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TR4 Head gasket replacement


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HI All, now the weather is starting to change, I've decided to finally fix the small oil leak from the head gasket (2 years :rolleyes:) , as it now seem to be leaking water from the other side too. And whilst it's off get the valve sets looked at for unleaded fuel.

 

Given I've never had the head off a wet linered engine, is there anything I should be wary of or should do/not do etc.

 

The key issue seems to be not lifting the liners with the head, is this likely or would a few taps with a soft headed hammer on the head break this seal?

I've already cut some tubes to drop over the studs with some large repair washers to stop the liners lifting when I turn the engine over.

I'm not totally convinced the TDC mark on the pulley is at TDC.

 

Any hints or tips gratefully received (even the obvious) so I only have to do the job once or not have to spent time/money rebuilding other things.

 

Thanks

Mark

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Always a bone of contention but I would check the liner heights whilst the head is off. Measure in 4 positions around the liner and compare, check out the search facility there are a good number of threads there on what and how to do it.

 

Mick Richards

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Thanks Mick and Bob.

 

Yes I do recall that article, now I think about it, very detailed I recall.

 

Do you know if the back issues of TR Action available on line yet? Or I'll have to search the house to see what I've done with it.

 

Now I've bothered to go and look they are available on line :rolleyes: .

 

Must have been after June 2017.

But what a wonderful resource going back to March 1970, fantastic.

 

Mark

Edited by MRG1965
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Hi, so quick update.

Heads off, eventually, thought it was seized on studs, just turns out it weights a ton and I was not lifting hard enough (wimp). Every things looks okay except the tiny water leak turns out to be a hair line crack from the no4 plug hole running behind the exhaust pushrod tube :-( hopefully it can be repaired, if not...

 

Valves out, decoke tomorrow and off to the machine shop next week for the good/bad news.

 

Only question, valve springs have open and closed coil ends, which end goes where as they were in any order the last person picked them up off the bench in.

 

Mark

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  • 2 months later...

HI, all sorry for the delay, but back on task now, slight delay with an MRI and some physio. The head was obviously much heaver than my body could deal with at arms length.

 

Heads been sitting on the bench following new value guides, inlet values and some unleaded seats, plus a light skim.

 

Tried to put the head on at the weekend, but could I find the head set I'd purchased all thoes weeks ago, no, could I hell as like, so new ones arrived in the post today.

 

Quick question, looking on the Moss site (https://www.moss-europe.co.uk/shop-by-model/triumph/tr2-4a/engine/cylinder-head-fittings/cylinder-heads-tr2-4a.html) item #40 (other sites are available), there seems to be an option of shims under the rocker pedestals, mine did not have any.

So what do they do, apart from raise the relative height of the pedestals, I'm assuming to ensure correct load/no load on the rocker shaft. Do I need them and how do I check if i need them.

 

Looking at various posts they seem to be used to get around a lack of valve clearance adjustment, but if these are OE parts, thats does not seem to be be their original purpose, or maybe I'm wrong.

 

So before I actually continue can anybody shed some light on their purpose please.

 

Regrads

Mark

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If a lot is skimmed off the cylinder head ( 4 mm or more) the geometry on the rocker arm changes ( the centre line of the rockers gets closer to the engine deck). To return the dimensions towards standard the rocker pedestals are shimmed up, unless you are going for it a light skim shouldnt matter.

 

Mick Richards

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Surely, the proper way to compensate for skimming of the head is to shorten the push rod tubes.

However, that is not such an easy operation (see Kastner's Competition Preparation Manual).

Ian Cornish

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"However, that is not such an easy operation"

 

Ergo...that's why we just shim the rocker pedestals, it's cheap, it's easy, and you make your own if you want to. Sometimes the best technically and correct way doesn't offer enough advantages to outweigh the costs and time involved.

 

Mick Richards

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HI All, head all back on and runs a treat, just needs a bit of tunning, too cold yeserday after the test drive to play any more.

 

Had the head works done at David Knights worshop, just off J16 of the M1 near Northampton, I had no previous connection, but if you looking for some maching work done to either to the head or block, he's a very knowladgeable guy and got it spot on with the things I'd find and what was and wasn't going to be an issue before I even had taken the head off when talking to him over the phone.

His workshop is the type of place you imge (well I do) a good machine shop should be, lots of finished, cleaned and baged up works ready for collection along with a variety all you could imgine to be worked on.

I'd recommend and reuse in the future.

 

Mark

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Hi all, so just one update after the tinkering and tunning.

Following the works, 3 of the pushrod tubes now leak a small amout of oil from the base. Looking at associated threads here, the proper fix is to secure both ends with a ball bearing and a press.

Now given its only done 25 miles and its running so well, I'm loathed to take the head off again.

So thought I'd give one of the Loctite products a try.

Loctite 648 looks like it can handle 200 degrees plus, and the spec states it does not need to be dismantled and will wick in to the interference fit and the bonus is it does not need to be super clean as it will fix through oil. Although I plan to clean with a Dremel with a suitable bush and some brake cleaner.

 

Hope thats works as the whole point was to fix a head gaket oil leak in the first place, the unleaded conversion was a nice to do while the hed was off.

 

Let you know how it goes.

 

Mark

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  • 4 weeks later...

HI all, just a quick update, I tried the loctite 648 and it worked a treat, sealed the little buggers in niciely even after a couple of week and a few hundred miles (cold miles). Trying to get the miles up so I can retorque the head in good time for Lemans clasic this year.

Just received a can of the green engine paint (sombodys painted it a nice shade of lime/apple green at some point in its life.

That should tidy up around the bottoms of the tubes where I used a Dremal with a briush attachment to clean away the old paint and some break cleaner to wash away any oil and grease.

 

So if you're thinking of taking the head off to fix a leak like this try the loctite, according to the blurb you don't need to strip things down as it finds its way in to the tiniest of gaps and even works through oil, which I boubted, but obviously it does seem to.

At the very least it'll stop the leak until you do need to take the head off for a good reason rather than just an annoying one.

 

Mark

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Hi, so quick update.

Every things looks okay except the tiny water leak turns out to be a hair line crack from the no4 plug hole running behind the exhaust pushrod tube :-( hopefully it can be repaired, if not...

 

Mark

Mark you mentioned the crack.What was the outcome of this ?

 

Roy

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On a hair line crack like that it's made for a bottle of K Seal.

 

It's a mix of copper and ceramic very small particles which percolate into hairline cracks and clog it causing it to seal. NO...it doesn't clog heater radiator or car radiators, the mix is extremely fine and happily passes through anything other than what it's designed for, very small gaps and hairline cracks. I've got a Stag which has got a bottle in now for the last 2 years, (a weeping inlet manifold gasket) and many Stag owners run with it in as standard fitment. With a car like the Stag noted for overheating (not it's fault) to run with a water sealant is an act of faith in case it inhibits radiators and cooling (it doesn't), it works.

 

Mick Richards

Edited by Motorsport Mickey
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Mark you mentioned the crack.What was the outcome of this ?

 

Roy

HI Roy, very odd, before I took the head off there was always a small (much less than a tea spoon sized pool) amount of water just by #4 plug after a couple of days in the garage. When I took the head off and cleaned it up, I thought I could see a crack about mid point through the plug hole at about the 3 o'clock point, but the shop tested it and when I got it back I looked again, now it had been in the proper hot cleaning dishwash type machine and all I could see was a casting line, so just my eys seeing what I wanted to see.

Since it's been back on, I've not had any water there, so not really sure how or where it was coming from.

The odd oil leak from the head gasket joint under the carbs between cylinders 2 and 3 has also stopped. But I also changed the copper washer on the oil way bolt at the back of the head, so it must have been that weeping and wicking aaround the joint, I think Mickey mentioned it may have been that in another post some time ago as there was no other oil gallery near there.

 

I also took the opportunity to replace the core plug at the back of the head whilst it was on the bench as that looked damp and did not take very much to punch through and leaver out.

 

Mark

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On a hair line crack like that it's made for a bottle of K Seal.

 

It's a mix of copper and ceramic very small particles which percolate into hairline cracks and clog it causing it to seal. NO...it doesn't clog heater radiator or car radiators, the mix is extremely fine and happily passes through anything other than what it's designed for, very small gaps and hairline cracks. I've got a Stag which has got a bottle in now for the last 2 years, (a weeping inlet manifold gasket) and many Stag owners run with it in as standard fitment. With a car like the Stag noted for overheating (not it's fault) to run with a water sealant is an act of faith in case it inhibits radiators and cooling (it doesn't), it works.

 

Mick Richards

Good to know for the future, if it starts up again.

 

Mark

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