Help - My nuts are bleeding! Any issues with silicone gaskets?

[RarlyL8]

I've got one valve cover that is a chronic leaker. I've checked it on a flat surface and it is flat. Dunno why it leaks but I can't stand it any longer.
Thought I would try a set of the ultra-expensive silicone gaskets as sold here at Pelican. Before I throw more money at this problem I'd like to hear of any reasons NOT to do this.

I know you're dying to see a picture of my bleeding nuts so here you go:

[BReyes]

Dave white always put the silcone gaskets from day one so that is all I know, and its been a while since Dave has done a valve job job for me so not sure he did this too, but Frank rubbed silicone on the nuts as well. You've gotta have seen the silcone rubbed on the nuts.

[Nitrometano]

I also put silicone on the nuts to avoid that. I always use the high-temp cooper silicone. No more bleeding.

[john walker's workshop]

can't tighten the nuts much at all with silicone gaskets. customers get them back in a bag, as i can't stand behind them. just doesn't feel right to leave the nuts loose. to each his own though.

[RarlyL8]

Do understand this correctly, you put silicone cement on the nuts themselves?

(I dunno, my nuts seem to leak even more when someone rubs silicone on them. )

John, any non-silcone recommendations on what to do about this? I'm at my wits end with this one valve cover. The other 3 are always dry as a bone.
If it were warped I could understand it but the darned thing is flat and only bleeds from the nuts.

[Jeff Alton]

The gasket makes the seal, not the nut. If you have oil dripping through the threads of the nut, you have a leak between the seal and the valve cover. Period.

Cheers

[Natchamp]

I have heard the machined valve covers don't leak ;p

[Cipotifoso]

I've got the silicone gaskets with the turbo valve covers and have no leaks (from the valve covers, at least). I think they work great and they're reusable. You just have to be careful on how tight you get the nuts, but they don't loosen once you have them set.

[slodave]

I am using the silicone gaskets as well. I was having similar problems, but now they are dry. This is even after 2 hours at Willow Springs. There is a bit of leeway with tightening the nuts.

[WPOZZZ]

Brian - Your situation is terminal. Time to sell the car to me.

[mb911]

to be honest I can't believe you have time to work on it.. Just so you know mine do weap just a bit. its always the lower one closest to the trailing arm

[DUK]

Did you use the alum. crush washers? I used stainless an washers and had to go back and put a dab of silicone on the stud to keep them from weeping.

[RarlyL8]

Actually I don't have time to work on this issue but the car is way overdue for an oil change, not due to the miles but the time sense the last change.

Custom covers would be cool, maybe you can carve my company logo in them, ha!

Firesale - 1978 911/930 conversion. Leaky valve cover. $500. Not!

Don't recall the washer material, seems to me they were copper or aluminum. Don't think they were steel.

Looks like I need to try the silicone gaskets and some copper high-temp silicone cement. Any other tips?

[Gunter]

You may have an issue with the cam tower being warped or ?
To check: Clean both mating surfaces thoroughly.
Apply machinist blue liquid to the mating surface of the cover.
Without the gasket, and real quick before the blue dries, install the cover with tightening the nuts from the center out.
Remove the cover.
Carefully inspect the cam tower; it should have even wear-spots.
I re-used the same regular gaskets for the last 4 years.
No issues with the gaskets sticking to the mating surfaces because I grease them with Moly from both sides; they come off real easy and clean each time for valve-adjust.
As long as the mating surface is even and undamaged, any paper gasket will seal.
I have not used the Silicon gaskets or Silicon on the nuts and don't see any need for that unless the Silicon bead on the gasket makes up for uneven/damaged surfaces.

And BTW, we have used the trick with the grease on both sides of the gasket in industrial applications, like reducers or gear boxes, for many years.
No extra cleaning/scraping; the covers/gaskets come off real easy.
While you at it, with the covers off, take a close look at the rocker shafts for leaks.

[Halm]

I have seen cracked rocker shafts cause leaking from the nuts.

[RarlyL8]

What would cause a cracked rocker shaft?
This one cover has been a bleeder sense day one. It got worse when I let some numnuts "Porsche" mechanic change the oil when I was out of town and he put in Mobile 1. I've changed it 2-3 times sense with dino and it isn't getting any better.

[911boost]

That would be annoying. Since my 3.3 is twin plugged, I have tried a couple of different valve covers (currently have the billet IA covers on it), and mine all leak at the nuts as well. Its horribly annoying, and I hate continuing to throw $$ at it.

[john walker's workshop]

the nuts are the lowest point there, so any oil seeping from rocker shafts, oil return tubes, cam thrust gaskets or the head to cam tower sealing area, etc, will collect there. not saying yours are not leaking there, but it's hard to believe how a stud surrounded by a wide expanse of thick gasket material, no oil pressure behind it, and squeezed between two flat surfaces could feed oil past all those threads to collect on the outside of the nut.

[Halm]

Originally Posted by RarlyL8

What would cause a cracked rocker shaft?

I don't remember the specifics, but when I bought a '70E in LA, Otto did the PPI and prep to drive it home to Charlotte. We had an oil leak from a nut after a shake down cruise to No. Ca. He took one look at it and said "rocker shaft." He pulled the valve cover and sure enough there was a hairline crack on one of the shafts. He replaced it and I never had another problem.

[john walker's workshop]

the rocker shaft leak simply heads to the bottom and collects along the edge of the cam tower and runs down onto the nuts.