Failure analysis

[sedanman]

When I took my "new" 015 to the saw shop the owner gave me dead one from the scrap pile for parts. It was/is seized solid. I took it apart today to find the rod bearing siezed but he piston is not, the main bearings are also toast. What caused the rod to die but spared the piston/cyl. The cylinder on an 015 is only sold with the whole crankcase so this is a great thing to have fall in my lap, but I wonder about the stuck rod bearing.

 

[stihltech]

015

Is the rod bearing and piston pin blued? Is the main crank bearing blued or very dark brown?

 

[sedanman]

The big-end rod bearings (individual rollers on a one piece crank) are a burnt almond color, haven't taken the piston off the rod yet. The piston still flops freely on the pin. The crank appears to be missing chrome where the bearings ride.

 

[stihltech]

015

Sounds like a fuel breakdown. Those rod bearings seemed to be the first to seize. Pull it apart and check the crank journal for wear and scoring.

 

[Fish]

Someone may have used a milkjug for a gas can.

 

[sonny]

bleach bottles work better.Than milk jugs.

 

[rbtree]

Work better for what, sonny, wrecking saws quicker? LOL

Before I knew of this problem, when working on a big bluff view prunes, I would pack gas into washed out one gallon oil jugs. never did it very often, dont know if it ever had any adverse effect.

 

[Rick Stafford]

It could be from low octane fuel as well.Low octane combusts before the ignition ignites causing a hammering effect on the rod bearing and crankpin!

 

[Fish]

I was voting for too rich of an oil mix, but low octane is popular.
But I thought low octance torched a huge hole in the piston.
I am joking of course as I don't see either around here. Have
not heard any pinging as well. Maybe in saws that have had the compression ratio kicked up would the low octane would be a
factor. But here in Ky. milkjugs are a common problem. I
guess we figure it holds our corn liquor ok without too many
ill effects, so us Kentuckians wrongly assume gas is OK as well.
The result is toasted bearings and a totalled saw.
It does give the shine a weird taste come to think of it.

 

[hooch27]

hi all
it could have had an air leak too. Over revving will casue thoose bearing to do that too. I have seen it in a couple of friends saws that they thought it was a hotrod. All they did was turn ini the high side needle.
later
mike

 

[Dieseldog]

From my experience as a diesel and equipment mechanic and having seen many lube related failures for whatever reason it always seems that the rod bearings seem to burn up the first. Must be the load factor is higher then the mains or piston/rings. Thats all Thanks Dieseldog!

 

[ricksvar]

Well I'lllll Beeeeee,somebodys done put milk jugs in both my saws for gas tanks....

 

[ricksvar]

Well I'lllll Beeeeee,somebodys done put milk jugs in both my saws for gas tanks....

 

[Mack]

I had two Jonsy's come in the same way, same time, same outfit, same gas can, same mix. Seems some one mixed a mess of fuel stabilizer instead of oil. Jugs looked fine, bottom end was toast.

 

[Methoss084]

My favorite is when the Happy homeowner mixes their fuel in a mountain breeze Purex detergent container, does wonders for displacing the oil in the mix. Gee, why did my saw seize? I mixed the fuel properly. I love hearing that.

 

[Dennis]

I had one of my high lead logging contractors bring me in 3 saws in one afternoon...the crew dropped off two more by the end of the day....all burnt up on the exhaust side...ONE guy burnt up all 5 saws without realizing..."we have a problem" Straight gas through 3 2171's 1 288 and an 036 I think it was...If anyone has work I know a guy looking for a job...