When to write off a cylinder as bad

[Mark71gtx]

When do you write off a cylinder as junk? I ask because I have a questionable one here and I am curious to see what you guys think. I recently picked up a Jonsered 2095 Turbo with a bad P&C. I grabbed up an aftermarket setup and put he saw back together (mostly). I figured I would try to save the cylinder. I used acid to get the transfer out, but I noticed there is a vertical scratch about 3/8" long in one spot and a "pinhole" spot about 1 1/2" away from the scratch. The scratch is about 3/8" from the edge of a port. The pinhole is about 3/4" down from the top of the combustion chamber top. I know no plating damage if certainly preferred, but I didn't want to toss this in my scrap pile if it would still be considered salvageable. Thanks in advance!

 

[Landmark]

 

[Definitive Dave]

pixous evidentiarity




(give us some pics man)

 

[Mark71gtx]

It's still in the ultrasonic right now...

 

[Mark71gtx]

Here are a few. The scratch is closer to the port than I remembered...

 

[Mark71gtx]

What I was calling a pinhole

 

[Mark71gtx]

I have not started with scotchbrite or anything yet, I have only removed the transfer with acid. I was not going to waste anymore time on it if it was deemed junk...

 

[Frank bierce]

Here are a few. The scratch is closer to the port than I remembered...

Looks an awful lot like flaked plating to me.

 

[drf256]

IDK,

I'd hit that spot lightly with a diamond ball, just to blend in any sharp edges.

I just hope the acid didn't get under it. This is one place I wouldn't use acid, but you may not have seen it.

Blend, sand and polish. See what it looks like.

You may lose a drop of starting compression, but at 13,000 rpm, not much is gonna leak past that tiny area.

 

[Mark71gtx]

The piston looked like hell. I didn't see the damage to the lining until I got the rest of the transfer out.

 

[SixGun]

I would keep it for sure. If nothing else its a good jug to practice porting on
drf255 said it right in above post.
I took down a new 372 with about 8 hours on it , and there was a big chunk of plating gone above exhaust port.
I never would have known if I didnt take the jug off . Dont know long it would have lasted, but saw ran great and piston OK

 

[Mark71gtx]

Cool. I didn't know if this was a death sentence or not.

 

[mdavlee]

I quit using acid for killing a cylinder. The plating was fine until I put acid on it and it got in a pinhole. It popped a big chunk out. I sand with 220 grit and sometimes finger sand with 80 grit.

 

[Frank bierce]

IDK,

I'd hit that spot lightly with a diamond ball, just to blend in any sharp edges.

I just hope the acid didn't get under it. This is one place I wouldn't use acid, but you may not have seen it.

Blend, sand and polish. See what it looks like.

You may lose a drop of starting compression, but at 13,000 rpm, not much is gonna leak past that tiny area.

Beautifully said. Using acid, there is a possibility the acid got behind the plating causing it to chip. Get it cleaned out good using the stickied mastermind video technique. It would now be a great cylinder to play with..and will probably last a good while cleaned up properly.

 

[drf256]

Im wondering what glass beading will do to the plate.

I gotta say, I just played with it and it left a nice finish on the plating. It ground out all the imperfections embedded in the plating.

Im gonna play with removing transfer with it.

 

[Frank bierce]

Very interesting...hope that works!!

 

[Terry Hennessy]

Here are a few. The scratch is closer to the port than I remembered...

Scratch at port height is a non-issue