M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Engine + Driveline => Topic started by: SoupieMelody on December 14, 2009, 05:32:44 AM
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Okay my issue is that there is play in the crankshaft keeps going in and out. Today the altenator belt fell off. Is it worth it to replace those bearings or replace the engine ? It's a BMW 1991 e30 318i sedan with m42 engine
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If your thrust bearings are worn to the point that you have significant play, you've probably got big problems internally.
How did you diagnose the play in the crank. How far is it moving?
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If your thrust bearings are worn to the point that you have significant play, you've probably got big problems internally.
How did you diagnose the play in the crank. How far is it moving?
well i just look at it from sight and used a screw driver and it moved about .25 inch
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If it moves that much I think your thrust bearing are MIA as I do not think the combined thickness of them are a 1/4", check to make sure your crank pulley is tight, there is a center bolt that holds the hub to the crank and requires somewhere around 200ft/lbs (i think) and there are several that join the hub to the actual pulleys.
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well i just look at it from sight and used a screw driver and it moved about .25 inch
That's huge! I don't know the exact BMW spec, but that thrust distance should be less than .010 inch or so.
As above, check the pulley first. If it's tight, then you've got bigger issues.
I'll bet if you drop your oil pan (difficult on these motors in the car, I know) you'll find the thrust wahers there. If you're lucky, you haven't trashed the crank/block yet.
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Yeah, sounds like some more serious issues. By the way, If you want to keep your car then its worth it to get it properly repaired.
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Definitely big problems there. I'd pull the crank pulley & hope that the woodruff key (part 9 here (http://www.realoem.com/bmw/showparts.do?model=AJ93&mospid=47318&btnr=11_0334&hg=11&fg=20)) has broken. If the crank nose is cracked it'd cause trouble like you mention. Happened to an old Nissan of mine; I overtorqued the crank pulley & cracked the crank nose. That was a cast shaft, not forged like our trusty M42.
Looking at that diagram it looks like there are lots of places for off-center pulleys, don't condemn the engine just yet...might be perfectly good as-is with a few cracked bolts or a bent/pinched pulley.
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ok thanks for the help and advices guys...the pulleys are fine...well today my mechanic and i took down the whole thing and one of the thrust washer wasnt there...i had ordered a set of main and con rod std bearings from pelicanparts.com and we installed them...everything is going well so far....changed the oil, filter, sparks plug and fuel filter, ICV and the car feels way better now
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I'm surprised the car ran like that...glad it didn't kill the engine.
The real question on my mind is...what the heck was the PO doing? Or was some shady mechanic tossing it back together? Maybe back in 1990 the Bavarian engine assembly guy was having a bad day?
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the m42 only has 180 degree thrust surface stock.
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I'm surprised the car ran like that...glad it didn't kill the engine.
The real question on my mind is...what the heck was the PO doing? Or was some shady mechanic tossing it back together? Maybe back in 1990 the Bavarian engine assembly guy was having a bad day?
Lol that's what I'm saying. Like when we removed them, you could see the lining where the washer should have been at compare to the other one... Glad that's fixed and over with hopefully I don't have anymore issues for a long time
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the m42 only has 180 degree thrust surface stock.
The old Triumph 1300/1500 engines used in Spitfires from the 60's and 70's (and MG Midget 1500s like mine in the late 70's) had this design, and these engines were notorious for dropping thrush washers into the pan. I'm very surprised BMW would have gone with this kind of design.
One thing a lot of Triumph guys do is pin the thrust washers in place so that when they do wear, they don't drop into the sump and cause crank/main bearing cap damage. When I refreshed my 1500, I used a red Loctite to keep them in place. So far, so good.
The other thing we do is keep our foot off the clutch pedal as much as possible (i.e. don't keep the pedal pushed in at a red light).
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I am curious since this is not something I know a lot about but want to learn.
I would conclude that according to this:
http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?pn=11-21-1-706-829-BOE&catalog_description=BEARING%20SHELL
all of those BMW inline engines also only have 180 degrees of thrust.
What is the difference between yellow, green, and white?
http://www.realoem.com/bmw/showparts.do?model=AF93&mospid=47305&btnr=11_0292&hg=11&fg=20
What would prevent one from using two thrust bearings for 360 degrees? The bearing sets on Pelican show 2 bearings per set, so I thinking this is an after thought.
Where are the thrust washers?
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bumpity because I want to know too :)
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if you get an aftermarket set it will come with a 360 degree bearing. Someone should PM Peerless and ask him what bearings he uses
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peerless (Robert) mentions that he uses the m20 bearings which are 360-degree but the original M42 main caps need to be machined by MM.
http://m42club.com/forums/showpost.php?p=66024&postcount=3
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I use standard M50 thrust bearing, 360 deg and no problems so far.
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I use standard M50 thrust bearing, 360 deg and no problems so far.
Part number or link to where to buy it online?
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Sorry I don't have a p/n for it but it's a standard M50 bearing, bought it from my local dealer.
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And the M50 bearing fits straight up to the M42 bearing cap?
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Yes.
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The M42 only has half a thrust main bearing (i.e. the corresponding bottom thrust bearing is a plain main bearing with no thrust surface). Strypt, did you use the M50 thrust bearing for the bottom as well?
Did you use M50 main bearings all the way or just for the thrust bearing?
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M42 and M50 use the same bearings except for that one half of the thrust bearing. The M42 "bottom" bearing is therefor the same as in the M50.
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While we are on the subject of thrust bearings.... I was just inspecting the oil filter from my 200k oil change and found a bunch of "copper leaf" in filter folds. The shavings look quite flat to me. I'd expect crank bearing to have a slight curve to them, so I suspect these are shavings from the thrust bearing.
Any thoughts on what else these could be? How bad does this look?
Can the thrust bearing / crank bearings be replaced by pulling the pan w/ motor in place or is pulling the motor the best way to go at this. Any tricks for measuring the end play?
Thanks.
(http://eyemoto.com/bmw/IMG_0066_550.jpg)
(http://eyemoto.com/bmw/IMG_0050_550.jpg)
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that is probably your rod bearings from my experiences with this engine
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Upon closer inspection of the "shavings" found in the oil filter... I'm not sure they are metallic... They are very flat and thin, like 90min cassette tape and come apart easily. No metal slivers or "metallic dust" was found in the filter.
This was the first oil change after a timing rebuild and dose of AutoRx in the oil. I'm thinking the "shavings" are either from gasket compound or cooked sludge loosened by the AutoRx. I inspected the current oil filter w/ 300 miles on it and no shaving or debris was found... I'm keeping her on the road but keeping a very close eye on her....
Cheers,
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Good luck.
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Copper colored material is what you see after the other metal has worn away, I have seen it three times in this engine and several times with others. Did the oil look somewhat milky? I will dig around and see if I can find pictures of the metal shavings that came out of the three M42's that I blew up.
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Here is a rod bearing that came out of one of my engines, you can see the copper in the picture and I wish I could show you how thick it it because it is only a couple thousandths thick
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Here is a rod bearing that came out of one of my engines, you can see the copper in the picture and I wish I could show you how thick it it because it is only a couple thousandths thick
So there's a copper coating on them? I guess mine that are silver are toasted then...
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There is a copper coating under a silver colored coating, so if you have copper flakes in the oil you have already worn through the outer coating. How noisy is the engine?
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There is a copper coating under a silver colored coating, so if you have copper flakes in the oil you have already worn through the outer coating. How noisy is the engine?
Engine is currently being rebuilt. I've never seen any copper flakes. My rod bushings are still silver and look to be in pretty good shape.
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Copper colored material is what you see after the other metal has worn away, I have seen it three times in this engine and several times with others. Did the oil look somewhat milky? I will dig around and see if I can find pictures of the metal shavings that came out of the three M42's that I blew up.
Oil was not at all milky. Compression is good.
Thanks for posting those photos.... scary.... I'm pulling her off the road till I can show the shavings to a local expert.
--If I really have bearing shavings... what are the chances my crankshaft and rods are still salvageable?
--Is it possible to swap-out bearings from under the car... by pulling upper pan w/o pulling the motor?
Thanks again.
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Oil was not at all milky. Compression is good.
--If I really have bearing shavings... what are the chances my crankshaft and rods are still salvageable?
--Is it possible to swap-out bearings from under the car... by pulling upper pan w/o pulling the motor?
Thanks again.
it really depends on alot a varibles, I have seen bearings go bad but the crank still look good, but I have also seen them ruin a crank. The last engine I tore apart, which is the engine that the bearing in the picture came out of, the crank needed to be reworked.
As far as doing it from underneath, It is possible but in the time it will take you to get the oil pan out, which in this car I think it requires the removal of the subframe, you may as well just pull the entire engine which takes me about 2 hours for the tranny and all. It isn't an extremely difficult job but there are a few things you need to remember to get it back together.