lowering to euro specs

ldillow · 08-20-2001, 08:19 PM

I am in the process of lowering my 79 930. I have pulled all of the info I could find. I have evrything marked and apart, other than the torsion bars from the swing plate. Is there an easy way to separate the bar from the plate? I have marked the spring plate as well as the torsion bar to the plate. All I need to do now is figure out how to separate the bar from the plate and get a grasp about the movement of the bar and plate to lower. pbs911 said to turn the inner spline 1 notch and the spring plate one notch in the opposite direction to lower 8mm. Is that torsion bar movement up (in effect to lower car), and spring plate the opposite direction (in the direction to raise car? I am at 26 1/16, so I will need to lower approx 56mm and then set my eccentric in the middle for corner balancing.

You guys let me know regarding the separation of the torsion bar from the swing plate and if I have the spline movement concept down!

Thx
larry

ldillow · 08-20-2001, 09:02 PM

Correction on the lowering numbers. I am going from 26 to 25 in the back and 25.5 in the front so i only need 28mm of lowering not 56

Quote:

Originally posted by ldillow:
I am in the process of lowering my 79 930. I have pulled all of the info I could find. I have evrything marked and apart, other than the torsion bars from the swing plate. Is there an easy way to separate the bar from the plate? I have marked the spring plate as well as the torsion bar to the plate. All I need to do now is figure out how to separate the bar from the plate and get a grasp about the movement of the bar and plate to lower. pbs911 said to turn the inner spline 1 notch and the spring plate one notch in the opposite direction to lower 8mm. Is that torsion bar movement up (in effect to lower car), and spring plate the opposite direction (in the direction to raise car? I am at 26 1/16, so I will need to lower approx 56mm and then set my eccentric in the middle for corner balancing.

You guys let me know regarding the separation of the torsion bar from the swing plate and if I have the spline movement concept down!

Thx
larry

Colby · 08-20-2001, 09:11 PM

I just did this whole mess last month so let me give you a few personal observations. I too was at about 26" in the rear. First thing I did was just turned the plate (outer splines on the torsion bar) one notch. This dropped me way to low (under 24"). So I knew this far was bad. I also knew stock was too high (at 26"). So I marked each the angle of each location (the spring plate) and knew I wanted to be somewhere in the middle (to get close to 25"). I found one turn inner counterclockwise, and one turn outer clockwise (I am pretty certain...I may have them reversed) landed it right in the middle of the two lines I had previously drawn. Sure enough, passenger side was 25". For some reason, the driver side was stubborn, and sat way down at 24.5". This is why you NEED the special wrench to adjust height. Sorry Pelicanparts, Vertex has the same wrench for $22 (half of what Pelican wants), so I got it from them. A turn of the wrench and the driver side was back up to 25". Everyone said that the one turn inner and outer in opposite ways would lower about 8mm, but I found it closer to 1", at least on my car. Good luck!

Colby

Colby · 08-20-2001, 09:12 PM

One more thing. My outer spline came apart first... I had to wiggle the inner one loose. If yours did the opposite, no big deal. Just wiggle it loose.

Colby

Clark Griswald · Clark Griswald's Garage

The tbars just rest in the spline of the spring plate. They are not even pressed in, just loose.

However, after 22 years they can get a little sticky and may not slide out easily. If that is the case, grab the tbar in your hand an pull on the spring plate. See saw the spring plate back and forth until it wiggles loose. Shouldn't be too tough.

You said you marked everything. Be sure you mark the declination angle of spring plate on the inner fender before pulling out either side of the tbar splines. Do this when the spring plate is fully disconnected and hanging loose. That angle can be an important reference point for setting your new angle.

Counting splines can be tough.

I always just set a new angle using the old one as a reference.

Well I see Colby hit the return button before me, all good advice. You should also check out my tech article (yes I know it says Mark Jo) here:
http://www.pelicanparts.com/techarticles/911_suspension_bushings/911_suspension_bu shings.htm
------------------

Chuck Moreland '86 Cab - "Sparky", '77 Targa - "Sweet Pea"

[This message has been edited by Clark Griswald (edited 08-20-2001).]

ldillow · 08-21-2001, 05:52 AM

Thank you for the info! I am still a little confused on the spline turning. clockwise and counterclockwise won't work because it will be different depending on what side of the car you are on. I am assuming that the inner has less teeth than the out spline on the tbar. So by turning the inner in the direction to lower the car will add significant drop like colby experience (2"), and then by turning the outer in the direction of raising the car brings you back to 8mm drop as explained earlier by paul in another post. If this is corret it makes sense. I am also assuming there is no real significance to the up one inner and down one outer, other than having a measurement like 8mm of drop. So you could do inner spline 1 by itself and get 2" drop and all is well if that is what you wanted instead of 8mm with an inner and out movement. Us novices get nervous when an instruction is given like one inner spline and 1 outspline movement in the opposite direction is required to get 8mm of movement and then a slight variation works better, but what if there is more reasons for the original instructions than we knew.....

If anyone could explain this, that would make me feel better about this process!

IceBlueSC · IceBlueSC's Garage

Quote:

Originally posted by ldillow:
I am in the process of lowering my 79 930.

Great info guys! I have been thinking of lowering my SC as well, I will be watching this thread intently.

------------------
Mike Florendo
'81 Ice Blue SC Coupe
Pelican Page
Porsche Owners Gallery Page

Colby · 08-21-2001, 10:13 AM

Ya know, I think you may have explained my "stubborn driver side" sag (which was 1/2" lower than the other). Clockwise on one side is counterclockwise on the other (or is it?). I did the same turns on both sides which may explain why the ride height was different. But really the difference is insignificant (if you have an SC or Carrera) since the difference is really only 1/4" to 1/2" which can then be adjusted using the height adjustment eccentric nuts. However, should I do it again I would do inner clockwise, outer counterclockwise on the passenger side, then inner counterclockwise, outer clockwise on the driver. This would have the same effect on both sides. Whatcha all think about this. Maybe it really doesn't matter...I dunno. But as I said, it really is insignificant as you are only splining to get close, then fine tuning using the nuts afterwards.

Colby

ldillow · 08-21-2001, 11:03 AM

Colby, that makes sense. I have the day off, so I'm going to pull the rest of it apart right now. I'll take a look at the splines and see if in fact the outer has more teeth than the inner. I'll let you know.
thx
larry

Vipergrün · 08-21-2001, 12:59 PM

Hey ya'll, I just did this last week. No matter which side of the car, you want the spring plate further off the ground when you are done, which drops the car. I was at 26.25 rear and came down 1.25 inches. Once the spring plate was disconnected (not removed) I was able to measure the distance from the bottom most part of the plate to the ground. This was 10" in my case. They I removed the plates, replaced the bushings, and did a test fit. I re-assembled the spring plate with the eccentric bolt *in the middle*. I then repositioned the spring plate on the splines so the measurement was as close to 11.25 inches off the ground as possible. I made minor adjustments after that to get it on. When I was done I got exactly 25.0 both sides

I do have some pics if anyone is interested. BTW, go with the Neatrix bushings, they are great.

-Brad
80SC

Colby · 08-21-2001, 02:57 PM

Idillow: I know for a fact that there are less splines on one side of the torsion bar than the other. I can't recall which has more or how many, but it's something like 41/44 inner/outer. I'm sure someone will chime in with the exact number.

Colby

pbs911 · pbs911's Garage

Be careful that you have both sides set at exactly the angle! While you can adjust ride height by the adjustable swing plate, you cannot compensate for improper weight distribution if you inadvertantly set the torsion bar/swing plates at different angles. Use a protractor to ensure that both sides are set at the angle. Once bot hsides are set at the same angles you can make minor adjustments in ride height via the swing plate adjustment nut.

Bruce Anderson provided the info that one notch "up" on the inner spline (thereby bringing the swing plate upwards) and one notch "down" on the outer spline (thereby putting the swing plate closer to the ground) will lower the car by 8mm. This is because there are a different number of splines for the inner and outer. This worked well for me with the stock torsion bars. Not so good with thicker torsion bars.

If you are having a difficult time separating the swing plate from the torsion bar, you may have to drill a hole in the cap covering the end of the swing plate and use a rod to tap the torsion bar free.

Overall, this can be a trying process but rewarding.

------------------
Paul
78SC Targa

ldillow · 08-21-2001, 06:22 PM

When I first took apart both sides the driver side had more angle than the passenger side. I thought it was just a weight distrubution thing from the factory to compensate for driver wieght. I am now on my third goo around. I ended up with 24' my first try. I have now had to move the spring plate down where it is nearly impossible to connect it to the knuckel. Am I doing something wrong? How do you get the spring plate up to connect to the knuckel if it is lower than the knuckel? I have already disconnected the sway bar to assist inlowering the knuckel.
Confused?
larry