Bad98SS

engine turns over pops through exhaust , turns over easy then hits hard like if you had distributor off 1 tooth.we are really at a point were we do not know what direction to go.we had the pcm base line tuned for engine break in the cam specs for the base line ended up being slightly different but not much would that make a big difference? any help would be highly appreciated.also could it be a reluctor ring problem on crank it is a new callies comp star all codes on scanner show normal. please someone help i talked my son into this project rather than get a subaru sti and he is getting totally bummed on this car. thanks the motor is a 408 stroker with trick flow heads if that helps any

HotSilverBird

Well it does sound like a timing issue. Pull the plugs and check compression in all the cylinders and look to see if maybe the plugs are oil fouled or fuel. Oil from building the engine could foul um.

If the crank has the wrong reluctor wheel its never gonna run. Tough but you have ALOT of guess work to do. i would probably start by checking all the basics then pull the pan and count the reluctor wheel and check to see if its in the proper position on the crank. Good Luck

Bad98SS

I was told today that it could be a ground issue it would not fire at all until i sanded and cleaned up the surface were the copper braided line goes on driver side under fuse box on side of frame. we sand blasted k member and all front end components during disassembly repainted every thing and put it back together

JFM-jr

iTrader: (23)

Do you know how many teeth were on the reluctor wheel? I am assuming this is in a 98-02 F body and should have a 24 tooth wheel on it. Are you sure the cam is timed correctly?

Bad98SS

i do not know a reliable engine builder put it all together. we are pulling engine tomorrow i hope we can count teeth on reluctor wheel with crank sensor out and turning engine over by hand.we tryed to start again today and still same results just pops through exhaust and intake,more exhaust than anything.i am ready to give up myself. this is a 98 ss 6spd

JFM-jr

iTrader: (23)

If by some chance the wheel is a 58 tooth there is a conversion box available
https://ls1tech.com/forums/new-produ...er-module.html

Taspeed

iTrader: (1)

You really need to check the timing chain. Make sure its set correctly. I've seen experienced builders install them off. check the push rod length. Valves could be stuck open if the wrong ones are used. Are you using adjustable valvetrain? Valves adjustment could be off. Really need more info about the motor. There are several things that could be the culprit.

i wouldn't pull the motor just yet. you may not need to do that much work. Pull the valve covers and check the valves first. You can pull the radiator and pull the front coveroff to check the timing chain. If then you cant find anything ...pull the motor

JFM-jr

iTrader: (23)

Sound advice above I would not be surprised to find out it's a valvetrain or cam timing issue.

Bad98SS

Here is info on motor.Don't know how much detail you need but will give it all.
lq9 block
bore4.030
stroke4.000
finish bore4.0305
align bore2.7515
deck height 9.225.
Crankshaft Callies C-series
Rods 2-0992
Mains 2.5593
Fully counterweighted, NO
Heads Trickflow 225 cc for GM LS includes .650" lift dual springs
Pistons Dss
Compression Distance 1.110
Effective Dome -5cc
Ring combination Top 1.5 Second 1.5 oil 3mm
Gas ported yes
Camshaft Lift 623 In 612 ex
Duration @ .050" 239 In. 244 ex
Lobe Center 112+2 Installed 110
Rods Eeagle H-Beam
Center to center 6.125
Housing size 2.225
Pin size .927
cut for cam NO

Here's what I have for push rods
Trick Flow 7.500" pushrods 5/16" dia.
JP performacnce Billet double roller timing chain - LS1/LS6
Yella Terra LS1/2/6 ultralight 1.7 ratio rockers
Degree camshaft
Align Hone mains w/ stress plate
Clearance Block for stroke, mock up block and check clearance
square deck block (v6/v8)

There's more machine work ...... but probably won't matter
if you need more info let me know.
Do you think the ground problem is far fetched??
A couple of GM Mechanics have said...it sounds like a grounding issue?
Thanks for all your help.
Really appreciate the feedback.......will take any helpful info you can give! We are LOST trying to figure this out!
FRUSTRATED DAD & SON

Taspeed

iTrader: (1)

I don't think its a ground issue. If a ground is left off on these cars things won't work, and spark won't happen. First check to make sure the sensors are plugged in. Passenger side above the starter...thats your crank sensor. Next you need to do a compression test on all 8. that will let you know if its a valvetrain issue. Open valves or valves not closing =no compression. If you find there IS compression pull the front cover off the motor and find TDC. Make sure the cam and crank gears line up. I've put timing chains on and missed a tooth or two, it happens. If you can't find anything there, pull the motor and take the oil pan off. check to make sure the reluctor ring isn't bent.

Couple of things to note...are the rockers adjustable...I'm not sure. Also i've seen new lifters collapsed when there isn't any oil in them which could affect valve openings.