i just put in a 383 stroker and right around 1000-1500 rpm, there is a vibration. i used same mounts and it did not have the vibration. i didnt use my old harmonic balancer and didnt see anything wrong with the one that it came with.....im guessing its the balancer thats bad or is it the crank and pistons that were not balanced correctly....anybody has any ideas?.....

 

The 383 is externally balanced and uses the 400 harmonic dampener and flexplate/flywheel. Make sure you have both.

 

Damn....ok...so i used the balancer that it came with but had to use my flywheel and clutch because it came out of a automatic...so does that mean i need to get it rebalanced with my flywheel and clutch?

 

That motor uses a 400 crank which requires a 400 hb n flywheel. Automatic or Manual it doesn't matter long as it's a 400 flywheel. Running it the way it is your asking for trouble.

 

Thats not definatly the problem. It all depends on how the engine was built. If the builder sent the 400 crank off to be balanced you would no longer need a 400 balncer and flywheel. If it wasnt balanced and yo are useing a non 400 flywhee they make a balance plate you can bolt on between the flywheel and crank.

 

Justin is correct in saying this may,"not defiantly the problem". I was just stating simple facts about 400 Crank Shafts. In the original post he never stated if the car was rolling when he felt the vib. or if it was parked and running etc. But he pointed to the crank ands rods area from the start.

 

I'm still putting my money on the non-400 flywheel being the cause of vibration. There's more to balancing an engine than just sending the crank off. As far as the crank is concerned, there are two ways to build a stroker; a conventional 400 crank style assembly, using an externally balanced 400 flywheel and harmonic dampener, or an internally balanced crankshaft and assembly using a neutral flywheel and dampener. Neither of these "kits" requires you to have the rotating assembly balanced to have the engine run correctly. What's involved with having the rotating assembly balanced? The pistons, rings, wrist pins, clips, bearings, caps, nuts, and rods (only on the crank end) are weighed. Corresponding bob weights are attached to the rod journals on the crank. Then the flywheel and harmonic dampener that you are using is bolted to the crank, and the entire rotating assembly is balanced. This is an extra step in performance which gives you a well balanced engine that will allow it to reach higher rpm's before it wants to tear itself apart, and it'll get there quicker too. The rotating assembly in my stroker motor is balanced, and I can tell you that the engine gets to 6 grand literally at the blink of an eye.

 

thanks guys...i think its pretty much gonna be my flywheel since it was changed from auto to manual and i had to use my flywheel from my 327.....i'll see if i can find me a 400 flywheel and see if the problem goes away...thanks agian.

 

You don't need a whole new flywheel, just add a balance plate: Quick Time Engine Balance Plates - JEGS

 

yeah, i ordered one on ebay.....we'll see how it works....thanks guys.