Valve Cover Grommets

[RubyRed300ZX]

Replaced the valve cover Grommets 3 years ago when replacing numerous gaskets, hoses, sensors, etc. Probably only have less than 2,000 miles on the car since then. Just tore it down again because of a nasty oil leak. Started leaking last year actually. With a mirror and flashlight between the block and the firewall, I knew it was the intake valve covers. Found this:







These were all torqued to spec when i put them in the last time. Actually inserted a screw driver tip in a torque wrench.

Anybody have any words of wisdom on keeping them from cracking again? Or perhaps an alternative to using the grommets?

[DCaff300ZX]

Wow, that's not good at all.
I know that my Z guy didn't use those type of grommets on mine although not sure what he did since there doesn't appear to be a big rubber ring like yours pictured on my engine...perhaps just a thinner rubber washer under a similar sized metal one, as the seal for the cam cover is not from the screw hold down other than sealing the hold down hole and screw. The ones on yours seem unnecessarily fat for the job they do, and seem prone to the damage they have just from tightening.

[itsa300zx]

BDE makes a bolt kit for the intake valve covers that eliminates the rubber washers, about 50 dollars though.

http://www.bde-performance.com/arp.htm

[RubyRed300ZX]

The grommets aren't actually round (doughnut shaped) as new. These are the OEM grommets. I guess my question was more a matter of why the over engineered fastener and grommet. I definitely will use something else this time around though. Went back to check my receipts from the last time. New ones I just got in ... bought them from the same supplier, same manufacturer, same part number ... and it is the Nissan part number. As for the $50 S.S. bolt kit being expensive (post above), I was quoted $9.78 each from a local Nissan Dealer ($9.78 X 16 needed = $156.48 for f-ing grommets). Several places selling these for $3 to $4 each. I paid something like $1.13 for them. They are actually molded around a metal sleeve with a washer type base. All of which gets flattened when they are torqued to spec.





When I say over engineered, this wasn't overly expensive on behave of Nissan in the entirety of a full car assembly cost; however, it was certainly more expensive than merely an off the shelf fastener and washer. Look at the shoulder and relief they had turned up at the head:



What puzzles me is why? The rubber seals nothing. These are on the intake cover which gets a rubber gasket. The gasket is perhaps 3/16" thick and loops around the fasteners; thus, no issues of sealing for oil:



Z1 sells a Stainless socket head cap screw and aluminum washer set for $22 which is about than what i paid for the grommets: http://www.z1motorsports.com/popup_imag ... imageNum=1

They state you need to use loc-tight with them. I'm assuming they mean the blue. Not sure the anodized finish for the washers is all that necessary considering nobody will ever see them buried under the plenum. All of this was just A) a curiosity as to why all the engineering for a valve cover fastener; and B) looking for a solution that doesn't require a plenum pull and grommets every 2 years.

Just looking to see what others have used. I'm thinking at this point just stainless steel socket-head cap screws and a washer, with loc-tight. Though, the Z1 aluminum washer might be a good idea to avoid problems with corrosive welding.

[DCaff300ZX]

I agree that going with the Z1 kit sounds like a good idea, and an aluminum washer since the covers are aluminum. The rubber part does seal against oil escaping past the fastener which is exposed to the interior, but somewhat unlikely at the top of the cover and also prevented with the washer you mentioned.