to piston or not to piston that's the question.

[ken morgan]

So I put a new OEM single ring P&C on my 372 (the one that was all original to begin with) and played with the cylinder as well as gasket delete and muff mod....

Since my other 372 has a chicom cylinder and a supposed meteor piston, I was considering putting my used OEM from saw #1 on it. there was nothing wrong when I took it off other than it was the original and its compression was down some. neither cylinder nor piston have any scoring at all and I was considering just doing a set of caber rings. anybody know what the wear limits for the piston are prior to replacing? I can precision mic it and if its below spec I was going to just go with a meteor on it. or is this not a concern if its undamaged?

thoughts, sage advice... & dead horse defibrillators are all welcome.

Ken

 

[Dolmar Junkie]

So I put a new OEM single ring P&C on my 372 (the one that was all original to begin with) and played with the cylinder as well as gasket delete and muff mod....

Since my other 372 has a chicom cylinder and a supposed meteor piston, I was considering putting my used OEM from saw #1 on it. there was nothing wrong when I took it off other than it was the original and its compression was down some. neither cylinder nor piston have any scoring at all and I was considering just doing a set of caber rings. anybody know what the wear limits for the piston are prior to replacing? I can precision mic it and if its below spec I was going to just go with a meteor on it. or is this not a concern if its undamaged?

thoughts, sage advice... & dead horse defibrillators are all welcome.

Ken

Sorry Ken, but your post does not meet the minimum time space continuum requirements to activate the Dead Horse Defibrillator squad.


Will check back later to see if use can actually be justified.

In the meantime, I hope all is well in Yamasuki, and we are currently trying to collect and fill a shipping container with the Wildthangs that you requested, please make necessary pmts to gov officials, since Japan has a ban on importing saws that powerful... Matt

 

[Dub11]

Some meteors have the size written on the box if that helps.

 

[drf256]

So I put a new OEM single ring P&C on my 372 (the one that was all original to begin with) and played with the cylinder as well as gasket delete and muff mod....

Since my other 372 has a chicom cylinder and a supposed meteor piston, I was considering putting my used OEM from saw #1 on it. there was nothing wrong when I took it off other than it was the original and its compression was down some. neither cylinder nor piston have any scoring at all and I was considering just doing a set of caber rings. anybody know what the wear limits for the piston are prior to replacing? I can precision mic it and if its below spec I was going to just go with a meteor on it. or is this not a concern if its undamaged?

thoughts, sage advice... & dead horse defibrillators are all welcome.

Ken

Ken,

I believe standard Max is .002 to .003 piston to bore spacing total. That’s if you can slide a .002-3 feeler gauge into the jug on the side of the piston. So .0015 max each side.

 

[XP_Slinger]

Morning Ken,

Something I look for on a piston is whether or not it has any visible wear on the skirts. I rebuilt a 371 for a friend recently, he bought the saw new in 1998 and it still had the original piston in it. The cylinder looked great and the only wear on the piston was on the intake side skirt, it was polished to a near mirror finish. I opted to replace it for just that reason. I am no pro, this is just something I look for based on past 2-stroke experience.

 

[Moparmyway]

Pics of the piston, a few from all different views, probably the easiest way for us to help you

 

[huskyboy]

If you do get rings for the old piston make sure you get the right thickness ones. Single ring piston uses a 50 x 1.5mm ring and the double ring piston uses two 50 x 1.2mm rings I believe.

 

[a. palmer jr.]

I used the OEM cylinder and a $5 Chicom piston along with the Caber rings on my 372 EPA version (2 ring). I haven't put it back together yet..piston hasn't arrived.

 

[ken morgan]

Sorry Ken, but your post does not meet the minimum time space continuum requirements to activate the Dead Horse Defibrillator squad.


Will check back later to see if use can actually be justified.

In the meantime, I hope all is well in Yamasuki, and we are currently trying to collect and fill a shipping container with the Wildthangs that you requested, please make necessary pmts to gov officials, since Japan has a ban on importing saws that powerful... Matt

Ha ha ha Great one! We are headed up to Yamanashi this weekend..got another two big elms my neighbor found to cut for firewood. Might need a couple of them wild thangs

please mark the container as LBFM markI mod II and note the quantity


Ken

 

[ken morgan]

Ken,

I believe standard Max is .002 to .003 piston to bore spacing total. That’s if you can slide a .002-3 feeler gauge into the jug on the side of the piston. So .0015 max each side.

thats what I am looking for

Morning Ken,

Something I look for on a piston is whether or not it has any visible wear on the skirts. I rebuilt a 371 for a friend recently, he bought the saw new in 1998 and it still had the original piston in it. The cylinder looked great and the only wear on the piston was on the intake side skirt, it was polished to a near mirror finish. I opted to replace it for just that reason. I am no pro, this is just something I look for based on past 2-stroke experience.

Sounds totally reasonable to me.

This P&C ran really well, I just wanted new P&C on the saw as if I was going to go to the trouble of grinding on it and the rest I wanted the results to be untainted by possible low compression or what not so I just put new P&C with rings in. the ones I pulled off i will measure this weekend and check for wear on the skirts as well. If i can get by with just the caber rings it will be loads better than the Chicom cyclinder I am sure. the chicom cylinder had good compression, but it does not make near the power of the older saw with the low compression..I think it has to do with the ports probably...

 

[XP_Slinger]

thats what I am looking for



Sounds totally reasonable to me.

This P&C ran really well, I just wanted new P&C on the saw as if I was going to go to the trouble of grinding on it and the rest I wanted the results to be untainted by possible low compression or what not so I just put new P&C with rings in. the ones I pulled off i will measure this weekend and check for wear on the skirts as well. If i can get by with just the caber rings it will be loads better than the Chicom cyclinder I am sure. the chicom cylinder had good compression, but it does not make near the power of the older saw with the low compression..I think it has to do with the ports probably...

Looking forward to hearing it run.

 

[huskyboy]

Meteor or hyway would be the only aftermarket pistons I’d use. There is also the dominant saw popup weisco piston but that’s about 120$.

 

[ken morgan]

Meteor or hyway would be the only aftermarket pistons I’d use. There is also the dominant saw popup weisco piston but that’s about 120$.

Priceisnot an issue, quality is so if Ineed a piston it will be an OEM or a meteor...no need for the wiseco, not building a racecar here so need for them or crower or lunati

 

[smokey7]

Stock type replacement is what i thonk you want. I would recommend a i believe 371 single ring. If i recall it puts the ring end on top of the intake. I also prefer the single 1.5mm ring over a dual setup. Ive used some haway pistons and p&c kits and all have been pretty dang nice especially the plating quality.