I was just given 1993 240sx because it had knock and they were just going to donate it.

Some people have told me that if you replace the bearings, then the cranks shaft must either be polished or replaced as well.

What would happen if i just replaced the bearings and didn't polish or replace the crank?

Also, do i have to remove the engine from the car to get at the bearings or can I just jack the car up and get at them by removing the oil pan?

Is there anything else that absolutely NEEDS to be replaced when the rod bearings are replaced? (wristpins, rods, etc...)

I'm going to check for shavings in the oil once this snow melts.
Luke

 

well to remove the oil pan you have 2 options. break the motor mounts and lift the engine a little bit or you could drop most of the front suspension.

 

ahhhh you picked a great time to post, just put new rod bearings in my 95 SE last night. (finished at 4am this morning) really your taking a game of chance, how long had it been driven with rod knock?? i drove mine for >150 miles. you can replace just the bearings alone, but it really depends on the damage done to the rod journal and crankshaft journal. rod bearings are around 25ish dollars at NAPA. its a cheap fix, but very time consuming. you have to drop the crossmember. id really suggest getting the chilton for it, if i would have had that, it would have shaved a 1/3 of the time off. make sure you get bearing lubricant (aka motor assembly lube) and id suggest replacing the oil pan gasket (its an older motor and it could have had/has a leak, the reason you may have developed the rod knock) ive searched club240, zilvia, freshalloy, and a few others and youll kinda come up dry on this subject, but just get the chilton and read it carefully.

 

i would go with dak2007 later comment, thats what i did, it wasn't bad, but you have very limited room. i would suggest disconnecting the crossmember from the control arms and unlocking your steering wheel to swivel it out of the way.

 

Thanks for the replies. The car had been driven for less than 20 miles i'd say with the knock. It started knocking and they drove straight home and parked it. (According to them)

Pesudo, How many hours total did it take you? And were the rod bearings and gasket all you replaced?

 

yes rod bearings and oil pan gasket is all i replaced. how many hours heh around 10 (from 6pm to 4am) hours, but i went in there without a chilton/FSM and loosened some bolts that i didn't need to. id say if i were to do it now, i could do it in 6 for sure. also, does it knock at idle?? my friend that was helping me told me he was pretty sure it was only rod bearings, not the mains as well, because it did not knock at idle. you should start it up for a minute or so and check for knock at idle. (he has a probe and when he went to changed the rod bearings in it, it locked up, and he thinks because it knocked at idle w/o any load on the engine) hope that helps out man. (also, just wondering, is it a coupe or hatch)

 

It is a hatch, will that make anydifference? or are coupes rare or something?
Thanks for your help. I'll go start it up and see if it knocks.
Luke

 

just wondering, just seeing what your projects gonna be. good luck man.

 

it knocks a little at idle, does this mean the main bearings are bad also?

how do I fix those? or can I?