head sealing rings

[scotty914]

fast answers needed because the heads go on tommarrow .... i got new sealing rings can i use the copper based rtv in a very thin coat to help seal the head to cylinder ring (the package say it can be used to seal head gaskets) or is it a bad idea .. i just want that extra ins. with the head it is alfully exspensive to replace or machine

scott thacher
75 1.8 under constuction
75 under rust
(fine german rust that is)

[BenI]

Ive never used RTV on the head gaskets and have had no leaks with a 2.0L 4-cyl.

[DDS]

Tom Wilson's book mentions Permatex 3h for the base gaskets but nothing for the head other than clean, scratch free mating surfaces.
No mention of either in Haynes.
FWIW on that basis I won't use any goop on my newly 'big valved' 2.0 heads.
Dave

[paulhagedorn]

I believe I read somewhere where you actually could forgo using the head to cylinder sealing ring...bumps up the compression a little bit, but I would still probably use them because it helps seal the surface if it is a little imperfect. Oh, and no, you don't use any sealant on the ring on top.

[TimW]

I thought I read you can only forgo using the head to cylinder sealing ring on TypeIII’s, but TypeIV’s require them? I’ll concede that I could be wrong.

In either case, I’ve never heard of using, or ever have used, anything but a sealing ring – no RTV.

Then again, I’m a computer programmer not an engine rebuilder so what do I know ?

[jmcleod]

I have a copy of a VW tech bulletin that deletes the head sealing gasket. This was in reference to a vanagon motor but you may know the vanagon motor and the 914 type IV motors are very close cousins. That said, when i rebuilt my vanagon motor and my 914 motor, I did install the head sealing rings. I asked an air cooled mechanic who said he hadn't heard of the bulletin. I also thought that in some type 964 motors, there was some sealing problems between cylinders and heads (the case if you delete the sealing rings) that Porsche of North America made a repair by machining a groove for an o-ring to help seal. One final thing, I read that for larger than 94mm, the walls of the cylinder where they touch the heads are so thin, that the cylinder actually cuts into the head loosening the sealin pressure and providing a source of a leak.

[KWales]

Probably wouldn't ruin anything if you did. I have used cyanoacrolates (sp?) (superglues)to temporarily hold the rings in place during assembly but I knew that combustion temperatures would burn out the glue.

As a geek mechanical engineer, I know that silicone burns above a certain temperature. As a bug and 914 engine rebuilder I have used silicone as a quick and dirty way to seal leaking heater boxes. As I recall, this ritual usually occurred the day after the windows begin to frost. Apply the red hi temp stuff in a bead around the leak between the heater box and exhaust pipe. Allow the silicone to cure and start driving. The silicone next to the exhaust pipe will char and burn away from the pipe, but the gap will be smaller than before. Might stop rattling too!

Anyway, I think the silicone will burn away.

Ken

[scotty914]

well thanks all for the info the reason i asked is i did not rebuild any thing just giving it a check up because it was burning oil i found out it was blowing out of the oil breather ( too much oil)... but dave ( screen id dds ) gave me a great tip ... lapping the cylinder to the head i did it and the small imperfections are gone in ten minutes i will be using the sealing rings so lests hope for the best

scott thacher
75 1.8 under constuction
75 under rust
(fine german rust )

[sammyg2]

Lapping the heads is a good idea, IMO. I lapped the heads on the 2 liter turbo motor I built, using the stock head gaskets, and all I used on the sealing surface was a very thin film of triple boiled linseed oil. Probably not necessary, but the oldtimers used in on turbine split lines, so I tried it. I know it didn't hurt.

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Gerald Gore II (Sam)
73 914 350 small block