Update on Engine Rattle

[79pace]

I did a compression check. I have 238, 238, 238, 210, 210, 225. All in all not bad. I checked the tension on the camshafts and they turn together perfect in both directions so no slack in the chains, Cranked it over on the starter a bunch and couldnt hear any rattle or any noise out of the ordinary. I banged on the cat with a rubber mallet and it sounds solid as can be and it has no worn shims. What else could sound like something banging on the under side of the valve cover? Could it just be that all the plugs were in an inch of oil causing major detonation even when its cold? The cams both lined up with their marks on the belt but I didnt pull it apart to check the mark on the crank but the thing runs perfect other than the noise so I doubt the belt slipped. Any more thoughts on this fairly loud top end knock?

 

[Machspeed]

Could be a exaust manifold, possibly a shim, have you had a 60k tune up?

 

[SLOSHO89]

FOR SHO:
Could be a exaust manifold, possibly a shim, have you had a 60k tune up?

How could it be an exhaust manifold?

 

[sdpatt]

How were those compression numbers measured? Was that inch of oil allowed to drain into the cyilnders? Those are higher than new values and if valid, indicate that there is a reduction in the combustion chamber volume from stock. Buildup on the pistons hitting the valves?

 

[projectSHO89]

FOR SHO:
have you had a 60k tune up?

The 60K service is NOT a magic bullet for everything. While performing skipped or overdue service is always a good idea, actually diagnosing the problem is a far beter idea.

79pace:

Use a mechanic's stethoscope ($10 at AutoZone) to try to pinpoint the source of the knock.

If the noise is isolated to the end of the engine closest to the driver and on the top, timing chain tensionsers might be the cause. Listen carefully at the bulges in the valve covers. A defective chain tensioner or a stretched chain will cause these noises.

Put the stethoscope directly on the center of the crank bolt and listen there. If the knock is most prominent there, be on the lookout for crank cancer or an improperly tightened crank bolt.

If the knock cannot be pinpointed to either of those two locations, think of rod bearings. Just be aware that rod bearings will often make noise that appears to be coming from the top of the engine, but are actually being transmitted from the bottom of the engine.

Good luck and go get a stethoscope.

Steve

 

[79pace]

Yes some of the oil did drain back into the holes. I tried to get most of it out but there was a BUNCH. The crank bolt was tight. I checked that after reading some past posts on this board. The shims are good like I said we checked that out. The tensioners seem to work I put a wrench on the cam and moved them and they moved both directions perfectly together. At least they are tight that is. I do plan on putting it back togther and seeing if the noise still exhists and if so try and track it to one location. Hopefully it was just knock from those plugs looking like the factory plugs and covered in oil.