Piston cleanup...how much is too much?

[RI Chevy]

I use the green. Only ones I could buy
Lol

 

[I Know Something]

I can only assume from memory that the red is more aggressive. But, that information is forever old. I'll look into it more when I have time.

 

[kyle.kipple]

I don’t see green on this chart but the green I’ve used is in between the fine grey and the maroon/red.



Sent from my iPhone using Tapatalk

 

[I Know Something]

After my eyes bleeding from every search engine turning up nothing. All I have is some text ripped from a place called Ballreveiw.com.

SCOTCHBRITE GRIT CHART (courtesy of Charlest) back to top
3M Scotch Brite Nylon Pads:
7445 - White pad, called Light Duty Cleansing - (1000) 1200-1500 grit
7448 - Light Grey, called Ultra Fine Hand - (600-800) 800 grit.
6448 - Green (?), called Light Duty Hand Pad - (600) 600 grit
7447 - Maroon pad, called General Purpose Hand - (320-400) 320 grit
6444 - Brown pad, called Extra Duty Hand - (280-320) 240 grit
7446 - Dark Grey pad, called Blending Pad (180-220) 150 grit
7440 - Tan pad, called Heavy Duty Hand Pad - (120-150) 60(?)
Green Scotch Brite is available EVERYWHERE. It's 600 grit.
Blue Scotch-Brite is considered to be about 1000 grit.
(The value inside the parentheses is directly from 3M.)
3M Chart
Less Aggressive --------> More Aggressive
7445 7448 6448 7447 6444 7446 7440
Finer Finish --------> Coarser Finish

I couldn't find it on 3M's website. Go figure. But. Here it is.

 

[Lightning Performance]

I use 120 sand paper on the intake side and 220 on the exhaust. A very few passes off the skirt sides from center. Be-burr the piston and clean the ring grooves till you see metal in the gas port area behind the rings. Don't touch the ring seat areas top or bottom of the land. If you sand or groove the land floor you pass gas.

 

[a. palmer jr.]

What I would do would be determined by what kind of saw it was, whose it was and how much would be spent on the repair. On an old EZ I would clean the piston if it wasn't scarred too bad. I would check the cylinder also and the reason for the scarring. On a Stihl 290 I would go for aftermarket parts usually..