cylinder head pressure testing

[Nigel C]

Just noticed I started this thread on 26th October, what I bumpy ride I've had!

I've managed to focused on the car for a couple of hours this week (after getting back from a week dealing with the London Classic)

So here's what, I hope, is the final outcome of this saga.

After the disastrous head gasket annealing debacle I talked to Simon at TR Enterprises as their copper gaskets come already annealed. He suggested that I fit it with the "goo" that they regularly use supplied by Worth. It is a very strange product and hard to describe (chewing gum/jam/hot Mozzarella!) but I did think it may be well suited to an aluminium head application as it seemed very flexible.

All torqued down and took for a test drive. after about 3 miles and up to temp check it over and I see coolant coming up a head stud (long) between 3 and 4 (BUT no creamy oil), I've had this before so not overly worried. Carry on test drive and check again after about 20 miles. Stud still leaking. Talked to Simon again and he says common enough, get yourself some Wynns Stop Leak (Other products are available).

I duly did and after another 30 miles or so it hadn't stopped leaking......

  so returned to the workshop and implemented "A cunning plan"...

heat shrink around the head nut and then I put tissue paper inside as surely the coolant has to flow to enable the stop leak to work?

Then the Penny drops, perhaps if there's a stud leaking on the outside could there be one leaking inside the rocker cover....YES, 2 of them and the start of creamy oil again.

You could just see, when the engine had stood for a 10 minutes blue coolant around the threads/top of the head nuts on both long studs inside the rocker cover. I did think of extending the "cunning plan" to these 2 head nuts as well but bottled it as I didn't want it coming adrift within the engine....

So, nothing to loose (other than my sanity) I removed, individually both inner studs, clean out the holes, applied wellseal, re fitted and torqued up.

No coolant leak from the 2 inner studs  and no head gasket leaks so I have done the 2 outer ones today.

On reflection this is has probably been some of my issues with this project (but not all) and was compounded by the amount of times I have taken the head off as to get most of these gaskets to fit (without distortion/bending) I have had to remove the studs (which were new when the engine was rebuilt) to fit the gasket ...all the time disturbing/cleaning out the holes/threads that clearly have fishers/hair line cracks etc.

I now have clean oil and a top hose that feels under pressure all the time so fingers (and most other things) crossed we're getting there. Good hot run today of about 150 miles then dropped the "slightly" contaminated oil and filter and refill tomorrow.

On another topic, I've been using "relatively cheap" 20/50 whilst all this has been going on and it only confirms my thoughts over the years that you can't beat good quality oils. The oil pressure has been down by about 10% across the running pressures/temperatures using this oil compared with my "usual tipple"

Thanks to all that have contributed and lets hope this thread slowly slides down the ratings through lack of use!

 

[iain]

So have you revealed a cracked block, common around the rear studs especially at the rear

 

 

 

Edited March 4, 2023 by iain
Inaccurate annotation of photo

[Motorsport Mickey]

21 minutes ago, iain said:

So have you revealed a cracked block, common around the rear studs especially this one

 

Err...that's the offside front stud. Not surprisingly the rear studs are at the other end and the favourite stud for cracks is across the block nearest the oil transfer hole in the block.

Most can be reclaimed or just fit the studs with non setting "goo" in place, 105 lbs makes a good job of sealing these areas. Sometimes I think we try too hard to make engines "perfect". Back in the day making it "good enough" for tomorrow to drive to work, often made it good enough to leave alone.

I hand scraped the rear of one block surface, (25 scrapes to the square inch as I was taught in the toolshop), where the area around that rear stud on liner 4 had lifted and reduced the liner height to 1 thou which reduced the gasket clamp and was weeping and causing a hot engine. I scraped it down to a 3 thou clearance around the liner and blended it into the block surface around liner 3 hoping to just run the summer, but I got "distracted" and the engine  was still running well and cool 5 years later !

Mick Richards 

 

Edited March 3, 2023 by Motorsport Mickey

[Ian Vincent]

When I took my engine (dismantled) to Hamlins for a number of issues to be addressed, they found two areas where the block had cracked and welded them up for me. One was the back nearside stud and the other same side on the front. 

Rgds Ian

[BlueTR3A-5EKT]

The Standard Triumph training film build instruction for the wet liner engine demonstrated the use of a wrap of lead linger around the top of each head stud, on the top of the head, before the washer and head nut are fitted and torqued……to stop cooling water that might pass up the gap between the head stud and head stud hole and leaking either to atmosphere or worse still into the rocker cover area.

It is the same technique used to seal the oil pressure relief valve adjusting nut on the wet liner engine.     I have a dwindling reel of lead linger if you want to employ the ancient technique.

[Nigel C]

Iain, The rear studs are fine, just the four long studs in the central area.

Mick, fantastic work fettling the block to create the levels and it held for so long and totally agree about getting to work tomorrow pressing you to "make do and mend"

I remember driving my BLMC 1100 (running 1380/twin carbs/LSD/Cosmic's but nothing declared) to work on Monday morning with just the rear boot floor board strapped over the engine and a pair of Cibbies for lights as I had inadvertently lost the complete front end whilst passing through a hedge on the Friday night and didn't finish the GRP flip front graft by Sunday night  

Also remember its an Ali head so not 105lb although I have gone to 75lb not the mythical 65lb.

Ian, Hindsight and all that, wished I had taken more time to check the block over after dipping....

Peter, interesting and someone mentioned to me about just gluing up the head threads but I didn't like the idea of coolant sitting in the stud "housings" and thought I would try and stop it at source.

with this slightly thinner than I wanted head gasket I have 235lb Combustion chamber pressures across the board. Start/Stop it about 8 times today and it only ran on once  

I'll keep a close eye on things and keep you all in the loop...hopefully this saga may help others (who are stupid enough etc etc) 

[iain]

10 hours ago, iain said:

So have you revealed a cracked block, common around the rear studs especially this one

 

Posted in error, I thought I’d deleted clearly not! Whoops.

[iain]

Here is what I should have posted, yellow circle is where Hamlin’s find most cracks these days.

Mick, is the red circle where you have found bridging between the oil and water ?

[stuart]

So after all this I think we can safely see why the race boys dont use ally heads.

Stuart.

[Motorsport Mickey]

5 hours ago, iain said:

Here is what I should have posted, yellow circle is where Hamlin’s find most cracks these days.

Mick, is the red circle where you have found bridging between the oil and water ?

Nope...still not got the posting of photos working Iain, or does that refer to the original photo ? 

If we are talking about the rear passenger side head stud Iain, nearest to the oil transfer hole, happily the cracks propagate from stud to the water jacket  around the liner via the shortest distance. It appears on those I've had to be a surface crack likely caused by the lifting of the surface around the stud over some years (a 1 thou or more lift is not unusual) causing a flex on the deck surface causing a crack which propagates downwards and across into thy water jacket around the liner. I've not had it spread inwards into the oil transfer hole, which may cause problems if it occurs. 

The block surface can be repaired with a circular thick insert bored into the block surface in situ (been shown in use on the Forum about 18 months ago)

Full Torque Thread repair is the system, there are Youtube videos on it.

Repaired stud hole.webp 

and then the stud threads doctored with Wellseal or similar "gummy" thing, to help stop water creep across and up. The Stag lads ( I used to have one) swear by K Seal which is a copper and ceramic mix of VERY small particles, and being in a Stag couldn't be considered if cooling was impaired. These get drawn into fine cracks and eventually clog up the water flow and stop it over a matter of weeks. The mix is so thin that it happily flows through the normal water system and radiators without inhibiting flow. I used to use it on all my race engines as an insurance, messing about mid season with a weepy stud or machined surface was not what I wanted. I think any of these short corner studs can develop a hairline crack but it wouldn't bother me in use,...we have ways...etc.

Mick Richards

Edited March 4, 2023 by Motorsport Mickey

[iain]

Anybody else having problems with iPads of late? :-)

This is the photo

[Nigel C]

I thi9nk I may well regret this next statement ....no problems with those two studs.........

[Nigel C]

On 3/4/2023 at 12:38 PM, stuart said:

So after all this I think we can safely see why the race boys dont use ally heads.

Stuart.

I have heard the same but I do feel in my case Stuart your comment is somewhat unfounded. Yes/maybe the first failure was due to an ali head. The second was definitely IMHO due to the ali head but the subsequent four (!) attempts have not been "the heads fault" but annealing/one head gasket fits all scenario etc and towards the end of this saga the studs leaking coolant which again has nothing to do with the ali head.

All the studs are now dry and I have plenty of boiler pressure 

Whilst I'm on and have your undivided attention I have a non standard breather outlet on the back of an ali rocker cover and was going to link it up to the take off on the inlet manifold (TR4).

The I.D. of the outlet is 9mm which I'm sure is waaay to large and will probably allow the sump to be sucked through to the carbs if I'm not careful.

I can turn up a "restrictor plug" to go in the end of this aperture but what dia hole would you all suggest would be the most efficient?

[Motorsport Mickey]

I use 1mm.

Mick Richards

Sorry wrong hole...that's the oil feed to the rocker gear. I agree with Hamish on breather clearances.

Mick Richards

Edited March 7, 2023 by Motorsport Mickey

[Hamish]

You may wish to consider a breather catch tank. 
it’s what I use. I have a rocker breather tube mid point in rocker cover that’s about 8mm id and a crank case breather that about 25mm id both to breather tank with a 28mm vent from the tank to atmosphere.

 

[stuart]

What you would need to check Nigel is whether there is an oil baffle in front of that hole to stop large quantities of oil being ejected down the breather hole. Then as Hamish says fit a nice big catch tank thats not vented under bonnet but through a large diameter pipe that goes down and underneath facing rearwards to take advantage of the venturi effect to draw any fumes outside.

Stuart.