The Ford Barn - View Single Post - Is a lightened flywheel overrated? (I think so)

40 Deluxe · 11-17-2012, 08:12 PM

Another factor to consider when worrying about that "heavy" original flywheel beating up on that poor defenseless rear main:
How much pressure (or "weight") does the rear main see when #4 fires? A lot more than the weight of the flywheel!! Peak cylinder pressure at light loads is about 300 PSI, and piston area is about 10.7 sq. in. So we have a force of over 3,000 pounds pushing on that Babbit bearing! Even having just 50# or so of compression puts almost 600 pounds of pressure on the rear main before the cyl fires.
I really doubt the rear main notices whether a few pounds have disappeared from the flywheel!

11-17-2012, 08:12 PM	#19
40 Deluxe Senior Member Join Date: May 2010 Location: now Kuna, Idaho Posts: 3,818	Re: Is a lightened flywheel overrated? (I think so) Another factor to consider when worrying about that "heavy" original flywheel beating up on that poor defenseless rear main: How much pressure (or "weight") does the rear main see when #4 fires? A lot more than the weight of the flywheel!! Peak cylinder pressure at light loads is about 300 PSI, and piston area is about 10.7 sq. in. So we have a force of over 3,000 pounds pushing on that Babbit bearing! Even having just 50# or so of compression puts almost 600 pounds of pressure on the rear main before the cyl fires. I really doubt the rear main notices whether a few pounds have disappeared from the flywheel!