swftiii

All,

I have read so many threads on the lower valve cover leaks that many of our cars experience and mine was experiencing. Based on all the reading most have moved to the billet aluminum covers and have had good success and no leaking.

So, I had the shop replace the old stock valve covers with new billet aluminum versions I purchased when they did the valve adjustment last fall. They have been leaking pretty badly, so I recently removed the covers and replaced the gaskets with new Porsche ones thinking that would address the leaks. I followed all the recommendations and didn't overtighten the new valve cover nuts.

The result is that they are still leaking pretty badly, so where do I go from here? I'm thinking that the valve covers may be off a bit and the grooves for the gasket are too deep, but have others experienced this?

Fortuitous timing, but should I consider the following: https://rennlist.com/forums/964-foru...ve-covers.html Should I have the billet covers machined down a fraction of a milimeter? Other options?

Thanks,

-Skip

Vandit

Pelican sells a silicone gasket kit that is suppose to be slightly thicker and reusable. Perhaps a set of those will help stop the leaking.

theporscheguy

Replaced the valve covers on my 993 with billet units and they worked really well. I think the key was that the new covers were also provided with thicker gaskets that were reusable. No leaks after that.

boxsey911

My new billets leaked too. These were the earlier Imagine auto versions. Many have put these on with great results e.g. I know that they have been leak tight on Marc Shaw's car (he was kind enough to chat with me by PM about my experiences with the IA billets).

The good news is that mine are now also leak tight. However this was achieved by my P-car shop skimming them. Their experience is that the channels are too deep for the gaskets so they don't get compressed enough. Skimming them to make the channels more shallow means the gaskets now compress enough to do their job.

swftiii

Fred - I was worried about that - I don't want to be tied to a non-factory gasket kit going forward.

Steve - thanks and that is what I was thinking.

So, now looking at the $ side, I could pick up the covers from Rennspd and install myself for probably less than the cost from the shop to remove, skim, and replace. Which way would people recommend:

1. Skim the billet covers
2. Pick up the covers from Rennsp

-Skip

axl911

The way/sequence you tighten the the screw IS VERY IMPORTANT. This was the only I can get my 964 and my 993 valve cover to stop leaking or weeping.

1. put on valve cover with fresh gasket seated evenly and lightly oiled.
2. put on all the screws by finger and don't tighten at all. Just very lightly to hold the valve cover in place.
3. then start fom the Center top screw. Tighten to spec at 7ft-lb.
4. then tighten the Center bottom screw to spec.
5. then tighten the next right top screw to spec.
6. then tighten the right bottom screw to spec.
7. do this for all the screws to the rigth of the center screw.
8. then tighten the top left screw next to the center screw to spec.
9. then tighten the bottom left screw next to the center screw to spec.
10. do this for all the screw to the left of the center screw.

swftiii

axl911 - I completely agree and followed the procedure you outlined exactly and to the right torque 7 ft-lbs.

Gotta love these cars...

-Skip

stevepaa

Curious, why were the originals leaking? I have 218k miles and no leaks. Are you applying a circular three stage torque pattern? Do you have a precision straight edge to see if covers are warped?

Oops, my response was a little late, but I see you don't use a circular patttern.

993James993

Just curious, what billet covers do member's recommend? I may order them for an upcoming valve adjustment.

swftiii

Steve - one of the original covers warped, the other was OK, but the billet covers are sold as a pair.

deutschland-dobson

Gents,

Sorry to bump an old thread, but who would you recommend for billet valve covers in 2014.

Has the requirement to skim been designed out yet?

At the moment it's Rennline vs Harget Precision.

Anyone have any discount codes?

Thanks
Chris

SuperUser

I just put on the Rennline ones, they are very nicely made and stopped all my leaks. They are a little heavier than the old early 1990 ones I replaced. One other thing to note is the spark plug hole is a little larger than the stock covers so the plug boot does not fit tightly like the original covers. I am not sure if this is an issue or not.

Goughary

I have hargett covers. I had some issues with them out of the box. The edges were very sharp everywhere. So I sanded those off a bit. There were no holes to mount the wires, so I drilled and tapped those and use oem clips for the wires. And I painted them so they wouldn't corrode. And then I thought there would be an issue with the plug boot fitment, but there is no problem there. Have to say, over-all they are awesome. They needed a very slight bit of finish work to make them as good as stock, but in the end, are a much better product than stock and mine have never leaked, going on three years...

deutschland-dobson

Thanks gents

Bit disappointing that you have to drill the Hargett covers. Do the Rennline covers fit out of the box?

I notice that the Rennline ones have a powder coat option. I take it there's no issue applying heat to cure a high temp paint finish then?

Chris

Johnny G Pipe

I have Hargett from a few years back. Cheaper than Tarrett and Rennline from memory, but they always leaked. Just had 1mm skimmed off each (50 quid a side), having previously changed gaskets and driven myself mad torquing in correct order over and over - and now they are dry. Finally.
The machine shop said the channels were exactly the depth of the gaskets. Fail! Should have bought the expensive ones...