The Triumph Dolomite Club - Discussion Forum

Where did it start to leak? Exhaust side or inlet side? And then front or rear or whole lenght?

Jeroen

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Sealant on a headgasket is not durable. Headgaskets do seal themselves and if not something went wrong or is wrong.

Jeroen

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You need to torque it to 58-60 ft lbs. I've seen them leak before at just 55.

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1997 TVR Chimaera 450

Hi
I have torqued it down to 62lbft and tryed again but it still leaked. Will have to strip it down and have another look.
Thanks for the advise and will let you know how it goes.
Mike.

Or:

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Hi Jeroen
It started to leak on the exhaust side first.
But after a short time was coming out on the inlet side.
I torqued the head down to 62lbft like mad mart said it seemed to slow it down but didn't stop.
Do you know what size the head can be skimmed down to before I would have to fit the thicker gasket.
Mike.

Hello Mike,

Compression wise you don't need a thicker headgasket directly. For tuning purposes I also skim the engine deck and have the pistons 0,5mm above deck in TDC and still use std. thickness headgaskets.

As the studs are angled and the stud/bolt bores in the head also these come closer to eachother after every skim. At one point the head rests at the studs and cannot reach the engineblock deck anymore. Early heads have smaller diameter stud/bolt bores and later heads slightly larger. Skimming a later head gives less trouble than an early one. Some aftermarket studs and bolts are thicker than original and can cause the same trouble. I once used a competition stud set but these studs were larger in dia than the holes in an early head and wouldn't even go through.

At 1977 your head is probably a later one so it can handle a few skims. If it did rest on the studs you would think the inlet side would start leaking first. The best is to take off the head again and try fit it with no gasket but with all the studs and bolts in and see if the head is reaching the deck totally or that it rests on the studs. Sometimes an enginedeck is skimmed slightly to clean the surface. If the chain cover isn't skimmed with it or changed by another sometimes the edge isn't flush with the engine deck making it also impossible for the headgasket to seal properly.

Something very simple should make your gasket leak. Start at the beginning having a few checks and post some pics here so we can see what is wrong. A headgasket should seal and if not there's obviously something wrong.

Jeroen

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As with what Jeroen say's about fitting without a gasket, i think it might be an idea to put a very thin film of blue hylomar to one surface and then remove. You should then see where contact is made or not. Similar to using "engineers blue" but more readliy available.

Tony.

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That wouldn't be my method. I would check visually and use feeler gauges when in doubt.

Jeroen

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The head should be 120.5mm minimum apparently, I assume you would measure with some calipers in 3 or 4 locations to get an accurate measure of the thickness.

When you fitted the gasket, you did make sure that both surfaces were clean? Any dirt or remnants of the old gasket would cause it to leak or potentially blow.

I have used a non payen gasket and it seems to be fine. No leaks, no issues. Are you sure that it is leaking from the head? Mine was leaking at the junction of the inlet manifold and head. It looked like it was the head but I traced it to that area.

I also got allot of white smoke on startup but that was because I had spilt oil on the exhaust manifold, it looked dramatic but soon cleared. Was the smoke definitely coming from the head?

Hi all thanks for the advise and sorry for asking so many questions.
Here are some pics of the head and block faces before it was put together. I will take more photos if needed when I strip it down again as well as checking the timing cover and the head touches the block some time this week hopefully. I was told by the engine shop who crack tested the head that it would be fine.
Mike.

Hi Mike, from your pics, the head does not look that good around no3 on the inlet side. Had it been skimmed before fitting?

Tony.

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It's hard to see on those pics but it looks indeed the pitting is causing the leakage. Judging by the combustioncamber view the head is hardly skimmed. Post some clear and close up pics when all is off again but I think that does cause and a good skim would cure.

Jeroen

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Hi Tony
No the head wasn't skimmed at the time it was checked and the machine shop said it was Ok with no cracks.
I will measure the head and check it touches the block when the studs and bolts are fitted when I strip it down tomorrow. Does anyone know the size of a standard head.
Mike.

Hi Mike, could you put another pic on of the head when it comes off. I zoomed in on the pic and on no3 inlet side of the head it showed corrosion. would be better with another pic to make sure

Tony.

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