Kaama drives on a 38' Flatdeck Scarab with 750HP????
 

With the engine rebuild I am planning for my 1980 377 flatdeck Scarab, Im guessing that I might get 750 HP out of the twin turbo 454 engines. Even if I fall short of that and am in the 650 hp range I'll be happy. But the biggest problem is the drives. Right now I have TRS. Ive thought about going with SSM III's but the used price is up there. I plan on redoing the transom sometime in the next 2 years too and was thinking of doing Kaama drives on it. How much power can the 502 trans hold? How much power can the drives hold. I understand it it considerably more than a typical stern drive because you don't have the gears in the lower unit to contend with.

My understanding after researching the same thing led me to believe the Kaama setup is happiest around 700hp and keeping the rpm as low as you can.

As I recall, Kaama would guarantee their drives up to 600 HP.

That would make sense to give them a bit of cushion. The most knowledgeable people I could find say 700 is safe. The lower the better rpm wise to help keep the transmissions happy.

I was always told 700hp and 6000rpm was their limit, however I have several friends that "exceed those design perimeters" and they have run (and still run) them hard for years without even a hiccup.

Do you know if a transmission other than the MG 502 was ever used?

Anybody have input on how they might work on this hull?

Get in touch with Hblair. He has a restoration thread going on his 38 in the Scarab section. He's talked first hand with the owner of a 38 with arnesons and Dan M. as well regarding this hull and surface drives. I believe he found out it should be acceptable.

I have never heard of any Kaama with anything other than the Twin Disc MG502.
My understanding is it is basically their folklift tranny, and it's disc packs are designed to run either way without a difference, so you simply switch the lever and change rotation. They eat a little horsepower, but they are bulletproof!

I've heard the forklift thing before and don't believe it at all. I believe it's a dedicated marine gear (MG) that's designed for hundreds if not thousand of hours use behind commercial diesel applications. That's my 2 cents anyway

I don't know what is in a forklift but the 502 is a diesel transmission and the ones for the KAAMA have the pumps modified for the rpm as high rpm builds a lot of heat and hp loss

I was lucky enough to find a shop that was familiar with the transmissions from the kaama days. They put some special springs in them to raise the fluid pressure and maybe some other things. Rebuilds by an authorized twin disc dealer were rather painful for that transmission. I could have bought the highest output sold by Bam or Huber for the $ and gotten change.

That transmission runs a special cooler as well doesnt it?

I don't know how special it is. Its one of the long cylinders. It fits nicely, but I bet it's a standard size.

I thought it was designed to handle the increased pressure of the trans as opposed to just normal water psi

Not sure. Maybe Rik knows if he stops back. I have a service manual somewhere, I'm sure it lists the fluid pressure.

Transmission MG-502 normal operating pressure range is 300-350 psi water negligible as compared (from the Twin Disc SM 179 Manual)

[ATTACH=CONFIG]564810[/ATTACH]

Any of these look like tranny coolers?

Check the hull at the transom for a hook. Surface drives like rocker, not hooks.

The short one in middle is power steering. The oil and trans look similar. I'd say the top ones are oil and are rusty from where they're mounted under the engine. I'd guess the trans are the cleaner ones because they are mounted high and dry alongside the trans. So, yes either the top or bottom pair look like trans coolers.

the bottom set with the 90* hose barb ends are the ones, they mounted vertically on mine on the starboard side next to the trans. fit into a 1/3 moon plate via two hose clamps. bck you have a pic?

I could get one. Don't feel like going into the garage. Cold out there.