Replacing cylinderhead

[Charles Levien]

Just getting ready to fit my new alloy head and was wondering if the headgasket should be coated with grease or gasket sealer prior to fitting.
What do you use on a modern copper gasket?

There seems to be a wide variety of opinions and experiences on this, from just grease it to using blue hylomar. 
I use the latter — spraying a thin film on all four surfaces which works well for me. Important though to torque down the head nuts with the central three leading the way.

[Alan]

Depends. If your surfaces are perfect, a thin coat of grease will do. Otherwise loctite 5920 applied sparingly works for me.

[AustinWood]

I use a smear of grease. It is there to lubricate the gasket and allow it to take up its position as it is tightened down.

[rubyman]

When I bought my Ruby with a seized engine because the bores had been left with water in them, after removing the pistons the bores looked like yours I honed the bores till they were nice and shiny fitted new pistons and now I have compression's of 110 on all cylinders, I also use loctite when fitting a head gasket & having overhauled more engines than I can remember never had a failure yet 

[Steve Jones]

Depends. If your surfaces are perfect, a thin coat of grease will do. Otherwise loctite 5920 applied sparingly works for me.

+1. 

Steve

[Charles Levien]

Depends. If your surfaces are perfect, a thin coat of grease will do. Otherwise loctite 5920 applied sparingly works for me.

This forum is particularly good at getting a consensus of opinion — I’ll certainly try the loctite next time

[Paul Nott]

Nice to know that whatever I do someone will agree with me !

[Paul Nott]

    Finding it difficult to obtain Hylomar spray or Loctite 5920 locally, has anyone use Loctite si5990?

[Steve Jones]

Loctite 5990 and 5920 are exactly the same thing. 5990 is just a later reference number.

Steve

[Chris KC]

Personally I find a smear of grease sufficient.

But yes when suggesting 'Loctite' do please specify which specific product!