Disappointing

[mole42]

Today was the day I intended to start the engine in Mabel after the long process of putting the car back together.

First thing, check all the hoses are secure, then start to fill with 50/50 glycol and water - my usual coolant mix. I got to about 6 litres when I noticed a dribble of coolant on the floor, damn, I thought, I forgot to tighten something. Investigation showed that the coolant was dribbling out between the LH cylinder head and the block, all along the side. The right was weeping a bit too. I checked the head stud torques - correct at 50 lb/ft and still weeping coolant. Having followed the correct procedure (tighten RH head, fit inlet manifold, tighten LH head) when installing, using quality gaskets from R*mm*rs, I'm puzzled. It's not the first time I've fitted Stag heads but it is the first time I've had them weeping from the head gasket.

Before I left the garage today I've pulled the carburetters off, removed the inlet manifold, released and removed all the head studs and all but two of the bolts on each side and removed all the coolant hoses. I used up all my enthusiasm before I got under to drain the radiator and remove the exhaust manifold nuts so I haven't got the heads off but they are loose.

[Chris01573]

Had the heads / block been machined Richard ? sounds very odd especially as they were leaking without any pressure build up... could it be core plugs leaking ?

[NeilR]

Unfortunate !.

What make of gaskets were they & did you use any kind of sealant ?

[mole42]

Rimmer's GEG3305 "Standard Payen Type" gasket fitted as usual with Stag Wellseal.

A bit of background - this engine was built by Tony Hart's team and has been used by me for about 50,000 miles including some mild competition work. It's been very reliable until I had the heads welded and skimmed a couple of years ago when I found (eventually) that one of the heads was a bit thin and the exhaust valves were (just) touching the pistons. While running the car, including a tour of Yorkshire and then the Club Triumph Round Britain Run, I bought a pair of heads that were said to have been built by a RR Merlin engineer. They look good and came with an inlet manifold, I was told the set had been machined to fit together perfectly. I inspected the heads, found nothing to be concerned about, and fitted them. Now it seems there may be something to be concerned about!

Until I get the heads off and inspect the gaskets I can't be sure what the problem is but it's odd that both heads leaked with no pressure at all.

[NeilR]

Odd indeed.
Only time I had one leak (only when under slight pressure though) was on the 1st one I ever did after fitting them dry.
Always used a product called CURIL - which is no longer available, then switched to Wellseal after that, not had any leakage since.

[dasadrew]

Odd indeed.
Only time I had one leak (only when under slight pressure though) was on the 1st one I ever did after fitting them dry.
Always used a product called CURIL - which is no longer available, then switched to Wellseal after that, not had any leakage since.

Curil is still widely available here in DE. It's the sealant series from Elring - the gasket people. Whilst I also love Wellseal, I can get hold of the different Curil products online with no problem if you need it.

[JeffW]

That is heartbreaking Richard.

I am struggling to understand how coolant could get out so easily without any pressure and with the heads torqued.

Could there be a hole or holes in the water jacket(s) in the heads? Just a wild stab in the dark...

Jeff

[NeilR]

Thanks drew, good to know that it is still available if I need some.

[trunt]

Had the heads / block been machined Richard ? sounds very odd especially as they were leaking without any pressure build up... could it be core plugs leaking ?

My core plugs seeped a bit and it did run all along the head/block margin.. worth a check?

[mike@thenook]

This is not good news at all Richard, what a p I t a!
I’m intrigued at the use of sealant though on the head gaskets as I’ve only ever fitted them dry, yes I’ve used Wellseal on the inlet manifold gaskets but not heads.I always read they should be fitted dry.
Could it be that the sealant is not uniform and created some unsealed areas?
I’ve a set of Cometec gaskets I will use when I finally start getting mine back together (still not got the RH ahead off yet!) and they say they should be fitted dry…

Hope you get it sorted without too much trouble

[jbuckl]

Sounds frustrating.
could be core plugs leaking. Unusual if it’s both sides.
maybe worth getting pressure tested when they are off.

the other week enginuity said they had Cometic in stock but down to just a few pairs.

[mike@thenook]

I was lucky enough to buy a set off Steve Hill he had with one of his external pump kits as he was selling all off all his Stag stuff

[mole42]

Enginuity have some but they’re £220 per pair. Plus shipping. I need to find out why the Payen ones are leaking before investing in Cometic gaskets.

[DJT]

Looking at that part number on the Rimmers website the image shown does not look like a Payen gasket. Genuine Payen gaskets had the red seal around the edge, which has been replicated on the quality BGA gaskets. Genuine Payen gaskets have not been available for many years, but BGA are available from most suppliers.

Still does not explain why the heads leaked coolant before being pressurised, unless the heads have been skimmed wrongly.

[mole42]

Pulled the heads off today. Nice contact around the fire rings and oil passage but no evidence that the rest of the gasket was in contact except at the front around the chain guides. Using a straightedge across the fire ring locations on both heads and both block faces I get drag on a 1 thou feeler guage in the middle. If I hadn't checked the torques I'd say the heads hadn't been tightened down enough.

Here's some pictures:

LH & gasket.jpg LH detail.jpg RH head.jpg RH detail.jpg