Two questions about an ugly valve cover

[DoctorZaius]

1995, 530i, ~120K mi

Doing the valve cover gaskets, and have two questions:

1) Do you need to change the profile gaskets? Is it even recommended? Excuse the foolish question but do they really need to have a good seal between the top of the valve cover and the plastic top cover? (Profile gasket seen in top pic)



2) What could have caused the split/twisted damage to these two tabs in the following two pics? (the tabs receive a bolt in one, and the other tab w/the bolt in it is for a Bremi coil). They are the only tabs with damage.





Bonus (third) Question: Have you ever seen a dirtier, uglier valve cover? I think if I don't replace it outright, I'll spend a weekend cleaning it.

Thanks

[Ross]

I've never seen damage like that either. Since it was a coil attatchment I would speculate that some acring was going on that burned away some metal. Looks like it exploded. Maybe an extreme case of electrolysis between the dissimilar metals?
There should be a ground strap at one of the coils. Was it there?

[Bill R.]

a galvanic reaction plus the fact that the v8 valve covers are a mag alloy so salt water or water exposure period really eats them up quick... I see this even here in the desert on the v8's all the time.. not quite as severe as that but even the gasket sealing surface on some of them is corroding away.

[Bill R.]

to use a lot more magnesium alloys, which is good in one way for lightness and rigidity but bad in other ways such as extreme corrosion on exposure to salt water... the m30 valve cover is aluminum so you never see it eaten like this. The newer bmw engines are now using this for the block alloy also, the n52 motor is mag, but the twin turbo n54 motor is aluminum, mag wasn't suitable for that power output... but the aluminum motor is about 75 pounds heavier

[Ross]

to use a lot more magnesium alloys, which is good in one way for lightness and rigidity but bad in other ways such as extreme corrosion on exposure to salt water... the m30 valve cover is aluminum so you never see it eaten like this. The newer bmw engines are now using this for the block alloy also, the n52 motor is mag, but the twin turbo n54 motor is aluminum, mag wasn't suitable for that power output... but the aluminum motor is about 75 pounds heavier

I don't want to be the guy who accidentally grounds a battery cable to one of those magnesium blocks.

[DoctorZaius]

Thank you all for the replies.

Yes there was a coil strap (see new pic below). I'm assuming it was placed on properly, but I wouldnt know. Was wondering myself about arcing or some sort of violent electric event, given the gnarly look of that tab.

Had the car 2 yrs. From PO's service records it's had a few valve cover gasket replacements. The sealing surfaces are rough in several places from bubbled up paint? In the process of stripping them down now.

The other comment about galvanic reaction is also interesting. PO was in Newport beach, me in Huntington Beach; both less than a mile from the shore. Maybe not the best environment for some metals. My new chrome wheels didn't last a full year being outside near the beach here. Dang!

I tell ya, the underside of those 'exploded' tabs are all grey powder. I can scrape with a screwdriver and get lots of loose powder; one tab would just turn to a pile of grey dust if I kept at it (Oxidized Magnesium?). Oh well. Maybe time for a trip to the junk yard to pick up a used one?

Anyway, thanks again for the comments. After I strip/sand/grind/paint/whatever the valve covers I'll post the after pics. They HAVE to look better than the before pics! What's up with that crappy paint peeling all over the place?

[yaofeng]

There should be many junked Nikasil engines out there I'd imagine it is probably easy to get a set replacement cover.

[russiankid]

This happens on M50 engines as well. As for painting; its a pain in the ass to strip the covers. Only real way is to sand blast them.

[attack eagle]

I would suggest you never ever sand blast a valve cover. if you must you can have it soda blasted (baking soda is water soluable) and then soak it and wash it in hot water.