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Piston ring file?

53K views 18 replies 11 participants last post by  MRGM 
#1 ·
I just would like to know what most of you use for filing your piston rings to achieve the proper end gap. I am finding very little info on the subject, which is weird because it seems very important now that I understand it.

I have searched all the local parts stores and cannot find a piston ring file/grinder.
I could order one of the small hand crack grinders, but it is pricey and looks like it would be easy to build if I knew what grit to use. Also I only need to file 4 rings!

I also bought a small hand file that is for cleaning points type ignitions. I may try that, but I wanted some input from you guys first.. These are wisco rings for a V twin and a not cheap. I want to get it right the first time..

Thanks. ;)
 
#3 ·
The Speedway ring filer may seem expensive to you, but it will keep the filed edge square, which is important. Doing it by hand with a hand file,if you have never done it before, you can trash a set of rings in a hurry by the gap not being square. Also, file away from the outer edge toward the inside of the ring. You can chip a moly coated ring easily if you file from the inside out :nono: Also you will likely raise a burr on the top edge(flat) of the ring and bottom side, so with your hand file,gently knock the burr down before installing it onto the piston :thumbup:
 
#4 ·
Ok thanks for the replys guys..

If I could buy that lil hand crank grinder locally I would have bought it already.
I was just wondering if thats what everybody uses.

It is really amazing to me how little info I can find on piston ring end gap filing. Anyone that has built up an engine has done it right?
Nobody uses hand files? :confused:
 
#5 ·
Unless you build more than several engines a month, many people might no invest in a crank style filer. Doing it with a hand file is very time consuming. And if you need to file a set of stainless rings, its very tough to do it by hand. I have a motorized ring file, and it can still take upwards of 45 minutes to do a set,depending on how much material you have to remove. That of course is a set of "file to fit" rings, not a set of .030 over rings for a .030 over bore, where very little might need to be ground off if any.
 
#6 ·
Thanks CNC dude.
If I was building a V8 I would not want to hand file all those rings, but with my Harley we are just talking 4 rings to file. I don't mind if it takes a while. I could still do it faster than it would take to get the hand crank grinder shipped to me.

I am looking all over for the proper technique for hand filing piston rings, but I can't find anything at all. I know to file toward the inside of the ring and that's about it. I can't even find the proper hand file for this job! :eek:
 
#9 ·
Really.. 120 seems course to me.. :confused: Maybe not.. I have never filed a ring. ;)
About rather or not to file both ends.. That was another question have.. I just can't find good info on the subject. The grinders look like you pinch the ring on the grinding disc and it takes material off both ends, but I don't know that. It might just be abrasive on one side. :rolleyes:
 
#10 ·
You will just grind off of one side of the ring! Doing it off both sides doubles your chances for getting the gap crooked. Also, make sure the ring sets square in the cylinder when you are checking the gap. I usually make a ring squaring tool for the bore size I need to do this so you can stay consistent each time you insert it into the cylinder....
 
#15 ·
I know it's an old thread but feel I can put this out there to help those who haven't done this. I don't have access to a shop and the "right" tools so I proceeded to look for any ideas on ring filing by hand and maintaining a square edge.

To add to the thread: I don't see how clamping the file in a vise and cutting both ends at the same time would keep the ends squared to each other. The thickness of the file would prevent this. May be "acceptable" if the file was only ~.020 thick. When you put the ring in the bore the end at the cyl wall will be tighter than towards the piston. ....Unless you're running a gap the thickness of the file. which I doubt.
 
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