Nikasil erosion at high velocity ports

[motosierra]

I have 3- 272 cylinder that have varing degrees of erosion of the nikasil around the intake port and I have a friend who says he has a 2100 cylinder with this condition. Is this a common occurance?

The piston ring does no get down this low on the cylinders and it seems that maybe this is not big problem. Anyone have any experience with this?

 

[timberwolf]

Look at the piston skirt, they usually show pretty heavy wear on the lower intake skirt, lots of pressure from the intake side skirt against the cylinder wall, that pressure will be concentraited around the port, esp if it has been widened.

 

[Lakeside53]

When I see this on Stihl it's because of bad air filters. In concrete cutoff saws, the nikersil often is completely gone beneath the intake port!

 

[bama]

If I have a small chip of nikasil coating that came off of a cylinder below the intake port, will there be a different expansion rate due to the bare cylinder wall being exposed. Will it rub against the piston skirt?

 

[motosierra]

That is the $64 dollar question.

If I have a small chip of nikasil coating that came off of a cylinder below the intake port, will there be a different expansion rate due to the bare cylinder wall being exposed. Will it rub against the piston skirt?

....That is the $64 dollar question... Will the area, around the port, that has no nikasil, rub against the piston?....And ultimately cause the piston to fail? Has anyone had this experience?

 

[jhellwig]

Is, $64, the, cost, of, the, jug, or, the, commas?:hmm3grin2orange:

But in all seriousness, if you have the money or the saw is important to you why chance it?

 

[Jacob J.]

I have to agree with Lakeside, 98% of the time any kind of erosion or scarring beneath the intake port is from a dirty air filter. This was especially common in the 272s that have the clamp-on cartridge style filter and the 2100 because most of those filters were just a fine mesh which still allowed a lot of dust through. If you take some time and clean up the underside of the intake port with some emery cloth and cutting oil, you'll get more service life out of the cylinder without any problems.

 

[motosierra]

Is, $64, the, cost, of, the, jug, or, the, commas?:hmm3grin2orange:

But in all seriousness, if you have the money or the saw is important to you why chance it?

I agree with you whole-heartily..."why chance it"

I don't know if you are old enough to remember the TV Game show called "The $64,000 Question"? It was popular back in the late 50's, I belive. So that is where the $64 question came from...hahaha... my joke.. probably not funny to anyone else.... but I still remember..."The $ 64,000 question"... that was when you could buy a new car for 800 bucks...so it was a lot of money.

Thank all of you for your much appreciated input. You guys are what makes this Forum ..great!

 

[bama]

But in all seriousness, if you have the money or the saw is important to you why chance it?

Part of the trouble is finding P/C for this vintage of saw. It starts to cost an arm and a leg. I will give it a shot and run it for awhile. It isn't too hard to pull the carb and see what is happening to the piston.

 

[motosierra]

Part of the trouble is finding P/C for this vintage of saw. It starts to cost an arm and a leg. I will give it a shot and run it for awhile. It isn't too hard to pull the carb and see what is happening to the piston.

I'm going to give it a shot too...and old (but good) piston with a new ring and the battered cylinder. I will open it up periodically and report any aberrations of any sort..They may run dam good and maybe they will last. :rockn: :rockn: :rockn: :rockn:
:rockn: :rockn: :rockn: :rockn:

 

[jhellwig]

Part of the trouble is finding P/C for this vintage of saw. It starts to cost an arm and a leg. I will give it a shot and run it for awhile. It isn't too hard to pull the carb and see what is happening to the piston.

I see. Well then my next seguestion would be to clean it up shine it up and store it on a shelf for the rare occasions when you want to show someone that the old beast still runs or feel like playing and go buy a new saw.