Piston Rings Question
Thread Starter
Drifting
Joined: Feb 2005
Posts: 1,583
Likes: 5
From: Richardson Tx.
Piston Rings Question
I took my bare block down to the machine shop as a newbie. The guy there called me a week later and says that he recommends a .020 bore.
I asked him if this requires new pistons and he said yes. I seem to have heard that you can keep your original pistons and just get bigger rings to adjust to the oversize bore. Is this true?
I asked him if this requires new pistons and he said yes. I seem to have heard that you can keep your original pistons and just get bigger rings to adjust to the oversize bore. Is this true?
Drifting
Joined: Dec 2004
Posts: 1,714
Likes: 42
From: Austin Texas
.030 is pretty standard for a first time rebuild. on a 350, this would give you a whopping 355. i havent bought a whole lot of pistons in my life. However. i thought the standard increiments were .030, .040, .060. it is very possible that i have no cue here. but i would ask them what the proposed new size would be. if he is recomending .020 could it already be at .040? this would put you at the max.
might be something to think about... it is easy to spend thousands of dollars at a machine shop and still not have a running motor.
i started mine 6 years ago. it looks cool just sitting on the stand... STILL.
might be something to think about... it is easy to spend thousands of dollars at a machine shop and still not have a running motor.
i started mine 6 years ago. it looks cool just sitting on the stand... STILL.
Drifting
Joined: Mar 2005
Posts: 1,806
Likes: 3
From: Burlington WI
.020 is good
For a first rebuild only having to go .020 over is good.
The advantage of boring is that it makes the cylinders round again.
Normal wear makes them oval shaped.
Front to rear doesnt wear that much but the other way does because of the thrust of the rods pushing the pistons and rings against the cylinder walls.
That larger ring myth is something dreamed up by someone that never built an engine and has no idea of the close tolerances requred.
Chris B
The advantage of boring is that it makes the cylinders round again.
Normal wear makes them oval shaped.
Front to rear doesnt wear that much but the other way does because of the thrust of the rods pushing the pistons and rings against the cylinder walls.
That larger ring myth is something dreamed up by someone that never built an engine and has no idea of the close tolerances requred.
Chris B
