Chainsaw Repair

How To Basics - Carb Fixes + Mods - IPL and Service Manuals => Stickys of How to Basics commonly ask questions => Topic started by: Cut4fun . on December 12, 2012, 02:32:14 pm

Title: Piston Failure Analysis
Post by: Cut4fun . on December 12, 2012, 02:32:14 pm: Piston Failure Analysis

Just a little guide to help people out. In 2 links to read below in this post.
Title: Re: Piston Failure Analysis
Post by: davbell22602 on December 12, 2012, 02:40:27 pm: Quote from: Cut4fun_ on December 12, 2012, 02:32:14 pm
Piston Failure Analysis

Just a little guide to help people out. Should be 2 links to read.

Thanks for sharing that info.
Title: Re: Piston Failure Analysis
Post by: Cut4fun . on January 27, 2014, 02:11:17 pm: What do you think? Aftermarket P + C on 360 intake side. He says exhaust side looks good. Ate something? Says crank bearings are not loose, but are not very smooth.

(http://img.tapatalk.com/d/14/01/25/original/zy3y5e3e.jpg)
Title: Re: Piston Failure Analysis
Post by: jmester on January 27, 2014, 08:21:37 pm: I would say ate some thing for sure. Would be looking on the flywheel side for what happen. I would lean toward a piece of the cage has came out.
Title: Re: Piston Failure Analysis
Post by: Cut4fun . on January 27, 2014, 09:06:35 pm: Quote from: jmester on January 27, 2014, 08:21:37 pm
I would lean toward a piece of the cage has came out.

Thats what I was thinking.
Title: Re: Piston Failure Analysis
Post by: jmester on January 27, 2014, 10:33:19 pm: I say the flywheel side for the deep score by the ring lands on the flywheel side. Looks like it came up the lower transfer. But you are probably already ahead of me.
Title: Re: Piston Failure Analysis
Post by: aclarke on January 27, 2014, 11:45:18 pm: Bearings aren't smooth because of the crap they were fed. Intake port shape is clearly evident in the damage profile on the piston. Foreign object damage wouldn't be to concise
Title: Re: Piston Failure Analysis
Post by: KilliansRedLeo on January 28, 2014, 10:01:42 am: Had a Jred 2171 that came in here a while back with almost identical damage but on the clutch side. Bearings rough also. Turned out that the ball retainer in the clutch side main failed. (Metal retainer not plastic) Got caught (I think) between the skirt and the jug on the up stroke more than once. Most of it was still in the crank well. Also scored up the bottom of the crank well.
Title: Re: Piston Failure Analysis
Post by: 660magnum on January 28, 2014, 10:21:14 am: My experience with the ball bearings is that the cage is the first thing to wear out. It is best to change the bearings before roughness or looseness failure because the damage the metal of the cage does. Even the plastic cages actually mess up the edges of the rings. So if you have a plastic Polymide cage failure, you should also replace the rings as you will find the edges to no longer be sharp.

Any high time engine should have the case split and the bearings and seals replaced even if you are just slipping ring(s) in it.

The higher rpm the engine is run, the faster the cage wears.
Title: Re: Piston Failure Analysis
Post by: KilliansRedLeo on January 28, 2014, 11:11:10 am: Agreed, 660!
Title: Re: Piston Failure Analysis
Post by: 660magnum on January 28, 2014, 11:19:59 am: I got into some Chinese bearings 4 or 5 years ago and the metal cages wouldn't last a dozen tanks of fuel.

I then changed to name brand bearings but some of these were even made in China - But I didn't have any more trouble.
Title: Re: Piston Failure Analysis
Post by: Cut4fun . on January 28, 2014, 01:10:31 pm: What bearings Jim? So we stay away from them.

I didnt buy the ms360 even for $120 + ship. By the time I got done with it figuring I would have more then it would sale for local. Looks like a $250 tops type saw when rebuilt, so $200 - $250. JMO . Not worth it to me.
Title: Re: Piston Failure Analysis
Post by: KilliansRedLeo on January 28, 2014, 01:13:01 pm: The way I understand it even SKF and Nachi have plants in mainland China.
Title: Re: Piston Failure Analysis
Post by: 660magnum on January 28, 2014, 02:05:26 pm: Quote from: Cut4fun_ on January 28, 2014, 01:10:31 pm
What bearings Jim? So we stay away from them.

I didnt buy the ms360 even for $120 + ship. By the time I got done with it figuring I would have more then it would sale for local. Looks like a $250 tops type saw when rebuilt, so $200 - $250. JMO . Not worth it to me.

Those bearings had no lettering whatever on them. They came from that RCBearings company in AZ. I'm sure he has a different source after that fiasco. You had to measure the bearings and look the measurements up to know the bearing number. They were cheap but worth even less.

Those 036 and 360 saws are very nice but I have too many Husky's and Dolmars that do that work to be interested.
Title: Re: Piston Failure Analysis
Post by: Cut4fun on January 28, 2014, 02:31:32 pm: Guy sold it for $100 shipped.

I traded away my oem 036 pro topend anyways.

Thanks for info.
Title: Re: Piston Failure Analysis
Post by: Philbert on January 28, 2014, 03:59:27 pm: Great Reference. Thanks for sharing this!

Philbert
Title: Re: Piston Failure Analysis
Post by: SDB777 on January 31, 2014, 10:31:39 am: Is anyone else getting a "Can't be downloaded" message when you click on the pdf's?

Yes, I have the most updated version of Adobe.....

Scott (need more reading) B
Title: Re: Piston Failure Analysis
Post by: KilliansRedLeo on January 31, 2014, 10:59:41 am: Not having a problem here and I am doing it on some goofy 'open system' android tablet! If you are on Windows check your security settings.
Title: Re: Piston Failure Analysis
Post by: SDB777 on January 31, 2014, 01:13:37 pm: Quote from: KilliansRedLeo on January 31, 2014, 10:59:41 am
Not having a problem here and I am doing it on some goofy 'open system' android tablet! If you are on Windows check your security settings.

Dang Windows....that was it. Thanks!

Scott (photos are a big help) B
Title: Re: Piston Failure Analysis
Post by: Cut4fun on February 28, 2017, 12:12:27 pm: TTT for member asking in PM
Title: Re: Piston Failure Analysis
Post by: Cut4fun . on October 28, 2020, 08:47:52 am: https://www.efcopower.com/sites/default/files/Piston%20Failure%20Analysis_1.pdf