Patrick1903
ArboristSite Operative
Hi everyone, I picked up a decent looking MS391 (PHO) on CL for $40, about 5 years old. The seller told me he accidentally straight gassed it. Thought he had put the oil in the 1 gallon can, then filled at the station, and the rest is history. He had bought it to mill with and it didn't seem abused and was pretty clean (no sawdust caked in cooling fins, no bluing from heat around clutch drum, etc). I ordered a Proline piston & cylinder, (didn't want to do the $300 right now for OEM, and it's a project really. I don't have too much of a need for this saw - but it could certainly be put into the farm saw rotation.) I've only done 1 top end before, on an 041 (I have a thread about my 041 issues, which I think are now resolved!).
After talking to some folks, they recommended I try to clean the cylinder up first before writing it off. I have never cleaned up a cylinder before, so I made an attempt at that tonight. I watched Mastermind Saw's videos on cleaning with sandpaper and scotch brite. I couldn't figure out a decent mandrel setup for my drill with emery cloth, so I just went straight to the scotch brite (I read green scotch brite was around 600 grit, so not sure skipping the 150-200 grit was a good idea).
So I'd like to hear if anyone has thoughts on:
1) Should I consider just replacing the piston? I think I could get a Metor cylinder for around $50. And maybe use the Piston/Cylinder kit that's in the mail as a backup in case the cylinder doesn't work out with a new piston?
2) It may be hard to tell from the pictures, but are there obvious show-stoppers with the cylinder? I think there is still some aluminum stuck in there - I was trying to figure out if it was the plating gouged out or if it was proud of the cylinder walls, so I took a letter opener and knocked off some aluminum. I can't tell if there is obvious pitting or wearing away of the coating. There are a few "grooves" but don't seem to catch my nail exactly. It's also hard for me to tell b/c can't get my finger into some of the top of the cylinder.
Pics attached.
New saw
Piston - not good. Disintegrated in part.
Cylinder - after I cleaned with scotch brite and drill.
Last pic - Cylinder before scotch brite and drill cleaning. Lighting is bad , flash only. The cleaned cylinder pics I was holding a light and taking pics. I think that was better.
After talking to some folks, they recommended I try to clean the cylinder up first before writing it off. I have never cleaned up a cylinder before, so I made an attempt at that tonight. I watched Mastermind Saw's videos on cleaning with sandpaper and scotch brite. I couldn't figure out a decent mandrel setup for my drill with emery cloth, so I just went straight to the scotch brite (I read green scotch brite was around 600 grit, so not sure skipping the 150-200 grit was a good idea).
So I'd like to hear if anyone has thoughts on:
1) Should I consider just replacing the piston? I think I could get a Metor cylinder for around $50. And maybe use the Piston/Cylinder kit that's in the mail as a backup in case the cylinder doesn't work out with a new piston?
2) It may be hard to tell from the pictures, but are there obvious show-stoppers with the cylinder? I think there is still some aluminum stuck in there - I was trying to figure out if it was the plating gouged out or if it was proud of the cylinder walls, so I took a letter opener and knocked off some aluminum. I can't tell if there is obvious pitting or wearing away of the coating. There are a few "grooves" but don't seem to catch my nail exactly. It's also hard for me to tell b/c can't get my finger into some of the top of the cylinder.
Pics attached.
New saw
Piston - not good. Disintegrated in part.
Cylinder - after I cleaned with scotch brite and drill.
Last pic - Cylinder before scotch brite and drill cleaning. Lighting is bad , flash only. The cleaned cylinder pics I was holding a light and taking pics. I think that was better.