knocking after rod bearing job

[Detenator]

I replaced the rod bearings at 137k, and now, almost 2000 miles later, the knocking came back. I torqued the caps to spec, in stages, just like everyone said. Then i filled her up with 10-40 and the engine ran smooth as ever. I changed the oil after 1200 miles, with 10-30 and the knocking comes back duing city driving under acceleration with the engine hot. Where did i go wrong?

 

[sdpatt]

There is a chance the source of the knock is not actually the connecting rod bearings. Does the noise sound any differently after you changed the bearings? If not, the source was something else. It could be the piston wrist pins (rarely) or a reduced diameter crankshaft journal that had already been damaged by the last bearings. What did the removed bearings look like and did you inspect the crank journals?

 

[Detenator]

they didn't look too terrible, except for 2 or 3 of them, and i didn't plastiguage the crank. I just took the old ones off and put the new ones on. The old ones were rattling noticably for probably 1000 or 2000 miles, then i got down to it and changed them. if it is a worn crank, does that mean i have to take it to be ground?
This is a pic of the worst of the bunch
http://sinc.sunysb.edu/Stu/pczyz/rod.jpg

<small>[ September 17, 2003, 08:50 PM: Message edited by: Detenator ]</small>

 

[NinjaMike]

Unfortunetly you drove you car for about 999 - 1999 too many miles.

The car should have been pulled out of commission at the first sign of noise.

Chances are the crank is gouged and will have to be machined and fit with oversized bearings. You're at the point right now where it might just be good to swap the motor, if this is indeed your problem.

At least it gives you an excuse to do the 3.2 swap.

 

[BeatDaSHO]

That bearing doesn't look bad to me. It didn't wear down too far because the oil hole isn't elongated or anything. I think your problem is something other than the bearings. But you could always take of the crank case and find out.

Greg

 

[ckinart]

sdpatt:
Does the noise sound any differently after you changed the bearings? If not, the source was something else.

Detonator,

Has there been no change in the "knocking" that you're hearing? Have a look here for some discussion regarding my rod bearing replacement experience. This may not be relevant in your case, but it may provide some insight. Like Greg said, the picture you've posted of your bearing wear does not appear to be abnormal or severe, so unless you are certain that it's your rod bearings that you're hearing, I would suggest looking elsewhere.

Good luck!