Subject: Re: Thanks for advice on Fork Assembly Problem, TFN
Author: Robert Hawkes
Date: Feb 20, 2002, 6:32 PM
Post ID: 1709687518
Neat info dude!
----- Original Message -----
From: Martin Cooke <cook-@virgin.net>
To: <Loopfram-@topica.com>
Sent: Wednesday, February 20, 2002 12:07 PM
Subject: Re: Thanks for advice on Fork Assembly Problem, TFN
| ------------------------------------------------------------ Two Great Bonus Offers From Palace of Chance casino Get $50 Free with a $50 Purchase - Use Coupon: EB74R and up to $200 in Match Play - Use Coupon: Q637Y http://click.topica.com/caaahsGb1dfltb1FlG8a/Palace ------------------------------------------------------------ reading L&A Robertsons(?) post got me interested in the nicasil process, this is what i found if anyone is interested: "Nicasil is NOT a coating as such, it is a process whereby the chemical constitution of the aluminium alloy itself is changed to withstand the action of the rings scuffing against it. It is ONLY used on the barrel, i.e. the inside of the cylinder, the surface against which the rings scrape. It is not used on piston- crowns nor cylinder heads, as these have no need for low-friction surface. Because aluminium is way too soft and far too abrasive to cope with rings scuffing along it, the first aluminium cylinders had steel inserts, then chromated sleeves, but the Nicasil is the modern way. Not only Hirth, but many other manufacturers use this process, pioneered by Mahle in Germany many years ago. Very simply, they coat the cylinder with a Nickel-rich clay (ceramic) then bake it at very high temperature. Finally they machine off the glazed ceramic down to the original dimensions, where the newly re- exposed aluminium surface is now much tougher and extremely resistant to abrasion, known as Nicasil-treated cylinder wall. Nicasil treated aluminium cylinders are sieze-resistant, but not entirely sieze-proof. Even if they do suffer a severe heat seizure, you often need to replace the rings (and often piston too) but the cylinder is usually still perfect. Only if some of the piston rubbed off onto the cylinder-wall, do you need to "scrape" this contaminant aluminium deposits off the cylinder, using a cylinder-honer. This Cylinder-honer is an expensive device, not to be confused with the "cheaper" spring-loaded gadget fitted to a hand-drill. The proper honer will remove aluminium deposits without damaging the Nicasil surface. The cheaper device, springloaded, three- legged abrasive-pads, is used mostly to remove "glazing" from the cylinder, a contaminant from burning gasoline and oil, which undergoes high-temperature polymerisation and caramelisation. Yes, gasoline constituents could break down into various sugars (curcular hydro-carbon chains), which could then form caramel of sorts. This is that brown goo often found on the exhaust (hot) side of the piston. Glazing is usually invisible but can be identified by the way it reflects light. Excessive use of an anti-glazing cylinder-honer will eventually remove your Nicasil layer, leading to constant seizures of the rings against the exposed aluminium ally. If your barrel really needs a good honing after a severe seizure, rather take it into a decent 2-stroke workshop for a proper job." _____________________________________________________ Keith Pickersgill Xplorer UltraFlight, Performance Paramotors Cape Town, South Africa. Tel: +27(0)21 555-1752 Fax: +27(0)21 555-1753 Mobile 082-414-8448 email: in-@x... http://www.xplorer.co.zaWorld's best paramotors http://www.xplorer.co.za/hangsimFlight Simulator http://www.paragliding.co.za/ppgPowered Paragliding in RSA ----- Original Message ----- From: "L&A Robertson" <lymana-@earthlink.net> To: <Loopfram-@topica.com> Sent: Wednesday, February 20, 2002 4:42 PM Subject: Re: Thanks for advice on Fork Assembly Problem, TFN
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