JDM engine rebuild questions??

[Wayne G.]

I have just begun the rebuild of a JDM 7M-GTE purchased off Ebay. After the teardown must say all looks very good. The head gasket was a stopper type with stock head bolts but showed no signs whatever of leakage. I have purchased an HKS metal head gasket and ARP studs to put it back together. The questions are while I have this thing down would you go ahead and replace the bearings (rod and main) or reuse the orig. ones. I plan to get the block skimed to tru it up therefore the pistons and crank will have to come out. Would you go ahead and replace the rings also? Whats the consensus on replacing the Oil pump. these things seem to be around $200-$250 so if it is not needed I would not replace it- what do you think. All replys helpful.

PS the engine is slated for mild hop up - filter downpipe, turbo elbo, 550 injectors, Lexus AFM and maybe intercooler kit with stock turbo running up to 12psi or so.

 

[flubyux2]

i would Plastiguage the main and rod bearings IF the bearings fail a visual inspection. In order to pass the visual inspection, ALL the bearings must have at least 90% of their original Top coat of babbit. this means MINIMAL shiney/polished silver spots, absolutely NO copper showing, and virtually no pittings/gouging/scratches. If the bearings dont have almost all of the original Dull-appearing top coat of babbit, replace the bearings.

also, have the machine shop Mic the bores to make sure they are still within a few Ten-thousandths of an inch/Hundredths of a Millimeter tolerance compared to the Stock Bore... NOT the wear/service limit. If the bores turn out to be only a few 0.01 mm's off of the standard bore size, you could throw in the standard size pistons w/ new rings.

the Oil pump has wear limits too. if the oil pump gear's specs are not close to or past the service limits in the TSRM, reuse it. if they are Close to the max service limit or Past it, get a new pump. sometimes, you dont always have to buy a new pump because the old one isnt Worn out. sounds logical right?

ask the machine shop if they have access to a Surface grinder. a Surface grinder is more precise and leaves a perfect finish when compared to a fly-cutter on a milling machine. I had my block done on a surface grinder and it was PERFECT; absolutely NO marks anywhere.

 

[arz]

Im in the process of looking for a Dingle ball hone. What is the diameter of the stock piston/bore?

 

[IJ.]

Arz: 83mm