is the same with doctors and diagnosis of health issues, and anyone who is involved with problems on a daily basis is all too aware of the difficulties faced both by mechanics and doctors alike (and those poor souls like me in industry).

Finally it is a good thing to demonstrate to those who have not heard of it before but it should be noted equally in any article that a head gasket may be gone even if it does not show up using this test. :)

By the way when the headgasket is gone as badly as that sometimes the water fills the cylinder completely and the engine will suffer hydraulic lock. I have only experienced that on 2 occassions. :)
Bob Turbo Midget England

Bob,
You are quite right. I wasn't meaning that other comments would necessarily be taken as criticisms. I am always ready to learn new constructive ideas. But rather that I was surprised at myself for not having heard of such a simple test before.

Of course I did do other tests; mayonnaise, bubbling in the header tank, and using a "sniffer" to test both the header tank and each of the exhausts. All indicated a head gasket, or at least some form of inappropriate association of coolant and combustion. But you will also notice that this is only half of an engine. What I wanted to determine was not just HGF, but which bank this had occurred on. The only other tests that would have confirmed which bank of cylinders was faulty was a compression test - but my compression tester would not fit this particular engine which uses very small plugs (M/cycle style); an infra red temperature gun, which I don't have but wish I did or use of a borescope, which I also don't have.

But what I did like about this was the simplicity and the fact that it doesn't require any expensive equipment - just some garage wipes!

Incidentally, on this car a head gasket change is an engine out job so I am replacing water pump, cam belts and cam chains all at the same time. It takes rather longer to get the engine out than my normal 1 hour job!

Guy
Guy

Sorry, Bob, I missed a good point that you make: you are quite right in your comment about hydraulic lock. An important point. I would not have attempted to start and "run the engine up to operating temperature" if I suspected a serious amount of water leakage. Nasty and expensive damage could have occurred! I would certainly advise caution before starting a car with HGF.

I had already ascertained that the amount of leakage was fairly slight. Even with plugs removed and the "assistance" of the pressurised coolant it still only dropped the expansion tank by a few mm overnight. And obviously for the test itself hydraulic lock could not occur because it relies on spinning the engine with the plugs out.
Guy

Oh dear Guy, is that Nigels car? The one that was a 'good buy'?!
Tarquin

Good to see you agian tarq, hows the little one doing, is she home from the hospitial yet.... Im sure she is by know

You have been in my thoughts.... I wish your family well.
Prop

Hi Tarquin,
Keep up! This one is #5, two more along in the series! And the problem was not unknown, but bought as a judged risk that currently looks like paying off rather well. Car number 4 is off to Australia in a few days time!
Guy

This thread was discussed between 19/09/2011 and 21/09/2011

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