911SC Alignment - Page 2

karleick · 08-03-2007, 01:58 PM

All,

I had a brain-fart when I wrote my ride height at 14.5 and 14" I meant to write 24.5" front and 25" rear.

Wil Ferch · 04:42 PM

The wheel arches are such that if the measurement is 1/2" taller in the front ( simply by the way the cut-outs are shaped), then the car would have a 1 degree negative ( nose down) attitude, per Bruce Anderson. If the front numerical measurement is indeed smaller than the rear as you state, then the nose down attitude is even more severe. I thought maybe your 14" (or so) numbers were radius numbers from wheel centerline instead of "from ground"...no problem.

Stlrj...The negative camber can come from a number of things. I mentioned in this post that my pristine, unmolested 85 Carrera ( before I got it !!).. was found to have severe passenger side neg camber too! ... yet all the black gook was still there on the shock tower, meaning no previous adjustment. It was about -1 or -1.1 degree. Who knows?... a severe crash landing by the PO on the RF causing the spindle to bend up slightly ?? I never found the relative torsion bar heights to make any sense in the Porsche spec books. No matter how I looked into it, it never reconciled ( or "triangulated") in a way that made all the numbers work, especially in the back. I agree, however, that if the car was slammed down excessively, then raising the car to Euro will likely "bring back" a lot of the "bad" numbers like excessive negative camber.

RoninLB, the earliest Porsche specs required a "pressed" condition to measure toe. Later Porsche factory specs removed this "pressed" condition, but ( I think) this resulted in slightly altered numerical values of spec toe, too . I think you mean 7.5 minutes...not degrees, right? Your last sentence is a particular sore spot with me for alignment shops. Toe-in measured in arc ( minutes, degrees) makes sense, and is always true for whatever wheel/tire you run. Toe-in expressed in inches ( ex: 1/16") never made sense to me. Where is it measured? Tip of tire radius? Tip of wheel radius?. Front of tire relative to back of tire? If you assume one and get the other, you'd be "off" by....maybe 80-100%, using inches !!

RoninLB · 08-03-2007, 04:57 PM

Quote:

Originally Posted by Wil Ferch

RoninLB, the earliest Porsche specs required a "pressed" condition to measure toe.

the pressed/preload came from a 2/76 article by Stoddard.

His front toe-in was 0 pressed to +6' on each wheel

His rear toe-in is between +5' and +10'

Wil Ferch · 08-03-2007, 05:02 PM

I consider 1976 as "early" and do not disagree with you that this was done.

RoninLB · 05:48 PM

Quote:

Originally Posted by Wil Ferch

.

Toe-in expressed in inches ( ex: 1/16") never made sense to me. Where is it measured? Tip of tire radius? Tip of wheel radius?. Front of tire relative to back of tire? If you assume one and get the other, you'd be "off" by....maybe 80-100%, using inches !!

i use the tip of wheel radius for 1/8" toe-in non-pressed. I check settings on a long straight flat road with a temp probe at 3 spots on each wheel. I only do 2 wheels at a time. Works for me through 2 x4 similar sized sets of tires. Not that they were perfect as i need a little more camber all around to balance tire wear. [I'm not hard around turns]

ps: 1983 War Bonnet Tech, Stoddard suggested 5-10 minutes more toe-in on each side to compensate for not using a pressing tool.

RoninLB · 08-03-2007, 05:33 PM

Wil Ferch · 08-04-2007, 12:08 PM

As I said Ronin...no agument that this was Porsche's preferred method. They clearly removed this requirement and slightly altered the toe settings for the later cars......and later technical references. Funny how Porsche says stuff like "absolutely essential" one time..and then ignores it's own advice later. Much like the dire predictions of the earth coming to an end if we apply even the smallest amount of "anti-seize" on plug threads because the heat transfer characterisics ( heat range) will be "all wrong" if we do so......etc, etc.....

RoninLB · 08-04-2007, 01:50 PM

I use anti seize loctite Graphite 50 for plugs

deputydog95 · 09-06-2016, 12:32 PM

Old thread, but which shop was this in Sarsaota? I need an alignment on my 85 and was wondering where to go.

karleick · 09-06-2016, 01:23 PM

I use shops which have a Hunter alignment bay, have the understanding of how to do 4-wheel alignment on early Porsches, and have the proper tools to do the rear alignment. I"ve used both Renn Haus and Sunset Porsche with good results. I prefer a shop which will allow me to watch the procedure and converse with the technician. On one occasion, I noticed my rear was slightly out of spec, and the technician admitted he didn't have the tool to adjust the rear. I wonder how that would have worked out if I hadn't been there?

impactbumper · 09-06-2016, 03:55 PM

your alignment can also be corrected if you get adjustable strut tops and bump steer kit, since you are a tad lower than euro spec, which is fine.

impactbumper · 09-06-2016, 03:56 PM

another note, that is exactly what i did. Before the car was a bit uneasy on high speeds and following the tracks. After i installed those two items i was able to dial it in right. Straight as an arrow, stable on high speeds and handles like it is on rails. Otherwise raise the car up. You might still run into issues with caster though.