vanmejt

I have just rebuilt a mercruiser 454 330hp bravo 3 with a 496 stroker kit. I also removed the mercruiser fresh water pump and installed a Johnson crank driven pump. The pump oscillates when running like it is off center or has a bent shaft. Either way I think I have a balance issue with the damper and flywheel. This is a Pro Comp gen V stroker crank that is internally balanced. My vibrations start at 1200 RPM and continue. My buddy used the same kit on his car with a gen IV without problems using the same damper that he had. My difference is of course the heavier flywheel for the boat and the gen V block. Can I use a Fluid damper to take care of this? I plan to remove the crank pump to eliminate this possible cause, but I think I have bigger issues. Please advise. Thanks.

mike tkach

if your stroker kit is internally balanced you can not use the counterweighted balancer&flywheel.i don,t use the pro comp stuff.do you have a part number for your kit?

ezstriper

did you have the engine balanced ? NEVER just throw in a kit like this without having a machine shop balance it..no matter what they say..pre-balanced etc. what Mike said is correct, most stroker kits are internally balanced and use a 396-427 balancer and flywheel, but with having this crap(what most of the pro-comp chinese junk is) checked for straitness, roundness, balance, the pin will have been removed..

vanmejt

my main concern is the mercruiser flywheel....since it is not a flex plate. I was under the impression these fly wheels were zero balanced. I was wondering if I can use a Fluid damper to solve this.....

F-2 Speedy

if your internally balanced you need a neutral balancer and flywheel as Mike stated, you run a risk of breaking that crank if not done properly

Mr Maine

the mercruiser flywheel is simply a manual transmission flywheel as opposed to an automatic trans flexplate. as has been stated you need the correct balance which in your case appears to be neutral on both balancer and flywheel.
a fluid damper isn't the answer. a machine shop could probably neutral balance them but would probably be cheaper just to buy the correct ones.

mike tkach

the balancer&flywheel from a 396 or a 427 will work,they are neutral balanced engines.

mike tkach

i would not continue to run your engine until you get it right,it won,t take long to eat the main bearings up,then it is all over.

mike tkach

i would look closely at the paperwork that came with the rotating assembly.it will tell if it is int or ext balance.with pro comp the balance is no doubt not right and should be balanced at a machine shop as already stated.

getrdunn

Right on. Many of the cast rotating stroker assm are externally balanced from I remember. Why I have no clue but remember seeing some that are externally ballanced but only the cast ones.

Like everyone said don't run it til you get this taken care of or you'll be pulling engine and not happy.