85.5 rings on 85.0 pistons

Silent_White · Jul 16, 2013

so i bought some pistons for a stock rebuild from dsmgraveyard, .020 over. They finally got here and i am holding pistons that are 85.0mm and rings that are 85.5 that fit on the 85.0 piston. I was expecting 85.5 pistons and matching rings, not 85mm pistons and over-sized rings.
NPR Piston Set - 4G63 - 2G DSM Turbo

should i use these? Had i known that this is what i was getting i could have just ordered the over-sized rings and saved a few bucks. or am i wrong?

Firsts tuner · Jul 16, 2013

Wouldn't it be easier and more beneficial to call them directly? Rather than asking and getting a plethora of answers. It may have been an oversight on their part or it may just be the way it is. They ought to know what they're selling. Pistons are always going to be smaller than the bore, if they fit tight we wouldn't need rings. Did you measure your old pistons? They're going to be smaller than 85mm

BogusSVO · Jul 16, 2013

No.
The arch of the 85.5mm ring will not seal in the 85mm cylinder bore.

Hence why file fit rings are about .005

What is the bore of the block you are building?

Also there is a market place tab at the top of the screen, you may check out the vendor reviews before you spend your money...

Also a simple search of the parts supplier you chose to buy from may have changed your mind....

phunny · Jul 16, 2013

OP did you not look at our review section? I'd say you or exactly what these clowns sell. Of course it won't work.

Silent_White · Jul 16, 2013

First, I was unaware of the review section.
2nd, I didn't foresee any issues purchasing a new in box part that they wouldn't be working on.
3rd, I came here because i wanted an unbiased answer, not criticism; Thank you for the responses that were constructive.
4th, I don't know if the factory piston is slightly smaller yet as I don't have them out of the block, which a local machinist is going to bore .020 over to match the pistons for me.
Last, I think the label on the box is just confusing me, and that I got what I ordered.

BogusSVO · Jul 16, 2013

If your local machinist is going to bore the block .020/.5mm then your pistons you have at 85mm will not work, but the rings will.

donniekak · Jul 16, 2013

If the pistons you bought are not .020" over you are wasting your time on a bore, and hone. Or, you'll need to buy .020" over pistons.

nitrouskris · Jul 16, 2013

Silent_White said:
First, I was unaware of the review section.
2nd, I didn't foresee any issues purchasing a new in box part that they wouldn't be working on.
3rd, I came here because i wanted an unbiased answer, not criticism; Thank you for the responses that were constructive.
4th, I don't know if the factory piston is slightly smaller yet as I don't have them out of the block, which a local machinist is going to bore .020 over to match the pistons for me.
Last, I think the label on the box is just confusing me, and that I got what I ordered.

Sorry to be the dick here but you have 96 post and you NEVER seen the BAD reviews from them ????? How are they still in Business. Why didnt you just buy from a vender who surpports this website ????? Want the right parts for you DSM order from Magnus / extremepsi / buschur /FFWD / map / moralesracing / RRE

honda_burner · May 30, 2015

Bringing this one back. I've got a block I don't know the history on. Only that it's been rebuilt at some point I believe a couple owners ago.
My piston rings are bad and I'm putting new ones in.
Question is, Pistons measure 85mm but say .020 on top. So do I use 85 mm rings or 85.5 mm rings?

donniekak · May 30, 2015

If the Pistons have .020 marked in the top of them, chances you are measuring incorrectly getting 85mm.

What tool are you measuring with, and where on the piston are you measuring? Pistons are usually measured 90* from the pin at the skirt. Measuring the top of the piston will give a smaller measurement, as Pistons are barrel shaped.

BogusSVO · May 31, 2015

Could also be that the pistons are collapsed.

honda_burner · Jun 9, 2015

Sorry, I have since finished this job and went with the .020 rings. I was indeed measuring from the top though, and I was using a digital caliper.

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85.5 rings on 85.0 pistons

Silent_White

Firsts tuner

BogusSVO

phunny

Silent_White

BogusSVO

donniekak

nitrouskris

honda_burner

donniekak

BogusSVO

honda_burner

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