M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Engine + Driveline => Topic started by: evbrad2002 on October 08, 2013, 02:42:25 PM
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Son was driving car on a rather long trip when he started intermittently losing power and getting some shuddering at highway speed. Thought it was a bad plug or ignition coil so pressed on. Upon arrival at my house noticed a rather loud timing chain noise. Popped in a new tensioner the next day to no avail, still had the timing case noise.
While trying to sort out the timing chain noise, pulled valve cover (removed plugs) and started off rotating the crankshaft clockwise to get to TDC to check timing marks. Made a full turn plus with no issues. However, I realized that I was looking for the alignment arrows on the gears in the wrong place so rotated past TDC about 1/3 turn. I then stupidly rotated counterclockwise to get back to TDC and moved past a minor bind (chain did buckle slightly - moved a tooth?), then nothing, full stop. Then attempted to turn clockwise but only made it about a 1/4 turn before hitting another full stop.
So, am I fully screwed here? Suggestions? Any good sources for used M42's? :-\
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I'd be hopeful that you didn't bend anything. You might be mistimed now, though.
I'd pull both front chain cases. Definitely check that lower idler gear - it's problematic. The later M42 and M44 replaced it with a deflection rail.
I have a used M42 sitting on my driveway, LOL. I was planning on rebuilding it to install in my sedan.
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Thanks for your quick reply. I was intending to use the starter method to free the crankshaft bolt. That's out now. So what are your suggestions for getting the crankshaft bolt removed? Thanks!
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You can still use the starter method. I'd remove the cams to ensure that the valves are all closed. Then the only thing you'd need to worry about is the cam chain...and the small bit of rotation from the starter bump likely won't cause any trouble.
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Wow, removing cams sounds daunting. Doing the timing guides is new territory for me as it is. can you direct me to a quality DIY for cam removal/install that will keep me out of trouble? Again, thanks for your help!
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Wow, removing cams sounds daunting. Doing the timing guides is new territory for me as it is. can you direct me to a quality DIY for cam removal/install that will keep me out of trouble? Again, thanks for your help!
I haven't done it on an M42, couldn't find a pictorial guide either. Remove the cyl cover, it should be pretty obvious. IIRC, you just unbolt the gears, then remove the bolts from the cam bearing caps and lift the cams out. They sit in alu carriers that also seem easy to remove. Don't mix up the caps once you have them off - it's best if the caps and cams stay matched. The bearings wear together to make a perfect match.
If you're even remotely nervous, buy or download the Bentley BMW E36 manual, they detail the whole procedure. The E30 manual is good too, but I've heard it doesn't have a section on the M42...only the M10 and M20 motors. They also have a table that specs torque values for all those fasteners, very useful. Money well spent.
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Ahhh, yes! I actually have a Bentley E36 Manual that I purchased years ago for an M3 I had. Totally forgot the M42 was included in this manual. Thanks! I'm concerned I may have buggered the engine anyway so nothing really to lose in diving in with manual in hand...might even learn something...
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Ahhh, yes! I actually have a Bentley E36 Manual that I purchased years ago for an M3 I had. Totally forgot the M42 was included in this manual. Thanks! I'm concerned I may have buggered the engine anyway so nothing really to lose in diving in with manual in hand...might even learn something...
That's the spirit!
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Sorry to hear of your troubles. You've got to be careful with the cams. They are hollow grinds and brittle. The valve springs exert quite a bit of pressure and if done incorrectly you run the risk of fragging your cam. The Bentley talks about a special tool. I found this youtube video to be very helpful when we pulled ours. It's not an M42 but it's still apllicable to us. http://www.youtube.com/watch?v=12CTLgtaV9A (http://www.youtube.com/watch?v=12CTLgtaV9A)
I followed the video and it's a piece of cake really, not bad at all.
Let's hope it's just an idler pulley or chain rail that gummed up the works. I don't have a spare engine but I do have cams and crank in very good condition and some new VW lifters if you need anything.
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Sorry to hear of your troubles. You've got to be careful with the cams. They are hollow grinds and brittle. The valve springs exert quite a bit of pressure and if done incorrectly you run the risk of fragging your cam. The Bentley talks about a special tool. I found this youtube video to be very helpful when we pulled ours. It's not an M42 but it's still apllicable to us. http://www.youtube.com/watch?v=12CTLgtaV9A (http://www.youtube.com/watch?v=12CTLgtaV9A)
I followed the video and it's a piece of cake really, not bad at all.
Let's hope it's just an idler pulley or chain rail that gummed up the works. I don't have a spare engine but I do have cams and crank in very good condition and some new VW lifters if you need anything.
Thanks for your help! Yes, hoping for the idler pulley or chain rail, which brings up a question...if the crank is not turning due to idler pulley or chain rail, then crank's still going to have a stop in it even with the cams out, right? So would not be able to loosen the crank bolt using the power bar/starter method. Suggestions?
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Maybe this http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?pn=TOL-3034-2&catalog_description=&Crank%2520Pulley%2520Securing%2520Tool%252C%2520For%2520M%2532%2530%252C%2520M%2534%2532%2520and%2520M%2535%2530%2520Engines%252C%2520Each%2520%2520 (http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?pn=TOL-3034-2&catalog_description=&Crank%2520Pulley%2520Securing%2520Tool%252C%2520For%2520M%2532%2530%252C%2520M%2534%2532%2520and%2520M%2535%2530%2520Engines%252C%2520Each%2520%2520)
and then a lever Archemidis would be proud of.
If you have access to one of those inspection scopes take a look around the idler sprocket and crank sprocket (my kids named their cats sprocket and crank long ago but I digress) and see if there's something wedged in there that could be fiddled out with one of those grabber things.
***disclaimer*** I've only got my engine apart and not back together yet so take my rookie advice as just that. There are plenty of wrenchers with much more experience that will come to your aid.
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what position should the crankshaft ideally be in to ensure pistons are lowered to avoid contact with the valves? That is, where should the little notch on the tooth be in relation to the timing mark arrow near the oil filter housing?
Also, did you find the "sweet spot" for the cam behaved the same way as that shown in the video for the M3? And, did you have a helper hold the camshaft still or were you able to do that without help?
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When the arrow in the oil filter housing is pointing at the notch in the toothed crank wheel, things are at TDC. As long as you turn the crank ~90 degrees from there, the pistons will be at the middle of their travel and well away from the valves.
One of two things is going on here.
a) When you rotated the crank CCW, the chain loosened and jumped some number of teeth when it got bound up on the (stupid) lower plastic guide. The "stop" you feel is pistons touching valves. It generally takes 2+ teeth jumped to get to this, at least in my experience.
b) When you rotated the crank CCW, the chain loosened and is getting all bound up on the (stupid) lower plastic guide. Is the tensioner piston still installed? Basically, you never ever really want to rotate the crank with that tensioner piston out. Turning things CCW with it out is an even bigger no-no.
You can try taking the cam sprockets off and rotating the cams so that no valves are fully opened. That might buy you enough clearance to turn the crank further and try the starter trick on the damper bolt. You'll probably also need to try pulling up on the chain to get it properly engaged with the crank sprocket if it is binding in the lower plastic guide.
Before doing anything, try draining the oil and see what all is in it. If you have lots of aluminum shavings, then the idler sprocket most likely snapped off of the timing case (been there myself). If you see some ball bearings, then the idler sprocket's bearing blew out (also been there). The latter situation seems most likley and it has happened to a lot of folks. The idler setup is junk in the original M42 motors. I HIGHLY recommend swapping in an M44 timing case. You need to make sure to use M44 oil pump gears, and you will need an adapter bracket for the crank position sensor (I know that Metric Mechanic can probably sell you one). I had the bearing fail on my idler sprocket. So I replaced the thing ($170 part!!!) and then a year later it snapped off of the timing case entirely. The casting probably got damaged when the bearing blew out.
Also invest in a magnetic oil pan drain plug. Turner Motorsport sells one, and it is worth its weight in gold. I had one in there when the bearing blew, and all 6 balls were neatly stuck to it.
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Thanks so much for your detailed reply bmwman91. Very helpful.
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Thanks so much for your detailed reply bmwman91. Very helpful.
There are plenty of wrenchers with much more experience that will come to your aid.
See? Told you. You're in the right place!
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Learning, Learning, Learning! So, I went ahead and pulled the cams off to ensure that I wouldn't bang on the valves while getting the crank bolt off per your suggestion DesktopDave's. The cam gears actually looked good. Teeth had nice flat tops. Cams came off without a hitch following the technique outlined in the video you referenced,Mabeer. Was able to starter bump the crank bolt free, drained the oil per bmwman91' and was happy to find no bearings or shavings present. Finally after fussing with the compressor/bracket was able to pull the lower cover. The idler sprocket was intact, all bearings present as the oil check suggested. I found eight different loose pieces of the driver's side chain guide in the case and the lower chain guide was broken in the middle.
Now, before I pony up for timing kit parts, I've got to look further in to the M44 case update option. Hope to find a link or two with guidance and a parts list (anyone have one handy?).
More importantly, before I spend any money on timing case, I need to assess my valves. If they're damaged, may have cry uncle and let a shop take it from here. I know I should have done a compression test before breaking things down, but getting the chain bound up as I was trying to assess alignment at TDC took that option off the table. At this point with the cams off, is my best bet to blow some compressed air into each plug socket? 5-10psi? Unfortunately my tools are limited so will have to borrow a tester from a local parts place. Any other ways to assess valve status at this stage?
Again, thanks for all of your help. I wouldn't have made the progess I've made thus far without it.
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Phew, well it is good to know that you got it safely apart.
I am not sure how much out of alignment things can get with a blown-up driver's side guide. The M42 makes a distinctive "diesel engine" sound when the timing is off and valves are kissing pistons. The engine is remarkably tolerant of that. Back in 2004 I did my first timing case job on the M42 and managed to get things off by a couple of teeth. Being young, dumb and impatient, I thought it was lifters not pumping up and went for a few miles of spirited driving. Got back, fixed the timing and it was good for another 80k miles, until the idler sprocket snapped off (unrelated). If your son didn't hear a constant diesel sound and it just ran poorly, then the valves are almost guaranteed to be fine.
For the M44 timing case swap, I THINK that you only need the M44 timing case, M44 oil pump gears and a custom bracket to hold the crank sensor in place. Metric Mechanic should be able to sell you one, I think. The timing case (with oil pump gears still in it) should be had for $100 or less used on a forum. I picked up one for about that much. A little cleaning and elbow grease and it's as good as new, and no stupid idler sprocket. You should also replace all of the oil pressure relief stuff (parts 5-8): http://www.realoem.com/bmw/showparts.do?model=CG73&mospid=47506&btnr=11_1120&hg=11&fg=30
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Have begun the hunt for a late M42 or M44 case. Will update as I have more and will try to compile a little DIY/parts list when (if) I get that far and don't cave and just go with a refresh of the existing case to get this daily back on the road as soon as possible...of course, I may have it back off the road in a couple months with a disintegrated sprocket/casing like others of you have experienced and be kicking myself....
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Well, this is turning into a big adventure...
Good news: did a leakdown test and got 8-10% on each cylinder on a cold engine.
Bad news: dropped the oil pan after reading about the pan bolts....found 5 in the pan, and the one remaining bolt had backed out a couple of threads...holy canoli!
Wait, it gets better: also found an alarming amount of plastic and metal bits from the disintegrated timing chain guide lodged in the oil pick up; together with the bolts rumbling around down there, I'm thinking, ruh-roh, oil starvation, but just don't know how much over how much time.
And it gets better still: pulled the oil filter housing off to do the gasket while all is apart and found an impressive amount of sparklies in the oil...need to filter some out to better check the color but I'm afraid of bearing damage, of course. Already have all the timing case rebuild parts here or on the way.
Would sure appreciate some guidance at this juncture. Is there any way I can assess for bearing damage without pulling more things apart? Is there any degree of bearing damage that still allows for a serviceable motor for daily driving? I'm already in to new territory, so pulling heads, replacing bearings or rebuilt blocks, etc. is way out there for my experience level, though eager to learn...the problem is the need to get a daily back on the road sooner than later. Perhaps I should shop for a tested used M42 and have the fresh timing parts installed before having the engine dropped in? Thoughts, advice welcome and appreciated.
Update: So, I'm guardedly optimistic after further inspection. The particles appear to be primarily silver in color, though I did see a very few that appeared copper. Very difficult to discern at first due to amber color of oil and reflections in sunlight. When I took a closer look at the busted up chain guide I saw at least one area that had clearly been milled by the chain and noted some copper colored metal used in the guide construction, which you can see in the attachment...also included a fun pic of the guide pieces-parts in the attachment.
I also confirmed with my son that the oil pressure light never came on. So, I'm hoping the particles are from the milled guide rail rather than a bearing, but, WOW!, that oil pain and oil pick up looked scary, so still not sure about the bearings.
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You are probably fine. The chain has a tendency to gnaw on the aluminum stuff in the timing case. When my idler sprocket snapped off, my oil was FULL of aluminum shavings. Just do not get any debris into the round hole that the filter housing plugs into. If the oil light never came on, you are probably OK. There is a rather notorious issue with the lousy thrust bearing that these motors originally had (only half of a shell), so that may or may not be chewed up. You can usually tell how messed up it is by measuring the crank's end play. You might be able to pull the upper pan and do a visual on it too.
It looks like this engine had the original timing components in it. The main guide rail (driver's side) was updated to an all plastic one in the mid-1990's.
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Well, this is turning into a big adventure...
Good news: did a leakdown test and got 8-10% on each cylinder on a cold engine.
Bad news: dropped the oil pan after reading about the pan bolts....found 5 in the pan, and the one remaining bolt had backed out a couple of threads...holy canoli!
Wait, it gets better: also found an alarming amount of plastic and metal bits from the disintegrated timing chain guide lodged in the oil pick up; together with the bolts rumbling around down there, I'm thinking, ruh-roh, oil starvation, but just don't know how much over how much time.
And it gets better still: pulled the oil filter housing off to do the gasket while all is apart and found an impressive amount of sparklies in the oil...need to filter some out to better check the color but I'm afraid of bearing damage, of course. Already have all the timing case rebuild parts here or on the way.
Would sure appreciate some guidance at this juncture. Is there any way I can assess for bearing damage without pulling more things apart? Is there any degree of bearing damage that still allows for a serviceable motor for daily driving? I'm already in to new territory, so pulling heads, replacing bearings or rebuilt blocks, etc. is way out there for my experience level, though eager to learn...the problem is the need to get a daily back on the road sooner than later. Perhaps I should shop for a tested used M42 and have the fresh timing parts installed before having the engine dropped in? Thoughts, advice welcome and appreciated.
These engines are tough little things, unless they overheat. I think you're good, and it's good to hear about what seems like you're heading toward a happy ending.
I'd suggest a used oil analysis to verify wear metals in your used oil, if you're concerned. I'm a big fan of UOAs. They tend to really put my mind at ease, and they're less than $30 ($25+shipping). I've always been very happy with the used oil analysis at Blackstone (http://www.blackstone-labs.com/) - their service is excellent. Sample collection kits are free if you request them. If you do send them a sample, be sure to note how it was collected. They recommend a sample directly from the sump, but if that's not available they'll compensate their tests to suit your collection method.
There are other labs out there too, but I have no experience with them.
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Encouraging feedback. I'm going to go forward expecting the best at this point; again, it's all a learning process and I really enjoy the heck out of this stuff, so if I end up with bigger problems, I'll have still learned a ton in the process. The oil analysis is a great idea. I may have already tainted it beyond a valid analysis, but will look into it. I continue to find little bits of plastic debris in the little nooks and crannies of the timing case. Also found some small bits in the oil filter housing. It's definitely important to comb through several times to ensure it's all out of there.
Funny, my idler sprocket is fully intact, spins smoothly and has only the tiniest bit of play in it. I know it's not ideal, but after reading the timing case replacement posts and having difficulty sourcing an M44 or newer M42 case for a reasonable price, I decided to keep the existing set up and replace the feared sprocket along with the other bits. Pray for me ;)
I've got the upper oil pan bolts threadlocked and back in place (still need to check on the others that can be accessed through the bell housing), and the oil filter housing back on with fresh gasket (+ sealant) and o-ring. Hope to make some more progress tomorrow, but still waiting for some key parts so, with my schedule, I'm still a good week out before having it buttoned back up and putting it to the test. I'm moving pretty slowly trying to clean things up a bit along the way, and getting the old gasket material off is painstakingly slow when you don't have the little bristle brush drill attachment (does this really work without marring up the surfaces?). Still have to get the cams back on as well and have some trepidation about getting the timing back in order....have been reading as much about this as possible, including the very helpful threads on this forum, so I think I'm going to be okay.
Again, all of your helpful input has been most appreciated. I'm sure I'll have more questions as I continue on.
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So it's about time to get my camshafts back in (I may have some separate questions about this later) and I wanted to get some input on the best approach to take at this point to get things timed back up without bumping valves and pistons. I have read a great deal on this forum and others but a couple of points I'm not confident about in my situation. Below are the steps I have in mind; please correct, clarify or make suggestions where necessary:
Before replacing cams, turn crank to about 270 degrees past TDC (the point of alignment of oil filter housing arrow with mark in crank tooth). This will put the pistons in the midway position across all cylinders for the last time prior to reaching TDC at 360 degrees. This will allow me to install the cams at the "sweet spot" (where load is only on cam at cylinder one, valves will be open) referred to in the Pelican Parts article and, once installed, I should be able to turn them to TDC without bumping valves on pistons.
Once cams are at TDC (I plan to lock in place with rigid metal rule with C-clamps at rear squares), I should then be able to rotate the crankshaft the final 90 degrees to TDC without bumping valves. I don't have stock flywheel so have no holes to lock crank at TDC....suggestions? I do plan to confirm crank TDC using the 81mm measurement between cylinders 1 and 2. But not sure how to ensure that it stays in place as I install and tension chain.
From here I'll pretty much be following Brendan Purcell's DIY.
Any input welcome and appreciated.
Thanks!
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I always use the 81mm measurement technique. There is a fair bit of friction from the rings holding things in place. Once you get things in phase and reassembled, carefully turn the crank a few revolutions manually and then re-check that the cams are still where they need to be with an 81mm difference between 1 & 2. Hopefully there's not massive carbon build-up on the piston crowns or it could make that measurement a little tricky!
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Well, I've got it all back together and it's essentially running very well. The 81mm technique was a lifesaver in the process of getting timing together. Again, my thanks to the helpful input provided along the way. The only flies in the ointment are:
1) I've been fighting the dreaded idle gremlins since getting back up and running. I got the AFM code (1215, as I recall). Was initially getting the crazy rapid surging or high idle with rythmic drops. Now after reseating and snugging up a few fittings things seem to be better, but I'm still getting high rpm idle (2kish) at cold start at times and then, either on its own, or after a quick restart, idle will drop down low briefly to near stall and then settle in to a healthy range. Once going, it runs like a champ; pulls strong. I've sprayed around a bit with brake cleaner and so far have not found any clear signs of vacuum leaks. Any suggestions of likely sources of idle issues after doing the timing chain?
2) I noticed the first couple of days some white smoke coming out of the exhaust with a bit of water collecting at the tail pipe. Bleeding was a real PITA; temp kept creeping up past mid point at extended idle, so a bit concerned about my head gasket. Hoping its just moisture/condensation from sitting a bit and coolish mornings in the always humid south, but the smoke seemed heavier than I recall seeing before and did have a rich (maybe sweet?) smell to it. Haven't noticed it smoking the last couple of days but the exhaust still smells a little funny to me and still seeing some moisture collecting/dripping from exhaust. May just be being paranoid...?
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1) Could be a sticky idle control valve. Clean it out thoroughly with TB cleaner.
2) Could be normal water vapor at start up and you are just paying more attention than usual.