502ss

iTrader: (3)

Look what I just bought!!

Who on here is the resident expert? I have tons of questions and would love to pick someone's brain!!

Thanks in advance!
Jim

502ss

iTrader: (3)

ttt

38fountainecman

I had the same drives on my formula 357. The inner transom plates do not appear to be original equipment. The original ones are cast aluminum with ridges in them. I lost one of the tail fins on mine, I've also seen some where the tail fins were cut off, I don't think they effect performance. The gear sets are interchangable. You do not necessarily need to change props, but can change the gears. There is a big gear and small gear, changing their locations on the input shaft and prop shaft changes you from overdrive to underdrive. I have seen 1:1 gears 0.8:1 gears and 0.135:1 gears. I would first disassemble the drives, inspect all internal bearings and replace all the seals, propshaft, inner seals between the drive assembly and the transom assembly and then the inner transom assembly. I lost a drive at 70 mph due to a bad prop shaft seal, cost over $2.5K to fix. If you mess up a prop shaft, they are hard to find. The bearings and seals should be standard american available at any shop that handles that kind of stuff. Your drives have a lot of corrosion, make sure when you disassemble, you make sure you have the grounding wires between the transom assembly, gimble ring and drive. Also, ground all through transom fittings. I had twin disc transimssions with mine and had them re-built. Once went bad, when they go bad, they lock up in forward. I guess that gets you home, but I almost took out a dock. Parts can be obtained at Team Archer Marine in Costa Mesa? California. Also, boots can be found somewhere in the forum. They did make my Formula go fast and it looked great with the rooster tail.

502ss

iTrader: (3)

That is some great information to start. Thanks!!

Stupid question, I assume the direction of the drive is being done in the transmissions (which I don't have) it appears the twin disc gear box is the common setup, do you know if this is the only option?

I do plan to completely go through the drives but only if I think there is a chance I can get these to work in my setup. I need to answer the tranny question first as that might be an expensive item and difficult to locate!

38fountainecman

If I remember correclty, the twin disc is designed to run in either direction just by adjusting the direction the shifter moves the shift arm on the transmission. Also, I think the kamma was specifically designed for the twin disc gm502 transmission due to alignment, drive position, engine position, etc. I thought the twin disc gm502 transmissions were a dime a dozen, but that is only when you don't need one. There is also a company in the northeast (New England area) that made the gears and had spare parts, I just can't remember, sorry.

CDShack

Not an expert but I've live with them for over 25 years. If this is the set that was on here for sale, there is a short shaft and a long shaft drive. Originally, the "Inner "plates" were just stainless fender washers on the original set ups, but the drives eventually "twisted" enough to cause water incursion into the transom (generally from the inside) so most folks did some form of plate to replace the washers. Over the years, Kaama did some different things to combat that, like the "teardrop" gimble. I did a plate that went around the drive studs and up to where the trim cylinder attached, helped alot. Gears are Casale V-drive gears, but they have a METRIC spline unique to Kaama. There are several places that can machine and harden gears, or make a new prop shaft with SAE splines. Neither option is inexpensive. Realistically, hard to mess up a gears unless there is a catastrophic failure. All the bearings, seals, races, u-joints, flanges are all available at any bearing or driveline shop. Boots are supposedly available from GM-Powerboat.com in Austria, but I make my own.

Castings are the only problem. Blow up a casting your down for a bit. Most Kaama guys buy parts here and there to have for spares, just in case. Easier to find them when the "pop up" than when you're down, needing them. Shafts are 19-spline and run all the older ssm props. Kaama's came with cool props that matched the diameter of the shaft housing, but those are rare rare rare and really not helpful. My fastest props are 3-blade, but hard to live with. 4-blades are great and within a couple of MPH on the big end. You'll be limited to running short hub props because of the one short shaft. I've never run a 5-blade. I was told in the day when Archer and those guys were still Kaama guys that they felt like the shafts wouldn't handle the weight or load. Tranny is a Twin Disc 502. Easy rebuild, reverse rotation by changing to forward or reverse (both packs the same in the transmission, so it doesn't care) Industrial tranny, parts still available.

I rebuild my drives every 2 years, oil changes with screens twice a year. The reason I do this: I let it go for a long while when I first got it (1988)I lost a prop shaft seal and most of the fluid and puked the thrust bearing which took out the gears in one drive. At the time, parts weren't near as hard to get, and I found a set of 13% gears out of Costa Mesa. No harm, no foul. Today, those gears are almost non-existent. If I see parts or drives, I always inquire and buy them if I can. If you need some more info, I'd be happy to tell you what I know! As I said, not an expert but I've enjoyed for years what I consider to be the best drive ever invented.

502ss

iTrader: (3)

Cdshack - thanks for the informative post!

Any chance you have some photos of the back of your scarab or inside the engine compartment? Any idea how far from the v are the drives mounted?

I think my next step is to find out if I can find tranny's!

BlownScarabI

Great now I'm going to have to go for more power so I can keep up.

502ss

iTrader: (3)

LMAO - don't go crazy yet. I am a long way away from making this pipe dream a reality if ever!!

At this rate I am looking at a couple years worth of locating parts! never mind the engineering that needs to be done!

CDShack

I'll see if I have some pics, the boat is being disassembled for resto. The distance from the back of the transmission to the front drive flange of the Kaama is the same as a 1310 splicer double U-joint/carden joint. There should be a slip yoke flange that has four bolt hole on the front of the drives. The twindisc transmission output is a 4 hole flange, and the carden fits in the middle and bolts up. Exact alignment is not necessary, although the working angle of the carden needs to be considered. The engine is mounded on a crossmember frame with mounting plates and mercruiser standard mounts. The transmissions have bolt holes on each side, and an "L" mount is bolted up, and again, Mercruiser mounts are mounted to the stringer. In essence the motor and transmission are mounted in 4 points, aiming the transmission output flange at the front flange of the drive. It may be a few months before the motors are out completely, then I will take some pictures of the brackets for you. Really dead simple when you see it. The trannys do run an oil cooler, but just a generic 14" x 2-1/2" (1-1/4 hose) two fitting cooler.