Diamond B question.

Jack Shaft said:
Big journal C crank helps too..
Click to expand...

Down side is the rear flange the flywheel mounts to doesn’t have as much meat as the A crank. I suppose , because the flywheels were getting lighter as the roads got smoother. I was behind a friend when his flywheel flange sheared off. I don’t know if he was running a stock A flywheel, or a cut down.
 
Flange's do fail. I will measure tonight against an A, will post the difference. I modify for better performance but don't race. In fact I'm quite happy with the power my modified flathead A puts out ( basically double of stock using my seat of the pants dyno), just want the long distance touring capability the B offers, I don't chase the dragon...yet :) .Plan on using a stock B flywheel behind the C crank and use modern fasteners with loctite to retain the flywheel. No lightened flywheel for this engine, want the mass for smooth drivability.
For racing(someday I might bump my head) I do have a late B that was bored to 4.060 and has balanced rods. I also have a 31 A block bored to .125 fitted with a beavertail A crank. The A block would get the lightest flywheel I could find, make a hillclimber..using the lightest rotating group I can muster insures fast application of torque, It might not last but will be fun while it does.
 
Chuck Sea/Tac said:
Down side is the rear flange the flywheel mounts to doesn’t have as much meat as the A crank. I suppose , because the flywheels were getting lighter as the roads got smoother. I was behind a friend when his flywheel flange sheared off. I don’t know if he was running a stock A flywheel, or a cut down.
Click to expand...

Beavertail '28 A crankshaft flange : .3875

counterbalanced ford 'C' crankshaft flange : .3875
 
There are lots of issues with the crank flanges, mainly due to the slinger and resultant reduction of material where it needs to be.
Once you have seen a flange broken off the crank, and the lack of material you will really start to wonder.
Now, there is quite the debate on putting the Chev 2 pc seal into the Mod"B"/"C" cranks.
Just as many different ways of doing it also but, to reduce the likelyhood of breaking off the flange the only way is to fill weld up the slinger area and remachine for the seal.

Reducing the flywheel weight does take a lot of stress off the flange, especially if you are revving the motor up.

John
 
You must log in or register to reply here.
Back
Top