I'm in the process of starting to assembly my shortblock...as far as mains with the .0001 bigger bearings I have like 3 thousandths main oil clearance (checked with tools not plastigauge). Engine is fully forged/ported head/fp black/meth/etc running over 35+ psi and around 600+ hp range....Will be running 15w40 or 20w50 oil. Should I stick with this oil clearance or get the stock size bearings and run 2 thousandths clearance?

Haven't checked rods yet

Thanks

 

.003 on the mains is pretty big. I shoot for about .002-.0023 for my builds. OEM spec is .0012-.002.

 

Do what you can to get it to the .002-.0024 range then run 20w-50.

 

What should he oil clearances be on Maine and Rods on a 800+ 9000rpm + motor

 

.003 is not too large. Lots of factors on the mains...RPM, stroke, oil used, reciprocating weight. You'd be surprised at some of the clearances in race motors

 

the "service limit" is .009". while i wouldnt recommend it, loose mains arent the end of the world. .003" isnt bad.

 

.003 is fine for a engine making 600whp.

a general rule of thumb is .001 clearnace for every 1.000" in diameter.

Since the mains are ~2.2xx, a .0022 clearance is fine.

Since your going to make big power, you'll probably run a heavier oil, ~20w50, so a .003" clearance will be well suited for a thicker oil.

 

Thanks..I can see mains can handle more clearance but what about the rods? Since it has pushing and pulling on it constantly it would be better to have less clearance right? Since all the mains do is basically spin in a circle

 

rods should be between .002" and .0025".

 

Woo, good info here!

 

+1
It's been a while since we had such good info