[rsss396]

does anyone notice this on there aluminum axles? i get this between the hubs and axle, I have tried anti-seize and dry and it still occurs.

I have helped fix 2 banshee cranks in the dunes that had this happen to their cranks, we used valve grinding compound and my electric starter to spin the flywheels until the surfaces looked good again.

Banshees have very large OD flywheels and with the very high acceleration rates of the big HP motors I think a rocking action happens very much like my aluminum axles get causing this welding.

I once removed the clutch bolt from my snomoquad and forgot to put it back in and made 2 full passes until it broke loose when I let off the gas so taper fits can very tight if seated good.

[okbeast]

I've seen it on axles, but wouldn't necessarily call it a welding. It more looks like a white powdery subtance when it's sanded off, almost like a gunk build-up like with anything else that gets rode in dirty conditions.

[gpr]

I have seen what your talking about with aluminum axles. I always thought that was water deposits or something, this is way different.

The engine is running the stock oem plastic cover, also doesn't have drag pipes on that side. also it can't be getting that hot as it had dyno tuning and tops 10 minutes of dune riding before shift forks bent again....

I have had both oem and ricky stator flywheels and it happened to both. I have tried both oem and ricky stators stators and it happened and i believe it is a stock stator on it this last time... I need to go check that. How do you tell the difference between oem and a ricky stator? maybe i need to double check that cause its the one thing I'm not 100% certain what was running on it.

Also after lapping it this last time it didn't weld itself as bad, not sure if its from the better fit between the two or from the little time on the engine.

I appreciate the help and idea's guys.

[Turboshee421]

gpr, on 05 December 2011 - 03:46 PM, said:

Not only that but i was thinking and really it isn't the key holding the flywheel in place it is the friction from the taper fit. the key is only to get timing correct. Heck my 150hp snowmobile with a primary way heavier than a fly wheel doesn't need a key and it has no issues.

Its gotta be something with the two different types of metals. Crankworks should start making flywheel hubs out of the same material as their cranks so it isn't an issue.

Hear's your prob crankworks taper is off a 1/2* so when u lap it in the taper on the flywheel is no longer 7*, 7* is the magic #, even a 1/4* off mean's instead of holding 2 tons of psi now it will only hold around 300psi, so now the key way has to hold the flywheel from moving. So make sure your key fits snug in the flywheel and crank, make sure there is no play. Lap your flywheel back in until u have full contact all the way around. Clean everything really good and place some plastigage on top of the key (side going in flywheel) put flywheel on and TQ it, pull your flywheel back off, u want your gap no more than .010 and no less than .005, clearance if u need to. Now clean it really good and put back on clean and dry (any loctite will make taper lock come lose over time) put blue loctite on nut and TQ it.

[2-330s]

it sounds like dissimilar metal corrosion to me but i have never seen this for myself on a crank.if you put aluminum into steel,or stainless steel into steel,brass,copper,ect,ect you can have a "welding" effect buy the metals not reacting well together or elements corroding one or the other and them together.some pics might help?

[camatv]

with all the problems with billet cranks. why do people still buy them?

i have a forged 10 mill crank and have had NO problems with it EVER EVER EVER the flywheel comes right off it hasnt seperated it hasent broken or exploded.

maybe its time we as a whole and comsumer start to require a better product.

[gpr]

Turboshee421, on 06 December 2011 - 06:32 PM, said:

Hear's your prob crankworks taper is off a 1/2* so when u lap it in the taper on the flywheel is no longer 7*, 7* is the magic #, even a 1/4* off mean's instead of holding 2 tons of psi now it will only hold around 300psi, so now the key way has to hold the flywheel from moving. So make sure your key fits snug in the flywheel and crank, make sure there is no play. Lap your flywheel back in until u have full contact all the way around. Clean everything really good and place some plastigage on top of the key (side going in flywheel) put flywheel on and TQ it, pull your flywheel back off, u want your gap no more than .010 and no less than .005, clearance if u need to. Now clean it really good and put back on clean and dry (any loctite will make taper lock come lose over time) put blue loctite on nut and TQ it.

I'm wondering if this is my issue as the only place it welded last time was right next to the key. I was also thinking if lap it and take material off i would need to take some material off the key so it didn't sit to high. The plastigage is a great idea and i will for sure do that this next time.

BTW, to get the plasticgage to stay on the key should i use a little grease to hold it, or will that throw off the measurement?


thanks for the help

P.S. I'd buy a forged crank but they don't make a 16 or 18mm forged crank. I think a forged crank would be plenty strong as well.

[Turboshee421]

gpr, on 07 December 2011 - 11:31 AM, said:

I'm wondering if this is my issue as the only place it welded last time was right next to the key. I was also thinking if lap it and take material off i would need to take some material off the key so it didn't sit to high. The plastigage is a great idea and i will for sure do that this next time.

BTW, to get the plasticgage to stay on the key should i use a little grease to hold it, or will that throw off the measurement?


thanks for the help

P.S. I'd buy a forged crank but they don't make a 16 or 18mm forged crank. I think a forged crank would be plenty strong as well.

Put it on dry, plastigage is kinda sticky, it will hold it's self, if u put grease on it, it will give u a wrong reading. No prob and good luck.

[Moser Racing]

This is just my opinion and what we have found on snowmobile engines(I work at D&D Racing, Arctic Cat and Yamaha Dealership) Have seen flywheels and clutches "welded" to crankshaft before on high rpm race engines, twin cylinder engines worse than tripples. Bad vibrations/harmonics at high rpm will cause havoc with cranks. for example, our pro stock twin 1000cc (naturally aspirated) makes 250hp at 9200 rpm, cranks are dynamically balanced to run that rpm, clutches and flywheels will at times "weld" to crank. Our turbo 1200's (same base engine) making anywheres from 300-500 hp depending on turbo and boost, spinning 7500- 8000 rpm have way less issues with flywheels "welding". It may not be big hp causing flywheels to "weld", but more high rpm versus harmonics. Again just my opinion, hope this helps.

[lotuseater]

Good Thread. It took me a while to figure out the taper is suppose hold the magneto from turning, not the key. A buddy told me to lapp them in, and I have not had any problems since. When I first started the process it was only contacting on each end of the surface, not in the middle.

[RJATV]

I know there are probably alot of reasons why this is happening but I have never had a problem, I use anti-seize and always comes off with no problems at all.

[gpr]

Moser,

You guys ever figure out a way to stop the flywheel welding, or at least slow it down?

[BVH Developments]

HI

I have been reading this thread just now.... I had a customer that brought me a 421 cub, it ran on pump gas with the wrong domes and detonated very very bad.... This is the 2nd time it happened to them... The flywheel welded itself to a hotrods crank, the flywheel itself cracked, big end of the crank also blew, there was clear signs of detonation.... Now I don't say it was deto, that causes it to weld, though the temperatures on the crankshaft was EXTREMELY high... After we sorted the detonation issue it ran flawlessly and no more welding... Deto is a weird thing and can cause all sorts of issue... I strongly believe this was the cause on this motor.... I can share pics if someone want to see it.... I got the motor already stripped from the customer, so I took a few fotos... Liek said, this was not even a billet crank and also the first time I have seen this.... I could not believe my eyes that a crank could be destroyed like this...

[Moser Racing]

gpr, on 12 December 2011 - 11:20 AM, said:

Moser,

You guys ever figure out a way to stop the flywheel welding, or at least slow it down?

When we are using billet stroker cranks we have lapped / seated flywheels to crank, make sure big offset timing keys are small enough, have had issues there, top part of key does now follow radius of crank, leading edge may need to be "rolled" off.
Properly torque flywheel nut, it does help, impacts are not good here. Give your flywheel a "test fit", install it and properly torque, remove it with puller, if it comes off with an audible bang and all at once the taper is perfect, if it "smears" off and comes off slow- somethings wrong. hope this helps.

[WINDYCITYJOHN400]

I made a spacer out of 1/2" copper pipe that I put on my flywheel puller. It holds the center portion out far enough that it won't hit the crank whn I thread it into the flywheel. I tighten the pieces together locking them into one solid piece. Then I thread it into the flywheel. Next I put an adapter into my drill so I can mount a socket on it. Then with the drill in reverse, I can use it on my flywheel puller as a flywheel driver to spin the flywheel. I put valve lapping compound on all the mating surfaces and spin the flywheel at a slow speed while slightly pulsing in on and off. (Toward the motor and away) I'll spend 4-5 min doing this and apply fresh compound 3-4 times.

At some point you will get an even "etched" look to both the flywheel and the crank. At that point you have a good matched surface. Then I clean the crank and flywheel with brake cleaner. I put in a NEW key and smear blue loctite on the shaft, flywheel and threads. I put a "Hardened" washer on against the flywheel. (This in theory prevents the nut/lockwasher from digging into the keyway and giving a faulse impression that it's tight/torqued properly.) Then I tighten to 75 pounds. My flywheel issues ended with this method.

I agree that DETONATION could cause the "Metal Transfer" that your describing.
Also, when flywheels go bad...they can get HOT. Try riding with the side cover off for 5-10 minuets or while on the dyno. If you can grab it with your bare hand after the motor is warmed up from a ride, your stator is ok. But if it gets hot...or makes noise like it's full of sand when you shake it real hard, then your flywheel is junk. (I've had 3-4 that made power and "Worked Fine" but were not fine when it came to the heat and noise tests.)

I'd look into the heat issue a little closer. I'm sure that it's not getting hot enough to "Weld" the parts together. But if the parts heat up at a different rate than each other, they my transfer material from the movement that comes from the metal growth rather than from the flywheel "Moving/spinning/slipping" on the crank.

I'm no expert and you sound like you have tried it all. but I figured one more guy chiming in here couldn't hurt. LOL
Hope you get this figured out before you get frustrated enough to start building splined crank ends and splined flywheels.

[rsss396]

WINDYCITYJOHN400, on 20 December 2011 - 11:00 PM, said:

Also, when flywheels go bad...they can get HOT. Try riding with the side cover off for 5-10 minuets or while on the dyno. If you can grab it with your bare hand after the motor is warmed up from a ride, your stator is ok. But if it gets hot...or makes noise like it's full of sand when you shake it real hard, then your flywheel is junk. (I've had 3-4 that made power and "Worked Fine" but were not fine when it came to the heat and noise tests.)

I'd look into the heat issue a little closer. I'm sure that it's not getting hot enough to "Weld" the parts together. But if the parts heat up at a different rate than each other, they my transfer material from the movement that comes from the metal growth rather than from the flywheel "Moving/spinning/slipping" on the crank.

i know he said he changed the flywheel once to a new one but I had once read that if the magnets crack that many times the flywheels will overheat because of the lines of flux but it would amaze me that it would weld a crank.
detonation that can't be heard is the most likely culpret