pwrtrip75

iTrader: (8)

I have a 6.0L crank and block I am working on. I got new Clevite H series bearings, standard size. I had the stock crank polished, I think it measured out .0005 smaller than standard size. I test fit it together with oil only, it takes a bit to get it spinning and then if you spin it it does make a revolution... My question is... it seems on the tighter side of tolerance.... These clevite bearings H series.... What are they made of and how will the clearances change once this heats up? The engine will be around 800hp at the crank.

Im comparing this to another engine I have also, a 6.0L based 421... You can touch the crank and it spins over very easy... but this is assembled with assembly lube.

I would think oil would be less resistant...????

LSPerformance

iTrader: (23)

Spinning the crank is not a test for bearing fitment. If you don't have the proper tools (2"-3" outside micrometer and a dial bore gage), at least get some plastigage and check them that way.

Jon@HKE

Something definitely doesn't sound right if it feels weird when you spin it over. You should really measure all of the crank journals and check all of the housing bores w/ bearings in them with a dial bore gauge anyways.

jjcamaro02

iTrader: (34)

What do you run for rod and main bearing clearance in an aluminum block ?

Tony Mamo @ AFR

iTrader: (13)

I'd be more worried about the crank that spins super easy with assembly lube....LOL

Sounds like that engine will have very low oil pressure to me. When I spin a crank on a fresh built short (with assembly lube) it turns smoothly with consistent light drag but it doesn't easily spin (and keep spinning if I start it quickly) by any means. And yes....it would spin easier with motor oil as you speculated.

Not sure how you could possibly consider making 800 HP and not know every clearance to the fourth decimal.

Like others have mentioned....time to break out the right tools or purchase the right tools to check everything is exactly right. If its not your engine will let you know sooner than later and it will cost a whole lot more to freshen it than the proper measuring tools will cost you now allowing you to properly check things (a 2"-6" dial bore gauge with .0001 resolution preferred and a decent 2-3" mic). Or use plastigage to see if your at least in the ballpark....its actually fairly accurate if done properly.

-Tony

THE SHOP

At least plastiguage.

pwrtrip75

iTrader: (8)

Like I stated.... It was .0005 under when polished... So using the standard bearings I'd think it wouldnt have a prob. 800hp I dont think is a lot to ask. I made over 700 with a bone stock 5.3 with over 100k miles on it and it lasted 3 years. If I would have put some rod bolts in it...it would still be running.

It does turn consistently, and smooth. The 421 dont spin with super ease... but there is a noticeable difference,, not much.... i'll rip it apart and see. again. I dont remember the exact journal size, but I remembered the difference at the time.

Thanks...

KCS

iTrader: (20)

Bearing clearance is not something to leave to guesswork. At the very least, use plastigage.

Also, being able to spin an assembled V8 by hand worries me. Haven't seen that except in Pro Stock/Hot Street type engines with low tension rings and super slick honejobs.

pwrtrip75

iTrader: (8)

Its just the crank in it... no pistons or cam yet. I ripped it all back apart, and made sure nothing got in it.. it seems fine now.

HotSilverBird

The line bore and how straight the crank is the thing. You can plastigauge all day long and get good readings but if the crank is wrong or the alignbore off it aint gonna spin fer sheeet. When
I put the mains in if the crank doesn't spin freely EVERYTHING gets checked.

KCS

iTrader: (20)

Oh ok. I thought you said it was assembled.