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New BMW Owner

Discussion in 'E31 (1991-1997)' started by phoenixop, Apr 11, 2015.

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    phoenixop

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    Garrison;
    Love the exhaust falling off. "I don't care who you are that was funny" to quote Larry the cable guy. I'm going to try the emissions as is, will probably fail, but ya gotta start someplace. I've got some extra time cause I can't drive the car. (Driveshaft). I found a complete photo tech thing on changing the cables when the seat does the twist, so I'm prepared for that. In addition to the serious stuff, driveshaft, surge, chronic check engine light (good call by the way), ABS and EDS issues, there is a plethora? of little stupid things that are just the result of a lack of care. I have 3 pages of note paper full of fixes. The only bright spot is I kind of stole the car. Believe me, I would have hated to buy anything with these same issues for more money. Trust me, they're out there because I think I found them all when I started looking for an 850. At one point I was thinking about an 840, but it's just not exotic enough and I guess I needed more punishment. But I do love the thing...

    I'm gonna try every trick I can to diagnose it's issues, so keep 'em coming. Again extremely appreciated.

    Here is yet another example of previous owner stupidity. Someone broke out all the vertical vanes in the center dash vent assembly. Really?

    Oh well...
    • Member

    MGarrison

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    No doubt the V-12 is cool, 300hp, and if it's running right, as Charlson said, super smooth. At the '92 'CCA annual O'Fest, which was in Florida that year, one of the execs who was a former BMW pro racer (& dang if I can recall his name at the moment) drove down in a manual 850csi, which was added into the pool of vehicles O'Fest attendees could test drive - was lucky enough to get a test drive in it, awesome vehicle & a memorable, though all-too-brief drive. You can't argue with the looks of the 8's, but, yes, as a tech. tour-de-force icon vehicle for BMW at the time, it also comes with just that much more potential issues - a plus is that there are enthusiasts out there familiar with them, and since they've now been around for quite awhile, there's less chance you'll have something arise that's a total mystery or that no one's ever heard of.

    Broken dash vents, blah. You have to wonder what someone was up to on that one. Something else to be aware of though is that German plastic doesn't seem to age well, tends to get brittle - be careful disconnecting wiring harness connectors or plastic plugs, especially underhood that have been subject to engine heat soak, you might find them breaking or crumbling in your hands. One upside is that BMW is pretty good on supply of stuff like that (plastic plug fittings) until you get to cars earlier than the 80's.

    The exhaust story - the first set of headers I put on my E30, they weren't made with mounting flanges; I didn't do that kind of work on my car then, so my mechanic's speedy solution to mount the exhaust system after getting the headers on was to cut the mounting flanges off the front of the cat and literally whap the cat pipes on over the header pipes. That was ok for awhile, but the couple of times the exhaust had to come off, boy did it take a lot of hits to knock the cat free from the header pipes. Think baseball-bat type swings with a 4lb deadblow mallet. The last straw was when I rounded a corner downtown one afternoon and all of sudden BRAAAAAAAA! along with, you know, a rather loud metal scrapin' noise - pulled off to the side and a quick look underneath, the cat's separated from the headers, is on the ground, and the only thing holding the muffler was the rear hanger (it was summer, but I was only in shorts, t-shirt, & loafers that day; still better than dead of winter though). I can't remember if I dug the 10mm wrench out of the trunk toolbox or screwdriver, but I either quickly unbolted the 10mm hanger bolts or used the screwdriver to free the hanger doughnuts, and threw the whole exhaust system in the trunk, cat end dangling in the air. Drove straight to my mechanic buddy at the fab shop where he worked and handed him the whole setup to work up some sort of flange connectors - didn't have something else to drive, so had several days there of driving around minimally with no exhaust whatsoever (thus the less-than-pleased neighbors). The flange setup worked ok for awhile, but leaks were always a problem, as having to use custom-cut gasket paper between the flanges, it would tend to blow out. Those headers were eventually trashed, since being replaced with some Bav. Autosport headers - still no flanges, but their lower pipes are sized to fit the headers, now held on with exhaust clamps. Hopefully little chance of the same type of failure previously experienced - so far, so good! :)

    One more random thought - sometime when you have it in the air, take a good look at the metal fuel & brake pipes on the underside of the car and confirm their condition. If the car's seen salt/winter exposure, going on 25 yrs, you want to ensure no rust bubbles indicating an imminent problem. That stuff is a nuisance to replace, but if it hasn't lived in winter climes, is probably fine. Kinda hate mentioning it, but @ 166k, wheel bearings might come up sooner rather than later, but there's a chance they've been done already - deal with the other stuff first, wheel bearings are easy enough to check and unless obliviously ignored, will likely give plenty advance notice identifiable by typical wheel-bearing noise.
    • Member

    phoenixop

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    When I was doing the worm to spot the now invisible fuel leak I did see that the exhaust flanges were there. Fuel was dripping off them. Today, I pulled the front wheels to get a grip on the brake situation also to see if anything else was disconnected/missing. Pads & rotors seemed fine except I noticed the drivers side caliper seemed to have a bit more grip on the rotor than the passenger side. Right side just spun quite easily. It's like the caliper on the left isn't releasing. Anything model specific, or just a pull apart and throw some anti-seize on the areas where the calipers slide on the support for centering the caliper? It may need to just loosen up.

    I'm kind of tempted to go through everything under the car and what needs replacing just replace it, then of course there is real life. This is not nor will it ever be a 100k 850. When I took it to the dealer, both the mechanic and service writer told me these things have been known to go for a hundred k. That I'm thinking would be a 20 mile car with impeccable service. This ain't one of those.

    I was always under the impression that 850's were the first and only v12 BMW did, but I guess the 750 preceeded it and something later, but I don't know what.

    I keep looking at it trying to figure out why it literally weighs more than the '67 Buick sitting right next to it. There's no frame to speak of, the engine is tiny, cubic inch wise, their both autos, both power everything, a/c, etc. I keep thinking how cool it would be to rip about 800 pounds out if it, drop it another 2", jack up the hp to about 650-700 at the wheels, wow, what a blast that would be to drive. All that sex at 200+mph. Cool...

    Speaking of blasting, I understand these things are governed to 155mph. Has anyone found a way to bypass it or is that a matter of re-writing the code?
    • Member

    MGarrison

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    Yes, clean & re-grease the caliper slides - I would say pins or bolts, but they're not exactly either. If the car sat for awhile unused, some possibility for rust or pitting/corrosion of the caliper pistons (rebuild kits are cheap, dust boots for each piston and a sealing ring for each piston). Point being, also possible for a stuck, or partially stuck piston. If the brake fluid reservoir isn't over-full, you should be able to push in the piston(s) from one caliper without backflowing the reservoir. If a piston is badly rusted, pitted, or corroded, then new/rebuilt calipers are a good idea. Again, shopping around should be able to source for less than full dealer retail (don't forget some dealers have 'CCA members parts discounts, including some that advertise in Roundel, my local dealer offers 10% off retail, but other aftermarket sources may also be less, sometimes a lot). I wouldn't be surprised if 850 calipers were also used on 7's, presumably availability wouldn't be a problem. If they're cross-compatible (use realoem.com & search the part number for applications), might be possible to source good used calipers from ebay & elsewhere, if you eventually find you need to replace a caliper.

    Sounds like you got plenty to start with - get what needs fixed to get it rolling, so you can get an idea what else it needs before just throwing money at stuff (tempting though that may be!) ;).

    BMW engines at that time tended to be on the overbuilt/understressed side of things - with normal usage, no overheating, and keeping oil in it and up on the basics, (basically no blatant abuse), the basics of the engine, far as I know, ought to run for a long time before the bottom end or cyl. heads might need much attention. I'd guess likely to suffer an oil pan gasket needing replacement well before anything else at the bottom end, barring M70-specific issues I wouldn't be up on. The iron-block aluminum-head large straight-6 M30 engine, with maintenance as it went & not abused, could run 300k-400k without major bottom or top-end work. Finding a low-mileage E34 was always a challenge, driver's didn't seem to give 'em up until they got to 200-250k. BMW built a reputation for longevity off its cars of the 70's & 80's; new ones I think will run ok to the 200k range, but I think getting them there or beyond might end up being a lot more expensive over 100k than the old bimmers. Time will tell!

    Yes, heavy - lots of sound/cabin insulation all over that car I'm sure, and no doubt every nook & cranny stuffed full of control modules, wiring, and everything else. I think the M70 v-12 came to the U.S. circa '88 in the 750i & 750il. The v-12 designs evolved - M73, N73, & now turbo N74. The sohc version that is yours might not have the efficiency and power potential of the later ones with valvetronic, 4-valves per cyl., etc, but, the simpler design means less maintenance headaches long-term, with the others over time having all kinds of additional stuff needing attention.

    A standard modification back in the day was replacing the control chip in the ecu with a performance version - the E31 community out there should have a word on what's available on that front. Might be less options since 850's were so much less in production numbers. Don't know what all folks have tried for upping hp on V-12s; I imagine rebuilding the motor with bigger displacement & cams, headers, bigger throttle bodies, higher capacity fuel injectors, perf. exhaust, honed/enlarged intake runners, larger maf's, all that might stand a chance to get you closer to 400, and going from there it would take turbo-charging or super-charging. And, unless you have your own machine shop, doing all that would cost an order of magnitude, probably several times over, what you paid for the car! Not that it wouldn't be FUN, but - it would be expensive!

    Fuel running down exhaust headers can't be good, obviously a fire risk and a no-brainer to have that on the priority list!

    Whoa, that was lucky - sidenote, must have had a frickin' power surge that reset my surge protector, computer shut off with no warning, thought I'd lost everything written above, looks like firefox kept it in memory & salvaged the post after I rebooted & re-started firefox - sheesh!
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    phoenixop

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    It must be computer glitch night. I just finished typing a whole bunch of stuff, I blinked and was back at the login screen. So I'm keeping this short and sweet.

    1. The build sheet for my 850 says and I quote, "theft alarm system with ZV" WHAT IS ZV?

    2. I need to get it up on 4 jackstands. I think I can get the back end up by putting the floor jack under the differential support. It's the front I don't know about. Any ideas would be appreciated. I'm hoping for a cross member or something. It seems to be a unibody car so no frame. Wow, I miss frames...

    HELP, HELP...
    • Member

    MGarrison

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    Sometimes I get caught out on the nature of flash-based reply boxes; If you find yourself getting something written that's getting lengthy, or know you will, it's best to write it in a word processor (or notepad/wordpad, for something simple in Windows pc's,) and then copy & paste it into the reply box - then no chance of getting logged out while writing the reply, etc.

    I have no idea what ZV is, sorry!

    Unibody BMW's tend to have strengthened areas somewhat inboard underneath on the front that stick out, that's one potential jacking spot - you don't want to jack on the floorpan though. If there's a lot of underbody cladding, they might not be so easily seen. Not sure on the 850, you might see that there are some reinforced areas along the sills where the factory jack fits - cupped jack pads can squish vertical sill ridges, if you opt for the stock jack sill points, a flat jack pad with some sort of durable cushioning isn't a bad idea, I was lucky some years ago to acquire some 1.5" thick rubber that's about perfect for a supplemental jack pad. I've heard of folks using hockey pucks for jack pads, I discourage anyone from doing that ever since I had a friend's wife at a track event explain that she broke her toe changing brake pads when the car dropped down onto the jack after the hockey puck she was using as a jack pad unexpectedly broke with no warning.

    From post #34 in this thread - http://www.bimmerforums.com/forum/s...-steering-in-your-E31&p=24741278#post24741278

    At the top of this picture, the swaybar mounts and those black brackets are mounted to the BMW unibody equivalent of frame rails - the rails are beefiest just aftward of the bend, where they level out.
    [IMG]

    This is looking from the front towards the back - doesn't look like they're buried by underbody cladding, if you look under the car from the side behind the front wheels, you should be able to see them easily. My E30 is similar, that's what I tend to use to jack up the front, one side at a time.
    [IMG]

    The rear, yes, you can jack on the diff, it's far enough under sometimes it can be a little hard to gauge if you have the jack positioned correctly. You don't want to go nuts on it, but I've never had a problem carefully jacking (1 side at a time) where the front part of the axle-carrier mounts on the similar part of my E30, #'s 1, 2, 4, & 6, on the left side in this diagram: http://realoem.com/bmw/showparts.do?model=EG23&mospid=47335&btnr=33_0196&hg=33&fg=30

    The axle carrier/rear subframe might be the best thing to get jack stands on, the E31 setup looks a little cluttered - if you jack on the diff, that might leave more room for placing the jack stands - might be that if you jack on the subframe mounting points, those, or maybe on the subframe arms the subframe bushings go into, are the best/most secure spot to place the jack stands, and having the jack right there doesn't allow you room to get the jack stands in place. You'll see space clearances when you get a look-see at it.

    The other rear axle diagram: http://realoem.com/bmw/showparts.do?model=EG23&mospid=47335&btnr=33_0198&hg=33&fg=30
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    phoenixop

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    They're kind of like most unibody cars, like the mini coopers I used to own. 8 at one time as a matter of fact. Front and rear sub-frames. On a mini we could swap out an engine and trans in under an hour from key off to key on because of sub frames. Mopars are the same way . Drop the k - member in front and the whole front suspension, engine and Trans comes with it.

    850's on the other hand don't have sub-frames in the true sense of the word. They seem to have sandwiched stamped steel assemblies that are stressed in only certain ways and in certain directions. Last night I Google'd "how to jack up a BMW 850". Wow you should see all the stuff for sale. Which is mostly what comes up. It also doesn't seem to be just 850's with this problem, most if not all BMW's have this problem. One thing was a gizmo that goes into your jackhole? and has a flat plate on the end to put your floor jack under. Seems like a good idea. I have round wood pads on my floor jack with 1.25"w x 3"L x 1"h wood blocks on top. The floor jack doesn't touch the plastic body part, besides if they break I can make a million of them. I was just hoping for a cross member I could just stick the floor jack in the front dead center on the car, jack the whole front end up at once evenly, stuff the jack stands under the two front jackpoints, drop the floorjack, run around the back, jack up the whole rear of the car, put jackstands under the rear jack points and there you are. But no...

    To add insult to injury, the Buick has a cruciform frame, which is essentially an X. So it has similar jack points to the bmw. It also has a two piece driveshaft with a cv joint coming out of the rear of the center support and another at the differential. Kinda like the BMW

    Driveshaft Specialist of Texas is the only place that can rebuild and balance a '67 buick driveshaft and do it right. I'm having them do the driveshaft in the 850 also.
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    MGarrison

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    Yes, not exactly clear from realoem.com if it has a front subframe AND a x-brace extra support, or if the x-brace (wishbone in the realoem front axle listing) replaces the front subframe (front axle support in realoem.com). If there's a front subframe, jacking on that should be fine - I can only guess whether the x-brace can take the weight of the car without deforming if it's only that and no front subframe. From the diagrams, kinda looks to me like the x-brace doesn't look like it has plainly-seen engine mount bushings support areas. Even though BMW calls the front subframe an axle support, it's also what supports the engine. In any case, once you do get it up on jack stands, you'll be able to see it all better. http://realoem.com/bmw/partgrp.do?model=EG23&mospid=47335&hg=31&fg=05

    I'm not sure which model they started with the separate jack supports that mount into reinforced jacking holes, I don't think those are on E31's, and it would be obvious if there were - you'd see 4 circles on the lower sills, two on each side, and the cars that have them have pop-off covers.

    Good luck with the starting projects, sounds like you got enough to keep busy for awhile!
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    MGarrison

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    Just recalled a couple engine-longevity related thoughts - Timing chain tensioner(s) presumably should be should be checked & replaced at appropriate intervals, and timing chain guide rails, which might be plastic. I think BMW timing chains are typically pretty long-lived, although maybe not a bad idea to replace around 200k (250k?), I know they stretch some over time.

    This is for E34's, some of which might be of general interest, since E31's & E34's are of comparable vintage.

    http://www.bmwe34.net/E34main/Trouble/What_will_break.htm
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    phoenixop

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    I do have reinforced jacking points. I have 4 circles on the rockers. I believe all e31's have them. I read somewhere that you can use the jack, raise one side put a jackstand there then go to the other side and repeat the process. If nothing else I might try that so i can get a look at potential floorjack sites ubder the front end.

    Thanks for all your suggestions. You never know where the next great idea may come from.
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    MGarrison

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    ooooh yeah lookin' at that there jack, it's the kind that goes straight into the openings in the sills hidden by the round covers - didn't think to see if realoem shows that jack, but yep it do. If somebody makes a jack-lift pad doo-dad that fits into the sill opening that you can get a floor jack on, then that could be one way to get 'er up in the air.

    [IMG]
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    phoenixop

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    Found one on ebay and I think Autohaus has them also. I'll let you know how it goes.
    Thanks again.
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    MGarrison

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    phoenixop

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    There's one picture showing a crossmember supporting the engine. It's obvious that trying to lift essentially 2000 lbs via a floorjack with an approx. 3-3 1/2" steel plate would cause that thing to collapse. If someone made a cradle that spanned the width supporting the ends equally with the full length of the center, it might be a go. I'm not a welder, but I think someone could make one. It would need a round plate on the bottom to sit in the floorjack pad. Oh well back to the drawing board.

    Did show me one thing though. PrevOwn removed the cats. So where the cats used to be there are straight pipes. Maybe if I can get the front up I can remove the driveshaft without having to remove the whole exhaust, which would require the whole car up off the ground, or just drop the front of the exhaust.

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