I'm getting my stock motor stroked to a 383 and the machine shop guy told me that I might have to get a special balancer or he might have to put Heavy Metal in the crank to balance it. He's a cool guy and has been recommended by a lot of people so I don't get it. Anyone heard of this before?

thanks...S.J.S.

 

Usually it's a better (and sometimes cheaper) way to do it by getting an aftermarket damper. The machine shop will supply the crank and engine parts data to the aftermarket company, and they will custom build the damper specifically for THAT rotating assembly.

 

Its a harmonic balancer thats usually filled with fluid, so not only does it help balance your rotating assembly, but it filters out a lot of vibration (via the fluid). NHRA mandates the use of one eventually, although I can't remember the exact ET (may tnthub or someone else will chime in).

 

Could this be the reason my brand new Crankshaft seal is leaking?

 

Like he said, I've just read that they are mainly to help with all the vibrations.

 

He's talking about balancing the engine. Depending on piston and rod weight, a stroker may need lots of weight added to the crank counterweights to completely internally balance the rotating assembly. This is done by inserting "heavy metal", which is denser than steel into the crank. The stuff is costly, so a couple hundred $ worth might be necessary. The other option is to use a balancer and/or flywheel that is purposely out of balance by a certain amount so that less/no heavy metal is used. Because some of the balance weight is outside of the crankcase, the engine is "externally balanced"

GM did this with 454 and up big blocks, as well as 400 small blocks. It's not optimum, but neither is it a bad thing. This is something your engine designer/builder should have discussed with you before the build, or maybe that's where you are now.

If you haven't started the build yet, discuss what parts are required to economically internally balance your 383.

96Z's 383 was internally balanced, and the rotating parts are not exotic, nor super expensive.

 

Thanks Old Stoker.....very much. Thats the kinds of replies I like. About as detailed as it can get.

S.J.S.

 

10.99 and quicker nhra wants you to have a SFI 18.1 balancer

 

just internal balance everything INSIDE the engine! then neutral balance everything OUTSIDE the engine ie. flywheel, damper etc! i personally got a fluidamper with my setup although it wasnt completly necessary but i figured might as well they carry a HEFTY price though! you could just stay with the stock damper to be honest. till you start making wicked times at the track

if u do decide to get one there are pretty much TWO main choices that you could go with, theres the fluidamper which performs best UP TO 7k rpms! then theres the ati super damper which performs best ABOVE 7k rpms! fluidamper would be your wisest choice