MS 460 blows crank rod bearing after dyno runs. Should have spent the extra $ on oem

[chadihman]

:msp_sad: My MS 460 that has been the test saw on my dyno blew the rod bearing today. I have a large walnut tree to cut up and I took it off the dyno bar and put the 25" bar back on to prepare it for wood cutting again.
I got the bar on and started it and let it warm up before giving it full throttle for a couple seconds to check my carb settings. It was tuned a little fat at 12500 but I wanted it there for a little longer. I gave it full throttle again for a couple seconds and rattle rattle clank clank screach it came to a halt fast. I never heard that noise before and I had a pretty bad feeling it was the after market crank I installed.
The jug and piston are in great shape. Damn I should have spent the money on oem. I heard the warnings but ignored them and thought I'll give an after market crank a try. Never again.[video=youtube_share;9DdbkO0RqeI]http://youtu.be/9DdbkO0RqeI[/video]

 

[pioneerguy600]

That`s one AM part I would never run on a work chainsaw.

 

[chadihman]

That`s one AM part I would never run on a work chainsaw.

The crank looked good. I should have known $59 for a new AM crank was to good to be true. I'm living and learning.

 

[RiverRocket]

Damn, I'm Sorry to here that...But thanks for posting..I know now not to ever try an A/M Crank.

 

[Jacob J.]

I didn't even know there were a/f cranks for 046 available. I'm sorry about your saw blowing.

 

[LegDeLimber]

Bummer!

But thanks for keeping "tales from the dyno" coming.

 

[chadihman]

I didn't even know there were a/f cranks for 046 available. I'm sorry about your saw blowing.

I don't want to say where I got it but I'm pretty sure there not a sponsor here.

 

[chadihman]

Bummer!

But thanks for keeping "tales from the dyno" coming.

The dyno is getting reworked. The part I'm waiting for should be here on Tuesday. Don't worry there will be many dyno tales to come.

 

[brokenbudget]

what happened to the original crank?

 

[chadihman]

what happened to the original crank?

This video is of the same saw. This saw had a AM cylinder on it that the piston rings raked the plating off of the walls of the cylinder at 9000 rpms in solid oak. It came to a sreaching halt that time also. I knew it was bad when the exhaust opening in the muffler was coated with metal dust. I was really close to parting this saw out before I bought the new crankcase and AM crank. [video=youtube_share;4T99O5BkYmc]http://youtu.be/4T99O5BkYmc[/video]

 

[TBrown]

I have an extra ms460 crank if you are interested

 

[moronmountain]

This may sound ignorant on my part, but can't you just replace the crank bearings?

 

[mdavlee]

This may sound ignorant on my part, but can't you just replace the crank bearings?

Not on the big end of the rod. The cranks are pressed together and if you have the machines and tooling to split it and then realign it back together you could. A big motorcycle shop probably could.

 

[parrisw]

What oil and mix ratio were you running?

That dyno looked like it can be hard on a saw? Do you think it contributed?

 

[watsonr]

I'm confused, which bearing failed.. the center bearing that the crank rod is on and as stated in the title or a bearing that rides in the side of the case that the video shows?

Did you buy both the crank and the aftermarket case bearing from the same place? It looks to me like the crank and the rod bearing are OK and the case bearing is not? And now its spinning in the race?

This happens quite often in the 064 with OEM bearings if I'm not mistaken... and the older 066 as well and why the manufacturer updated the bearing in the MS660... correct?

So maybe the blanket statement that the aftermarket cranks are bad is not completely correct, but maybe the bearing may not be very good?

Not here to start a fight, I'm trying to get the facts straight so I can decide if I need to pull a product that I may be selling and not have all the correct information on.

 

[moronmountain]

Not on the big end of the rod. The cranks are pressed together and if you have the machines and tooling to split it and then realign it back together you could. A big motorcycle shop probably could.

I see. I've only replace bearings on old V8's, so I don't know much about 2 strokes yet other than jetting motorcyles.

 

[Mastermind]

Was this a Raisman Platt crankshaft?

 

[chadihman]

What oil and mix ratio were you running?

That dyno looked like it can be hard on a saw? Do you think it contributed?

40 to 1 with hp and I don't think the dyno puts more stress on the saw than a milling set up would

 

[chadihman]

I'm confused, which bearing failed.. the center bearing that the crank rod is on and as stated in the title or a bearing that rides in the side of the case that the video shows?

Did you buy both the crank and the aftermarket case bearing from the same place? It looks to me like the crank and the rod bearing are OK and the case bearing is not? And now its spinning in the race?

This happens quite often in the 064 with OEM bearings if I'm not mistaken... and the older 066 as well and why the manufacturer updated the bearing in the MS660... correct?

So maybe the blanket statement that the aftermarket cranks are bad is not completely correct, but maybe the bearing may not be very good?

Not here to start a fight, I'm trying to get the facts straight so I can decide if I need to pull a product that I may be selling and not have all the correct information on.

Sorry about any confusion. The first video is of the current bad am crank. The second video is the original oem crank and the reason for a new case and crank

 

[chadihman]

Was this a Raisman Platt crankshaft?

Not sure what brand but I bought it from hl supply