View Single Post
Old 11-22-2010, 11:19 AM   #5
ralphyost
Senior Member
 
ralphyost's Avatar
 
City: Cape Coral FL
Vessel Name: Say GoodBye
Vessel Model: 21 Mako
Join Date: Oct 2007
Posts: 261
RE: Borg Warner velvet drive question

Quote:
awpptdt wrote:

I have a velvet drive hooked to my Ford Lehman 120, it is a 2.57 to 1 ratio; the first question; is the round part on the aft end the reduction gear?**can the direction of rotation be reversed? I would like to put a 4 blade prop on and I can find right hands but not left hands. Currently there is a 26" dia by 19" pitch 1.75 shaft left hand propeller on her. Thanks, Ted
I think we should ask you first why you want to change the prop. Your question about the Velvet Drive is a solution to some problem you are trying to solve.
If your Lehman engine is turning up full rpm under load, then your prop is correct.
No load engine RPM for the Lehman 120 should be 2650 rpm and under load is 2500.
Going to a 4 blade is still going to require you to meet those specs, so the pitch of the blade has to achieve 2500 rpm at full throttle.
R.

*
ralphyost is offline   Reply With Quote