Well said Kkritsilas.
The balance issue is something that Chrysler started to do in ’69 as a work around for the 440 6-bbl that uses heaver internal parts and trying to get that engine released sooner.
In about ’72 (more or less) Chrysler started to go with crankshafts made of cast iron instead of forged steel. Cast iron is not as strong as forged steel, but it comes out that forged steel is overkill in most cases. You can “build” an extremely stout engine with maybe 3-4 times the original horsepower and use a stock a cast iron crankshaft (but nobody wants too, if forged parts are still readily available).
Cast iron has a different density than forged steel - which requires the balance weights on crankshaft to be larger – and that is not possible in many cases – so additional balance weight was added on outside of engine (i.e.: harmonic balancer (front) and torque converter (rear)).
318 engines (all) and all engines with forged crankshafts (except for the 440 6-bbl engine) have a neutral balance to them (no external weighs).
All engines with cast iron crankshaft have externally balanced harmonic balancers and torque converters (except for 318’s) - and the amount of balance differs with engine (i.e.: 340 is different from 360, which is different from 400, which is different from 440).
About 15 years ago, maybe, the aftermarket came out with an externally balanced flex plate that takes the place of balance on the torque converter.
The aftermarket also came out with a harmonic balancer that weights bolt onto it so one can use one balancer for several engines, with add-on weights available for the different size engines.
Does this clear up the mud, just a bit?
The balance issue is something that Chrysler started to do in ’69 as a work around for the 440 6-bbl that uses heaver internal parts and trying to get that engine released sooner.
In about ’72 (more or less) Chrysler started to go with crankshafts made of cast iron instead of forged steel. Cast iron is not as strong as forged steel, but it comes out that forged steel is overkill in most cases. You can “build” an extremely stout engine with maybe 3-4 times the original horsepower and use a stock a cast iron crankshaft (but nobody wants too, if forged parts are still readily available).
Cast iron has a different density than forged steel - which requires the balance weights on crankshaft to be larger – and that is not possible in many cases – so additional balance weight was added on outside of engine (i.e.: harmonic balancer (front) and torque converter (rear)).
318 engines (all) and all engines with forged crankshafts (except for the 440 6-bbl engine) have a neutral balance to them (no external weighs).
All engines with cast iron crankshaft have externally balanced harmonic balancers and torque converters (except for 318’s) - and the amount of balance differs with engine (i.e.: 340 is different from 360, which is different from 400, which is different from 440).
About 15 years ago, maybe, the aftermarket came out with an externally balanced flex plate that takes the place of balance on the torque converter.
The aftermarket also came out with a harmonic balancer that weights bolt onto it so one can use one balancer for several engines, with add-on weights available for the different size engines.
Does this clear up the mud, just a bit?