Help Diagnose a Sound Please

[H D]

I have a sound I can't quite figure out. It occurs ONLY at 2500 rmps, not 2400, not 2600. Only in gear. Can't replicate it in neutral or park. Metallic sounding, but not like anything I've heard before (and I have a car from 1969!). I haven't put it up on stands yet to test it in gear but wanted to see if there was something I should be looking for when I do get to it? I can't quite tell if it's coming from the engine or suspension but have had passengers say they can't hear it. Confused:banghead:



If nothing else, just lie to me and tell me it is probably something cheap and an easy 15 minute DIY project.

 

[Todd Z]

Timing chain noise...... Engine detonation........ Cat converter shield ratteling.....



Just a few of the basics.....



Todd Z

 

[H D]

Thanks Todd.



Would any of those be specific to only one exact RPM? I've been thinking timing chain considering the common problems to Sport Tracs, but I didn't think it would be only noticeable at a specific RPM.

 

[EddieS'04]

Hugh, our tracs that have the chain rattle. Seem to do it at the rpm. If that is it you might be able to change the cassete guides and stop it. Only need to pull lower intake and valve covers, I think. Caymen can give more info. Some have went to heavier oil on high milage and it helped.



Also I can tell from the exaust sound. Our tracs set up, different harmonics from the motor @ 2500rpm. If you find a loose cat shield. Just get some large hose type screw clamps. Go around the shield. Tighten it up that way.

 

[John G]

I've got the timing-chain rattle. It happens at about 2400-2500 rpm, especially when under load in 2nd gear. I know the TSB says it will be 6 hours of labor to repair.



Will any harm happen if I don't fix it?

 

[Kevin Palmer]

My bet is timing chain as well...