Setting Spring Plate Angle on Un-level Car

[rwest]

Hello,

I'm about to set my spring plates using Will Ferch's angle calculator; I'm guessing that this should be done with the car body level. I like the stability of having my front wheels on the ground and so I wondering If I can set my inclinometer on the door sill and subtract that reading from the number generated by the calculator and then set the spring plates to the difference?

[wildcat077]

Yup,

That's the way to do it ... I did mine last Summer with a small digital level and it worked out great,although i had the car up on all fours and pretty close to zero degrees on the door sills.

Have fun

Cheers !
Phil

[DRACO A5OG]

+1 ^^^

[Danimal16]

What you are describing is just the method in the late Shop Manual.

[rwest]

Thanks Guys,

I figured it would work, but I figure lots of stuff will work and then they don't!!!!!!!!

This will be a lot easier then trying to get the front jacked up safely and without damaging anything.

-Rutager

[wildcat077]

Originally Posted by Danimal16

What you are describing is just the method in the late Shop Manual.

Wow,i didn't know there was a late shop manual

Cheers !
Phil

[ivangene]

BTW there is an "APP" for that if you have a smart or iPhone - no math needed, just zero it on the sill

[Danimal16]

Originally Posted by wildcat077

Wow,i didn't know there was a late shop manual

Cheers !
Phil

It is the 84-89 manual. This is the link:

http://www.cannell.co.uk/911_72-89_Workshop_Manuals/84-89%20Workshop%20Manual.pdf


You can down load it for free. Go to the rear axle and it shows the math. it is good stuff.

DanB

[wildcat077]

Dan,

Thank you for the link,i have it on a CD which the PO gave me when i bought my car ...
It's already downloaded,printed and separated in plastic sleeves (dirty finger proof) and organized in different chapters. Keeps my Bentley clean

I'm sure a lot of people will appreciate the link !

Cheers !
Phil

[Danimal16]

Originally Posted by wildcat077

Dan,

Thank you for the link,i have it on a CD which the PO gave me when i bought my car ...
It's already downloaded,printed and separated in plastic sleeves (dirty finger proof) and organized in different chapters. Keeps my Bentley clean

I'm sure a lot of people will appreciate the link !

Cheers !
Phil

Phil,

You are welcome. When I saw the section that we have been discussing I tought that it was kool! The last PO did you goooood!

DanB

[Wil Ferch]

Section 420-16 of that bootleg manual works only to describe the spring-plate angle setting for stock torsion bar diameters of our cars,and then only to come to stock ride height....although it has the good point of advising 1 degree less angle for cars that have hi-pressire gas charged shocks.

The spring plate angle calculater used by this group, is more flexible in that it allows a different ( than stock) ride height and also can accommodate different diameter torsion bars.

[Wil Ferch]

Ohh...RWest..... the calculator knows that the car will never be totally level, and if the car on 4 jackstands is off by say 1-5 degrees or so.....yes...add or subtract to "correct".

Just a small caution......if the discrepency from horizontal is major....like maybe 45 degrees offset.....then there might be some new errors introduced into the equations that may not be properly accounted for. I can't put my finger on where the problem may lie....but big offsets may mess things up a bit...maybe not by much, if at all. But I thoght to throw the warning out.

[Danimal16]

Wil,

GREAT POINT. I used your calculator with the procedure described in the manual. So instead of the 33 degrees (or whatever) for the stock setting I used the setting from your calculator for the 27mm bars I upgraded to. Went with 23.6 degrees and it came out perfect. The car, however sat on the lift at a 5.9 degree tilt and the method for calculating it was in the Shop Manual. SOOOOO you are correct, the use of your calculator to find the setting and using the calculation method in the Workshop Manual is a hand in hand operation.

Danb

[rwest]

Will,

I'll check my angle and if its too much, I'll get the front up some and do the math.

Thanks for the help, and thanks even more for putting out the calculator!

Thanks everyone for verifing this and all your other information.

-Rutager

[Danimal16]

Rutager,

In my case, my car was at a 5.9 degree angle at the sill plate. It was not level.

I used Wil's calculator to determine that my spring plate angle for my suspension was 23 degrees. So I subtracted the 5.9 degrees from the 23 degrees and set the spring plate at 16.1 degrees and it was spot on. I have upgraded to the factory adjustable spring plate and I set the spring plate in the middle to enable me to go up or down. It worked out very nicely.

DanB

[Wil Ferch]

Well then.....even better...a bit less to worry about.... !