Timing chain knock and running rough

[TimboSHO]

I've been searching and haven't found anything like my situation, so here it is. My 91 3.0 started knocking one day while it was overheating and died on me. I put rod bearings in it and fixed the coolant leak and it still knocks, but now it runs kind of rough. Listening to the motor with a stethascope, I think most of the noise is coming from the rear of the motor where the timing chain is. My question is, is it possible for this chain to skip a tooth and cause a rough running condition? I will be taking the valve covers off next week to inspect the tentioners and the chain and I would like to know how to make sure the cams are timed properly. I just took the front end of the motor apart (2 times) so I know the timing belt is properly aligned. Thanks for any help!

 

[thecrew2999]

it is possible the cam jumped a tooth. if that tentioner isnt working right it could have very well jumped which is why it would be making the sound.

there is marks on the chain and cam sprocket that help you know when its aligned.

with me my noise i had before was because i forgot to tighten the tentioner down on the timing belt and it was slapping around and cause it to be outta time.

good luck with everything.

take the tentioner out and take it apart (theres a pin that goes threw, compress the tentioner in the chain and push the pin threw then the top part comes off.. clean it good and stretch the spring back out)

 

[93rev2sev]

I think thecrew is giving good advice for the timing BELT tensioner. You asked about the timing chain tensioners (I assume you mean cam chain tensioners).

These pump up with engine oil pressure (I think) and if you use heavy weight oil like 10w40, it takes them a bit longer to pump up (during startup).

I REALLY doubt one of the chains jumped a tooth...if you overheated, try new plugs.

 

[TimboSHO]

I think thecrew is giving good advice for the timing BELT tensioner. You asked about the timing chain tensioners (I assume you mean cam chain tensioners).

These pump up with engine oil pressure (I think) and if you use heavy weight oil like 10w40, it takes them a bit longer to pump up (during startup).

I REALLY doubt one of the chains jumped a tooth...if you overheated, try new plugs.

Yes, I mean the cam chain tensioners. I'm using 10W30, but the noise continues even after running the car for a few minutes. I guess I could try putting new plugs in it to see if it would help the running issue (although I never knew overheating could cause plugs to go bad?), but I'm still worried about the knocking....

 

[Denny]

Tim, there is a little indention mark on each camshaft sprocket. There are also two different colored links on each chain that are used as a guide when installing. The marks should level with the head. As well, there are flat marks on the camshafts themselves that should be level as well. There's a positioning tool that'll help you out here.

But here is a guide on the cams

http://www.autozone.com/servlet/UiB..._us/0900823d/80/0b/f8/0a/0900823d800bf80a.jsp

Good luck bro. I've had a tooth jump time up there too.

 

[TimboSHO]

Thanks a ton Denny. I'm trying to see if Bill has any more cam position tools left before I dig into it.

 

[TimboSHO]

UPDATE: I looked at the car tonight. My boss suggested a bad valve, so I did a compression check and sure enough, cyl. 5 only has 30psi (all others are at 180psi). Bummer. Looks like the heads are coming off! It's amazing how the noise can seem like it's from one place and be completely be in a different spot. Thanks for the suggestions though.