blown383z28

iTrader: (3)

hey guys, looking for some info/help. Got a 2010 camaro that has an lq9 block, 94mm turbo, runs on E85, auto 4l80, full weight (3900 w/no driver). Dynod on this set up 1180 rwhp. Problem I have it the mains went out. JUST the mains. Rods look almost perfect!! A few rods show a scratch or 2 that some debris went through them put other than that look brand new. Was told engine had about 10k miles on it. very little drag strip, mainly highway driving and pulls. One thing I found is the balancer hub was sloppy on the crank. I could grab the balancer and move it some. when I tore the engine down the balancer bolt was tight but the hub came almost right off by hand. Barely even had to tap with a hammer. The crank and hub is dual keyed (both keys where installed). The hub and crank both look like it was hit with a file, grinder, sand paper ,or whatever. My main question is could this have taken out he mains?? Almost all the mains where down to the cooper. No signs of heat either. Engine used to be procharged also. Have also been told the mains are gone from detonation… Car was running a little lean when I was at the track where I noticed low oil psi.

KCS

iTrader: (20)

Are all the mains toast? What were the bearing clearances?

Power adders are tough on the crank, especially the blowers. #2 and 4 take the most punishment.

blown383z28

iTrader: (3)

not sure on bearing clearances. i cant find the sheet as of now that came with the car. 2, 3, 4, were all the way down to the cooper for sure. 1 and 5 looked better than the others. i made the mistake of not taking pics b4 bringing parts in to clean up... i know is seen the normal wear on 1 from the blower it had b4 it went turbo. the side load from the bower belt.

RonSSNova

iTrader: (3)

I would think the upper bearing half in the rods would show signs of detonation if that was the cause.

How was the thrust clearance?

blown383z28

iTrader: (3)

not 100% sure. me not so experienced in taking engines apart should have checked it with my dial indicator.. I did take a pry bar and check it b4 I took it apart. it looked like it may have been a little loose but hard to say. if it was on the big end would that have something to do with it?

DietCoke

iTrader: (18)

What kind of converter? Sounds like thrust to me.

jblankenship

iTrader: (5)

If the converter is not installed and built with the correct tolerances for this much power converter surge can take out the thrust. I know you said not much drag strip but how about street pulls. Uncovering the oil pickup will kill the mains as well.

A.R. Shale Targa

iTrader: (2)

I'd be interested in knowing what crankshaft is in this engine
With 175-180 horse per hole pushing on the crank pins; there is an insane
Amount of torsional forces being applied
Even a super damper won't save the main bearings. If this thing got ten thousand miles on it before this happened; this isn't a clearance or oiling issue

blown383z28

iTrader: (3)

converter was from a shop out of texas, think by dallas. have look at paper work at home to make sure. i dont think i had a thrust problem i also remember looking at the thrust bearing and it looked out on the sides... if it did have to much play that will take out mains??
i went to the track one time (where it lost he oil pressure). and the guy b4 me was there very little maybe once or twice in the last couple years. one street i got beat on when it got driven (not even every weekend..

blown383z28

iTrader: (3)

PTC converter.

RonSSNova

iTrader: (3)

That's a good converter.
Doesn't sound like you had a thrust issue.
Maybe it was set up with improper clearances.

What's your machinist think?

Rebuild it and go play.

Old Geezer

iTrader: (3)

Loose balancer playing "ping pong" w/ the crank....