nine9six

With all the disinformation regarding leaking valve covers and tightening and over tightening; no one else has figured what Andreas has so plainly stated above.

Once the alum inserts in the valve cover come in contact with the top of the valve train surface, there is no further squeeze that can be placed on the gasket seal.
If one continues to tighten past this point, you're begging to pull the alum threads in the head. Then it'll be heli-coil or time cert, time

This existing design protects the valve cover and overtightening. I would use the sequence as stated above (inside; out) and repeat until no further tightening past the 7 ft lbs as spec'd by Porsche.

Billet valve covers are just not necessary, nor are they a realistic expenditure to a perfectly good design in the existing Porsche valve covers.

Clean surfaces are a must for a good, lasting seal.

95_993

Used this approach 5 yrs ago and my stock valve covers are still completely dry. Also replaced all the bolts....cheap enough.

AOW162435

Still dry o'er here.



Andreas

Mike J

I think the reason for 7ft-lbs is both the bolt is fairly small, and to reduce the galling that happens between that bolt and the cam carrier. I have pulled off a lot of covers by now and there are bolts that have oxidized in that require that a good allen socket and a firm grip to break free - usually with a **snap** and then they are free. So over tightening is not too much of an issue going in (other than stripping something) its the eventual service that is the issue.

If I get a stripped valve cover bolt, I usually try a Torx socket, then try to break it loose with a small chisel hitting the side of the bolt head to cause rotation, and if that all fails, out comes the carbide bits (using a die grinder) to grind/mill the bolts head off. If you are careful, you can take most of the head off, leaving just a washer thin section, and then it can either be started to unscrew using a chisel, or it just hand unscrews - its the bolt pressure that you are relieving so it can be unscrewed.

On some cars that have been driven year round, I have had to grind up to 3 bolts per cover. With a good bit, it does not take that long, just be careful.

Cheers,

Mike

nine9six

Andreas, Mike,

Do either of you recommend a thin coat of oil on the gaskets prior to insertion into the covers and installation; as this would seem to allow the rubber to move during the torqueing procedure?

I read that somewhere, while searching for the tightening sequence...

Mike J

I have been using Dow Corning 111 to pre-lube the gaskets for years - seems to work great!

That was a recommendation I received from Gerry Woods during an engine rebuilding class.

Cheers,

Mike