Here is a link to how to set the angle. In addition the two ujoints at each
end have to be in phase, and not rotated at all relative to each other. The
line of the tailshaft and the pinon shaft should be paralell when under
load. So set the paralell to start and then rotate the pinion shaft down 1-2
degrees. You see lifted trucks all the time with the rear axel pointe up to
the tailshaft. That driveline will vibrate like mad and break ujoints
regularly.
http://www.carcraft.com/howto/91758/index.html
Craig Wright
----- Original Message -----
From: "John Donohoe" <sevenamerica@yahoo.com>
To: <lotus@se7ens.net>; <vintage-race@autox.team.net>
Sent: Thursday, January 07, 2010 8:06 AM
Subject: [Vintage-race] Driveline angles and vibration? (General, but in my
Lotus Seven)
> For years I've struggled with a vibration in the Seven that seems to come
> and
> go at various speeds, and is the same regardless of wheels (I've run 2
> types
> of steel and one set of cast aluminum wheels all resulting in the same
> vibration). I balanced the driveshaft, and checked the u-joints, all good.
> Today I stumbled across this instructional booklet on drivetrain
> alignment: http://www.iedls.com/IEDL_PTS_LGL_091008_Secure.pdf and now I
> wonder about checking the alignment between my engine and differential
> pinion
> shaft. When I got the Seven, the the BMC smoothcase gearbox was attached
> to a
> Sprite mount, which was bolted straight to the aluminum floor of the
> transmission tunnel with a single large bolt! This also resulted in the
> bellhousing clunking against the lower, curved firewall frame tube over
> every
> bump, and yes, the vibration was horrible on the 6 inch wide, custom Lotus
> steel wheels that were on the car when I bought it. One of my first
> 'modifications back to original' was to make a crude aluminum bracket to
> raise the gearbox and spread the load on the tunnel floor. With hindsight,
> it
> seems the vibration is less now, but till present. Did I partly fix the
> problem by slightly changing the relative angles of engine and pinion
> shaft?
> Has anyone fussed with this variable? One other detail is that there is a
> pronounced angle of the engine/transmission itself--the engine is not
> parallel
> to the centerline of the car... could this be another cause? Input
> appreciated
> as I prepare to pull the engine and will have the opportunity to make
> adjustments! Cheers, John Donohoe SimpleSevens
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