[Willy]

Hi it is me again. (You guys have probably heard enough bullshit from me) but all you guys responses have helped me out enormously and I thank you and Snowmobile Fanactics. But guess what. I have another question. How can you tell If a cranks needs to be rebuilt. Such as new seals and things like that. I have heard that if that if the connecting rod does not move up and down on the crank pin then the connecting rod bearings are fine. Is this true.
What else can you look for on a crank to tell wether it is good or bad.
Thanks

 

[hotrod]

that depends on wether the crank is in or out of the case as far as what all you can check. There is also a measurement on the connecting rod that is determined by forcing the top of the rod over and seeing how far it can move axially.

Reasonable people adapt to the world around them....Unreasonable people try to change it.

 

[Picklektm]

I think its normal for the rod to move up and down a little out of the cases but is should not twist. And any side to side motion is fine as well.

 

[mattgross]

the rod should not move up and down on the bearing, if that is happening, it will break think about it the force of the piston fire will not all be transfered into rotation because some of the force will just be pounding on the rod end, i have a picture for you of what happens when the bearing asre loose, the only thing those rods should be able the do is spin, no side to side, look at this pic the rod accual broke

 

[Willy]

Ouch, That must have been a bad sound when it happened

 

[mattgross]

it also crack the case, if that bearing lets the rod ge out of alignment it will do that

 

[Falstaff]

There are a lot of variables to check with a crank. You can also measure connecting rod side clearance and compare with specs. This is how far the rod moves side to side. Also everyone else is right, it shouldn't move up and down. You can check crankshaft runout for crank twist with a dial indicator.

Move all the bearings by hand and you will be able to tell if they are bad. Outer seals piece of cake, center seals could be a challenge.

I would leave it to the pros since it is the heart of the machine.

 

[mattgross]

if you find you need to rebuild the crank there really is no way you can do it yourself, it take presses and jigs for keeping the crank in line, do anyone know of rebuild comapaines for cranks, and i did see in a magazine there is a newer process where they cut nutches in the weight i think they are called turbo cranks or something like that

 

[hotrod]

Hmmmm, that sounds interesting. Got any more info on that.

Reasonable people adapt to the world around them....Unreasonable people try to change it.

 

[mattgross]

i will look through my mags and see if i can find the artical

 

[mattgross]

heres a picture of what it kind of is, but i have not found the company for snowmobile yet

 

[hotrod]

Cool. Sweet. or what ever people use nowadays. Thats all I ever here from my 7 year old ......Ssswweet! Thanks Mattgross

Reasonable people adapt to the world around them....Unreasonable people try to change it.

 

[Tfin70]

That article is in one of my last Snow Tech mags, I'll get the info for you tomorrow. The guy drilled angled holes instead of the lines. It created more compresion or something, like I said, I'll find it tonight.

1997 XLT SP 600
"Engage the Mechanism"

 

[mattgross]

thats were i saw it i just don';t have the mag anymore, sent it off to my parents office so the patients can read it. instead of home and garden or womens world, shit like that, i send all my old car mags and things so the have the best waiting room selection

 

[bombieman]

Well you guys are righ about one thing. It is called a TURBO CRANK but it is not new technologie. It's been around since 1978, if not older. I know because I got one! Bombardier came out with that in there limited build 440 SNO PRO supper mod. They only made 500 or these. What it does, it helps to create a postive pressure in your crank case to help push more fuel up the ports and in the compression chamber. It also helps to to mix the air and fuel better. Now the performance claims very. I've had alot of mixed comments in the past. Some say its not worth it some say it is. The HP gain is not all that mutch for sutch a process it's about 3-4 hp gain but also carries other advantages. It seemed to work very well on my SNO PRO so I think it works. But to find a company to do it you would have to call some performance engine shop like D&L PERFORMANCE ,THE CRANK SHOP, D&D,BENDER OR HOT TO GO. These guys will be able to help you in finding a place to do it and tell you if it's worth it for your sleds.

Hope this helped shine some light

 

[Tfin70]

Sorry, I forgot to look in my mag last night. But it sounds like bombieman pretty well sumed it up for you. I'll try to remember to bring the mag with me to work tomorrow so I can give you the name of the guy/company that was actually doing this, if your still interested.

1997 XLT SP 600
"Engage the Mechanism"

 

[Tfin70]

The article on the Turbo Cranks was in the Sept issue of Snow Tech.

It states that "they drill a series of holes at a compound angel around the outer diameter of the crankshaft. The larger the crank, the larger the holes. The theory is the holes act like a fan, boosting the transfer of mixture up into the cylinders. This achieves a pumping action that creates more vacuum, pulling more mixture into the crankcase and therefore, packs more mixture into the combustion chamber. Increases of up to 200 RPMs have been reported from many of the thirty engines modified so far. All they know for sure is that it makes a difference.

One of the fastest sleds in their locale was a mod XCR 700 that produced an impressive baseline of 192 hp. After exchanging with a turbo crank, the engine dynoed at 209 hp at 9600 RPM; increase of 17 hp. Gains were realized throughout the whole powerband.

The guys name is Steve Miller, who is the owner of Advancing Racing Technologies. 989-781-6936 and are located at 300 South Thomas Rd in Saginaw Michigan 48609".

Snow Tech Magazine

1997 XLT SP 600
"Engage the Mechanism"

 

[bombieman]

I'd like to correct my self on something I said in my last posting. Bombardier did not come out with the TURBO CRANK in there SNO PRO 440 light mod. It was done by the original owner of my sled. Sorry for the mist information. But I talk to some people about it and they did not claim that mutch diffrence. They said it helped the engine idle better and some gain out of the hole but not mutch diffrence on top. This is based on the smaller engines that we have raced like the 440, although there is a increace in RPM of about 200 or up to 350 (from 10 000 rpm to 10 350 rpm with a 440 some have claimed) we did not feel it was a " must have " modification to are engines becouse of the cost of this procedure. I haven't got any prices on this in some time. I might have droped and be more affordable. But this may work better on bigger engines. In any case I hope I was able to help

ONE THING AT A TIME

 

[mattgross]

i found a place where they do the turbo cranks, and iot cost about 500 for a 2 cyclinder. www.advancedracingtechnologies.com