Changing external balanced 440 to internal balanced

[Supercharged Riot]

Im lookin to possibly get a late model 440
Its externally balanced but i want to run new internally balanced parts
Is it simply a matter of switching out the internals?
Or is there something different about the late model blocks that dictate the use of internally balanced parts?

[Cooter]

Nope, as long as you have all the clearances in the block checked and check out ok, you should be able to swap out the cast crank/rods/pistons for the steel crank/rods pistons. Blocks are no different. Strokers have been built for years doing this very thing. Just make sure you get the Harmonic balancer for the steel crank as well.


Just BE SURE to order the MAIN bearings to whatever year your 440 is. There's a difference in the thrust bearing between early and late engines.

[Aussie_Charger]

externally balanced cranks have an offset weight on the harmonic balancer/ pulley and the same weight on the flexplate/ flywheel that is 180degrees opposite that cancel each other out dynamically (end to end)

internally/neutrally balanced cranks/ balancers/ flexplate/ flywheels are balanced without any offest weights

i.e;
replacing a neutrally balanced flywheel, balance that to 0 and no dramas when swapped

replacing an externally balanced flywheel, balance new flywheel to match exact location and weight offset

with V style motors, they are very rarely symetrical (end to end) so a bob weight has to be made up to cancel out the counter weight on the opposite end as well as rotational

bobweights are made up to replicate the rotating mass on the big end, change any of these weights and you will most likely upset the balance of the crank

converting a externally balanced to internally balanced this is done with replacing the balancer, and flywheel/ flexplate with neutral componants, majority of the time, the crankshaft itself will need mallory (heavy metal) inserted as the big end may have too much weight in it but not enough material to have removed, the mallory is inserted 180 degrees opposite from the heavy end in the counter weight and parralell to the main tunnel (this prevents the metal coming out)

hope that helps

[Supercharged Riot]

 

Thanks for the clarification guys!

[John_Kunkel]

The alternative to Mallory Metal is light rods/pistons.

[JB400]

The alternative to Mallory Metal is light rods/pistons.

You give up some reliability if you do this.  That's why some racing engines need to be rebuilt quite often.  Drag racing comes to mind on this.  The pros rebuild thier engines after every round.

[Aussie_Charger]

Very rarely will a lighter rod/piston cancel out the in balance