Changed valve cover gaskets, Oil leaking out valve cover bolts?

[ogasman]

I was running Felpro composite gaskets.  They had a good squish pattern on both sides of the gaskets.   They were installed dry, no sealants or grease.  They had a pretty good leak on both sides.  So I changed the gaskets.  I used Felpro cork gaskets, Motorcraft T31, and red grease.  I made a full bead of T31 on the inside lip of the valve covers, inside the bolt holes.  I stuck on the gaskets, and lightly greased the head side.  I set the covers on the heads, and just put the bolts in enough to hold everything in place until the silicone set.  I snugged the bolts up the next day, and took it out for a run.  I can see oil running down from the bolts, on the top surface of the covers.  Not just the bolts on the bottom bolts, but also from the bolts on the sides.   A decent amount of oil leaking, considering I did not drive it that long.  Any ideas?

Paul

[cleandan]

Maybe with the non-torqued dry time the sealer set in a way that is not friendly to being moved. When the bolts were tightened it tore/moved the gasket just enough to cause leaks?

Bad gasket, as in old and brittle or cut wrong, or a sealing surface that was not completely flat and true.
I make sure to run my finger over any sealing surface to be certain it is flat and smooth...sometimes the remains of old stuff is a bit hard to see.

[cammerfe]

Way back when I was an engineer at FoMoCo, I was told to take a class in Statistical Quality Control. When I tell you the class met for one evening a week and was three hours long, you'll readily infer my relief when the instructor, another Ford engineer, said we'd go good for an hour, take a break, come back for another half-hour and go home.

The second, half-hour session was sorta a bull session. The instructor told us, at one meeting, that he'd just been part of a 'deep-dive' examination of the result of torquing a fastener when there was a gasket between the mating surfaces. The result of their studies is that there is no such thing as holding torque in such a situation because the gasket will continue to yield.

You may have simply encountered a situation where tightening the hold-down bolts {or what have-you} need to get an extra 'oomph' to compress the gasket so it doesn't leak. In my experience over the years, I've found that the sort of gasket that's really two layers of gasket material with a matrix of some sort in between is superior for FE valve cover gaskets. Some have two layers of rubbery material with a sheet-metal layer in the middle. It obviates squeeze-out which is a good thing. And it helps control the degree of crush you're placing on the gasket.

Good Luck

KS

[WConley]

Funny - I took that same Statistics class while a Ford engineer at EEE

Yeah, it was a bit hard to stay awake through the heavy stuff, but our instructor was a cool guy too.  Good stories from the trenches!

[cammerfe]

 

KS

[Jb427]

I used felpro cork gasket and i contact cement glue them to the valve covers and i don't use any grease on the head side. I have had mine on and off a bunch of times now and 0 leaks i just make sure when i remove the covers off the engine to be gentle as not to damage the gasket and i just try to get the bolts tightened up evenly i am running MT type cast valve covers

[machoneman]

Didn't see what the covers are made of, tin/steel or diecast aluminum. Well used tin/steel covers as folks here know often need some hammer work around the bolt holes to level them to the rest of the rails. Heck, even on new die cast covers I'd block sand the rails to ensure a nice flat surface all the way around.   

[SReist]

Don't use a split lock washer. Mine leaked constantly with them. Steve

[ogasman]

They are Lemans die cast covers.  I checked them before I installed them, they are flat.  When I installed them this time I snugged them down a little bit, but the gaskets started to squish out.  If I re-do them I will just glue them to the covers, and snug them down before I put on any grease.  The more I thought about it, the bolts and threads were all very wet with oil when I took it apart the first time.  I think all the leak is from the bolts.  I will probably be sorry, but I did it anyhow.  I took out the bolts and cleaned them and the holes with brake clean.  Then I put T31 on the threads and put it back together.  I want to see if this stops the leaks.

Paul

[cammerfe]

In the normal course of things there is no way for oil to enter the VC bolt holes in either the heads or the intake manifold. But weird things are possible. Maybe you've hit on something.

Bill, were you there when all the guys with offices in the west end of EEE got Recaro desk chairs?

KS

[JERICOGTX]

Go with the gaskets I posted in your thread asking which gasket to use, and your problems will be solved.

[Falcon67]

My take is that if there is "squish out" then you need a stiffer/better design gasket.  As an ex QA guy, can confirm the excitement surrounding statistical QC.  *yawn*  And can confirm that even a good pretty stiff valve cover gasket is going to need a few torque cycles to stay "tight" and work most of the compression out of it.  I usually run the motor for whatever or through a heat cycle, then go over things like intake bolts and cover bolts after it cools. 

[WConley]

...
Bill, were you there when all the guys with offices in the west end of EEE got Recaro desk chairs?

KS

Hmm - I would have remembered that!!  Was it after 1993?  I could see something like that happening in the 80's, when the engineers were on top.  When I left at the end of 1993 though, the bean counters had taken the hill.  No way would they approve something like that!

[cammerfe]

Trying to relate to other happenings. At one point, NASCAR thought seriously about going to 6 cylinder engines. I did some calling around and was informed that Ernie Elliot was doing testing and the guys at EEE had just received the latest head casting back from Dawsonville.

I was writing for Super Ford Magazine so I was invited over to EEE to take pictures and get info for a story. That was when I saw the new Recaro chairs.

When I was parking, Michael Kranefuss came out and got into his Cobra. Having been introduced to him at Roush's office a couple of weeks before, I said hello before going inside. Kranefuss was quite new in his job at that time, and, if I remember right, he instigated the chairs as a gesture of solidarity soon after he took the job.

KS

[WConley]

Trying to relate to other happenings. At one point, NASCAR thought seriously about going to 6 cylinder engines. I did some calling around and was informed that Ernie Elliot was doing testing and the guys at EEE had just received the latest head casting back from Dawsonville.

I was writing for Super Ford Magazine so I was invited over to EEE to take pictures and get info for a story. That was when I saw the new Recaro chairs.

When I was parking, Michael Kranefuss came out and got into his Cobra. Having been introduced to him at Roush's office a couple of weeks before, I said hello before going inside. Kranefuss was quite new in his job at that time, and, if I remember right, he instigated the chairs as a gesture of solidarity soon after he took the job.

KS

Michael Kranefuss started at SVO several years before I joined the company.  Yeah, that means the Recaro thing happened before I got there.  I must have walked past several of those chairs without realizing it! 

The late 80's were a fun, buzzing time at Ford.  Then the '89 Thunderbird program got too ambitious - went way over budget and a wet towel got thrown on the whole building