I have read a few threads where sleeve pinching is mentioned but no true meat and potatoes regarding the subject. How effective is "pinching" and does the engine respond like a new engine? Will I have to go through the break-in process again and where is the best place to send the piston and sleeve for pinching?

Thanks,

why not just buy a new piston & sleeve?

I can do that. However, I am more interested in knowing more about sleeve pinching and its effectiveness. Any responses to that end is appreciated.

ive had many of them done and only had one that was to tight yes a u will need to break in as needed. and it saves money untill its really needed i used os rocket out of ohio.

That's what I'm talking about!! Thanks. What's the turn around time like?

I have used rayaracing before. After the pinch and break-in, a completely worn-out piston/sleeve got me through an entire season. Performance was good. So yes, it's a good way to extend the life of your engine and save some money.

Yeah, I will be sending mine out tomorrow. I checked out OS Rocket's site, and that seem like a good place. I will look into Rayaracing and decide between the two. Thanks for the feed-back.

I have done a lot .21 engines and was payed with just a hamburger on the track and all were very satisfied

Roelof:

How are you my man? I was hoping you would comment on this issue. I think I will send the piston and sleeve out tomorrow. However, I would like to be able to do my own sleeves. Any idea where I can buy the equipment to start doing my own? Thanks for the reply.

You have to replace the matter than has worn away if you dont, once the pinch warms up and expands against the block, I'd expect you to be low on compression and expect it may be hard to tune .

PS: I could be wrong.

I don't quite understand what you are saying. Can you explain it as if you are talking to a 5 year old. I think I will get it then.

As I said I could be wrong and many prove that it works. To answer you, what I mean is an engine loses compression because the piston and liner wear away. Once that material is gone, it's gone!

Actually, I think you "are" wrong. The purpose of pinching the sleeve is to re-gain compression/tighten the sleeve as if is new, or better, to start the process of "fresh motor" over. Thanks for your comment though.

Surely the hard chromed liner wears much slower than the comparitively soft aluminium piston. Does just replacing the piston after a while help?

They must be available.....

Problem with our kind of engines is that the piston and sleeve have matching materials regarding the expansion. Materials can change due different suppliers so there is a chance that the piston of one production serie does not match the sleeve of other. Beside that due tolerances the dimensions aren't equal, they can differ up to some microns so you must have several pistons try to match your sleeve in size. To prevent that they just deliver a compleete matching P/S set.