HELP PLEASE!! Engine Vibration after rebuild LQ4
 

SORRY for my English..


Ok will start from start:

I have Hummer H2, 2003 (Car VIN # 5GRGN23U53H101047)

Engine: LQ4 Generation III,364 CID (6.0L) 16V V8 4.000" (101.6mm) General Motors Vortec

Magna Supercharger on it which were installed before and worked fine with engine: http://www.magnacharger.com/pdf/manual-HummerH2.pdf

So we decide to rebuild engine:

I spoke with Paul Hennelly from Paschal Performance Engines Inc
so after long desiccation we made part list:

Pistons 14510-030 Probe
Rings CR1009 35 (file fit set)
Rods LG3-6125LSH RPM
Main bearings BC409J 010
Rod bearings BB253J 010
Cam bearings
Coatings: Pistons ceramic top coat, skirt coating & rod bearing coating
Manley stainless steel valve 1.55" LS
Manley stainless steel valve 2.00" LS
Manley timing set LS 3-bolt with captive Torrington thrust bearing and 9 keyway sprocket.
Comp Cams LS valve springs
Comp cams LS camshaft XR265HR 212/218 degree @ 0.050" 0.558"/0.563"lift
Melling high volume oil pump Chevy LS
Head bolt set LS engine (2 req.)
Comp cams performance roller lifters Chevy
Comp cams Chevy LS pushrods
Edelbrock high volume water pump Chevy LS engine
Magnuson 2.8" supercharger pulley

The compression should be at 9:1

So after installing all this we decide to rebuild transmission to so I bought this monster rebuild kit: racetransmissions .com

along with Torque Converter: 1800-2000 stall converter with anti-balloon plating

so we did everything rebuild trans and engine!!

We start enigne, rpms hold fine not going up and down, but engine is vibrates much, we checked mount all fine, also belt idler start making noise and going up and down hard, not as normal, when you shift from P to D or R engine going off, when you push more accelerate it like no enough power to push car, and then stops again, we check ECU, it was shown ignition problems, we erase all mistakes and checked again no any problems in ECU, when my electrical fans start it start vibrates more, I mean when electrical loads apply to engine it also start vibrates more..

The issue is make me worried :

1. Fly wheel is factory (maybe I need to buy new) ?? or that thin peace of metal can really course so much vibration??
2. Harmonic balance also factory one, but it running straight if you look with the belt on it, when engine running
3. Comps camshaft which was changed maybe not matching computer ?? but we call to supercharger guys who was tuning ECU after charger installation, they said that it should be fine, and you do not need any tuning on computer
4. Torque converter which was on car is much bigger that the one I bought, maybe that can make so much vibration?
5. Crankshaft been not change, it is factory one we just grind it one size bigger for new bearings, when shop been grinding it they say it is not curved, but I`m not sure does they did balancing or did they need to do balance?

I really do not now what to do trying to find some help, i`m leaving In Azerbaijan, Baku and here no any professional guys or tech to support me, we do not have even GM dealer here, but I`m trying to do everything by myself with some good guys who rebuild engines before, so any suggestion from what that happened and why engine is vibrate too much PLEASE HELP, we build engine is looking nice but it is not working and we can not understand why

Please HELP guys really need help.. already one month can not sort this issue.. truck just in shop .. and we do not know from where to start....

valve timing ?
a lot of guys saying that this could happen because of your new comp shaft which use new timing chain maybe it is wrong gas distribution?

The LS engines are internally balanced. The harmonic balancer you refer to is actually just a pulley. It sounds to me that they didn't balance the crank like they should have or there is an issue with the converter.

Also, you need to record all of the codes that pop up.

another idea maybe the weight of rods and pistons can make this imbalance?

Con rod imbalance (not likely as new con rod was matched for weight with other 8 same like a pistons)

Throttle body balance (not yet performed due to unavailability of balancing tool - even not sure how to do it)
Do we need to do throttle body balance? and what is for?

I think maybe to order new fly wheel with crankshaft along with damper ? but I’m not sure if this new crankshaft will much my piston and rods weight?

my email: is gasanovr@gmail.com

checking it every 5 minutes maybe somebody will help me with this issue?

the converter guy wrote me : The smaller torque converter is for better performance and because of the higher stall speed.
Monster Transmission & Performance

?? is it only one way to know they didn't balance properly is to open engine again.?

THANKS A Lot for your reply!!

the guys also trying to help here
https://www.performancetrucks.net/fo...=1#post4518238

Sounds Like it ain't running off all 8! Coil packs plugged in?

thanks for your reply

coil packs are definitely in, but what will happen if the one of them goes in wrong way?

and if one of them is not in, if we miss one, does the rpms stay as normal or they starting to play?

It will idle for sure! But will be lacking power when u put in gear & a/c will kill it! I forgot to plug in my coil packs after my swap

will check them again... they all plugged, but maybe we did not plug right on to same place, we run OBDII test, everything fine:) that why I was sure that everything should be plugged right.. anyway will check again if we mess the places, but think that everything is correct..

what you think on balance the crankshaft.. ?
and how you think maybe we chose the wrong position from timing chain, it has different positions our one for a moment is R2 (Manley timing set LS 3-bolt with captive Torrington thrust bearing and 9 keyway sprocket)
it has A2, A4, A6, A8 , 0 , R2, R4, R6, R8

can this course vibration ?