clearances

[gsxitement]

alright i got my stuff from the machine shop and am ready to start assembly. what clearances on the rod and mains would be the right way to go....i think in the manual it's like .0008-.0012....i think i'm not positive. but anyways, heres the setup i'm running : 98 gsx, 6 bolt swap with ported 2g head, arp everything, eagle esp h beam's, ross 8.3 pistons, bored .020" over, sc-61 (probably), t-3 manifold, tial wastegate (not sure what size yet), and the venom sheetmetal intake manifold (probably, damn magnus sold out of theirs and don't know when they're making more....) 550's, gm maf, already got the 255 walbro and an afc so i figure i should be fine on fuel.....and ACT 2100 and ACT flywheel...not sure if streetlite or prolite yet.....so yeah...anyone got any suggestions on the rods and mains?....it is going to to be a daily driven car that i take to the track everyweek so i'm keeping that in mind also.

 

[NOSNUSE]

Rod bearing clearance is .0008 to.0020
Main bearing clearance is the same.

 

[gsxitement]

i knew i had one of those specs right.....so i should just run with the stock clearances?...even though i'm gonna be running more rpm and boost than before.....i guess maybe i should go on the closer side .0008 than the .0020.....and also, i'm running ross moly rings....i know the end gap on the upper should be tighter than the bottom to eliminate flutter, but should i go with the stock deal on those to?...i'm just trying to figure the right way to go about making a good powerplant that will be reliable..you know?....i don't want to get this all together and then have to tear it all down again or worse....code red....R-apid E-ngine D-isassembly

 

[Enigma_Man]

This is just to pose a question, I don't actually know what's better but:

On a "race" engine, aren't they built with larger clearances usually? I've heard that that lets more oil get to bearing surfaces, at the slight expense of minorly-increased oil use.

Is that incorrect?

-Jesse

 

[gsxitement]

the engines i'm learning on at school (winston cup v8's) the clearences are very tight, sometimes into the .0002 range....you would want to run tighter clearances in a race engine so theres less slop in the parts...example..you would want rod and mains tight so that theres no chance of spinning a bearing....trust me, the clearances in a race engine are much tighter than on a street car.....but this is also from a 2 valve per cylinder, carb'd, v-8, that runs 9000 rpm for 500 miles

 

[Enigma_Man]

Hmm... Well I'm curious to see what the experts have to add.

-Jesse

 

[gritsak]

Originally posted by gsxitement
the engines i'm learning on at school (winston cup v8's) the clearences are very tight, sometimes into the .0002 range....you would want to run tighter clearances in a race engine so theres less slop in the parts...example..you would want rod and mains tight so that theres no chance of spinning a bearing....trust me, the clearances in a race engine are much tighter than on a street car.....but this is also from a 2 valve per cylinder, carb'd, v-8, that runs 9000 rpm for 500 miles

yeah and they also change the bearings after ever run prolly...you will put alot of wear on the bearing with clearences that tight.

 

[gsxitement]

you're absolutley right that they tear down those engines after every weekend...but i wasn't saying i was going to run that tight...i've decided i'll probably run about .001-.0012, i think that should be good enough.