Piston resetting

Interesting setup!
Please humor me. What is the perfect piston play?

Thanks
Ice

.002 is the number that is usually thrown around. Enough for the oil to creep into. To be honest though it isn’t super critical. At least not in my experience. I do resets mostly for longevity and not for performance. I measure play by feel. Some are tight and some are probably just right. After being run they settle out pretty even with each other.

I like the apparatus you made to measure.

How do you eliminate that Photobucket Black Stripe across your pictures?? [url=https://servimg.com/view/19103929/1131][/url

Kinda ruins the view.

By paying subscription I guess but I am not willing to do.

Just attach the original image to this forum instead.

Are you sure? I thought that image has to be host somewhere! Gonna try it thanks.

It will technically be hosted on the forum (or another service "servim"?), and everyone will be able to se it here. Just use the "Host"-button with a tiny floppy drive disc on it.

Image test. https://i.servimg.com/u/f64/20/25/04/02/img_2010.jpg

Gordinir8 wrote:Image test. https://i.servimg.com/u/f64/20/25/04/02/img_2010.jpg

Hi, I saved your photo and it previews fine for me with Windows Photo Viewer.

I have the Cox .049 reset tool. When I use it, I place the "cup" on a very solid surface. An anvil usually. I like to use a small hammer and tap very lightly on the tool; checking the ball/socket clearance after each tap. Being careful NOT to get heavy-handed; I rotate the tool approx. 120 degrees after each tap.. until the rod will not drop by gravity.. but will move if shaken. If your "setting" feels a little tight.. it might be fine. Some people here have mentioned that they set theirs' on the snug-side.

I'm led to understand that the ball-socket joint need only be reset "once".. as part of a break-in measure. Under normal operation, it shouldn't need resetting again and should hold it's setting due to work-hardening.

roddie wrote:

Gordinir8 wrote:Image test. https://i.servimg.com/u/f64/20/25/04/02/img_2010.jpg

Hi, I saved your photo and it previews fine for me with Windows Photo Viewer.

I have the Cox .049 reset tool. When I use it, I place the "cup" on a very solid surface. An anvil usually. I like to use a small hammer and tap very lightly on the tool; checking the ball/socket clearance after each tap. Being careful NOT to get heavy-handed; I rotate the tool approx. 120 degrees after each tap.. until the rod will not drop by gravity.. but will move if shaken.  If your "setting" feels a little tight.. it might be fine. Some people here have mentioned that they set theirs' on the snug-side.  

I'm led to understand that the ball-socket joint need only be reset "once".. as part of a break-in measure. Under normal operation, it shouldn't need resetting again and should hold it's setting due to work-hardening.

roddie: That is exactly how I do my piston resetting. Always being sure to rotate the tool, and light to medium hits with a ball peen hammer. Anyone remember those??  My dad used those when putting rivets into sheet metal. WW2.  He was a single parent before he met my mom.

Happydad      

Thanks for info, this is what I have in mind also. Tool is on its way.

Some really great info thanks.

That’s a neat measuring technique! Thanks for sharing.

I just tap carefully on 90 degree rotations until play is reduced acceptably. I didn't have the tool to do it yesterday so made one in the lathe it is working very well.
I made the crimping end very snug on the tool and very easily shaped the piston socket.

Ice

I've found (based on others) that a smooth hard surface (glass) makes an idea anvil, also lots of light taps. set socket to rotate freely, but no real play. I'd also give it a drop of car oil prior to assembly, once its running the gap will open a little.

Cribbs74 wrote:.002 is the number that is usually thrown around. Enough for the oil to creep into. To be honest though it isn’t super critical. At least not in my experience. I do resets mostly for longevity and not for performance. I measure play by feel. Some are tight and some are probably just right. After being run they settle out pretty even with each other.

I like the apparatus you made to measure.

yep, about the only time it becomes an issue is high RPM and/or tight piston fit.