So im looking for some help / possible answers... i have a 2001 2.4l Z24 and So my motor got a nasty knock to it, sounds really bad. The sound is a basic blown motor knocking sound along with something that sounds like their are nuts and bolts bounching around in the engine. I checked the plugs they all look fine... the sound is more so from the bottom/center of the motor it sounds like maybe ever some on top, its loud and hard to tell for sure. i pulled the oil pan and found metal shavings. so my question is this looking under the motor how can i tell if the issue is a spun rod bearing or something of the sort? im trying to figure this out without pulling the motor and tearing it apart. Well if you got any idea please let me know, or any suggestions. I have replaced the motor once this motor was built by mantapart its a mild build with a blower and most bolt ons. Any tips on pulling the motor apart if i have to end up doing that which i think ill have to do and rebuild it. Thanks everyone!

Looks like you will have to pull it apart in order to see what the problems are. No other way to do it!

ok so i found that one bearing is toast the rest are fine. the one that was toast looking at it and it does not seem to have damaged the rod or the crank so i may just try putting a new bearing in after a good cleaning on each surface and see how it turns out....thanks

Is it the #3 rod bearing?

maybe its the 3rd one from timing chain. any ideas? i want to just try a new bearing and hope it works just dont know if anyone has given this a try or does everyone only do or fix crank and all new bearings? thanks again

I would only change one bearign if i could guarantee the rest of the motor is completely free of particles from the bearing. Heck even cheap mr goodwrench replaced all my bearings, though thereassembled it wrong and it blew again 3k later...

Personaly I would have the crank inspected. Its your call though, just dont be surprised if the bearing fails again.

i just look at it as its a quick easy fix thats worth the try worse thing it goes again or doesn't work and ill have to pull the motor and fix it again. the rest of the engine looks and seems spotless and fine so i think its worth the try.... im working on building my stock motor so if or when one goes i can just swap them out..

ok so one question for anyone on this topic... im looking into bearing and they come standard or .25mm undersized...which would i want any ideas? also would the size difference be width or thickness?

Undersized bearings are used when the crank journals measure smaller in diameter than stock, as in if the crank was damaged and turned down on a lathe to use the next undersize bearing. (An undersize bearing is "thicker" than a standard bearing.) The only way you can tell what to use is to measure the crank with a micrometer and see how it compares with stock specs. (I suppose you could plastigage it and get a rough idea, but I'd measure it.)

There are other tricks you can use too. If the measurements indicate there'd be a little more clearance than optimal, but the next undersize bearing will be too tight, you can use one half of the undersize shell. (For example, on a rod, you'd put the half undersize shell in the rod end and the standard one in the cap.) Of course, you're going to measure it all over again once you're done, right?








Edited 6 time(s). Last edited Friday, March 06, 2009 3:57 PM

Same thing happened to my son's motor. I measured the rod journal and it was oval. Had to buy a rebuilt crank and rebuild the entire engine. Rod bearings are this engine's weak points. Change oil often and don't run it hard when cold.
If you haven't ovaled the bearing maybe you will be lucky and just get by with polishing the journal and replacing the bearing.

ok thanks for your help everyone i think i will clean it up, measure it and go from there... Ill keep you informed!