I have two F1 Diffs, open drive....need to find out gear ratio... I thought that there was a number stamped on the banjo that you divided by another number and that would give you the ratio ?? I have looked and looked....NO STAMPINGS !!!! Hopefully,. I am looking in the right place If there aren't any number anywhere, maybe you could remind me what to turn and how to count, so as to be able to figure this out... Any and All advice or guidance will be much appreciated....
Open diff.......... .hold one wheel and turn the other 2 revs, counting the revs on the pinion.........pinion revs will = ratio Closed diff.......turn wheel one rev and and count pinion revs..........
Just a stupid question ??? Why 2 turns for open and only 1 turn for closed....Just Really Curious ???? Thanks for your help, I sure appreciate your time and expertise...
What he meant is a non-posi , you lock one rear wheel and spin the other wheel two turns and count pinion turns. and on a posi, both wheels will spin, so only turn a wheel one turn and count pinion turns.
It only takes one turn for open diff IF both wheels turn simultaneously. However, unless you have a helper, that may not happen. The reason is because of the differential gears (spider gears) in the open diff cut the motion by half. The limited slip turns both wheels at the same time and the spider gears are not a factor. Ray
on all of the banjos I've had I had to wire brush the web to find the numbers. on closed drive banjos the numbers are on one of the vertical webs (I believe the bottom one) on the top/bottom surface. my only open drive banjo is 3 hours away from here so I can't just run out and verify this information for it. anyway, if/when you find the numbers they will be the number of teeth on the ring gear and the pinion gear. just do the math to find your ratio.
OK...I went down to the storage....locked one side and turned the free one around twice (2turns) the Pinion turned about 3 3/4 times, maybe a hair more. SO.....as a guess, what might my ratio be ???????
Thanks for your lead on the "Web Castings".....Mine are only 30 minutes away, next time I got back, I will look there....already left the wire brush there... Appreciate your Time and Expertise...
Ray....Thanks....pretty sure it is the 3.78....it DEFINITELY didn't go 4 turns...appreciate your help
I put a video on youtube showing the method described above. here's a link. You can also hear my Birmingham accent. Think Ozzie Osbourne with less slurring. Mart.
Just FYI..if you're going to sell them, they are '42 to '47 PU rear ends, not F1's...good market for them too.
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