Borg Warner 71C Limitations
 

Was surprised to find from someone here that the 71C has a 300 HP rating. My boat had 500HPs before I repowered it with 420s so who knows how these things survived.

I dont know how a trans works so humor me:

1) if I feed it too much HP what happens?
2) Does it overheat or parts break or it slips?
3) What symptoms would I see?


If I decide to upgrade (since I could frankly use more reduction and I want to add more HP with small blowers - what straight (no down angle) trans could I use? I'm hoping not to have to move the motors or redo the drive shafts.

Thanks!

You need at least a 72C just because it handled whatever power dosen't mean it wil keep doing so. I believe the unit you need is a 10-18 Model 72 that has bigger internals and the biggest difference is in the size of the planetary gears.
I have some transmissions including a 72 but am unsure if you can use your tailstock with it. BBB

I also believe the 72c is a wee bit longer so you would have to move the engines fwd I believe about 3/4" to 1".

John:D

Thanks guys - the current set up has a 1" spacer between the trans and the drive shaft so I might be okay without moving the motors. The 72C can handle 450hp I think per the spec sheet.

Can it beefed up a bit somehow/somewhere if I want to run another 100 HP though it?

Can it run in both directions (one counter rotating motor) or is it two different models I need?

Yes it can run in both directions...You have to index the pump. With the tranny removed the pump is in front.

You can also beef these up to handle more horsepower. There are a number of people around that can do that. Just do a search on here for transmissions and I am sure a few will come up.

John:D

Try Paul at Long Island Marine Transmission. We had him do the trannys for the 38 KV Scarab with 588's and Konrads.
No problems whatsoever !
He also did the 72 V Drive in Joe Pepitones boat, retired Ny yankee 1958-1973. I worked on the boat and fixed one of his 454's.
I'll try to find his # I looked in my books, I' have to look more. BBB

thanks guys
I'm in S E Florida if that helps

send them to bam.

http://go-fast.com

Huber transmissions (http://www.hubermarine.com)will set up your 71c's if you have them. (Now the Transmissions are being done by Earl Zimmerman) He can add more clutch plates. He can build them to Huber 925's. They will hold quite a bit of HP. Of course the 72's are superior.

http://texomamarinegear.com/
Also Texoma Marine Gear, Kendal can get you taken care of.

Great turn around time.