SlickVert

iTrader: (5)

I am process of building a 383 stroker, stock 99 LS1 block 3.905 bore with Callies 4” rotation assemble.

I have heard of low oil pressure issues due to incorrect bearing clearances.

What do you all recommend for Main and Rod bearing clearances?
Bob

2001 Pewter WS6

iTrader: (43)

I did a lot of searching on this as well and from what I saw .0018 - .0020 was pretty good. Some went as big as .0025. Also cam bearings came into play as well and most said go with Durabond. I spun 2 rod bearings recently and I am making sure that it falls within this range. I am also going with the new High Volume/Pressure Mellings oil pump. Hope this helps...

Uthinkso

With an aluminum block put the mains between .0018-.0022

Camaro99SS

iTrader: (4)

It's always safe to go with the manufacturer's recommended clearances and keep as tight of tolerances as you can.


Jason

Joel_SS

iTrader: (8)

My shortblock i got from LME has .0022

kossuth

iTrader: (12)

The manufacture point I agree with but the tight part I don't. There is a point where it induces more friction than the oil can take and you can actually lockup the motor once everything gets good and warm. Also a tighter motor doesn't make as much power.

JL ws-6

iTrader: (50)

Bearign clearance depends alot on what you intend to do with the motor. if it's a race setup, the clearances are gonna be bigger, and you will be running alot heavier oil as well. I'm talking stuff that's being built ot see alot of boost/nitrous or a real radical n/a setup. If you are rebuilding because your factory motor needs it dur to high mileage, and is not aimed for performance first, then factory clearances are fine.

Bearing clearances are one of those things that people tend to change and not really understand.... alot of people have an engine built with the intent of making 500, 600, or even more power, then when they see the oil pressure low, they freak out, or can't understand why they now have to run 20-50 oil instead of their mobil 1 or whatever.. they complain about the thin oil gettign consumed really fast and the low oil pressure... but in actuality, it's because teh bearigns and whatnot are much looser, allowing for alot more oil to flow, therefore having less pressure ( less resisitance to flow )

Camaro99SS

iTrader: (4)

Clearance is the distance between moving parts. Tolerance is the margin of error among all all bearings. If I were building an engine and had the ability to set tolerances as strict as I wanted, all clearances would be, say, .0020". That's the point I was trying to make.

Jason

bulletLS1

I have in my ls6 new block
mains .0015 (oem said from .001 to .0025)
rods .0020

port, polished, radiused & shimmed O/P
tried to grind all sharp edges inside block oil galleries, blend and smoth 90 deg drill tubes...

oil p with motul 4100 10 w 40 in 25def celcius wheather is:

cold start 75psi @ 1000rpm
180*F 65-70psi @ 1000rpm
220*F 60psi @ 1000rpm
250*f 40psi@ 1000rpm


in all cases if rpm are > 1800 the OP is > 65psi
althou the oil gets hot very fast.
https://ls1tech.com/forums/generation-iii-internal-engine/519921-very-hot-hot-hot-oil-temp-after-rebuild.html