sounds like a tractor

Ok ive been trying to get the timing right on my buddys 350 and every time i turn the distributor to where the engine smooths out it doesnt wanna stay there when i tighten it. I set the timing and we shut it off and start it again and it sounds like a tractor, running really rough and vibrating a lot. since it has no timing pointer i have to do it by ear or by manifold pressure, but everytime i tighten the distibutor it doesnt stay there and sounds like a tractor.  

what kind of car????

did the distributer drop onto the oil pump shaft fully....   that will hold the distributer up so it cannot be tightened..

warning.. i have had people... who did not understand...  tighten the hold down bolt... and break the pump off the bottom of the motor...

there are ways to dead stick time the motor...

what kind of distributer...   points...  Hei,....  MSD???

you can loosen the hold down clamp...    unplug the coil wire...  since you have the engine almost running..  push down lightly while you crank the motor.. till the distributer falls in that last little ***

do you have oil pressure.. when the distributer is not locked into the oil pump drive... you will not have any oil pressure and it will sound like a tractor...  as there is no oil pressure..

you may have damaged the engine bearings..

i looked around the sites... and did not see an article just on distributer installation...

dead stick timing motors so they start on the first try...

but i bet there are videos of it online...  

yep been there done that but it was a good thing that it was a ford engine. The only way that the distributor could move is the threads in the intake are stripped or the clamp is bent. The only way i have herd an engine sound like a diesel is when  one was run without oil pressure.

This is from the hydraulic lifters The oil pressure is the (cushion) or spring to keep the slack out of the valve train This destroys the lifters in a very short length of time.