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



Jon K
03-05-2004, 11:42 PM
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.

http://www.orbitalinternet.net/projectM5/day1/1.jpg
http://www.orbitalinternet.net/projectM5/day1/2.jpg
http://www.orbitalinternet.net/projectM5/day1/3.jpg

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.

http://www.orbitalinternet.net/projectM5/day1/4.jpg
http://www.orbitalinternet.net/projectM5/day1/5.jpg

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.

http://www.orbitalinternet.net/projectM5/day1/6.jpg

HOWEVER, OUR PLANS QUICKLY WENT SOUR! OH NOES!

http://www.orbitalinternet.net/projectM5/day1/7.jpg

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.

http://www.orbitalinternet.net/projectM5/day1/9.jpg

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.

http://www.orbitalinternet.net/projectM5/day1/10.jpg

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
03-05-2004, 11:53 PM
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
03-06-2004, 12:04 AM
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
03-06-2004, 12:06 AM
Thanks mark

Paul in NZ
03-06-2004, 12:46 AM
please tell me it wasnt sitting outside..........

TheGeak
03-06-2004, 12:49 AM
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
03-06-2004, 12:50 AM
it was, but it was covered. Now its sitting in my garage!

MarkD
03-06-2004, 12:56 AM
I posted something so hopefully you get some help.

In the meanwhile, look at this link:
http://www.bmwe34m5.com/faqs/?theme=1&level=4&question_id_select=329&chapitre_id_select=38&document_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
03-06-2004, 01:00 AM
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
03-06-2004, 01:02 AM
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

Paul in NZ
03-06-2004, 01:05 AM
well good luck guys....i wish you all best and i hope the m5 is running well soon.How many miles has she done

bighc2000
03-06-2004, 02:05 AM
You guys will make it.

TheGeak
03-06-2004, 03:03 AM
Thanks for the words of encouragement guys!

she's at about 96k miles right now. I'm doing a Port & Polish while everything is off. We'll be taking lots more pictures tomorrow to document the whole thing. Hopefully everything else is going to get an acid bath to clean things up a bit. Also i'm going to get a valve job, MAYBE some 3.8 Euro cam sprockets, and hopefully a few other tasty tidbits. More Pictures and a complete write up web page will be to follow. expect lots of posts and queries about things in the next few days!

Thanks Again!!
Jason

Unregistered
03-06-2004, 04:15 AM
Hello, I'm facing the same problem as you (the difference is that my water has not yet mixed with the oil), and finding information about how to fix it. The following link has nice information from a guy who also did it in the past.

I wish you luck with it. I know it is not easy but if you work with a lot of order and discipline it can be done.

Ramon


http://www.austintx.net/echristie/M5/Projects.htm

George M
03-06-2004, 07:37 AM
taking on a head gasket change for the venerable M5 motor with all its complexity. You will get there and sounds like you are doing a good job of thinking things through. Couple of comments...as I plead ignorance with the M5 engine as well...but have done a couple of M-30 engines.
Don't believe it will help to remove the rear cam cover. Even if you get it off which is a chore but doable on an M-30 engine, don't think it will help much as you are severely limited by space in the rear of the head. I would strive to remove the cams without pulling your engine however. Pulling the motor escalates the difficulty of the job to another order of magnitude so if you can get the head off without, you will save a lot of time. The cams should come out with the head in the car...not certain of this but looks like it.
Why can't you remove the front upper timing cover and slip the front timing sprockets forward to free up the front of the cam?...this is the practice used on the M-30 engine. Most likely there is no master link for your timing chains.
One option before you cut a chain which is another viable option is to find out if a master link replacement chain(s) are available for the M5 engine as they are for the M-30...so another option may be to cut the chains but believe it is a whole lot easier to simply remove the front cover and unbolt/slide the timing sprockets forward.
Anyway...nothing definitive but a couple of thoughts. Mostly rung in to wish you well and give you credit for taking it on. You will learn immensely from this experience and the reward at the end will be very satisfying.
Good Luck,
George

donati
03-06-2004, 07:39 AM
...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.


Hi
I had to take the head of my 3.6 last year (broken valve).
The cover on the rear of the cam-tray can come off without taking the engine out. I used a standard 10mm wrench.
There is not much room, but it can be done with patience.
The bolts on that cover is probably the hardest part of the entire work.

I think i mentioned it to Jason in another forum, but no harm in mentioning it here too :)

TheGeak
03-06-2004, 08:48 AM
Thanks again guys. I considered all my options and decided that it is probably in my BEST bet to pull the engine. Yes it will be more work and YES it will make things much more complex but i think overall it will be worth it. I have a place where the car can stay with the engine out 'as long as needed' so i can take my time and do things right. I figure the engine will be MUCH easier to reassemble on the OUTSIDE of the car and the drop it into place as well. Plus this way i can make sure that everything that needs replacing will be replaced.

Well, i'm off to begin today's adventure. Look forward to a whole post and writeup of the situtation. Possibly a webpage with all of the pictures and a more detailed description of what went on.

Cheers!
Jason

Jon K
03-06-2004, 09:31 AM
George M.,

Our problem is on about 3 levels. We can't remove the cams cover because the are 7mm allen key bolts beneath and around each cam lobe. We can't get the bolts out becasue the lobes will not let the bolts back out enough. The 13mm bolts on the back inside of the cam cover are in such a position that we cannot turn them with an open wrench. The 10mm on the backside of the engine are in such a position dude to broken engine mounts that we cant get a wrench back there let alone see. We jacked the bell housing up, it alleviated it some.. but still too awkward because we also have to get these things back on! I think pulling the lump is going to be our best effort. Thanks guys for encouragement and reassurring us that we are, in fact, insane.

George M
03-06-2004, 11:54 AM
pulling the lump, though more effort will pay dividends as you say. If you pull it out...I would find an engine stand, bolt it on and go around and change all the gaskets...including the oil pan and all the front of the engine gaskets etc. Personally, I would replace the oil pump, timing chains, water pump...all new fuel line hoses, get the injectors ultrasonically cleaned while apart etc, etc. As to gain more clearance to the rear of the motor...this can be surmounted by putting a cherry picker on the motor up top...which you are going to do anyway to pull the motor, disconnecting the exhaust manifold from the CAT, undoing the trans bolts and scouching the motor forward in car...spacing the motor forward with a primitive wooden spacer...don't have to pull the motor out for access to behind the head, the rear bolts etc...only scoot the motor forward a bit more in the car with the trans attached. By disconnecting the trans, and pulling the engine...quite a bit more work, that's all, if it isn't your intention to rebuild the bottom end...only reason I would pull the motor. If you go to the trouble I would do all the stuff above at least. Also I would take a large complement of pictures of the cam positions, timing sprockets etc with the motor on no.1 cylinder before you remove the cams.
Good Luck either way,
George

MBXB
03-06-2004, 12:17 PM
Jason,
How bout you throw up a webcam and broadcast on Yahoo or something.
This could be the first M5 collective web teardown! Anyone tuning in could throw in their2 cents and pop a beer.
MBXB

Jon K
03-07-2004, 12:39 AM
MBXB, Don't laugh, i've considered.

mike wong
03-07-2004, 01:00 AM
it will be so sweet when you're done.

MBXB
03-07-2004, 02:13 AM
I was serious, man!!


MBXB, Don't laugh, i've considered.

Jon K
03-07-2004, 02:42 AM
I was serious, man!!


Problem is, no broadband @ the garage... I have my PCS modem but its only 144kbps and will be done with 5 people viewing

Jon K
03-07-2004, 02:43 AM
Part 2 is available (http://www.bimmer.info/forum/showthread.php?t=1615)
Problem is, no broadband @ the garage... I have my PCS modem but its only 144kbps and will be done with 5 people viewing

TheGeak
03-07-2004, 11:33 PM
Part 3!

http://www.bimmer.info/forum/showthread.php?t=1638