Piston/Ring issue???

RJ Sledge · 02-05-2015, 07:07 PM

I purchased a new set of pistons from a well known manufacturer and also purchased a new set of rings(Conventional) from a well known manufacturer.

Pistons are 1.5mm, 1.5mm and 3mm. Rings are .028 with .030 gas ported spacers for the compression and .028 Napier with .030 spacers for 2d position. Piston ring grooves are .0593 top and .0595 2d position. Correct radial depth groove for rings.

When I was ready to install I pressed the rings into the groove and rotated them. All the top rings were fine, but several of the rings in the 2d position would not rotate and would "Stick" in the groove.

Top rings with gas ported spacers no problem. Had several rings in the 2d position that were sticking. Lapped the spacers for a little more clearance but rings were still sticking. Even tried swapping non sticking ring/spacer, same problem.

Any feedback would be appreciated.

I will not identify the Companies involved at this time, as they are trying to figure out what the problem is.

This is not a Witch Hunt, just would like some feedback. PM would be best.

Has anybody had these problems lately?? At this time the pistons and rings have been sent back to their perspective manufactures to check for any problems.

Thanks in advance.

RJ

pmrphil · 02-05-2015, 10:01 PM

It would seem that after swapping non-sticking rings/spacers into grooves that still were sticking, the only thing left is ring grooves machined improperly. I'm figuring you already miked the rings and checked for flatness.

RJ Sledge · 02-05-2015, 11:02 PM

I mic'd the rings and spacers and they checked, but had no way to really check the ring groove width or flatness. I ran a .059 pin around the groove and felt no tight spots, but I am thinking the grooves might not be perfectly flat.

Thanks
RJ

Dave Noll · 02-05-2015, 11:19 PM

Just for my education, can I ask what your particular combo cost's ?

RJ Sledge · 02-05-2015, 11:46 PM

Way too much!!

RJ

Adger Smith · 02-06-2015, 12:15 AM

RJ,
I sure am glad you called today to discuss this problem. I still think they have a wave to the groves. I was just about to pull the trigger on a set of pistons for a Drag Pack customer. Since there are only 2 different companies that are approved I think I will choose the other. Not because of the problem, but because it wasn't taken care of. At this point I'm very glad I have procrastinated on ordering parts for this build. Like I said when we closed our call... Thanks, I think?? ;~)

Greg Reimer 7376 · 02-08-2015, 11:51 AM

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 · 02-08-2015, 12:08 PM

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 · 02-08-2015, 04:08 PM

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 · 02-08-2015, 04:38 PM

Quote:

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.

02-05-2015, 07:07 PM	#1
RJ Sledge Senior Member Join Date: Jun 2007 Posts: 783 Likes: 504 Liked 288 Times in 90 Posts	Piston/Ring issue??? I purchased a new set of pistons from a well known manufacturer and also purchased a new set of rings(Conventional) from a well known manufacturer. Pistons are 1.5mm, 1.5mm and 3mm. Rings are .028 with .030 gas ported spacers for the compression and .028 Napier with .030 spacers for 2d position. Piston ring grooves are .0593 top and .0595 2d position. Correct radial depth groove for rings. When I was ready to install I pressed the rings into the groove and rotated them. All the top rings were fine, but several of the rings in the 2d position would not rotate and would "Stick" in the groove. Top rings with gas ported spacers no problem. Had several rings in the 2d position that were sticking. Lapped the spacers for a little more clearance but rings were still sticking. Even tried swapping non sticking ring/spacer, same problem. Any feedback would be appreciated. I will not identify the Companies involved at this time, as they are trying to figure out what the problem is. This is not a Witch Hunt, just would like some feedback. PM would be best. Has anybody had these problems lately?? At this time the pistons and rings have been sent back to their perspective manufactures to check for any problems. Thanks in advance. RJ Last edited by RJ Sledge; 02-05-2015 at 07:10 PM.

02-05-2015, 10:01 PM	#2
pmrphil Member Join Date: Aug 2010 Location: CT Posts: 460 Likes: 1,814 Liked 348 Times in 152 Posts	Re: Piston/Ring issue??? It would seem that after swapping non-sticking rings/spacers into grooves that still were sticking, the only thing left is ring grooves machined improperly. I'm figuring you already miked the rings and checked for flatness. __________________ Phil Molski PMR Performance S/C 1623

02-05-2015, 11:02 PM	#3
RJ Sledge Senior Member Join Date: Jun 2007 Posts: 783 Likes: 504 Liked 288 Times in 90 Posts	Re: Piston/Ring issue??? I mic'd the rings and spacers and they checked, but had no way to really check the ring groove width or flatness. I ran a .059 pin around the groove and felt no tight spots, but I am thinking the grooves might not be perfectly flat. Thanks RJ

02-05-2015, 11:19 PM	#4
Dave Noll Senior Member Join Date: Nov 2007 Location: Div. 6, Eastern, WA Posts: 710 Likes: 2,676 Liked 240 Times in 112 Posts	Re: Piston/Ring issue??? Just for my education, can I ask what your particular combo cost's ? __________________ Dave Noll, EF/S ,?/SA 6526

02-05-2015, 11:46 PM	#5
RJ Sledge Senior Member Join Date: Jun 2007 Posts: 783 Likes: 504 Liked 288 Times in 90 Posts	Re: Piston/Ring issue??? Way too much!! RJ

02-06-2015, 12:15 AM	#6
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: Piston/Ring issue??? RJ, I sure am glad you called today to discuss this problem. I still think they have a wave to the groves. I was just about to pull the trigger on a set of pistons for a Drag Pack customer. Since there are only 2 different companies that are approved I think I will choose the other. Not because of the problem, but because it wasn't taken care of. At this point I'm very glad I have procrastinated on ordering parts for this build. Like I said when we closed our call... Thanks, I think?? ;~) __________________ Adger Smith (Former SS) Last edited by Adger Smith; 02-06-2015 at 12:17 AM. Reason: sp

02-08-2015, 11:51 AM	#7
Greg Reimer 7376 VIP Member Join Date: Nov 2008 Location: Glendora,Calif. Posts: 1,136 Likes: 172 Liked 705 Times in 219 Posts	Re: Piston/Ring issue??? 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.

02-08-2015, 12:08 PM	#8
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,118 Likes: 1,576 Liked 1,837 Times in 417 Posts	Re: Piston/Ring issue??? 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. __________________ Alan Roehrich 212A G/S

02-08-2015, 04:08 PM	#9
Bob Mulry VIP Member Join Date: Apr 2002 Location: Coarsegold, CA Posts: 1,016 Likes: 57 Liked 320 Times in 102 Posts	Re: Piston/Ring issue??? 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 __________________ Bob Mulry 7516 STK A & M Motorsports