Z28Caves60

iTrader: (8)

i got an LME 408 built last year, NA motor nothing crazy, well oil pressure dropped while driving a week ago, i had replaced the oil pump and o ring in attempt to regain oil pressure with no such luck, and i noticed after a short drive that the balancer has a small peice cracked off of it and the bolt walked its way about a half turn out. The balancer bolt is brand new from the dealership, just wondering if the balancer can be to blame for this??? and i believe oil pressure gauge can possibly be off? Any ideas?

JPH

iTrader: (2)

I would put a mechanical guage on it and check it. I think your balancer is not on all the way, causing your bolt to backout. Or the bolt just never got tight.

NVR_SPDS

iTrader: (39)

I would think that it could be one of two things. First, the balancer wasnt on all the way, or second, there isnt enough press for the balancer-crank clearance.

Z28Caves60

iTrader: (8)

what do you mean by press?

NVR_SPDS

iTrader: (39)

The way our balancers stay on is that the hole in the balancer itself is smaller than the crank snout by a few thousandths of an inch. The paperwork that came with my Powerbond recommended between .008-.012 press fit. I dont know if you have access to inside/outside mics to measure the crank and balancer?

This is why heating up the balancer before install really helps. Heating it up, will make the hole bigger, giving you more clearance to press it on.

pwrtrip75

iTrader: (8)

Loctite.......it works wonders.

vettenuts

iTrader: (4)

The harmonic damper is held on by the interference fit (the numbers above need one more decimal place) and contact with the timing chain lower sprocket/oil drive. If your bolt is backing out your interference fit may be too small. Did you re-use the stock damper (pulley)?

Second, when installed did you rotate the full 140 degrees or use LS1howto.com?

printmanjackson

iTrader: (1)

and right there is the problem

Z28Caves60

iTrader: (8)

well this weekend ill tackle the problem, im buying a new balancer and ill mic the od and id of the crank and balancer, im also buying an arp balancer bolt, hopefully this will fix thanks for all the replies

vettenuts

iTrader: (4)

To accurately measure the fit, you need equipment to measure to 0.0001". The amount of interference is around 0.0008" to 0.0012".

69LT1Bird

iTrader: (1)

If you don't do it right the ARP bolt will still fall out. The $6.00 GM is just fine.

Silver408z

iTrader: (1)

The $6.00 GM one is good for one use. The ARP is reuseable.

69LT1Bird

iTrader: (1)

I know, if you think you need to take the balancer off several times I guess its worth it, to me its not. That wasn't my point. If it does not get push on all the way and torqued correctly it will still come loose.

Z28Caves60

iTrader: (8)

thanks guys ill keep everyone posted on the progress