Author Topic: Need Help Identifying a Sound (Read 4797 times)

tonywonder · « **on:** May 30, 2011, 09:27:20 PM »

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.

http://www.youtube.com/watch?v=QBBo4XB8__w&feature=player_*****ded

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.)

http://www.youtube.com/watch?v=3rZG-jq1U20__w&feature=player_*****ded

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.

DesktopDave · « **Reply #1 on:** May 30, 2011, 09:56:06 PM »

I don't think the change in oil would make that much difference. I'd say it's a timing chain rail, but the other ones are usually the problem. The water pump & idler wheel are also common culprits.

Read this post if you have a few minutes, it's a pretty common problem. Fix it and you'll be good for another hundred thousand miles.

I hate to say this, but I'd pull the front cover & physically check to see what's going on down there. Problems get very expensive very quickly if the timing chain skips a few teeth.

I've been tending towards this theory for a while...I'm starting to strongly suspect that changing the timing chain tensioner on an old chain will result in an early failure. Tony, do you have an e30 with the early M42 motor? Did it have the original tensioner?

tonywonder · « **Reply #2 on:** May 30, 2011, 10:11:39 PM »

the tensioner is pretty new i barely drove it up til recently and it was one of the first things i replaced. the water pump is also relatively new. ive had teh car for a little over 2 years maybe. and started to DD about 2 or 3 months ago. the sound only happens at idle sometimes usually when its still warming up. but i take the highway to work and when i let it idle after my commute i dont hear the sound. my e30 is a 02/1991 E30 318is. i dont know if it had the original tensioner. i suppose its possible. it runs pretty well from what i understand but it might be due for a timing chain.

sqlpython · « **Reply #3 on:** May 30, 2011, 11:04:15 PM »

Hmmm... I listened to both MP4

I don't hear a mechanical impact (clanking)
I hear a sputtering.. Like a PCV (crankcase ventilation valve).......
Am I missing the clanging or knocking?
Pitch just seems to be a sputtering sound to me........

bmwman91 · « **Reply #4 on:** May 31, 2011, 12:28:10 AM »

The timing chain & related parts can make all sorts of funky noises when they are going out. I can't say for sure what might be the culprit from those sound clips, but I would not put the timing assembly out of the realm of possibility. Honestly, the only way to be sure is to pull the upper & lower timing case covers & check. That can be done in about 2 hours.

You need to:
- Drain coolant (dispose of it responsibly, not in the gutter)
- Remove engine fan & shroud
- Remove thermostat housing, water pump pulley (loosen w/ belt on, then release the tension at the alternator) & water pump
- Disconnect & remove cam + crank position sensors
- Remove PS & AC belts
- Remove crank pulley & harmonic damper
- Remove 22mm bolt on crank (usually needs 200+ ft-lbs*)
- Remove valve cover
-Remove upper & lower timing case covers.

- Inspect timing assembly components. Take pics & post them here, with close-ups of each component.

- Reassemble everything in the reverse order. You will need all new paper gaskets, and they should be coated with a non-curing sealant (both sides) that is rated for use in auto environments with coolant and oil at high temperature. You should also replace the rubber profile gasket & seal it along the perimeter & especially at the ends with high temp, oil resistant silicone RTV (Permatex Ultra Black is recommended).
- Before tightening the bolts on the upper cover, get some spare M6 (20-30mm) screws & bolt the valve cover (no rubber gasket) onto it so it pushes the upper cover flush with the head. The stock valve cover bolts don't work for this because of their shoulder. When held flush you can tighten the upper cover's fasteners.

This is a lot of work. I can't guarantee that the noise is timing related. The crappy thing is that these motors are all old enough that that stuff is probably going out. Oil changes & fresh tensioner pistons help a lot, but eventually it all needs a tear-down. Does the car run any differently when warming up & making this noise? Does your intake show a lot of soot or other carbon build-up? The noise almost sounds like a leaky valve, but I would think it would be noisy all the time.

Have you looked for vacuum leaks? Is the idle uneven & stumbling? Do you get check engine lights when you floor the car for more than a few seconds? It could be a big leak that closes up once things warm up & expand. Heck, maybe it is some sort of exhaust leak.

* Remove the air filter box. Place a block of wood over where it was. Get a 18" breaker bar on the bolt & rest the bar on the wood. Use the car's starter to break it loose (usually takes 2-3 tries). Some people leave the bar 6-12" above the wood so the bar smacks into it to break the bolt loose. I don't like that, but it might work better. Do NOT remove this unless you are sure you can get it back on with at least 200 ft-lbs, the spec is 240 ft-lbs. You will need some way of locking the crank...you might be able to put the car in 5th gear & press on the brakes. The clutch usually slips though. This step should only be done if you are sure you can put the bolt back tight enough! I machined a steel plate that bolts to the pulley hub & rests on the frame.

92BMW318is · « **Reply #5 on:** June 02, 2011, 12:12:48 AM »

This might be a longshot. but....
I mixed up the spark plug wires once and my car made this type of sound. after quickly shutting if off i found the mistake.

did you change out spark plugs.

tonywonder · « **Reply #6 on:** June 04, 2011, 02:45:15 PM »

i did not change my spark plugs. i do have some new ones im going to put in. actually i might go do that right now and see if that changes anything.

tonywonder · « **Reply #7 on:** June 04, 2011, 04:57:58 PM »

the noise is still present after changing the plugs. if this was timing related wouldnt it knock at all engine speeds? it only makes the sound at idle. and its not constant. the sound will becomes audible then goes away then back then gone, while its idling.

the car does not run any different that i can tell. i checked for vacuum leaks and there doesnt seem to be any. no check engine lights. the sound occurs AFTER the car has warmed up.

im wondering if theres a loose pulley. i only run the main belt crank water pump alt. i dont use power steering or ac. but those components are still attached to the chassis.

ive also pulled the oil pan before to check for debris. not recently but sometime last year i believe. there was none. and no loose bolts either.

tonywonder · « **Reply #8 on:** June 16, 2011, 11:43:04 PM »

heres something i noticed a while ago. and maybe it has something to do with the timing chain. but the crank pulley doesnt seem to be perfectly centered while rotating. it has a very slight wobble.but thats only looking at the center nut piece. ive only been able to replicate the sound when i drive from cold and idle. after i drive highway speeds it doesnt usually comeback. though ive made it replicate the sound by turning on my lights. which causes the idle to very slightly drop but it goes into that sweet spot for the sound. its pretty damn annoying to be honest. but im going to order a chain and hopefully its just that. ill find out when i pull the case off.

this is my daily right now and i dont really feel like dropping a ton of money to replace parts that are good. ive already started searching for a motor to swap so i rather put my money there than this engine. but i dont want it to fail on me either. again the car doesnt run any different. exhaust is a bit shakey but i think theres a small hole in the muffler.

do i absolutely have to remove that crank bolt? or would that be just to replace that sprocket?

tonywonder · « **Reply #9 on:** June 18, 2011, 06:14:43 PM »

updated first post with pics of cam gears and need some help. let me know any information you can share. thanks. im going back out to remove the top chain guide to check the chain slack.

tonywonder · « **Reply #10 on:** June 18, 2011, 07:01:56 PM »

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.

rjcaptsean · « **Reply #11 on:** June 24, 2011, 08:59:24 AM »

I wouldn't be too concerned regarding the location of that intake cam lobe. One of the basic performance mods on the M42 is to advance the intake timing 5degs while leaving the exhaust alone. That looks like what has been done to your motor.

stillmatick · « **Reply #12 on:** June 24, 2011, 02:05:30 PM »

sound like my stock rusted muffler lol

miss fire?? kinda sound like when you shut off the car.

tonywonder · « **Reply #13 on:** June 26, 2011, 09:02:47 PM »

my muffler does appear to have a hole in it and its been sounding quite rumbly lately. the cams were set back to stock timing. the gears were setup wrong and they were adjusted to extremes. so i just put them how they are stock. still listening for that sound.