I narrow rods are put on a wide journal, then the side clearance or the rod
flank and bearings will be way larger than the .010" to .014" that TR called
for. This will result in a lot more oil. being thrown off of the crank and
up on the cylinder walls while the engine is running. Especially at high
rpm. The rings may not be able to control all this oil. and the "windage"
losses from the crank and rods whipping through the oil will cost hp. It
would seem to me that if the rods and crank were designed as a matched set,
then it would be possible to get a combination that would work well.
\ Greg Solow
----- Original Message -----
From: "Bill Babcock" <BillB@bnj.com>
To: "'Jack W. Drews'" <vinttr4@geneseo.net>; "mordy dunst/ gasket works"
<gasket.works@verizon.net>; <fot@autox.team.net>
Sent: Thursday, August 26, 2004 4:13 PM
Subject: RE: bearing width
> It can't be the journal diameter that makes the Triumph rods expensive,
it's
> got to be the width. They are not particularly large diameter bearings,
> they're just very wide.
>
> There's a lot of ways to fit a narrower rod, including aluminum or steel
> spacers. They could be split and screwed or they could be wound on. They
> don't need to be much or they can be done away with completely since the
rod
> can be located by the piston with thrust washers on the gudgeon pin rather
> than by the edges of the crank journal--that's a better way anyway. Many
> high rpm motors use that approach.
>
> The biggest problem in all of this is that someone has to be the guinea
pig.
> Any solution tends to surface at least two new problems
>
> -----Original Message-----
> From: owner-fot@autox.team.net [mailto:owner-fot@autox.team.net] On Behalf
> Of Jack W. Drews
> Sent: Thursday, August 26, 2004 3:52 PM
> To: mordy dunst/ gasket works; fot@autox.team.net
> Subject: Re: bearing width
>
>
> I would not be nearly as interested in potential hp gain or ability to
rev.
> What I'm interested in is making available to the Triumph community some
> high quality rods at a fraction of the cost of Carillos.
>
> At 10:01 AM 8/26/2004, mordy dunst/ gasket works wrote:
> >Granted, the TR tractor motor has a stout three main crank.. it's ability
> to
> >tolorate what we through at it is really amazing. But, the key here
is
> >three mains. I am not convinced that decreasing the rod jo diam is a
> >good thing. It would seem that the advantage is reduced bearing speed
> >but, disadvantage in increasing the unit bearing load? So, if our
> >cranks are made with smaller rod journals will this be a problem in
> >three Main cranks? -especially with flex harmonics?.
> >
> >But, if the bottom end of the rod is narrowed the crank journal would
> >either have to be welded up or spaced would this then distribute the
> >load and mitigate against this increased load?
> >
> >
> >
> >M. Dunst
>
> uncle jack
|