why get a new p/s just pinch it

[redneck]

i had a piston that would go through the top of the sleeve so i told my dad who works at a welding and cnc and lathe and all that kind of shop so he pinched it on the lathe and now its so dam tight it feels harder then break in help on ideas how not to break pull starts

[]-[0pa]0ng]

might help to heat the head to 220 warm it up then try pulling it over w/o whaling on it

[ljrce]

Preheat the mill with a heat gun or hairdryer may half to loosen the glow plug a little then tighten it when it starts but i would start to look in to a new sleeve and pistion or a new mill

[redneck]

i am but i need some cash first have to put a down payment on it

[Purenitro]

You can't pinch a sleeve in a lathe, proper tooling cost thousands. Send it to rayracing for $20, he will do it right.

[Night]

What exactly is pinch and how do you do it?

[Londoner]

How on earth do you pinch a sleeve on a lathe? Did he squeeze it in the chuck?

[redneck]

yes squized in the chuck

[soulja]

QUOTE=redneck;167277]yes squized in the chuck[/QUOTE]


:smilie8::Nolol: holy crap

[frddyj]

when metal wears away & dis-integrates, how will "pinching" restore it?

i understand that it will change the dimension of the sleeve but not how it can provide any real (medium to long term) beneficial results.

i dont know any about the pinching & maybe you guys can help me understand it, but the title reads "why buy a piston/sleeve just pinch"

With my limited knowledge of the process, I'd think in the long run it would be most beneficial to buy the new parts?

[Purenitro]

Here is how it's done, the only way I recommend doing it!

http://www.rayaracing.com/

[Londoner]

Surely squeezing it in a lathe chuck would make the sleeve slightly square or triangular (unnoticeable to the eye) depending on whether it's a 3 or 4 clamp lathe chuck? As it's squeezed on 3 or 4 points round the sleeve as opposed to it being done properly which would leave it still perfectly round?

[Purenitro]

Ray maintains the taper which is crucial in the sleeve as well as keeping it perfectly round with the tooling he uses. There is such a slight amount required to regain the pinch that it is extremely easy to over pinch and get out of round without the proper equipment.

There is also the hose clamp and oven method :lmao:

[frddyj]

great discussion guys, great link robin, raya sure looks like its got the tools & the talent.

[Pope]

A racer from the hobbyshop has been using him for a while and swares by him. I can't speek to the work myself as I have yet to see one of the mills he has done in person.

[ljrce]

I did the hose clamp and it lasted for a quart of fuel lol of course I was pushing the mill to the exream also

[redneck]

i left my pistion in it while my dad did it

[soulja]

There is also the hose clamp and oven method :lmao:

i just did the Picco you modded like that!money man

[skinart]

Surely squeezing it in a lathe chuck would make the sleeve slightly square or triangular (unnoticeable to the eye) depending on whether it's a 3 or 4 clamp lathe chuck? As it's squeezed on 3 or 4 points round the sleeve as opposed to it being done properly which would leave it still perfectly round?

^^^

What Londoner said ..

he left the piston in it while squeezed ... id say the sleeve is jamming on the piston in 3 or 4 spots like mentioned above ... there is no way a lathe could "pinch" a sleeve evenly.

I hope in wrong for your sake ... but yah ..

[redneck]

it worked good untill i lew the rod then i bought a picco .28 it was just to get me though a few weeks

[angellewalsh]

i got a repinch tool off e bay.not to bad.the trick is to heat the sleeve then pinch with this tool and then dunk in cold water,seems to work.but you can easyily warp the sleeve.for 20 bucks have it pinched by rays racing

[Pikester]

Here is how it's done, the only way I recommend doing it!

http://www.rayaracing.com/


Thanks a million! I was so in the dark about pinching. I may have missed it but just how long will a pinched sleeve last compaired to a new one? On average that is.

[frddyj]

is it me or does the idea of pinching just sound hack to anyone else? :dunno:

[Bankrupter]

I have heard good things about Rays pinches at the track.

[frddyj]

I have heard good things about Rays pinches at the track.

im not doubting that it works, i just wonder how long it lasts for vs. replacing a worn-out part.

just 'sounds' like a duct-tape and super glue patch vs. correcting the actual problem.

[Pikester]

im not doubting that it works, i just wonder how long it lasts for vs. replacing a worn-out part.

just 'sounds' like a duct-tape and super glue patch vs. correcting the actual problem.

I am with you frddyj. I'm not saying it doesn't work. If it's what it claims to be it is a true fix. 20bucks plus con rod is nice and cheap. But someone who has had it done needs to let us know how long it lasted. Heck, Even a 3 gallon life span would make it worth the cash. money man

[bull8042]

I know this is an old thread, but I still felt a need to interject an opinion and perhaps some food for thought.
I have no first hand experience with Raya's service, or any other "pinching" service for that matter. However, aside from the Italian made Picco, how many of the other manufacturers get their components from overseas suppliers who actually manufacture them on potentially sub-standard equipment to high-output production-type tolerances? Raya however, is handling these parts one at a time and obviously inspecting them before, during, and after the process, as opposed to a machine spitting them out by the thousands. High-production quality control?.....If a few percent in a run check acceptable, the the whole lot is ASSUMED good and shipped out.
Remember, as I stated earlier, I have 0 (zero) experience with Raya or like services. But I am quite familiar with production processes and the differing variances in what is acceptable from manufacturer to manufacturer. Nine times out of ten, hands on one-on-one service usually results in a much better final product. Just sayin'....

[ezeraden]

here is a ctech resizing tool i found

[ezeraden]

here is a ctech resizing tool i found3876