STAR

iTrader: (1)

I'm going to build a 346ci LS6 with the stock crank, forged rods and pistons. This motor will be used with a power adder (supercharger) and see about 15-16 lbs of boost. The main and rod bearings will be clevite.
I have read that lsx aluminum blocks expand more over iron when at operating temps. Also, it seems GM has much tighter tolerances for these motors.
When at full temps won't your clearances reduce? Or should I build it with tighter specs assuming expansion will get me to the target numbers?

Any suggestions as to what shoot for on the main and rod bearings?

Thanks

THE LAST Z

iTrader: (5)

Just let a pro do it if your not sure

Ryne @ CMS

iTrader: (10)

no the clearance wont decrease when the block gets hotter, the clearance will get larger because the aluminum will expand larger around the main journal, or half of the main journal i should say

STAR

iTrader: (1)

Okay after some research I think I'm going to shoot for .0020 on the mains and .0025 on the rods. How does this sound to you guys?

crashly

what oil brand / viscostity you planning on running
which oil pump?

wht97ws6ta

The fact of the matter is thinner oils obviously wont support the load of thicker oils. Im going to start off by recomending that you go to forged crank for the power level you will be making with 15 PSI. May cost more now, but will save you money in the long run. Cast cranks werent intended for the torque you will be making with that setup. With that said, as far as bearings and clearances. I would definitly run a H series bearing, which stands for hardened and they have added clearance made in. Clevite is good but if it were mine i would go with a ACL race bearing. As far as clearances optimal for your build would be .0025 at a minimal preferably .003 on the mains and no less than .003 on the rods. And Shell Rotella 15W 40 Diesel oil is proly the best oil out there for the dollors, b/c they havent cleaned all the leads a zincs out of it to meet frigin emisions. Just be sure to run a higher volume pump than stock.

crashly

[ With that said, as far as bearings and clearances. I would definitly run a H series bearing, which stands for hardened and they have added clearance made in. Clevite is good but if it were mine i would go with a ACL race bearing. As far as clearances optimal for your build would be .0025 at a minimal preferably .003 on the mains and no less than .003 on the rods.






a few corrections here...
H series does not have added clearances...

" HX " , has to be ordered to have the extra .001' clearance

1 FMF

iTrader: (1)

on oil even all the "diesel" oils now which basically mean any 15w-40 oil such as shell rotella, mobil delvac, or chevron delo, technically do not have extra zinc and phosphorus as anti-wears because they are all meeting the API-SM spec, check the bottle. There is tons of emission bullshit on diesels now, including catalytic converters.
The diesel oil has more antiwear additives or it protects better is becoming a common misconception. But I do agree it is a better oil, based on price and it's viscosity range; the synthetic label is a bunch of crap.

can there be a clarification on the words tolerance vs clearance ?
It seems those two words get used in place of each other, more so tolerance for clearance.
Am I correct in saying that tolerances have tightened up (which is a good thing and is due to a better manufacturing process) but clearances for the most part have not changed?

ddnspider

iTrader: (26)

perhaps you should do some more research before making a post like that.The stock ls1 crank is incredible strong and has been in 1000+hp cars with no issues.Theres no reason to upgrade to an aftermarket crankshaft unless you purely want more cubes from stroke.Check out the Forced Induction section and do some reading/searching.

wht97ws6ta

Ah yea H series does have more clearance than a standard "P" series or vandervel series bearing. And your right "HX" bearings have an extra .001 of clearance in them.

wht97ws6ta

Yea your right, they have cleaned alot of the good stuff outta diesel oils now for this emissions BS. But its higher in detergants and is still a all around better oil than your conventional motor oils. Theres bullitins out by the cam manufactors that recommend it on flat tappet cams over conventional oil. But to each his own. Run whatever makes you feel warm and fuzzy.

wht97ws6ta

Haha ok... Just cause ole Jo Blow's car made 1000 hp on the stock crank dont mean that its a proven piece and is what every body should run. Hell i suppose that anybody who buys an aftermarket forged crank for a LS1 is just insane in that case. I bet if callies knew that the stock cast crank was so strong then they would drop all there LS crank manufacturing for the stock stroke. Yea anybody can make a 1000 HP on stock stuff, but if im not badly fooled here the whole idea is to make power and make the engine live. Everything with a beginning has an ending. And i promise you that a cast crank will fail before a quality forged crank will. So if you wanna save you 5 or 6 hundred dollors now to spend 3 or 4 thousand dollors later then go right ahead. Its not my motor. You know its funny how when you try to help someone up here, some forum goddess chimes in with a "1000" post and tells you you dont know nothing because you only have 50 post. Not sayin thats what you said but thats sure how it seems up here. And not knocking stock LS1 cranks, but your comparing a cast oem crank to a forged crank. You do the math. I guess its all about peace of mind. But again to each his own.

CodeRed2000SS

u sir, are the man



i got my turbos running my superchargers budday!

ddnspider

iTrader: (26)

Are you kidding me?SERIOUSLY do some research.Check out the stickies,check out the FI section,check out the nitrous section.The stock ls1 crankshaft is NOT the same thing as a regular small block crank.It has been proven time and again to handle ALOT of power, RELIABLY.And if by Joe Schmoe making 1000hp+, youre referring to MANY of the sponsors and moderators on this very site, THEN you would be correct.And, ps I have more than 1 stickie on this site as well, so you can shove the "well he's just throwing around his post count".You truely are acting like a newb.Maybe you should do your research before you try to give others advice.

CodeRed2000SS

well mr smartie pants u sure are getting ur panties in a wad over all this. ok a stock ls1 crank maybe can support 1000HP, but its not as reliable as a forged crank. thats all my freind was trying to say. if u are tryin to say that a forged crank is not better than a stock one then the aftermarket companies should just simply go out of business. and yes moderaters and companies on this forum do run stock cranks but im sure that they will tell u that a forged crank is better. i just honestly think u sir are having a bad day. so here maybe this will cheer u up my freind

ddnspider

iTrader: (26)

maybe you should bother to read your buddies posts and then make a comment."Cast cranks werent intended for the torque you will be making with that setup."

1 thing i cant stand is some guy who comes on here giving advice when he doesnt have a clue.Im amazed at the level of knowledge in this thread.If either of you bothered to look at the setups/builds being done on a weekly basis, the majority of them are using a stock crank and make somewhere between 700-1000hp. Not to mention its been done reliably.Im done with this thread.Nobody seems to watch to do any research,even by what was said by GM themselves regarding the ls1 crank.peace

CodeRed2000SS

well lets see, did u research before u built your motor? on a budget?, or did u just go a builder and say here is 10,000 build something that runs good. man i am no idiot, and yes this guy is my buddy. i AM on a budget and i do my homework. i dont think what i run is not half bad from two guys that built the car with a budget and 17 years old at the time.

ddnspider

iTrader: (26)

dont act all tough.I started modding my own car when i was 17 too.I saved and did research for a year and a half before i built my motor/turbo kit,on a budget,while i was getting 2 engineering degrees at a tech school, working 2 jobs.So dont try talking down to me.I went with cubes because i wanted to spool a 76mm turbo with a 6 speed transmission before 3k rpms.But i dont want to bore you with real world experience as opposed to what ur buddy reads online

wht97ws6ta

Well damn. Its just to bad GM didnt cast a 4" stroke crank so you could have ran the almighty stock crank in yours.

ddnspider

iTrader: (26)

I would have loved too seeing as how a 4" Eagle crank is $750