Crankshaft front bearing wear when supercharged?

[GreekGod]

Long ago, when Ford installed many accessories on the front of their FT truck engines, they went to steel crankshafts with a large diameter (1 3/4") front "snout" to mount the dampner and drive pullies. The purpose was to reduce bending of the front of the crank and probable wear on the front main bearing.

Anyone care to comment on the loads imposed by the front pully driven superchargers on a DOHC crankshaft and main bearings?

It seems with the likelyhood of a GMC roots 'charger being tried on a DOHC MM, the possibility of a problem with a even greater load from a less efficient design than the proven model from Trinity would require carefull and experienced engineering.

[thePunisher]

i wouldnt worry about this on our setups..especially when the stock tensioner is used...this rule really applies to the windsors where the supercharger drives are separate from the serpentine system. this means another pully system extended out farther on the crank. this puts more stress stress on the bearing due to the added leverage. also you can and usually do tighten those belts crazy tight..to get the most out of them...and this doesnt help....the procharger and vortech race setups that use big cogs put the supercharger drive closer to the engine to help in this area....this is how i have my lightning setup....

[TooManyFords]

I thought about that too before venturing down this path. I decided to wait till I got the forged steel 8-bolt crank to add to the durability. The only other question I was asked was whether or not I had a double-keys crank snout. it was recommend that if I was going to turn this motor "North of 7000 RPM" that I should have a second keyway put in.

Since I'm limiting it to "Just South" of that mark, I left it alone.

As usual, only time will tell if this has anything to do with crank bearings or not. When I tear it down after it blows up I'll try to remember to look.
:D

Cheers

john

[SergntMac]

i wouldnt worry about this on our setups..especially when the stock tensioner is used...this rule really applies to the windsors where the supercharger drives are separate from the serpentine system. this means another pully system extended out farther on the crank. this puts more stress stress on the bearing due to the added leverage.Ummm...Been a while since I peeked, but isn't the Trilogy kit also crank driven?

[thePunisher]

i didnt have the trilogy in mind...thinking mostly along the lines of centrifugals.....does the trilogy blower have a separate belt??

[Smokie]

i didnt have the trilogy in mind...thinking mostly along the lines of centrifugals.....does the trilogy blower have a separate belt??

Yes and extended crank pulley, there is also at least 1,000,000 customer miles on this setup; I haven't heard any front main bearing or crankshaft problems up to now.