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07-30-2009 02:59 AM #1
Pulling the head off my '91 735i tomorrow
I was pretty active here (thanks to everyone) up until 9/9/2005 when my head gasket blew (oil in water). I towed it to my garage where it's sat since (my mom quit driving and I commandeered her Buick)
Got a new battery Sunday (had a Sears 10 yr warranty) and clicked it over once to make sure it wasn't frozen shut before atempting to proceed - seemed OK.
I believe I have everything clear and labeled with hardware in baggies with labels. I can slightly pick up the head with the intake and exhaust manifolds still on (not quite as heavy as I imagined).
Have a Bimmer friend coming over 10AM (HST) tomorrow to lift it off - we have a plan for getting the timing chain around the plastic guide - at least we think we do.
Gonna take the head to a retired BMW mechanic who's excited (hasn't seen an M30 in a while). He'll make a diagnosis and plan on what I should repair / replace on the top end.
Don't have plans to do much to the bottom end if I don't have to?
Don't even plan on pulling the pan, but maybe if I have time (it didn't leak before).
I hope to have all the parts ordered by Friday.
I have a 12 day window here to get her running and registered.
Things still look nice under the hood - it was always cleaner than the body :)
I supplemented Bentley with Jon Evan's write-up, Gale's pages for various items and the link to the e38.org write-up than Shogun posted somewhere - thanks again to this board.
I'll keep y'all posted on what I end up doing once the head's off.
07-30-2009 09:09 AM #2
07-31-2009 07:02 PM #3
I'll be lucky to get it done in 12 more days...
My friend managed to climg in stradling the engine compartment (a slipper on each fender) and just picked it up the head and handed it to me - not recommended, but we didn't break the plastic timing chain guide :)
My head does not look easy to repair and I learned that someone before me shaved it already once (stamped 030). There's corrosion in the path from the water inlet to the cyliner closest to the firewall - you can see it's way cleaner than the rest! It didn't really even "blow" the head gasket - the water just got around it from the corrosion channel. It also was warped slightly looking at it with a straight edge (across short side - looked fine end to end.
On the plus side, my retired bimmer mechanic friend took a good look at the cam / rocker side parts and thought everything looked good.
The bottom end looks good too, no evident scoring on the cylinder walls (again - one much cleaner from the water bath.)
The same friend who lifted the head out with me happened to have a "spare" blank M30 head (same stamp). It looked in good shape and had never been shaved, so my plan was to take that blank head to the machine shop this morning to have it tested, cleaned, planed and welded in one spot on a water inlet where some corosion had begun.
Problem is I just got a call from the machine shop that they found a crack on the rocker arm side up above where the cam shaft sits. He thinks he can weld it - he'll let it cool and pressure test it again today.
Just it case it doesn't pass the pressure test, I'm working on scrounging up potential back up plan heads till I hear from the machine shop.
I also should get a new upper timing chain cover I believe. The one from my car was shaved down with the head. Seems a shame to shave down the new head just to line up with the old cover or just put extra sealant?
My mechanic friend thinks he has a upper chain cover for a '91 735i in his garage somewhere. BMW dealer wants $250 or a used parts store wants $125.
So, once I get a decent head, I'm hoping it will be downhill, we'll see. My drop dead date is Aug 12th 3PM to have it registered, insured, safety checked and on the dock.
Any other tips, tricks or moral support welcome.
I'll update once I think I have a good head and have the valves, cam, rockers etc swapped from old head to new.
08-01-2009 01:46 AM #4
Re: I'll be lucky to get it done in 12 more days...
Looks like I've got a decent head ready to go.
Machine shop welded, pressure tested and planed it - I pick it up tomorrow.
Now I have to figure out how to swap the parts from my old head to the new blank (Cam, Rocker Arms, Shafts, valve heads/stems/seals).
Should be a fun weekend. I hope to be ready by Tuesday when the new head bolts and gaket set come in. I even broke down and got 3 new MAF rubber seats/clips from the dealer - ouch!
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