Transmission question

[Greatdaneatut]

I have a question regarding my 98 Ski Nautique. The current transmission I have is a PCM 40 1:1.23. Is it possible to swap that out with a Velvet Drive 1:1 transmission? If so, what differences will it make with the boat? Keep in mind that I am a novice when it comes this. I understand the ratio, but just do not know why some boats are 1:1 and others 1:1.23. Any help is appreciated.
Thanks. Dane

[Jonny Quest]

Why would you want to do that? Most consider a gear-reduction transmission (1.23:1) to be superior to a direct-drive (1:1) transmission. The 1.23:1 allows you to turn a larger prop with a steeper pitch. That translates into greater prop efficiency, hole-shot and better wake turbulence. Also, the PCM 40/80 A transmissions are very strong, long-lasting units. Not to take anything away from a BW Velvet drive, but you are better off to stay put.

JQ

[Greatdaneatut]

I guess I should clarify. I am having trouble with my transmission and cannot figure out what is wrong with it. It makes a grinding/ratting noise when I put it into gear. Forward or reverse. I was convinced that it was the damper plate, so I replaced it with a new one. The damper plate I took off looked in pristine condition and the new one didn't fix my problem. While I had the bell housing off I changed the transmission fluid. That too looked as good as if I had just changed it. So, all this being said, I have a chance to pick up the velvet drive 1:1 transmission off of a salvaged boat. We are planning a week long lake trip next week and just wanted to make sure I could get through the week and will then figure out what exactly is wrong with mine. I will try to post a video of the noise that it is making to see if anyone has a better idea of what it is. Thanks for the advice on the different type of transmission though. Appreciate it.

[Greatdaneatut]

Here is a video. It feels as if there is a little play between the gears. I tried getting a video of the noise while it was running but you were unable to here it over motor noise. It makes the same sort of rattling while running that you hear in the video.

[Jonny Quest]

A direct change-out may not be an easy plug-&-play. I don't believe that the new damper plate that you just installed for the PCM tranny will work on a Velvet Drive. You also need to look at the output shaft angle of the Velvet Drive to ensure that it matches up with the PCM. Then you need to look at the shaft coupling. I don't believe that the shaft coupling is inter-changeable between the PCM and Velvet Drive. Also, your propeller(s) won't work. The 1.23 to 1 PCM tranny swings a larger and steeper prop. You will have to move down to a 13X13 or 13X12 if you go with the Velvet Drive. Prop rotation is also different as the PCM is a RH prop and the Velvet Drive is a LH prop (standard rotation engine). Lastly, be sure to do an alignment from the strut forward.

It may be easier/cheaper to have the PCM rebuilt. A new PCM from skidim.com is approx. $2,200 (see link below)

The noise may be from a clutch pack that is wearing out. You could likely squeeze several more hours out of the current tranny and save the re-build for a winter project.

[dan1166]

Prop rotation will also change with a 1:1 drive. You will have to go to a left hand prop rotation. Just get the PCM fixed. I have a 1999 ski Nautique with 750 hrs. Still running strong with regular oil changes. Never had a problem.

Dan, the Skier Man

[Tahoerider]

Now that you can't get a 40A rebuilt, a new prop is a lot cheaper then the $4500 for the 80A. Found a velvet drive complete dirt cheap. Just need the dampner plate and a coupler for the prop shaft.

[Jonny Quest]

Your boat's handling will take a serious downgrade with a lefty prop in a hull that was designed for a righty prop. There is a reason why CC ran reverse-rotation engines and right-hand props for all those years with 1:1 Velvet Drive transmissions.

JQ