Piston ring installation?

mike provence · Aug 22, 2009

Fellow Nortonites,
Like many of you I have other bikes. My 1970 Triumph T100C recently suffered a minor piston seizure on one pot.

I had a good shop lightly hone the bores, which were already 040 over, bought new pistons and rings and was ready to go. The pistons are Taiwanese JCC distributed by EMGO. I have had good luck with these before. The rings, however, also from EMGO, have no markings or tapered faces. I guess they can go in any old way? They appear to be Taiwanese too.

The rings measure within spec for gap and width, but I am hesistant to put the engine together with them. I used Japanese rings last time which were marked for size. The markings always go up, as I understand it.

Has anyone assembled an engine with these rings, or ones like them?

Thanks one and all--

bigstu · Aug 23, 2009

My rings for the T110 had a little T etched on, close to the split, or the top two did.

BrianK · Sep 16, 2009

No dot or other marking on the top side either? Be sure to check in strong light with a magnifying glass. They can be tough to spot. Good luck.

BrianK · Oct 27, 2009

Any luck?

PS, if I may, do you know what size grit your cylinders were honed with (assuming a ball hone was used)? That would be helpful to me for a project of my own. Thanks - BrianK

BrianK · Dec 5, 2009

Forgive the bump, just hoping for an answer to the hone-grit question. Thanks.

BrianK · Jan 10, 2010

one last try....

iceteanolemon · Sep 22, 2012

mike provence said:
Fellow Nortonites,
Like many of you I have other bikes. My 1970 Triumph T100C recently suffered a minor piston seizure on one pot.

I had a good shop lightly hone the bores, which were already 040 over, bought new pistons and rings and was ready to go. The pistons are Taiwanese JCC distributed by EMGO. I have had good luck with these before. The rings, however, also from EMGO, have no markings or tapered faces. I guess they can go in any old way? They appear to be Taiwanese too.

The rings measure within spec for gap and width, but I am hesistant to put the engine together with them. I used Japanese rings last time which were marked for size. The markings always go up, as I understand it.

Has anyone assembled an engine with these rings, or ones like them?

Thanks one and all--

I have these rings and cant find markings either! Know the proper gap measurement?

grandpaul · Sep 22, 2012

If the rings have no markings, and no chamfer, shoulder or radius on outer or inner edge, they can go either side up.

Triton Thrasher · Sep 22, 2012

My Taiwan pistons arrived with rings on.

Why did it seize?

concours · Sep 22, 2012

grandpaul said:
If the rings have no markings, and no chamfer, shoulder or radius on outer or inner edge, they can go either side up.

+1 This has always been the rule.

bill · Sep 22, 2012

the most likely answer is they were to tight or not enough cam in the piston for the specified clearance. pistons are NOT round or straight from top to bottom

Triton Thrasher said:
My Taiwan pistons arrived with rings on.

Why did it seize?

iceteanolemon · Sep 22, 2012

thanks for the clarification!

Triton Thrasher · Sep 23, 2012

bill said:
the most likely answer is they were to tight or not enough cam in the piston for the specified clearance. pistons are NOT round or straight from top to bottom

Triton Thrasher said:

My Taiwan pistons arrived with rings on.

Why did it seize?

Click to expand...

Yes, it's almost always a too-tight recent rebore or a weak mixture, but if the guy doesn't find out why this one seized, what's to stop it seizing again?

Photos of the damaged piston and its gudgeon pin might help with diagnosis.

It's too easy to imagine that the cause is evil Chinese spare parts.

GSRon · Oct 13, 2012

I would not use those rings... There are reasons a "good" ring manufacturer spends the money to make specific rings designed to do a speciffic job.. plain cast iron rings like that are very olde school... My $0.02 worth..

Ron

mike provence said:
Fellow Nortonites,
Like many of you I have other bikes. My 1970 Triumph T100C recently suffered a minor piston seizure on one pot.

I had a good shop lightly hone the bores, which were already 040 over, bought new pistons and rings and was ready to go. The pistons are Taiwanese JCC distributed by EMGO. I have had good luck with these before. The rings, however, also from EMGO, have no markings or tapered faces. I guess they can go in any old way? They appear to be Taiwanese too.

The rings measure within spec for gap and width, but I am hesistant to put the engine together with them. I used Japanese rings last time which were marked for size. The markings always go up, as I understand it.

Has anyone assembled an engine with these rings, or ones like them?

Thanks one and all--

Piston ring installation?

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