rod bearings and crankshaft help

[TsiJohn333]

im going to be buying a 1991 galant vr4 with some mods such as wiseco pistons, eagle rods, hks 272 cams, arp head studs, cosmetic head gasket, 18g turbo and a frontmount intercooler. now the guy i am buying this from said the the rod bearings are starting to spin out but there are no metal shavings yet in the oil so he hasnt started it or ran it to try to save it. im new to the internals of engines. i know the basics but dont know everything there is to know so please bare with me here.

My question is how hard is it to replace the rod bearings? Is there anything i should look for on the crankshaft ? Do you think i could just pop in some new bearings and call it a day or do you think the bottom end would need a rebuild? any suggestions on new rod bearings? i know i can drop the oil pan to get to the bearings but dont know where to go from there. im also tight on cash at the moment so i cant be going all out on the bottom end. thanks in advance

-John

 

[91mitsuman]

Typically you will see or be able to run a finger nail across the crank journals and see or feel the scoring on the crank. If there are no metal filings in the oil why does he believe the bearings are going out? If you do end up dropping the oil pan to check a few rod bearings drop a main bearing to see condition there. Do you know if the crank has been cut or not. Chances are it has and you will need to know the size in order to order the bearings.

 

[talonDSMerr]

If cash is tight, I would stay away. Spun bearings are the prequel to bottom end rebuilds. There really is no in between for a spun bearing, either it has spun or it hasn't. If he's right, then there's already been oil starvation at that crank journal. At the very least, you will have to pull the crank and have it inspected and/or polished so when you install new bearings, it doesn't spin again right off the bat. This in itself is already a good portion of a bottom end rebuild.

 

[TsiJohn333]

the crank has not been cut. he said it was starting to knock a tiny bit and he is 100% sure its the rods bearings. so basically im gonna need a new bottom end or rebuild it? there is no way to save it? even if i have the crank polished and put the new bearings in? i forgot that he told me that he has the new bearings that he will be giving me to put in.

 

[91mitsuman]

You can save it by pulling the bottom end apart and taking the crank to the machine shop. Have it inspected turned or polished whatever is needed getting rod and main bearings that match the crank journals. Then a new front cover gasket and rear main seal. While its apart if you don't know how old the timing belt is might as well get a new belt. When installing the bearings be sure to use plastigauge. Im sure im missing a few things but, as talondsmerr said don't take short cuts if you want it to last.

 

[TsiJohn333]

ok thank you... do you know of any machine shops i can send it out too?