rebuilt 350 won't crank. PLEASE HELP!!

[timg83]

Hey there, I've been reading for a while but first time poster.

here is my problem.
I just finished rebuilding a 350.
I had a machinist bore/hone/align hone the block and set up all the bearing clearances.

when finished assembling the motor, i set the valve lash and it turned over fine.
When i dropped the motor in the truck and tried to start it, it turned over a few times sluggishly, and it sounded pretty harsh.

now it won't crank at all.
the starter engages it just doesn't spin.

i took the plugs out and it still wont spin.
i took the starter off and the starter spins by itself.

now i cant even get the motor to turn by hand

any help or ideas anyone can offer would be appreciated.
Thanks

 

[MrMarty51]

Welcome to the forum.
You tried turning the fly wheel or flex plate ???

 

[HotRodPC]

Let's hope it's just cause you haven't got the torque converter and flywheel set up right. If it is, good news is, the motor is most likely OK. The part that scares me, is you didn't have the lugs on the conveter set into the pump gears properly, and you have a binding issue with pump gears, converter and flywheel. If this is the case, you might have broke your pump gears in the trans. Cross your fingers and hope not. The part that makes me think so, is you said it turned over a few times slugishly then quit altogether. I'd rather hear it didn't turn over at all and is stuck, then I'd say you bound it up so good it couldn't move at all therefore it could not cause any damage. So now that the motor is bound up, you won't be able to get your torque conveter bolts off, so now you'll have to loosen your bell housing bolts and back the trans off the converter FIRST. Do that and see if hte motor will free up. If so, this is your problem. Then, now that the motor will turn over, loosen all your converter bolts and try to set the converter on the pump lugs correctly and make sure the converter is all the way back on the pump gear lugs. Spin the converter now and hope you feel some resistance from the pump gears, and no screaching or metal to metal harsh noises. If not, now bring the trans back home to the motor and tighten the bel housing bolts. Again, spin the conveter and make sure it's all the way back on the pump gears and spins freely. If it does, now bring the conveter forward to the flexplate, put in the converter bolts, and fire it up.

 

[chengny]

I'm with HotRodPC 100% on this one.

If the torque converter was disturbed, it needs to be re-installed properly before attempting to bolt the transmission to the engine.

This is done by pushing in and gently rocking it back and forth. As the splines mesh, you should feel a series of 3 distinict "clunks". These indicate that the splines were properly lined up, engaged and ready to be meshed with the next step. After 3 inward steps the T/C is home.

To check for proper final assembly, measure the distance from the bolt pads to the face of the bell housing. The face of the pads should be 3/16" away from a straight edge layed across the bell housing where it would meet the engine block if bolted up.

Any less and the T/C is not fully seated - do not attempt to bolt the bell housing to the engine block.

Unfortunately, if you made the transmission up to the engine without the T/C all the way home, the pump bushing has most likely been damaged.


CHECK CONVERTER TO FLEX PLATE ALIGNMENT

After bell housing bolts are tight, check free movement of converter. It should have 1/16 to 1/8" (ON GM ONLY) of clearance between pads on converter and flex plate. If you have more than 1/16 to 1/8", install equal thickness washers to reduce clearance to 1/16 to 1/8" (ON GM ONLY). If not enough clearance, remove transmission and check to see if converter is seated in front pump properly.
Draw converter bolts up evenly so as not to pull converter into a bind causing vibration and pump bushing failure.
If vibration occurs after installation, mark converter to flex plate and rotate the converter one bolt hole at a time.