Blown out cam cover cap seals. What do you think?

[hasaramat]

I have a good friend that just finished some top end work on a 72 911S. He turned the car over on first start up to build some oil pressure and notice almost an instant oil leak from behind the chain housings. So we tore into it. We were hoping for something easy but that was not the case. Upon further inspection the paper gaskets between the cap and the cam housings pushed out! I did not like the sealant that he used but that is just my personal opinion. I think it was some type of permatex. I'm an 1104 yamabond man myself. What do you think? Oil pressure issue, sealant issue, installation issue? All of the above?

[HawgRyder]

First thing I would check is whether the galley ways in the cam towers are clear.
If the oil has no where to go .... it will build up too much pressure.
The paper gasket may have saved you from a very expensive lesson in checking oil passages.
Bob

[Flat6pac]

There shouldn't be any amount of oil pressure there. Looks like it was defective on install although the 3 ears were trimmed. I use 574 there, Yamabond, although excellent needs to be applied to both pieces to effectively seal and becomes too thick but excellent on center case line.
Bruce

[Lapkritis]

Install as bone dry, surgically clean on all surfaces if these are the Victor Reinz paper seals. The paper isn't plain; it will bond to the surface by itself.

Any dressing or glue will cause the paper to slip/squirt out when tightened down. If you over tighten, this may also cause the gasket to poop out.

[KTL]

Yep they don't blow out. They squeeze out when you assemble the thrust plate to the nose of the cam housing.

[E Sully]

Very common for that little paper gasket to shift or fold when installing. Not a pressure issue. I had a similar problem when a corner folded on install, and had to replace it. Read a couple others in the forum with similar issue.

[Daves911L]

Not caused by pressure. The only pressure there would be equal to what would be passing between the cam housing and the bearing journal, which probably isn't much since that interface is open at the other end, and the same limited pressure source must supply a bunch of orifices and 2 (or 3) other journals.

Problem most likely was the use of a sealant. Mr Lapkritis is correct on the assembly of this area. Clean, clean, clean and the correct gasket will seal perfectly with the modest clamping force applied by the three M6 bolts. I've never ever used sealant in this area, and never ever had a leak.

Never had one slip or squeeze out either. Put it over the 3 bolts and offer it up that way, starting each bolt a bit so it can't fall out of place.

DG

[RedCoupe]

For a long while I've referred to a little reference book put out by Felpro that discusses gaskets and the need or lack of need of sealants. The overriding message in this book was that in almost all cases gaskets should do all of the sealing between two surfaces. Sometimes a little adhesive is needed to hold things in place during assembly, but often when a sealant is used on gaskets it acts as a lubricant and things can move out of position causing the very leaks that the sealant was supposed to prevent.

[hasaramat]

Thanks for all the input. We will clean, clean, clean and put the gasket in dry.

[r-mm]

Exactly this happened to me. It turns out that the chain cover box was not perfectly centered on the cam carrier so that annoying little paper gasket got a tiny 90 degree fold in it when I sent the cam thrust plate home. Pulled it apart and "glued" the gasket to the cam carrier first then sent the thrust plate home. No drips in about two thousand miles since.

1st drop & top end observations & questions

[r-mm]

Originally Posted by RedCoupe

For a long while I've referred to a little reference book put out by Felpro that discusses gaskets and the need or lack of need of sealants. The overriding message in this book was that in almost all cases gaskets should do all of the sealing between two surfaces. Sometimes a little adhesive is needed to hold things in place during assembly, but often when a sealant is used on gaskets it acts as a lubricant and things can move out of position causing the very leaks that the sealant was supposed to prevent.

I can't comment on whether or not a bit of ultra gray (or pick your poison) is what kept things dry on my second attempt, but I am sure that the gluing action was of use - this gasket has a very very very low tolerence for rotating and or folding. I thought that the three bolts would locate it sufficiently but I hand't thought about the corner folding.

[Daves911L]

One more thought on the matter. The bolts used in this location are fairly long. Much longer than they need to be for strength, which probably speaks to their being intended to locate the gasket before seating the cam thrust plate. BUT, the holes in the cam tower are blind. If you were using a bolt slightly too long, you could bottom it out before bringing the cam thrust plate home and clamping the gasket. Since you mention the leak occurred on just the initial cranking of the motor, it just might be worth a quick double check on fastener length vs. depth of the hole.
DG