Date: Thu, 28 Mar 2002 10:27:19 -0600
Reply-To: Stan Wilder <wilden1@JUNO.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Stan Wilder <wilden1@JUNO.COM>
Subject: Re: Windage, Ullage, Oil Temps
Content-Type: text/plain; charset=us-ascii
> So why do most two strokes have roller or ball bearings in their
crankshaft/piston/rod assemblies?
----------------------
Possibly I'm living in the seventies but I've never heard of roller or
ball bearings being used in stroker engines.
Nobody wants to throw anymore weight than they have to at 7000 + rpm.
I've run AA Fuel rails and Funny cars up to the late seventies and we
used aluminum rods, roller cams, lightweight rockers, bevel cut piston
rings, dry sump oil pans, tuf-block filled heads, lightened valves,
shaved all traces of the valve guides out of the intake and exhaust
ports, Teflon valve stem seals, lightweight valve spring retainers, steel
O rings to seal the head to the block, Teflon buttons on the wrist pins,
full floating wrist pins (lightened), short skirt forged pistons, light
weight aluminum roller lifters, chrome molly light weight pushrods, Greek
coupler drive shafts and very precision balancing of every part that
rotated.
Everything aimed at throwing less weight. You have to remember that when
you spin the slicks in bleach at 7000 rpm, all that stuff comes to a
abrupt deceleration when you get traction. Often RPMs raced way past 7000
rpms and every ounce stretches your rods.
Yes I have heard of needle bearing rocker arms, roller/ball bearings on
the camshaft.
There was just never any point of exploring the route of expensive roller
or ball bearings for us since we tore the engine down between every race
event and often between the first race of the day and the last race of
the day.
If someone with too much money can figure how to relieve a block to take
the additional stroke and the larger rod required, more power to him.
Stan Wilder
On Thu, 28 Mar 2002 07:45:02 -0800 pensioner <al_knoll@PACBELL.NET>
writes:
> Part two. The windage tray or other baffles installed in the oil
> pan
> improve lubrication in two ways. The first is to maintain contact
> between
> the oil pickup and the oil by restraining the oil from moving to one
> side of
> the pan under suitable acceleration. The second is that it reduces
> foaming
> induced by the motion of the pistons, rods and crankshaft during
> normal
> operation.
>
> Less air in the oil, the more it can absorb heat and move it to the
> outside
> temperature through conduction to crankcase, oil cooler, oil pan,
> and other
> relatively cool parts.
>
> So why do most two strokes have roller or ball bearings in their
> crankshaft/piston/rod assemblies?
>
> pensioner
>
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