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machining a prov 8 case

11 posts in this topic

Posted

I know that someone has done this so I won't ask if someone has done this so I will ask this question

about what is involved in this. The case is a prov 8 case the holes is already drilled but not taped are there any more to do to the case other than drill the holes for the correct size and tap them to fit a rotax c box to it? do you have to do anything to the crank [a standard 582 crank]

 

thanks Bob

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Posted

Yes, there's more things to do, call Rotax ric

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Posted

239 572 0021

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Posted

The front (power end) is not machined to accept the gear box.

I've done several of these cases to the measurements of an original type 90 case

and assembled them but have yet to fly one.

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Posted

Thanks akflyerbob for the reply did you have to do anything to the case like milling the front surface so the gearbox fits flat? I have never owned a c box before so i don't know what it looks like on the mounting end. you mention that you have done this  on a   original type 90 case did you have any drawings for this that I could look at? by the way I just saw where you are located is it cold and snow  there today?

thanks Bob

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Posted

No snow yet .. still in the high 40's

 

I used a spare mod 90 case to get the measurements for machining the

582 snow machine case front to mount the gearbox after threading the 8 holes

Also, since the snow machine 582 is a single ignition, the rotary oil tube, upper, has 

to be rerouted to clear the coil mount plate and oil pump.

 

I'm not sure the hole process is worth it as you have to have the rest of the parts from a

mod 90/99 to complete the motor anyway

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Posted

[i used a spare mod 90 case]

 

I don't think I am going to have much trouble or too much cost involved with this engine I did not find anybody that is using the engine that I picked I have done a lot searching about this engine and comparing parts for different rotax engines the engine that I bought was a 1989 sea doo [rotax] 587 engine it is a provision 8 case it has the starter on the engine with a flywheel it is the yellow motor that is in the sea doo jetskis I have cked the horse power of the engine is  56 horsepower@ 5,750 rpm in stock form [1 carb and 5.9 compression] the mads that I have researched is a different rotary valve shaft from a 582,583,617 rotax because the the 587 has no impeller for the water pump a different head to bring the compresion up and for the water outlet ad different rotor valve cover for the 2 carbs and maybe the crank from a 582 or a 583 I know this sounds like a lot of work but I think it will be worth it I will have a new engine with a electric starter that is mounted to the block and the coils and everything is mounted inside the cover I bought this engine from an individual that his son wrecked the sea doo  for $150.00 it is a complete motor nothing missing..... so I think I can spend a little money and come out ahead..... what do you think?

Bob

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Posted

Ask the question on www.rotaryforum.com they specialize in alternative motors and there are several of the SeaDoo engines pictured, I don't know if the crank is any different you would have to look at bore and stroke, most aircraft engines also use cageless bearings, I am not sure if they are necessary but if the piston pin is the same size I would look into it. The first Rotax aircraft engines used a single ignition, not recommended but not impossible, the big news is in the Webr and the Yamaha snowmobile engines, for the same weight you can have 150 hp in a 4 stroke with fuel injection. Not trying to talk you out of using your engine, but if I had to do the machining I would look at those two especially the Yamaha. Most snowmobiles around here are shelled out at 3,000 miles and the first valve adjustment isn't do until 25,000 miles.

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Posted (edited)

<Ask the question on www.rotaryforum.com they specialize in alternative motors>

 

I looked at the snowmobile motors and did a lot of research on the Arctic cat engines I liked what i seen on them the engines are produced by Suzuki the engine that I was looking at was the zr600  with the efi setup I know that they had problems with the stator on the engine that I was looking at 98 and 99 model the problem that with that motor was there was no battery in the sled every thing was ran off the stator  so I did more research and got the wiring diagram for the 99 sled and saw how they got the power from the stator I am sure that I could probley change the wiring around and power the efi and everything from a battery  and just use the  lighting part of the stator to charge the battery I am a member of the arctic forum and have ask about the ecms I  know that the efi setup that is on the 2 strokes are a speed density setup meaning they work off a preset fuel table  I like this setup the problem that I seen was the high cost of the ecms I can not believe what the dealer wants for the ecms it is almost a throw away sled if it is very old because of the price of the ecm I have not given up on the arctic cat setup I could probley convert this engine to efi by using the setup from the arctic cat it would not be that hard to do my background has been in aviation until I was 45 years old then changed professions and worked in electronic repair for 10 years and then self employed 8 years .boy I am getting old quick.....lol by the way thinks for the reply I will go over to the rotory forum and ask there

thanks Bob

Edited by tbucket

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Posted

I know that you asked the question because you already have that engine, but did you get a chance to see what they are doing with the Yamaha engines over there? 118 lb fuel injection engine and little less if you get the carb models, In upper Midwest, these sleds are becoming throw aways now, the engines are still alive but we rarely get the snow that they need to keep a snowmobile alive, so they destroy the suspensions and seats but the engines are living on. I have been flipping a coin about switching engines, but I have too many projects as is, I have decided that I need priorities and my old Greyhead is going to power my plane until I get another built. Then I will look at buying the Yamaha Engine to Build, By that time I should have the discipline not to use all that horsepower.

I think you will find that almost anything is doable, I checked over on Southern Airboats and found someone who had done your conversion, but you had better have the tools to do it yourself otherwise you would be better off buying a used engine with a good case and switch your internals.

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