piston and sleeve

[Plaidfish]

like I said it's an art.....I know a kid who actually used a vise and a collar and did one, I laughed at him the whole time until 2 weeks later when he was supposedly running that half assed pinch and it was wailing on the track......he's a pretty nice guy and I really don't think he was pulliing a fast one...I think he just got really F'ing lucky....then I see guys w/ V-specs got pinched by a "pro" at pinching and they SUCKED.....it's worth the 20 bucks to try it before spending 120 on some of the P/S sets.....

 

[olds97_lss]

I'm sorry what is this {piching the sleeve}? how is it done can I do this my self I have a lot of 2.5 sleeve's and 1.5 thank's

At the top of the sleeve, there is a taper (it's smaller in diameter internally than the bottom). This is what creates the seal between the piston and sleeve. It's known as "pinch".

Over time, the piston wears and the sleeve wears (more the piston wearing than the sleeve) and the seal isn't tight anymore which creates blow by. Blow by creates poor performance and erratic tuning.

Guys like osrocket and rayaracing have a pinch service for around $20 a piece shipped. What they do is put more pinch in the sleeve to take up the excess wear. In return, you get a good piston/sleeve fit for a fraction of the cost of the new piston/sleeve set.

I used OSRocket and he did a good job. All I'd suggest is that if you send it to either one, tell them somewhere that you want a "mild" pinch if you have a pull start vs starter box.

Doing it yourself with the ebay pinching ring gives mixed results from what I've read and it isn't a very good way to do it. Your probably better off letting the guys with the right tools do it for you.