Engine won't crank over with a single plug in it

[KurtEsposito]

Have a rebuilt 1994 350 LT1 Vin P. I was just supposed to be installing it. When we try to crank it over it will spin free with no plugs in it but if I put a single plug in any cylinder it stops on that cylinder's compression stroke (?).

I have been told by an engine rebuilder that the timing should be set at cylinder 6 tdc, however the person that rebuilt it believes he set it at cylinder 1 tdc.

My 2 questions are:

1) Is it possible a cam being off 180 degrees would cause this
2) I want to rotate the cam 180 degrees but am unsure if this is an interference engine.

Thanks in advance

Kurt

[harner]

Are you sure it's not a weak battery?

[KurtEsposito]

I am using a known good battery hooked direct to the starter with a battery charger on it at 50 amps to ensure good power. Completely isolated it from the vehicle electrical system.

[SSlowBoat]

it doesnt matter if the timing is set cylinder 1 or cylinder 6 as long as the opti is installed right. both dots up is cyl 1 tdc, dot to dot (crank at 12 cam at 6) is cyl 6 tdc. its easier to mess up cylinder 1 tdc as it could easily be a tooth off. but i would stop before going that far

50 cranking amps is not enough, id say starter is weak as hell and or battery and cannot overcome the compression. if the valves were hitting, it would be hitting with no plugs in it too, so its not that

[KurtEsposito]

it doesnt matter if the timing is set cylinder 1 or cylinder 6 as long as the opti is installed right. both dots up is cyl 1 tdc, dot to dot (crank at 12 cam at 6) is cyl 6 tdc. its easier to mess up cylinder 1 tdc as it could easily be a tooth off. but i would stop before going that far

50 cranking amps is not enough, id say starter is weak as hell and or battery and cannot overcome the compression. if the valves were hitting, it would be hitting with no plugs in it too, so its not that

It's a 50 amp boost on the battery I should say. We have tried two starters, one stock, one hight torque. I suppose a third isn't going to hurt.

But are you saying that if the cam is off 180 degrees it would not cause this problem?

[SSlowBoat]

It's a 50 amp boost on the battery I should say. We have tried two starters, one stock, one hight torque. I suppose a third isn't going to hurt.

But are you saying that if the cam is off 180 degrees it would not cause this problem?if the cam was 180 out it shouldn't matter, cylinders are at top of stroke 4 times in cycle. you're splitting hairs. again if cam timing was off it should have hit already plugs out or in

Sent from my SM-S908U using Tapatalk

[KurtEsposito]

I have torn down the engine and on some pistons i see some rubbing. The bores are 4.0295 to 4.030. Pistons are measuring 4.029 to 4.030. Spec clearance is supposed to be .0010 to .0027.

Could this be the culprit? Not enough piston clearance?

[SSlowBoat]

could be, more than likely the starter was weak and she was building some compression