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Valve cover gasket?
Posted: Wed Aug 05, 2020 4:19 pm
by canada karl
What kind of sealant do you guys use on valve cover gaskets/ Blue Hylomar? ...Permatex?...nothing?...On the block side or cover side?

Re: Valve cover gasket?
Posted: Wed Aug 05, 2020 6:34 pm
by 528i-1981
I didn't use any dressing or sealant, just a new gasket and made sure both metal surfaces were clean, and coated with a light layer of fresh oil with a fingertip.
You probably know this, but I tightened in the order shown by Keehn incrementally, making a few passes in sequence. I ended up at no more than 25 ft-lbs. I also made note of bolt lengths and locations as I removed them after I noticed on RealOEM that my '81 has six 40mm, one 30mm in the front and two 55mm with bushes.
If you've never done this before on an M30, double-check that the bolts are actually passing through the matching holes on the gasket before starting the tightening. You can pinch and ruin the gasket ... or worse, not notice until later.
Re: Valve cover gasket?
Posted: Wed Aug 05, 2020 8:58 pm
by Mike W.
Technically you're supposed to use just a dab of something on the head side where the head and upper timing cover meet, but no need for anything besides that. And they seal pretty well, but are IMO definitely a one time use item. Unless you enjoy the aroma of oil leaking onto and burning off the exhaust manifolds.

Re: Valve cover gasket?
Posted: Thu Aug 06, 2020 6:39 am
by canada karl
Ah yes I'm familiar with that smokey aroma.

Re: Valve cover gasket?
Posted: Thu Aug 06, 2020 6:41 am
by canada karl
528-81 Good to know about the different bolt sizes

Re: Valve cover gasket?
Posted: Thu Aug 06, 2020 6:53 am
by keehn
Karl,
Just the ol' plain torque seal is needed
Mike is correct with using gasket sealer on the front, where the head and front timing cover meet on the metal surface (below the gasket itself). To use, just put a small dab on, press it down a bit, but let it then sit for 5-10 minutes to begin curing before installing anything (this varies among manufacturers/products). And, heed the warning by Eric! Hunched over an engine bay can lend one to rush jobs like these and end up making something small...something much larger (e.g. broken stud).
Then, place the gasket on top, ensuring it has free play up and down on the thread studs, then place the valve cover on that. Begin tightening down the centermost nuts first, and then working in a clockwise (or counter...doesn't really matter) manner, tighten down the remaining nuts. I believe they need to be 25 inch-pounds...not much!
What I do is I hold the ratchet almost on top of the ratchet head when tightening the nuts down. This prevents me from over-torquing when I'm not using a torque ratchet, as I can't "muscle" the ratchet. I then finish by going over each nut one more time, but "feeling" for no more movement on any nut.
To "feel" whether a bolt/nut is tight or not takes practice, but, if you tighten down either in stages, you'll eventually find there comes a point where the fastener no longer moves with the relative torque you've been using. This is especially helpful when tightening head bolts, as slipppage and/or compression can give false torque readings on the first pass.
Re: Valve cover gasket?
Posted: Thu Aug 06, 2020 11:24 am
by canada karl
Thanks for the info.

Re: Valve cover gasket?
Posted: Thu Aug 06, 2020 4:57 pm
by 528i-1981
inch pounds. Not pounds-feet. And now I recall I did use a little Gasgecinch or something at the timing cover. Always good to crowdsource your info!