Head Gasket Sealant

[davidk]

I am going to be changing the head gasket on my TR-6 for the second time in 6 months due to a small oil leak at the back of the head. To stop the leak, this time I will be using a Payen gasket, and I'm planning to use Permatex sealer around the oil passages. Will this stop the leak? I used the brush on high temp copper sealant last time. I don't want to cause more problems than I fix. The good news is that the head comes off much easier when it hasn't been on too long! Any suggestions will be appreciated.

 

[KVH]

You could be doing the right thing. I just want to share a story.

I had a small leak, a very, very small leak after replacing my head gasket with a solid copper gasket. I was meticulous replacing that gasket. I torqued everything carefully and used the sealant as directed.

Still, I had a slight leak.

A good friend of mine who has built and rebuilt engines for 30 years, including classics, told me not to pull the head again.

He said the leak was too minor and that I should instead just re-torque the head, and then drain the radiator, add some BarsLeak, and run pure water for two hundred miles or two weeks with the car sitting a few days between each drive.

I did that, and then drained the radiator and put AntiFreeze back in.

Running straight water was an important part of the process.

The head sealed itself, and has been perfect for three years.

 

[DougF]

What type of gasket were you using? As far as Payen brand, I've never used a sealant with them and have yet to have any problems.
You are positive the leak is from the head gasket and not the valve cover?
With copper gaskets, I was told the trick is to have rougher finishes on the head and block mating surfaces and use a sealant.

 

[KVH]

In my case it was a solid copper gasket from Moss, made, I think, by the folks at https://www.headgasket.com/.

I used a spray on sealer.

Leak definitely from the head, but small, right near the mating seam. Slight green antifreeze glow.

Leaks at the valve cover would typically be oil, of course, not water.

 

[TR3driver]

Unfortunately, pure water and Bars-leak is probably not a good thing to run in place of oil

I'll second the suggestion to be quite sure it's actually coming from the headgasket. It's possible of course, but oil is so much easier to seal than compression that it's not a common problem with a stock composition-type gasket.

Also if you do change the gasket, pay extra attention to both block and head surfaces in the vicinity of the leak. Make sure they are flat and smooth (but not too smooth).

My experience has been that, if everything is right, no sealer is needed. And if things aren't right, no sealer will help.
But if I did feel that a sealer was the only solution, I'd probably try the stuff Mordy developed to seal those solid copper gaskets (which are much less forgiving of minor flaws than the stock gaskets are).
https://www.headgasket.com/contents/_GWG%20P_5_label%20v1.pdf
I've also heard good things about "Yammabond", available from Yamaha motorcycle dealers. But I discovered my problem (cylinder block apparently cut wrong at factory) before I tried the "hard stuff"