Saw this today at the stihl shop. I presume the piston got too hot from being run too lean, that causes pre ignition and punched a hole through the piston?
Hole In Piston - Why?
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Being at the Stihl shop and all they should have been able to hand you one of these and you could look it up yourself.
Now you can make a video about it.
Now you can make a video about it.
It is definitely cooked. But, they may have poked the hole with a piston stop.
Hate to say it, but I have poked a hole in the top of a piston that way.
Hate to say it, but I have poked a hole in the top of a piston that way.
Tomos770
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I just use a big piece of starter rope now. Just watch where your piston is so you don't hang it in a port .
12 volt impact gun do yourself a favor.
Not a bad idea I'm sure . But, you'll never get the fan off a back pack blower with one I don't think.
Why not, i never tried, though?
Coincidentally I took one off about an hour ago. Guy broke the bottom of the pan off that holds the bottom starter screw. Had to take the hole thing apart to put one I robbed off a junker.
I imagine it took about 100 pounds to break it.
I have tried it with a plain old air impact wrench, but with nothing solid to impact against it would not do it.
For whatever reason the newer blowers don't have a threaded fan hub, but either on a taper or just two flat washers and a nut. Bad idea. Guess it saved them a dollar.
Problem is they get loose and it least ruin the fan, and maybe even the end of the crank shaft.
A ventilated piston is the result of pre ignition. Often times mild to medium detonation can get the engine hot enough to cause the head or spark plug to glow. Once this happens pre ignition starts and it rather quickly burns a whole in the piston crown. Usually caused by the spark plug ground strap glowing and the hole is directly below the plug in most cases.
The coking on the piston ring lands tells me this piston ran hot for an extended period before failed.
The coking on the piston ring lands tells me this piston ran hot for an extended period before failed.
A 1/4" drive impact will remove the fan just fine.
Your practice of using starter rope vs. A piston stop is smart.
I'm like the blind man. Find yourself a junk BR600 and let me know.
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The newer big backpack blowers need a factory piston stop
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Here. It is on the good stihl info thread.
Not, doubting you, but what's the reason for that?
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An impact style did nothing to it. The whole fanwheel was part of the nut, and it took an incredible amount of force. I never sat and thought about the physics of it, but with an impact wrench, it just unscrews the nut, there was too much mass I suppose for the impact's action to work correctly.
I hated like hell ordering the damn piston stop.
I hated like hell ordering the damn piston stop.
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With their piston stop, I was still worried about damaging the brand new engine, it required that much force.
I put it in the grass vertically and lay my chest down on top of it with the flat output down and use about a two foot cheater bar. Grass keeps it from squirming out from under me.
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Do you buy it dinner first?
Thanks mate
