M42 Engine goes GLUB GLUB GLUB -___-

[tonywonder]

When i first got the car a couple years ago i changed the tensioner. dropped pan for plastic or bolts blahblahblah. i did not change my chain or inspect any of the timing components. my engine was a bit noisy at first but when i changed the tensioner and started using 0w-40 mobil synthetic it ran quietly and smoothly. i also did mess under intake crap throttle body heat plate delete and i put in some bosch 710 injectors. anyways so just last weekend i changed my oil. but this time i changed to 5w-30 and now i have this damn glub glub sound. i used a long bar to see where it was coming from. i can mostly hear it standing on the driver side. but when i use the long bar the sound is loudest on the timing case. its also pretty loud where the intake manifold is. anyways. i recorded the sound and its pretty damn clear. so i just wanted to post it for two things. 1 for reference 2 confirmation of what the hell it is. i was thinking it was the tappets but now im thinking its the tensioner again or i might need to go in and do my timing chain. i only recently started to DD the car. within the past few months or so. wondering if i switch back to the 0w-40 if the sound will go away. let me know your thoughts.

oh this sound only happens AFTER the engine has warmed up. and at idle. not noticeable when driving.

first video i was just holding my phone at the driver side of the engine.



this second i was holding a metal bar against the intake manifold and the phone to amplify the sound. (the sound is even louder at the timing tensioner.)

[bmwm42]

Doesnt sound like chain rattle.

[tonywonder]

... sounds similar but this dude says his sound was a loose sparkplug?

[Simon S]

Man - I've been thinking about this off and on - and am having difficulty thinking out why changing oil would cause a sound like that.

You mention sound possibly coming from the timing case – and that certainly is the ‘heart’ of the oil circulation system.

After recently seeing an m42 oil pump mechanism – I just can’t imagine that it would ever fail.
There is the updated oil pressure valve.. but honestly – I don’t recall hearing or reading about one failing.

I guess if I were in your shoes – I’d think about purchasing the updated oil pressure valve parts (shit, they’re like <$20 I think) – then start making plans to pull the pans so that valve can get replaced.

That ‘glub’ sound – and the fact you just replace the oil – makes me think it’s oil related – but for the life of me, I can figure out how concerning it should be..

You love the car?
How many miles are on it?
You got a place to work on it?
The biggest thing that sucks is that there is a cornucopia of other things one can do – “while your in there”..

[tonywonder]

im not sure if its the oil thats causing the sound. i only i noticed it after changing the oil. but i cant see why going from 0w to 5w would make that much of a difference. the sound was loudest at the timing case when i checked, i want to check if its louder near the pan.

the weird thing is it doesnt happen all the time. only sometimes at idle. it seems to need to idle in a certain sweet spot when it happens. its almost like the idle is at the perfect speed where it vibrates the engine and makes that particular sound. i tried replicating it tonight when i got home but it hasnt done it. i think i counted 3 times it did it a bit tonight while i was idling on the way home.

thanks for your input

and to answer your questions.

Yes
around 200+mi
Yes

[tonywonder]

UPDATE

okay so i pulled my valve cover to look at the gears to see if they were okay. which from the looks of it they are good. so thats two things i wont have to replace. but i noticed that the rivets where the arrows point is 16 rather than 15 and the cam adjustment bolts are all the way to the side rather than centered. wondering what your guys thoughts are on this. other than the sound that happens intermittently and the little ticks that i was thinking was form the injectors, it doesnt run poorly. it pulls when and high speeds is nice. just the idle sounds weird at times. could it be the timing? anyways being that there should be 15 rivets inclusive the two arrows. how should i adjust the timing to correct? any way to do it without pulling everything off? i still need to check the chain slack.

here are the pics.






the arrows are on the inside of the cam gears rather than the edge closest to the chain so i marked with red where the arrows point to on the chain.


heres a video of the play in the chain. remember 16 rivets inclusive. i also think this engine was pulled apart at some point. there is a mark on the damper that shows what looks to be TDC the lobes are point toward eachother and are squared but i need to verify by finding the part on the bellhousing that can tell me if its TDC or not. again it runs well and doesnt burn oil much if any.

http://www.youtube.com/watch?v=quHIZfxWE50

okay now we are definitely at TDC. had it backwards before was looking at cyl 4 lobes instead of cyl 1 lobes. the rear of the cams are not perfectly flat bearly of by like 1mm. the intake cam seems to be slightly more raised than the exhaust cam.

[Dj Buttchug]

hmmm thats interesting. From the looks of your cam pics you seem to be off a tooth or more on the intake and exhaust. Its really hard to tell in those pictures tho. Are you positive your real cam squares are flush with the top of the head?

The oil change you did is not the cause, this is something else. If you have intermittent vibration id start by checking for loose parts in the engine bay. pulleys, mounting brackets ect ect. You may also have timing case/guide wear issues as stated above as well...

[Simon S]

Wow – what you describe with the timing is exactly what I found with mine. (way off sprocket slots, the extra ‘pin’ on the chain, etc.)

My related thread

Sounds like you all ready know what to look for - and that you're coming to the conclusion that one of the sprockets is off by a tooth. (I agree with this conclusion)

Set crank to TDC:



Use crecent wrenches or whatever on cam ends. (hold them in place or gently turn cam as needed)



In the above picture, you'll note the sprockets are off the cams. The answer to your magic question: Yes - you can adjust the chain around on sprocket teeth with out taking the front cases off.

It is tricky. You'll need to remove tensioner - so there is slack to play around with on the chain. Also - the most 'dangerous' part of this procedure is the risk of dropping a sprocket bolt down into the timing case. Obviously - this would suck - a lot. I kept a magnet on bolts as extra insurance while removing/installing them.

When I went to put sprockets back on cams - it was like the chain was 1-2mm too short - later on - I could slip them on no problem. What I think happened was that the chain was resting on the lip of a guide somewhere. Keep jiggling the chain around and/or re-trying if you run into this - the slack you need is there.


Magic combination: Crank at TDC + Cam arrows up and parallel (cam "squares" flat) + Centered cam sprocket slots


At this point - you may want to flush out your lifters "while you're in there". Detail about doing so covered in "I want a quite engine" thread.

[tonywonder]

thanks guys. im going to adjust the cams first to see if this is the issue. i think this will help for future reference of anyone that has a similar sound. if it doesnt fix it ill go in and inspect the components. what are the torque specs for the cam bolts when i put them back on? i didnt get a chance to do it today but i think im going to tackle it during the week. this is the car i take to work...is it horribly bad that i drive it this way? one tooth off? i suppose i could take the bus...

[Simon S]

Strongly recommend searching for and downloading e36 Bentley manual in pdf format.

It indicates 15Nm (11 ft-lb) tightening torque for camshaft bearing caps to cylinder head.

As far as driving it.. meh – I wouldn’t be too concerned – you said yourself that it ran/drove fine. So long was it wasn’t banging/knocking/tapping hard..

[Simon S]

Timing chain sprockets to camshaft:
M6 – 10Nm (7.5 ft-lb)
M7 – 15Nm (11 ft-lb)

Not sure why you'd want to put off correcting the timing at this point?
With the valve cover off - you're 90% done already.. lol

[tonywonder]

yeah i was 90% there...but i put everything back together lol. i didnt want to leave it exposed. i shouldve just kept going. ill let u guys know what happens thanks for your help. hopefully this fixes he sound.

[tonywonder]

okay so i did this last night after i got home from work. got everything done. dropped wrench in the timing case while i was taking off exhuast cam gear bolts. Thanks for the help. magnets are your friend.

im gonna give it a few days but im not sure if this got rid of the sound. ill verify in a few days.

[tonywonder]

dont know what it is still. only hear it periodically. but the car doesnt run any different. just going to ignore it for now...hopefully its nothing serious.

[rjcaptsean]

It was very strange that both of the gears were bolted on at the far end of the slots. I know that one of the mods for these motors is to advance the intake cam 6 degrees and I initially thought that what was done to yours, but you are supposed to leave the exhaust cam where it was. Odd.