Project ///Monster. Tear down and rebuild of 1991 BMW M5. *56k need not bother*

[Jon K]

oOMxPxOo02: oOMxPxOo02: As you all may or may not know, TheGeak, Jason, has a 1991 M5 that underwent a rather unfortunate blown headgasket. It has sat for months, dead. Seeing such a sight, we only find it appropriate to get this thing back out on the roads to destroy lesser cars... as soon as possible.

Today it began. The dreaded tear down. We anticipated being able to remove the valve cover down to the head to eventually remove the head and check for warp/crack/etc. It seemed pretty straightforward. The general consensus is that "these kids have no idea what they're doing." And, although entirely true, we're not idiots either. We've made some decent progress.





So it looks real simple, you see. Valve cover off... nice and... polluted with coolant. We nick-named the milky-brown solution "caramel apple". Looking at the cams, they appear to have good wear, nothing unusual with the valves. So we move on.

We decide promptly that the intake manifold must go, and thus the throttle bodies.




After we could see down onto the block, we could see what appears to be the area on the head wear the gasket failed. We also noticed corrosion and baked up coolant (red) in intake side of the head, soaking the valve stems in a nice... bloody solution.

Although we needed to remove about 300 hoses and a number of pieces of unknown function, we labeled everything in about 20 - 30 bags (and growing) and photographed each step so we know where everything goes. Jason got excited to see that our project was progressing, and he eloped with the ///M5.



HOWEVER, OUR PLANS QUICKLY WENT SOUR! OH NOES!



As you can see, the cams will not come out without removal of the retainers. The retaineres over cylinder 6 (E7 and A7 i believe) will not come out dude to the lip of the valve cover gasket surround overlapping ontop of them. We realized that we needed to remove the valve cover backside portion held on by 5 10mm nuts. No probl....well.... yeah there was a problem.



There, you can see that not only were Jason's motor mounts failed, but the nuts on the backside of the valve cover were concealed by the firewall being a mere 3/8 - 1/2" from the back of the engine. We used all sorts of contortionist methods with sockets to box wrenches. No luck. Then Jason got to thinking that if we could get the backside loose enough to undo the 13mm nuts in the valve/cam area, then we wouldn't even need to remove the backside to get the cams out and thus we could get the cam gears loose and the chain off and eventually the head off. The cams block the relase allen-bolts from coming up fully, because the cams are not supposed to be there to obstruct a removal, however we thought we could do it. No, we can't.

So, with little hope, I start thinking and realize that should we find the master pin on the timing chain we could drop the chain from the gears and not worry about the backside cover. However, there was no master pin in sight. So we need to move the crank. Next, I have the idea of rocking the car in gear until we can get the crank to move enough to show the master pin. This sounded like a good idea so we jacked the car up and turned the wheels in gear, only nothing happened. Then we rocked the car, and although the cams turned, it wasn't nearly enough to get the master pin (if there even is one!) to show. We had jacked the engine up from the bell housing (due to failed mounts) to try and gain space behind... no go. All seemed doomed. Then I thought "wow, we should really just pull the motor and work it on a stand." Yes, Jason and I came to the realization that it is in fact almost required that you remove the motor.



Here you can see the failed mounts. This car may be in big trouble right now, but give us time, and we'll rebuild this beast! It needs mechanical and cosmetic repair, but once completed we will see to it that it drives like new. Tomorrow (saturday) is serious time. We are lifting the engine out. What I need to know from the pro's is whether we should disonnect the drive shaft and pull the engine with the trans mission fixed or should we disconnect the transmission bell housing and such and pull just the motor. We're leaning toward the first option. Please guys, if you have any input we would love to hear it. I will be keeping this post up to date with all photos and eventually we will be writing a write-up on replacement of blown head gasket / potentially warped head, port & polish, and re-assembly. Tomorrow should be a fun time! Wish us luck!!

If anyone has any input (advice, complaints) contact me @ oomxpxoo02 on AIM or jkensy@comcast.net on email. Thanks guys!

[winfred]

i've never done a m5 but i have done several 535s, you may not have enough room to tilt the motor and get it out with the tranny atached, i generally drop the tranny then pull the motor, it saves parts and general ass pain, some cars it's not possible to yank the whole thing like a e28 535. take a good look before you leap

[MarkD]

If anyone has any input (advice, complaints) contact me @ oomxpxoo02 on AIM or jkensy@comcast.net on email. Thanks guys!

I'll post something on the yahoogroups E34 M5 list and maybe someone there can answer questions.

Mark

[Jon K]

Thanks mark

[Paul in NZ]

please tell me it wasnt sitting outside..........

[TheGeak]

Thanks Guys! Today has been quite the day. Tomorrow we're planning on taking off the whole front clip. We're probably going to have to remove the tranny with the engine, although i'm not sure of it. If i can get away with leaving the tranny bolted in then i definately will. Thanks again Jon and Wyn for the help, DEFINATELY apreciated!

[TheGeak]

it was, but it was covered. Now its sitting in my garage!

[MarkD]

I posted something so hopefully you get some help.

In the meanwhile, look at this link:
http://www.bmwe34m5.com/faqs/?theme=...nt_id_select=3

Read the pdf and you will see that somehow it's possible to remove the head without taking the motor out. (but in the end it was taken out as they found a crack in the block.

Mark

[TheGeak]

MarkD: I know its POSSIBLE its just not "easy"! especially not with 2 shot motor mounts :'( I think i'm just going to pull the engine tomorrow....that way i can get a better look at everything i need to clean/replace/repair. Hrm, maybe i should have my engine bay painted while the motor is out *gets to thinking*

[winfred]

the core support unbolts easyly, the only issue is breaking the ac system and loosing the freon if you don't have access to a recovery machine, if it's r12 that's over $160 in freon or about $15 in r134