Lower chain case install reassembly advice needed.

[DanOKC]

My love/hate relationship with this E30 continues. Had a problem with head or headgasket, so pulled the head to find head was warped. About 6 thousands between 1,2,  2,3, 3,4. Just got it back from machine shop. They took 10 thousandths off, no cracks in head.  This is my second M42 to tear down this far, but only my first to put back together. Previous experience was mostly M10's from many 2002's I've owned & 1 M20 from a 528e I had. IMO, the M42 in this E30 is more of a PITA, at least the front cover/chain case.  Broke 2 exhaust manifold studs on this car & the one before, just removing the exhaust. So this car got 4 new exhaust studs. Thought the broken studs would be pain to remove, but with a vise & a hack saw & a drill, they came out rather quickly. Which was sorta fun, gave me excuse to get out the mig welder, that I've barely used since buying it 10 years ago. Then I thought maybe I'd not remove the lower chain case, but decided since I had the gasket set, better to do so than not.  Now I'm realizing when I pulled the upper pan a few years ago, I just used gray permatex to make a gasket instead of using a factory gasket. I thought I was ready to reinstall the lower chain case, but realized the permatex gasket would be an issue, not likely I'll get a good seal since the case has to slide in on top of the upper pan. So now I'm getting ready to drop the pan again & this time will use a gasket instead of just permatex ultra gray.  I have one other lower case I bought for the other car, before hail storm totally wrecked the body. I wasn't smart enough to get the later style case without the idler sprocket then. So I am comparing the two after cleaning up the lower case. They both have a bit of corrosion around the profile gasket area. I'm guessing this is somewhat normal for a 150K to 200K motor ?  My main question, besides advice on re-assembly do's  & dont's:  Is permatex gray  or non hardening blue hylomar around that rectangle area in the center a good idea on both sides of the profile gasket or just on the lower chain case side ? It appears there was a yellowish sealer of some kind in this area when I pulled the motor apart under the gasket.  This zoomed in pic makes it look a bit worse than it is, there is still a ledge all the way around, just those 2 areas near red lines are lower.

[bmwman91]

I have used a little bit of Permatex Ultra Black on that gasket before and it didn't hurt. The gray is OK too, but it gets sort of rigid over time. I'd say that something that remains soft, or is non-hardening, is a decent idea. Just make sure that it is safe for use on rubber gaskets.

[DanOKC]

OK thanks. Now my next issue. I now realize the new passenger side guide rail has a bigger pivot bolt than what the original did. On realOEM, they list the same part # on earliest M42 to later M42 that uses the newer timing cover. Part # 11311721322  If I order that #, I should get the newer bigger pivot bolt, correct ?

[bmwman91]

Hmm, I didn't know that changed. Yes, I suppose that you should get the updated parts that go with it.

[DanOKC]

Part did not change, I just figured out I ordered the M44 part    So I have the correct guide rail on the way. Doh !

[DanOKC]

So about 4 weeks from start to finish. About 2 of those weeks for the machine shop to do their part. I've had plenty of M10 experience, with regards to pulling cylinder heads & taking to machine shop or just pulling head & replacing gasket etc... Did it once on an M20. Both M10 & M20 have much simpler front timing case of course. So to me, the M42 is much more to deal with in that area.    Plus I had to account for time to pull upper pan again to install a gasket, as I had removed it before right after I got the car & just used silicone to make a gasket. I didn't get fancy & clean the intake or valve cover & paint them like some do, but did spend a lot of time cleaning grease/oil from external covers. Replaced the O ring on the oil filter housing, replaced the oil pump regulator/valve thing, whatever it's called with the updated plastic version. Made sure to prime the oil pump & verify I was getting oil to the head before putting valve cover on & installing plugs. Closer examination of my profile gasket shows it was deteriorated in a few areas. Head was warped but not cracked. I did not go for the thicker headgasket, 10 thou taken off of head, no valve guides/seats or valves needed to be replaced. Near the end I cheated & used just ultra grey for top front timing cover. Did not want to wait on another parts order. So far so good.  Now back to my list of things to do for this car before it started pushing water out with pressure from the combustion chamber.   It never mixed oil/water. Would idle on the driveway for 30 minutes & not loose water. But if I drove it around, it could loose water within 20 minutes or so. At times you could see the pulse of the motor idle pushing out of the radiator with the cap off. So I think combination of head warp and profile gasket leaking a bit or maybe just head warp let it pressurize the cooling system so bad it pushed out water. Here is video of it's first start, you can certainly hear the clank from the valvetrain until the oil pumps up the lifters.
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