Piston/Ring issue???

[Greg Reimer 7376]

Years ago,I did a basic 350 Chevy engine for a neighbor's truck. One piston had a tight ring. This wasn't a rebore,new pistons,etc,but a freshen and fix of a typical 350 with a flat cam and worn out heads.When putting one ring assembly on one piston, it didn't want to retract into the ring groove so as to make piston installation possible. The truck had evidently been run hard and hot a few times, and the piston was distorted just enough to cause wavy ring grooves. I took that piston, broke the shirt off, and threw it into the junk scrap pile. One new piston and no problem. I didn't know at the time that could happen without breaking the ring, but there it was.Don't assume anything,take nothing for granted, check everything. Good advice. Also, watch who your vendors are.

[Alan Roehrich]

RJ, I'm a little confused. one post says you have not heard from the piston people, the other says you have not heard from the ring people.

I have a few really good contacts at most places, I'd be glad to inquire, if it will help you.

[Bob Mulry]

If you have access to a lathe with a 4 jaw chuck you can chuck it up and zero one side of the groove and then indicate the other......

A wavy groove would show up pretty fast............

Or...

You could use a surface plate and a height indicator on both sides of the groove......

And a plus would be that YOU knew for sure....

Just a thought from an old machinist guy,
Bob

[Mark Yacavone]

Originally Posted by Bob Mulry

If you have access to a lathe with a 4 jaw chuck you can chuck it up and zero one side of the groove and then indicate the other......

A wavy groove would show up pretty fast............

Or...

You could use a surface plate and a height indicator on both sides of the groove......

And a plus would be that YOU knew for sure....

Just a thought from an old machinist guy,
Bob

Too high tech for me ,Big Guy

I'd take a black felt tipped marker and color in the groove. Put the ring on and
squeeze it and spin it around a little by hand. You should see what's going on.

[RJ Sledge]

I appreciate all the advice, and I guess I need to let this thing play out. I don't want to mention any names right now, don't think that would be beneficial at this time.

After several phone calls on Friday, I was able to make contact with the ring people, they told me all several of my cast 2d rings were bent. All my steel top rings were fine. They are giving me a set of 1.5mm 2d rings made to my specs. They are sending my cast 2d rings back and told me I could try and take the bends out. They are charging me only for 2d day delivery ($31.50) for everything. Seems they are trying to make things good.

I don't know how you bend "several rings" and not all. I am not the brightest bulb on the tree and I may have inadvertently "bent" them while installing them on the pistons, but don't see how. A .8mm ring with a .130 radial thickness, is like a well done straw of spaghetti and installing it on a piston is effortless. I did have these rings on and off about 2 dozen times while I was lapping the spacers (at their direction). They(rings) were sticking from the first installation.

Hopefully I will receive my pistons and rings soon so I can renew my effort to finish the motor.

Thanks again for the advice, it is surely appreciated.

RJ

[carl hinkson]

Originally Posted by RJ Sledge

I appreciate all the advice, and I guess I need to let this thing play out. I don't want to mention any names right now, don't think that would be beneficial at this time.

After several phone calls on Friday, I was able to make contact with the ring people, they told me all several of my cast 2d rings were bent. All my steel top rings were fine. They are giving me a set of 1.5mm 2d rings made to my specs. They are sending my cast 2d rings back and told me I could try and take the bends out. They are charging me only for 2d day delivery ($31.50) for everything. Seems they are trying to make things good.

I don't know how you bend "several rings" and not all. I am not the brightest bulb on the tree and I may have inadvertently "bent" them while installing them on the pistons, but don't see how. A .8mm ring with a .130 radial thickness, is like a well done straw of spaghetti and installing it on a piston is effortless. I did have these rings on and off about 2 dozen times while I was lapping the spacers (at their direction). They(rings) were sticking from the first installation.

Hopefully I will receive my pistons and rings soon so I can renew my effort to finish the motor.

Thanks again for the advice, it is surely appreciated.

RJ

Use a ring expander instead of spreading them by hand.