911 Geometry :: More Alignment projects

Posted: Dec 14, 2008 11:11:13 pm

gwynsms
Newbie Posts: 10 Registered: 2008-10-18	Hi Some interesting recent projects included using the aligner on a 1988 P911, 3.2. Owner Andrew had had the rear suspension apart, to facilitate replacing the oil thermostat and associated tubing. Andrew had thoughtfully scribed lines around the spring plate/radius arm interface, with the aim of returning to the original geometry settings. Maybe 30 years of use had put things out of kilter, as Andrew could see by eye that the rear wheels in particular were not pointing entirely forwards! So after seeing my earlier report on this forum, I got summoned to measure things up, and achieve a baseline set up for road use. Some suspension bushing refurbishment is scheduled for next spring/summer, so we decided not to do corner weighting at this time. On went the equipment, and with everything leveled, we started studying the screen. The first image was a virtual view - a sort of exagerated characiture outline - and oh dear things looked pretty bad, particularly at the rear. Moving onto the actual measurement screens, we had a massive toe in on left rear, 1deg 20minutes, right rear was nowhere near as bad at 24minutes in. As this was unacceptable as a baseline, out came the spanners to make ajdustments. Managed to acheive a left rear toe-in of 10minutes in, unusually, one go! Took 3 goes to get 12min on right rear with its ajdustment cam on its max available, so we settled for this. Rear neg cambers were niceley balanced, without individual adjustment, at 1deg 36 and 1deg 17. To finish off, we then ajdusted front toe-in to 7minutes each side, Andrew's preferred/recomended settings. Like the rear, front camber balance was good, with 39min and 34min neg, and castor angles excellent at 6deg 40 and 6deg 25. Although not strictly relevant to this forum, I've included a bit of info in case readers have a BMW mini in their collection. Newest roadcar that I've ever worked on was aligning a 3month/3kmiles old BMW Mini Cooper S. Christ, dont BM get it wrong!! Same owner previously had an 06 Mini1 that gobbled rear tyres every 6k miles!, BMW even replaced 2 tyres for him FOC - "without admitting liability" - but didn't know how to correct the problem.... He came to me 3months ago to fix that one, and reported much improved handling and generally nicer to drive. And guess who he works for; BMW!! So, with his new Cooper S, thought it'd be smart to get me to sort it before needing new tyres. I found massive toe in on its rear wheels, one side just on BMW max limit, tother side worse than their max limit, corrected both to BM's min limit of 5min each side and did same at the front which was at max toe in of 2.5mm; reset it down to 0.5mm to give us nice stability on the motoways. So, if you drive one of these, check your tyre wear and get it checked. Happy motoring. Gwyn "where there's a will, there's an engineering solution"
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Newbie

Posts: 10
Registered:
2008-10-18

Hi
Some interesting recent projects included using the aligner on a 1988 P911, 3.2. Owner Andrew had had the rear
suspension apart, to facilitate replacing the oil thermostat and associated tubing. Andrew had thoughtfully scribed
lines around the spring plate/radius arm interface, with the aim of returning to the original geometry settings.

Maybe 30 years of use had put things out of kilter, as Andrew could see by eye that the rear wheels in particular
were not pointing entirely forwards! So after seeing my earlier report on this forum, I got summoned to measure
things up, and achieve a baseline set up for road use. Some suspension bushing refurbishment is scheduled for next
spring/summer, so we decided not to do corner weighting at this time.

On went the equipment, and with everything leveled, we started studying the screen. The first image was a virtual
view - a sort of exagerated characiture outline - and oh dear things looked pretty bad, particularly at the rear.
Moving onto the actual measurement screens, we had a massive toe in on left rear, 1deg 20minutes, right rear was
nowhere near as bad at 24minutes in. As this was unacceptable as a baseline, out came the spanners to make
ajdustments. Managed to acheive a left rear toe-in of 10minutes in, unusually, one go! Took 3 goes to get 12min on
right rear with its ajdustment cam on its max available, so we settled for this. Rear neg cambers were niceley
balanced, without individual adjustment, at 1deg 36 and 1deg 17.

To finish off, we then ajdusted front toe-in to 7minutes each side, Andrew's preferred/recomended settings. Like
the rear, front camber balance was good, with 39min and 34min neg, and castor angles excellent at 6deg 40 and
6deg 25.

Although not strictly relevant to this forum, I've included a bit of info in case readers have a BMW mini in their
collection. Newest roadcar that I've ever worked on was aligning a 3month/3kmiles old BMW Mini Cooper S. Christ, dont
BM get it wrong!! Same owner previously had an 06 Mini1 that gobbled rear tyres every 6k miles!, BMW even replaced
2 tyres for him FOC - "without admitting liability" - but didn't know how to correct the problem....
He came to me 3months ago to fix that one, and reported much improved handling and generally nicer to drive. And guess who he works for; BMW!!

So, with his new Cooper S, thought it'd be smart to get me to sort it before needing new tyres. I found massive toe in on its rear wheels, one side just on BMW max limit, tother side worse than their max limit, corrected both to BM's min limit of 5min each side and did same at the front which was at max toe in of 2.5mm; reset it down to 0.5mm to give us nice stability on the motoways. So, if you drive one of these, check your tyre wear and get it checked.

Happy motoring.
Gwyn

"where there's a will, there's an engineering solution"

Profile

email gwynsms

Pete
911Meister Posts: 1072 Registered: 2008-10-13	Good work Gwyn. Seems to have gone well and relatively quickly compared to others you have done. Andrew - How does the car feel now as compared to before Gwyn has worked his magic? 1974 Coupe plus bits! \| Stuttgart eXchange \| Channel P101tv \| My Porsche Blog
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AndrewPA
Newbie Posts: 8 Registered: 2008-11-04	It feels good - wheels no longer doing an impression of a 2CV under sail! Gwyn did a great job sorting it out, at my house. Hopefully next time it will be a bit warmer.... I will get the photos on to the forum soon - Christmas seems to be getting in the way!
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