M&W piston rings?

[Highwayman]

Anyone know where to find a set for 4 1/8”
Pistons?
Are they the same as firecrater or another aftermarket set.
Got a weak cylinder and I guess it’s time after 25 years.
Thanks

 

[Janicholson]

A good set of cast iron rings is far better than any high performance ring set. However, the answer is not in a set of rings. The solution in this case is assessment of condition of all cylinders. Doing a one cylinder ring job is as expensive as doing them all. Putting new rings in a worn cylinder, and on a piston with worn grooves does not work. If the cylinder has more than .006" taper or a ridge at the top that you can feel with your fingernail, rings will not make a good rewarding repair. A new sleeve and piston kit in all 4 holes is the answer. If there is very small taper, like .003", and any ridge is removed, and a balls on a stick hone is used, it could be OK if the piston to cylinder clearance is within spec. Compromising on cylinder repairs is pound foolish. Jim

 

[Highwayman]

I should’ve elaborated a little further.
I was thinking about getting a propane head for it and decided to do a compression test and found 1 cylinder 50 lbs short it’s my pulling toy. Comp test was 200,150,190,190.
No noticeable skip or anything though.

 

[Janicholson]

I should’ve elaborated a little further.
I was thinking about getting a propane head for it and decided to do a compression test and found 1 cylinder 50 lbs short it’s my pulling toy. Comp test was 200,150,190,190.
No noticeable skip or anything though.

That makes al the difference. M&W piston rings will make no difference compared to any replacement quality rings. Broken rings, or overheated collapsed rings, or defective/worn piston can lower compression. If the rings you purchase are the correct thickness (fit the groove) and have a gap when installed of .0045" in the least worn area of the ring travel per inch of bore they will be fine. Jim

 

[ss55]

I should’ve elaborated a little further.
I was thinking about getting a propane head for it and decided to do a compression test and found 1 cylinder 50 lbs short it’s my pulling toy. Comp test was 200,150,190,190.
No noticeable skip or anything though.

Before tearing into it, you might want to do a quick leak down test to pin point where compression is leaking in the one low cylinder: rings, intake or exhaust valve, blown head gasket, cracked or porous sleeve, cracked head, etc.

 

[Powered By IH]

Before tearing into it, you might want to do a quick leak down test to pin point where compression is leaking in the one low cylinder: rings, intake or exhaust valve, blown head gasket, cracked or porous sleeve, cracked head, etc.

That or dump oil in the cylinders to verify.

 

[rustred]

Anyone know where to find a set for 4 1/8”
Pistons?
Are they the same as firecrater or another aftermarket set.
Got a weak cylinder and I guess it’s time after 25 years.
Thanks

i would be focusing on the valves for that cylinder not seating properly. rings will be equally worn in all cylinders. unless you have a broken ring which will produce a scratch causing lower compression.

 

[used red MN]

I should’ve elaborated a little further.
I was thinking about getting a propane head for it and decided to do a compression test and found 1 cylinder 50 lbs short it’s my pulling toy. Comp test was 200,150,190,190.
No noticeable skip or anything though.

Must be an M and your running it without sleeves. I am surprised that the compression is that high, do you have a pretty good “shave” on the head?

 

[rustred]

super M can have 4 1/8 sleeves.

 

[Highwayman]

It has a 450 gas head and 6” stroker.
It is just an M block I had bored out 30 years ago to accept the super sleeves.
I don’t think I can safely bore it anymore without hard blocking it.
I should’ve pulled the sleeves and put 4.25 pistons in it then while they still could be found.