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Re: [Fot] aftermarket crank dampeners and pullies for TR4's

To: Tony and Annie Garmey <horizonracing@msn.com>
Subject: Re: [Fot] aftermarket crank dampeners and pullies for TR4's
From: Chuck Gee <chasgee@aol.com>
Date: Fri, 6 Dec 2013 13:50:57 -0800
Cc: "fot@autox.team.net" <fot@autox.team.net>
Delivered-to: mharc@autox.team.net
Delivered-to: fot@autox.team.net
References: <20131205235419.UEXET.10588.root@cdptpa-web34-z02.mail.rr.com> <52A129AD.9020602@dfn.com> <012901cef293$03d0e860$0b72b920$@gdhs.com> <000f01cef2aa$16065940$42130bc0$@com> <308F234C-9388-4C69-9C63-4DC4BA6FDFAC@aol.com> <SNT148-W144473F6FD84B9427C4BEAB2D60@phx.gbl>
Yes, it is a surface hardening process.  Not only does it help with wear, but
it imparts a compressive residual stress profile at the radii to help combat
fatigue crack initiation.

Chuck

> On Dec 6, 2013, at 12:55 PM, Tony and Annie Garmey <horizonracing@msn.com>
wrote:
>
> I may be incorrect here, but isn't nitriding a surface harding? It helps
with wear on the Bearing surfaces. The best precaution I have found regardless
if its a stock crank or billet,  is making sure the radius at the bearing
Journals are as big a radi as you can. Even if you have to chamfer the
bearings. Shot penning a stock crank will also help smooth the edges.  Not
Always, but a crack will start at a Corner or sharp edge.
>
> Tony G.
>
> > From: chasgee@aol.com
> > Date: Fri, 6 Dec 2013 11:59:23 -0600
> > To: tr4racing@googlemail.com
> > CC: fot@autox.team.net
> > Subject: Re: [Fot] aftermarket crank dampeners and pullies for TR4's
> >
> > And nitride it to try and keep the crack from starting in the first
place.
> >
> > Chuck
> >
> > > On Dec 6, 2013, at 11:39 AM, "MadMarx" <tr4racing@googlemail.com>
wrote:
> > >
> > > Unusual spot to break because the torque rises from front to rear. So
the
> > > first spot to break is the rear end with the highest load.
> > >
> > > I'm a civil engineer, so I have a small clue about forces.
> > > If the crank has no flywheel and not pulleys, just the crank with rods
and
> > > pistons it can freely bend on high load like a two field beam.
> > > A flywheel stops bending because the flywheel don't like to wobble, it
> > likes
> > > to run straight so the cranks rear end is forced to run straight, while
the
> > > parts between the mains swing. That induce forces into the last counter
> > > weight and maybe lead to a crack.
> > > The same with a damper on front. It reduces the swing in the middle
between
> > > main 1 and 2 but it rises the force on the counter weight.
> > >
> > > As a civil engineer I would say, let it swing and make the flywheel and
> > > clutch as light as possible and you get the most out of the crank.
> > >
> > > Cheers
> > > Chris
> > >
> > > -----Urspr|ngliche Nachricht-----
> > > Von: fot-bounces@autox.team.net [mailto:fot-bounces@autox.team.net] Im
> > > Auftrag von John Hasty
> > > Gesendet: Freitag, 6. Dezember 2013 15:54
> > > An: 'Michael Porter'; 'Randall'
> > > Cc: fot@autox.team.net
> > > Betreff: Re: [Fot] aftermarket crank dampeners and pullies for TR4's
> > >
> > > For what it is worth, we got 10 race weekends on our last rebuild
running a
> > > damper from BFE. The crank broke between # 1 rod and front main on last
> > > race, last lap, last turn while running 1st. in EP. I regularly turned
> > 6500
> > > in 2nd, 3rd, 4th and 6200 in OD. The motor always ran smooth with no
> > > vibration I could feel even with the front engine plate bolted directly
to
> > > the frame
> > > _______________________________________________
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> > >
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> >
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