Messages

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Engine + Driveline / Re: IDIOTIC MISTAKE - Sheared Top of Hex Nut for Timing Tensioner Piston

« on: November 30, 2015, 04:12:10 PM »

Those sound like good plans, definitely will look into doing them, but I'm not sure I have the expertise (I definitely don't have all the tools!) needed to do a full timing rebuild.


Dave, if I were to go ahead and get a late/last year M42 replacement engine (just because the ones on that site have an option to be rebuilt with better cams), would my engine accessories not be compatible with them? And could I use the oil pan that comes with the new engine, or would I have to keep mine? I know that's a dumb question, but I've seen something about that mentioned on here, and searching for late year M42 conversions/replacements hasn't yielded the answers I need.

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Engine + Driveline / Re: IDIOTIC MISTAKE - Sheared Top of Hex Nut for Timing Tensioner Piston

« on: November 29, 2015, 11:47:57 AM »

If you do decide to tear down the timing case / chain assembly, look for a 1994+ M42 timing case. It eliminates the awful deflector sprocket, which is a huge reliability problem, and uses another plastic guide instead. It is more or less a direct bolt-on, just make sure you get the proper gaskets in the cases where they differ. You should be able to get a used late-model timing case + covers on the forums for under $100. It is possible to swap timing cases without removing the head, but it is a real pain and I only recommend it if you are somewhat experienced in working on engines and comfortable with digging in to them.

Late-model timing parts:
http://www.realoem.com/bmw/enUS/showparts?id=BE53-USA-10-1994-E36-BMW-318is&diagId=11_1370

Related gaskets for late-model timing case:
http://www.realoem.com/bmw/enUS/showparts?id=BE53-USA-10-1994-E36-BMW-318is&diagId=11_2683
http://www.realoem.com/bmw/enUS/showparts?id=BE53-USA-10-1994-E36-BMW-318is&diagId=11_6003


Also think about replacing parts 5-8 if you pick up a used late-model case.
http://www.realoem.com/bmw/enUS/showparts?id=BE53-USA-10-1994-E36-BMW-318is&diagId=11_6009



The M44 timing case is also an option, with the advantage of a bigger oil pump. However, it is not a direct bolt-on and you would need to buy a custom bracket to hold the crank position sensor since the M44 case does not have anything to hold it.

Personally, I would consider doing what Dave mentioned and try to get the threaded collar out. Push the piston in a bit to make room, and then see if you can get a pick in there to try to push/rotate the threaded part out. Without the head on the cap, I don't think that the threads should be too hard to rotate out.

Thank you for the information, this seems like the way to go now. I'm still unsure as to what you folks are meaning by "pick." I looked up variations of "[noun/adjective] pick" and "mechanic pick" seems to show what's been mentioned. Is this correct?


Also, it seems unreasonably difficult to compress the piston again. I installed it whilst decompressed to avoid the "rev to 3K and pray" and a potential chain jumping due to broken guides. Would this have anything to do with the difficulty? Engine's in the car, leaving little room. My plethora (or lack thereof) of tools is somewhat limited, any ideas as to what to use to get this thing compressed?


Sorry for all the continuous questions, just figured I'd get all the info I can.  Thanks again for the help, all of you.

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Engine + Driveline / Re: IDIOTIC MISTAKE - Sheared Top of Hex Nut for Timing Tensioner Piston

« on: November 25, 2015, 12:41:38 AM »

I'd be tempted to get a pick in there and slowly rotate the stub of that hex-head plug out. I know the tensioner piston sticks out a bit, but if you pushed the piston in slightly with a drift or screwdriver you might just get lucky. I wouldn't use a hammer to drive the drift in there - you could crack the timing rail. Just use it to apply a little pressure to the hydro piston and unload the collar of that broken plug.

Otherwise...yep...it'll have to come apart. You might need a new case if a tap can't restore the threads.

You might have a bad bearing in the cam idler gear. Common problem with the older M42. Replacing it with the late-model M42 chain case eliminates the problem.

Thanks so much for your reply! What exactly do you mean by "drift" and "pick"? Is the pick just a type of extractor? I'm really hoping it won't have to be tapped, as hopefully the case's threads are still good... But I doubt it. I've tried pushing the tensioner in, but it won't budge. Maybe I'm too weak in this cold/can't get a good angle (the engine's in the car). I'll add some photos of the situation as it stands.


I'm assuming that later year M42s are nearly the same? Would they still be a bolt in replacement? Only asking because this engine's mileage is unknown, has god knows what else that's going to fail on it next, don't have the time to rebuild it myself, and may potentially have the opportunity to get a rebuilt M42 from Bavarian Engine Exchange http://www.bavengine.com/engine.html

There are drastic torque rating changes between the 90-91 and the 92-93, 94-95 M42s on the linked page. What's the difference? I haven't heard or read anything about that before, and am having trouble finding anything.

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Engine + Driveline / Re: IDIOTIC MISTAKE - Sheared Top of Hex Nut for Timing Tensioner Piston

« on: November 24, 2015, 11:16:44 AM »

Probably. You're unlikely to be able to get it out with the timing cover on the engine. Looks like it's time to pull it off and since that's a pain, you may as well replace everything you can afford to replace behind it.

Yeah, that's what I figured. Need the guides/gaskets replaced anyway, the tensioner piston itself did nothing to fix the horrible noise. Probably would just end up getting the whole timing kit some stores offer.

The threading from the top nut that broke is still in the tensioner hole. Would an extractor ruin the threads of the engine block (if I haven't already done that...)


What else do you think needs to go?



PS: The link in your signature needs modification; I had to remove all but the "www.r3vlimited.com/board/showthread.php?p=4162247" section to get it to load. Great build, by the way. I remember watching it from the beginning, long before I ever thought I'd be an E30 owner. Hope to have the same type of setup someday...

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Engine + Driveline / IDIOTIC MISTAKE - Sheared Top of Hex Nut for Timing Tensioner Piston

« on: November 20, 2015, 04:14:03 PM »

Well guys, I completely blew it. I've never messed up anything auto/engine related this badly.

I went out a bought a torque wrench, quadruple checked my settings, yet somehow broke the head of the tensioner piston's bolt clean off.

This leaves the tensioner piston in the engine, decompressed, but leaking oil as there's not a full seal around it.


Am I completely screwed here?

Thanks in advance.

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Engine + Driveline / Re: Scratching/Grinding Sound below ~3k RPM - 1991 318i - VIDEO

« on: October 19, 2015, 06:21:55 AM »

First thing I would do is, remove all the belts and run it briefly to see if anything changed.  If the noise goes away, it's either the alternator, PS pump, water pump or viscous fan clutch.  If you still have the noise with no belts on, the next thing to check is the timing chain and tensioner.  I would drop the front oil pan and see if there are any chunks of plastic or metal.  If so, chain guides are bad.  If not, I would suspect a bad chain tensioner.  They are cheap enough ($30 ish) and an easy task.  It is located near the A/C compressor.  This might also explain the failed A/C clutch diagnosis.  Compressor is hard bolted to the block and may be telegraphing chain noise.

The "torque improvement" is probably just the second stage of the throttle body opening coincidentally with the decrease in grinding noise.  Don't let it distract you, most likely not related to your problem.  Sound change of the noise is probably due to oil thinning as it heats up.

Thank you so much! I bet it is a tensioner, if my understanding of what that does is correct.


I must ask though, regarding the dual stage throttle body, I already notice a change in torque, and a bit of a rougher/stronger pull before the sound goes away, if I depress the accelerator further than the first 1/8-1/4 of its range of motion. Even after that increase in torque, the feeling is still there. Is this initial torque increase not the second stage throttle body?

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Engine + Driveline / Scratching/Grinding Sound below ~3k RPM - 1991 318i - VIDEO

« on: October 18, 2015, 04:10:09 PM »

Hi all, first post here. Sorry it's a negative one, but I suppose that's what this forum is for! I was so excited to discover a site dedicated to my favorite engine. I'm hoping that I won't have to take it to a shop and pay them to do something I can do myself.


https://m.youtube.com/watch?v=jkdeTUUuh3Y


This grinding sound has been happening since I bought the car three months ago. As you can see, it basically stops at 3K rpm, then as the revs slow, you can hear it come back on strong. PO says the PO before him (a family friend he knows well, both of whom know and love these cars greatly, had the engine rebuilt ~75,000 miles ago.

Previous owner said it was there when he had it too. He also says it's had the timing chain been checked out as an attempt to diagnose the sound, the shop said it was the AC compressor clutch bearing. Shop also claimed to have used a stethoscope to confirm this. After removing the AC belt today, the sound is obviously still there. I'm doubting the legitimacy of whoever inspected the vehicle.

Listen for the higher pitched, "oscillating", repeating pattern of scratching, scraping, grinding at idle. It becomes harder to hear in the video as the revs increase. But see as RPMs dip back below 3k or so, the sound returns, very loudly.


I notice an increase in torque around 3K rpm, then an even greater increase in torque at 4.5K rpm. Occasional when cruising at low RPM, low throttle, whatever the source of the sound causes slight acceleration/deceleration in sync with the noise's modulations.

I've considered timing chain guides, tensioners, or the cover. I also read somebody claiming that when changing their water pump, a sound described similarly to this one disappeared. My father speculates oil pump, but he's no car guy.


As a side note, there's occasionally a rough idle at start up, and the intensity of the sound changes every time I drive it, and after warming up. Also, a very recent development, there is sometimes a faint fuel odor from the engine bay, and/or a stronger smell from the gas cap area. Fuel level gauge sometimes reads incorrectly as well. Smell occasionally (quite rarely) becomes unbearable.


Thanks in advance for your time and suggestions!