Timing chain question/warning
Timing chain question/warning
Hey guys. So in this thread. http://www.superturbodiesel.com/std/show...p?tid=6353 I mentioned that I bought the only timing chain that Rockauto had listed for the 1985 OM617, made by Beck Arnley. I didn't think to directly compare the chain to the one in the car because I'm too lazy to pull the cover off till I replace the chain... But it looks pretty different. It's pins are a lot smaller and have floating bushings that look too large to work. And it's a linked chain with no master. So has anyone actually used one of these chains? If so, how the crap did you install it?? Or is Beck Arnley just being dumb about this chain being compatible...
The chain's part # is 143 024-0044
So I warn, don't be so quick to trust Beck Arnley compatibility!
I'll attach a picture in a bit.
Here's the Beck Arnley chain.
That is the chain to use if you are rebuilding an engine and haver the engine out of the car and torn down. I'm thinking you are wanting to replace the chain with the engine staying in the car.
To do that you will need to get a chain that has a master link. Like this one:
http://www.autohausaz.com/search/product...ng%20Chain
Yeah I think so too. I priced one out on Pelican for $120 I think... I'm not 100% sure that my chain is bad yet. I'm gonna try to see if it just jumped because of the tensioner being stupid. But I may need to replace both anyway.
Dirty Little Freaks huh? Sweet, I follow you guys on facebook. Good stuff!
Timing chains rarely fail on these engines. What kind of symptoms are you getting? It pretty easy to reset the chain if you think it has slipped.
Yeah that's what I was hoping to do. What happened was I was driving on the highway, got off at the exit and while decelerating the engine started making a massive banging noise. (btw my fuel economy sucked for like a week before the event) The noise was sharp and loud and didn't sound like bearings or a rod; didn't sound the right speed/rate to be either of those. I got it towed to a local Benz and Bosch shop. Waited till they got to look at it and they said that they weren't confident working on the engine and tried to tell me that it was real old and tired and not worth it and didn't give me any good reason why. No way is a 103,000 miles old... So I got it home (still drives but loudly. heard a little of what sounded like chain noise on the way. And with acceleration and deceleration the banging seemed to go away). I popped the cover off to inspect the chain and cam (no wear marks on the chain) etc and turned the engine over briefly and it roared to life even though the plugs didn't cycle for more than a second (it was winter too) then I shut the key off immediately. But that allowed me to hear the noise better. Long story short, my theory is that the chain skipped at the cam and the pistons are tapping the exhaust valves right as they're closing because the cam is falling behind. Maybe the tensioner wasn't doing it's job??
It's not too hard to check if the cam timing is off.
First remove the valve cover. There is a timing indicator on the cam. Manually turn the engine until the timing marks line up. (See photo)
Then look at the harmonic balancer and see what the timing indicator shows. Normal timing chain stretch is 3-5 degrees. If the cam skipped a tooth it will be off around 20 degrees.
Thanks! So the timing should be somewhere around 3-5 degrees on the balancer @ TDC?
When the marks are lined up on the cam the indicator on the balancer should be between 0 (zero) and 5 degrees. A new timing chain will be at 0 (zero) degrees. Most of these engines are between 3-5 due to chain stretch which is normal.
(I can't take credit for the photos. I grabbed them off of a post on PeachParts.)
(05-14-2015, 01:19 PM)atypicalguy I have at least 90k on a timing chain and it is still at zero.
Theyy were apparently tedesigned several times over the years and the ast ones are the best. Mine came from a 1985 car so maybe I lucked out. I also use a lot of synthetic oil. Car has 195k on it now and I bought it with 82k on it. Chain has not been changed to my knowledge.
Alright thanks for the info. I read a few conflicting things online. One guy was saying that it should be between 9-11 degrees... Not sure what to think about that unless it was a different engine or something.
11 degrees is when the intake valve opens. If it has slipped a tooth it equals 18 degrees (as stated in the manual). Attached is the factory manual for checking cam timing.
Anybody know if it is normal for one side of the gear to have wear from the links on the chain? They almost look machined in, but the other side does not have them. Teeth look fine.
Not sure about that... Seems like either something's off center, or maybe it's something to do with the tensioner. Maybe the tensioner pressure isn't consistant and it's causing it to "bounce" and making one side wear more. Unless it was defective or not make tolerance and it's just equalizing. Is it running right ok?
No, not running right. I would not have seen the sprocket wear without removing it. I just pulled the head. The chain has zero stretch though.
Odd... Sounds like it could be a defect maybe? Maybe it wasn't heat treated right or something. Who knows. What were the symptoms?
I only pulled it to rebuild the head because I lost compression in cylinder #4. The exhaust valve seat was bad and it looked like the head gasket was leaking oil out the side. As far as I know the sprocket wear pattern had no impact on anything. The wear is circumferential and on one side only. I was assuming any motor at 198k would show the same. Not an alarming amount, but it definitely wore into that side.
(05-20-2015, 02:37 AM)atypicalguy Anybody know if it is normal for one side of the gear to have wear from the links on the chain? They almost look machined in, but the other side does not have them. Teeth look fine.
(05-20-2015, 02:37 AM)atypicalguy Anybody know if it is normal for one side of the gear to have wear from the links on the chain? They almost look machined in, but the other side does not have them. Teeth look fine.