Re: Playing with puch

Thomas TPRF /
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> JBOT Admin Wrote:

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> > Thomas TPRF Wrote:

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> > -------------------------------------------------------

>

> > > JBOT Admin Wrote:

>

> >

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> > > -------------------------------------------------------

>

> >

>

> > > Pics of the carnage?

>

> >

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> > >

>

> >

>

> > It was my attempt to run an Airsal piston in a Polini cylinder since I

>

> > I couldn't find a Polini piston in a large enough oversize to account

>

> > for how much the cylinder had to be over overbored after the last

>

> > failure.

>

> >

>

> > The skirt used to have a window in it rather than a slot. I'm

> thinking

>

> > maybe I should have cut that into a slot? Probably didn't chamfer

> things

>

> > enough either.

>

> >

>

> > Worst part is it stopped hard with a chunk of metal in a port so I'm

>

> > worried that the crank may be tweaked.

>

> the base of the boost in the cyl wall looks awfully squared off. Looks

> like the bottom of the piston was knocking into it over and over. But

> it's hard to know. It's also very possible your piston had too much

> clearance so that skirt was whacking against the bore. Too much Wear or

> too much clearance can cause that.

>

> I mean, anything can happen with wear and big power, and a window

> creates a weaker spot but most times the piston would be destroyed with

> a window or not. Slapping in the bore fucks shit up.

>

> Btw, A massive window is only really needed on cyl reed setups without a

> dedicated boost port in the cases, like this treats reed. Otherwise

> you're severely limiting flow.

I showed it to a buddy of mine last night who has built quite a few dumb chainsaws over the years. He pretty much agreed with your diagnosis. He suggested that I should have probably turned the piston window into a full slot so it'd still have the "corners" but to prevent that bottom edge from tapping the cylinder.

This single post is part of a larger thread. Start from the top or view this post in context.
Subject Written By Posted
  Playing with puchTopic by: Totally normal JBOT Totally normal JBOT 02/06/19 09:26PM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/06/19 09:58PM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/06/19 10:01PM
  Re: Playing with puchRe: Buttcheeks BUZZARD Buttcheeks BUZZARD 02/06/19 11:01PM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/06/19 11:25PM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/06/19 11:32PM
  Re: Playing with puchRe: Adam Smith Adam Smith 02/07/19 06:47AM
  Re: Playing with puchRe: Alan Jackson Alan Jackson 02/07/19 05:46AM
  Re: Playing with puchRe: Brandon Weiss (Detective brandon to you) Brandon Weiss (Detective brandon to you) 02/07/19 09:40AM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/07/19 11:16AM
  Re: Playing with puchRe: Brandon Weiss (Detective brandon to you) Brandon Weiss (Detective brandon to you) 02/07/19 12:49PM
  Re: Playing with puchRe: Alex hernandez Alex hernandez 02/07/19 03:34PM
  Re: Playing with puchRe: Brandon Weiss (Detective brandon to you) Brandon Weiss (Detective brandon to you) 02/07/19 03:56PM
  Re: Playing with puchRe: Probably Fred Probably Fred 02/07/19 04:08PM
  Re: Playing with puchRe: Chris Straub Chris Straub 02/07/19 03:25PM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/07/19 08:18PM
  Re: Playing with puchRe: Chris Straub Chris Straub 02/08/19 02:12AM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/08/19 02:28AM
  Re: Playing with puchRe: Chöschi21 C.K. Chöschi21 C.K. 02/07/19 04:27PM
  Re: Playing with puchRe: Brandon Weiss (Detective brandon to you) Brandon Weiss (Detective brandon to you) 02/07/19 04:36PM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/07/19 08:34PM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/07/19 09:08PM
  Re: Playing with puchRe: Kevin Bishop Kevin Bishop 02/07/19 05:40PM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/07/19 08:22PM
  Re: Playing with puchRe: patrick stover patrick stover 02/07/19 05:47PM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/07/19 08:25PM
  Re: Playing with puchRe: Kevin Bishop Kevin Bishop 02/07/19 09:36PM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/07/19 09:42PM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/07/19 10:31PM
  Re: Playing with puchRe: EH 📣FCC of the QCB EH 📣FCC of the QCB 02/07/19 10:36PM
  Re: Playing with puchRe: EH 📣FCC of the QCB EH 📣FCC of the QCB 02/07/19 10:40PM
  Re: Playing with puchRe: Anthony Moody Anthony Moody 02/08/19 08:32PM
  Re: Playing with puchRe: EH 📣FCC of the QCB EH 📣FCC of the QCB 02/08/19 09:49PM
  Re: Playing with puchRe: Anthony Moody Anthony Moody 02/09/19 04:54AM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/07/19 10:50PM
  Re: Playing with puchRe: Kevin Bishop Kevin Bishop 02/07/19 10:40PM
  Re: Playing with puchRe: EH 📣FCC of the QCB EH 📣FCC of the QCB 02/07/19 10:52PM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/07/19 11:04PM
  Re: Playing with puchRe: EH 📣FCC of the QCB EH 📣FCC of the QCB 02/07/19 11:08PM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/07/19 11:17PM
  Re: Playing with puchRe: Thomas TPRF Thomas TPRF 02/08/19 12:03AM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/08/19 01:01AM
  Re: Playing with puchRe: Thomas TPRF Thomas TPRF 02/08/19 11:24AM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/08/19 11:42AM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/08/19 11:49AM
  Re: Playing with puchRe: Graham Motzing Graham Motzing 02/08/19 11:51AM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/08/19 11:56AM
  Re: Playing with puchRe: Graham Motzing Graham Motzing 02/08/19 12:53PM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/08/19 01:02PM
  Re: Playing with puchRe: EH 📣FCC of the QCB EH 📣FCC of the QCB 02/08/19 02:40PM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/08/19 04:38PM
  Re: Playing with puchRe: Graham Motzing Graham Motzing 02/09/19 09:32AM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/08/19 11:54AM
  Re: Playing with puchRe: Thomas TPRF Thomas TPRF 02/09/19 11:42AM
  Re: Playing with puchRe: niklaus _ niklaus _ 02/08/19 02:19AM
  Re: Playing with puchRe: Dirty30 Dillon Dirty30 Dillon 02/08/19 09:41AM
  Re: Playing with puchRe: Alex hernandez Alex hernandez 02/08/19 11:22AM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 02/08/19 11:32AM
  Re: Playing with puchRe: Graham Motzing Graham Motzing 02/08/19 11:45AM
  Re: Playing with puchRe: Alan Jackson Alan Jackson 02/08/19 03:49PM
  Re: Playing with puchRe: P D P D 02/09/19 12:15PM
  Re: Playing with puchRe: Satan Lucifer Satan Lucifer 11/01/22 06:38PM
  Re: Playing with puchRe: Totally normal JBOT Totally normal JBOT 11/01/22 08:36PM

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