Hey guys,

I'm doing a 2.1 de-stroker at the moment which will see around 700whp and 9000rpm daily and I'm having a hard time deciding which rod/main bearing clearances to go with, I've always used around 0.0025" on the mains and 0.0020" rods with 10w40 on engines revving to 8500rpm/550-600whp.
This has an uncut OEM 88mm crank, turbo tuff rods and wiseco pistons.
I was thinking of running 0.0025" on both the mains and rods coupled with motul 15w50. A lot of the threads with info on this seemed to be a bit out dated to me so i thought id bring up a new thread.
Any info is greatly appreciated!

 

You're asking for the secret sauce (clearances) in engine building man. This is something that gets come up with via testing to figure out what works at different power levels. Not something most engine builders will (or even should) share..

 

I haven’t had a problem with a few reputable shops sharing that info with me lol, from shop to shop it varies though that’s why I’d like some opinions. Hard to call it “the secret sauce” when pretty much everyone uses 0.0020-0.0025 for clearances on these engines.

 

Yet here you are, asking for advice. If you don't think its important, or "secret sauce", just slap it together. Should be "fine"...

 

Uhhh no haha I don’t think slapping things together without measuring and going with acceptable clearances is “fine”. I’ve done quite a few 4g63s that are still running today, without any problems. These all consisted of either 0.0020” on the mains and 0.0025” on the rods, or vice versa with different oil weights. I’m just looking for an opinion on going loose on the mains and rods, if you don’t have anything helpful to say than don’t bother. Thanks for your feedback!

 

@Adriank

Heres a relatively recent hard hitting thread on bearing clearance. Pretty good read!
https://www.evolutionm.net/forums/ev...need-help.html

Cheers, Joe

 

Hey I’ll check it out! Thanks man! Appreciate the help.