Top water rail to head seal

[Nigel]

Hi all,
The new seal that I got from Mark @ Betaboyz squeezed itself out of position,and leaked.

I measured the gap that needs to be sealed and its about 1mm [between the rail and head]
The new seal is around 2.8mm and is perhaps too thick?
I used hylomar in fitting. I'm now thinking that it may have been better to fit it dry
to stop it slip-sliding inwards.

I bow to your vast knowledge....

Nigel

[mangocrazy]

I know that Guy Croft, when fitting an in-head thermostat at that junction, just beds the whole lot down on generous amounts of silicone sealant (but not enough to clog waterways). Having said that, the thermostat would probably take up the 1mm gap you spoke of, leaving the silicone to seal and irregularities.
Perhaps a copper or aluminium crush washer of a suitable size might be better?

[mangocrazy]

Did a quick search, and this looks like it might do the job:

https://www.amazon.co.uk/DealMux-Copper-Washer-Sealing-Fastener/dp/B072TWN73C

[Nigel]

My thanks Sir!

I measured the outer size needed and it's 53mm so that particular one you found would be too big.

I'm now,after reading your first reply,going to reuse the one that came out,
which is much broader,i.e. a smaller hole,and thinner, and use silicon sealer,as per GC.

We'll see what happens!
Best wishes,
Nigel

[mangocrazy]

That's interesting - I happen to have a cylinder head that's been vapour blasted and sitting on the bench. I measured the orifice in the head where the top water rail bolts to, and the i.d. was 55mm. So is there more than one head/water rail specification? Italian cars - doncha love 'em...?

[Nigel]

Ooops. I mis-measured.
I've just been out and re-checked, and it is indeed 55mm with a tiny bit to spare I think.

So i'm going to order that ring. I think it'll be better than rubber.
I'll just have to make sure I don't tighten it too much,but that may depend on how crushable it actually is.

Thanks again and sorry to mislead!

Nigel

[mangocrazy]

Hi Nigel,

Have you road-tested the copper washer, and if so did it work? Interested to know as I will need to do the same at some point in the future.

[Nigel]

Hi Nigel,

Have you road-tested the copper washer, and if so did it work? Interested to know as I will need to do the same at some point in the future.

Sorry Mr mango, but I haven't yet.
I ordered 3, but the original rubber is holding up for now......so, if you'd like to be the guineapig.....
PM your address and i'll pop one in the post,pronto.

Regards
Nigel

[mangocrazy]

It's OK Nigel, I ordered a couple at the same time as you did, so no problems. It will be a few months before I become the guinea pig. My rebuild is proceeding at a glacial pace...

Graham

[mangocrazy]

Rather than start a new thread, I thought I'd add to the existing one. I've just undergone a trial fit of the top water rail using the 55mm x 48mm x 2mm copper crush washer and while it fits the orifice in the cylinder head perfectly, the 2mm depth means that it doesnt crush a great deal, if at all. If it had been 3mm depth it would be perfect, but the spigot clamps down fully without exerting much force on the washer. This could lead to leaks. I'm undecided whether to use 2 x washers or make up a washer from some 3mm thick gasket material I have.

I will report back...

[Nigel]

Graham,
I read somewhere recently that an 'O' ring has been used successfully.
I would imagine a 5mm might work, and would crush without shifting.

Nigel

[mangocrazy]

Hi Nigel,

In the end I made a gasket for the top rail from the 3mm thick material I bought and used red Wurth Special Silicone gasket paste as backup. It tightened down nicely and everything lined up correctly. Hopefully it should work, although it will be a while before I can put coolant in the system to test. The only problem with O-rings is if you over-tighten them they tend to twist out of shape and allow leaks to happen. Correct clamping force (i.e. not too much) is essential in my experience.

Graham