Ujoint drive shaft angle
 

Currently running a 36 Nor-tech w/525's and XR's. thinking about upgrading engines to 650 or so hp. the boxes and drives are set inboard of the engines and there is a pretty extreme angle on the u-joint drive shaft form the engine to outdrive. if i upgrade power i think this may become a weak point. How extensive of a project would it be to realign my boxes and drives and move them outboard. I could also raise the x-dim (already getting a lot of bow lift so this would be good).
or could i realign my engine, move up and inward and get a custom exhaust made.
or upgrade the ujoints?

any suggestions welcome.

thanks
-Rick

Re: Ujoint drive shaft angle
 

your best bet would be to talk to nor tech and ask them Im sure theyve tried all poss combinations

Re: Ujoint drive shaft angle
 

How much of a difference between the engine centerline and the drive. How long is the driveshaft from the motor to the ext box . Do you have a picture you can post.

My OL is set up with the motors at 34" and the drives at 29" .Drive shafts are approx. 18inch long . . My are motors 557" with 1071's and #5's on boxes. No problem with
u-joints . Tom

Re: Ujoint drive shaft angle
 

The accurate measurement method is to use a digital angle finder. My research into u-joints in a high performance/high RPM application determined the optional angle is .5 to a max of 2 degrees. I would not think the boat manufacturer would be a great source for accurate info. Sometimes the focus is to get the X-dimension right and then to just get the rest of the drive line and engines to fit into the boat with the hatches closed.

Re: Ujoint drive shaft angle
 

I rigged a 35" Motion cat a few years ago with a set of 1000's we did and 6's. I moved the engines as far forward as I could and still had the driveshaft on a pretty good angle. I talked to the driveshaft shop that built the drive lines and they said we should replace the u-joints every year just as a precaution. I never have heard of the boat having any issues and I know it has been used quite a bit.

just another .02. :D

John S.

Re: Ujoint drive shaft angle
 

my quick rough calculations puts you at about an 8 degree shaft angle. I'll be able to visually inspect mine tomorrow night and get accurate #'s but i estimate mine to be about 12.

What type of shafts/u-joints are you all using?
I had a u-joint blow on my rover on the highway and take out my trans, something i do not want to repeat on my boat.

thanks for the info, keep it coming.
-Rick

Re: Ujoint drive shaft angle
 

To keep vibration to a minimum and provide decent service, no more than 3 degrees. That's how we set up the military boats.

Kurt

Re: Ujoint drive shaft angle
 

The shafts are steel with large spicer u-joints , I had them made at a drive shaft shop out on the east end of Long Island. They said they could handle 1000 hp no problem. I'm not 100% sure on the 18" length but its in that ball park. I had them made four years ago. I cant get to the boat right now , but I will look to see if I have a picture in which you can see the shafts. Tom