I have a 45 Commander with DD 8v71s. Does anyone know what Brand, and gear ratio was installed. I have a set of Allison M15R and M15L, 1:5 ratio that I was hoping to be able to use.
The 45 Commander used an Allison behind the 8V71s. Reduction ratio is 2:1.
The M15 would be at the hp limit of your 8V71s. I think your boat has the M17. I do know the 55 Commanders with the 8V71TI used an M20.
Thanks for your input. So you are saying that my boat should have Allison's in it. Do you know if the rotation is set in the drives or the engine. The M15 are M15R and M15L. (My boat is a 1000 miles away, so I cant get the numbers off of them right now.
The engines and drives took on water in my boat, but I could go through the drives, if that is the better option. My plan is to have fully rebuilt engines and drives ready, so that when I remove mine, I can just install new in one swoop.
Correction, I think your transmissions are M20s. Your engines should be standard rotation and the Left hand and right hand transmissions corrected for proper propeller rotation.
I am sort of doing a swag on this as I am much more familiar with the 47 8V53/ TD506 combinations. I really would strongly recommend to get the engine and transmission tag information. The only reason I suggest this is that it is the only way to verify exactly what you have/had in your boat. There is theoretical and then there is reality. 45 yr. plus boats have the potential of surprises. Now is the time to uncover as many surprises as possible.