front end raising-lowering adjustment screws

[cgh911sc]

In the picture does anyone know which screw (A-red/B-yellow/C-blue) is the adjustment screw you turn to raise or lower the front end on a 911sc.

Any idea how high or low the screw will raise or lower the front end using the adjustment screw?

Any thoughts on alignment considerations before or after adjustment?

[jeffs9146]

Here is a technical article on this site!

Pelican Technical Article: Lowering the 911 - 911 (1965-89) - 930 Turbo (1975-89)

[Flieger]

It's B.

It is pretty intuitive when you look at it:


Front Suspension Geometry_ 017 by Max_911S_fahrer, on Flickr

[Eagledriver]

You can actually calculate the expected ride height change by measuring the distance between the center of the torsion bar and the adjustment screw, then compare to the distance from the center of the torsion tube to the tire. The screw with be either 1mm per turn or 1.5mm per turn (measure this also). I did this last time I changed my ride height, but I don't remember the ratio.

-Andy

[cgh911sc]

Thanks for the link. The artical shows the screws. No sure about how to adjust the rear hight using radius arm screw.

[Flieger]

The rear is a lot more fiddly.

[cgh911sc]

Can you measure the distance between the center of the front torsion bar to the level ground or from the fender to the ground?

Looks like I need to find a alignment shop with an alignment rack equipment.

[DRACO A5OG]

Yeah, if you mess with the ride height it will certainly mess with the alignment. If you don't have a home string rig then go to a known good Porsche alignment shop and have it done right.

FYI, if you lower the front, it will effect the rear and worse yet lower left front will bring down the right a bit a well. The other issue is if you lower it too much you will most likely need a bump steer kit to compensate for the geometry of the steering assembly.

[Alan L]

And if you 'screw it up', ie get it out of whack, you will alter the balance of the weight distribution and handling/braking of the car.
You need to do a good bit of reading and know exactly what you are trying to achieve before tweeking it.
Alan

[porwolf]

If you lower ride from US specs to Euro specs you want to check whether you need to take out the US spacers at the top of the front shocks! Otherwise the shocks don't work in the right range. Do you know whether you have the US front shock spacers?

[cgh911sc]

I'm not sure if I have US front shock spacers. How can I tell?

[cgh911sc]

FYI, I went to two local shops. One wanted $1,800.00 the other $2,800.00 to raise the front of the car.

Where I am all the shops try to screw you. None of the shop want your business if your not willing to be screwed for at least $10k per visit. I'm not sure if their price includes alignment or balancing as they didn't care if they fixed my car or not as the job was under their shop minimum I guess.

The dealers are even worse around here. I'm sure the dealer will want 3 times that price so I haven't bothered to call them for a quote. Not being able to get my car fixed without being over charged is what has lead me here as it has others like me it appears...many others. What do you think it should cost?

[porwolf]

Originally Posted by cgh911sc

I'm not sure if I have US front shock spacers. How can I tell?

I am facing the same situation, but have not doene anything about it. My US 79 SC front height seems tall by about 1/2 inch, the rear seems more like Euro height. The car is all original, no height adjustments have been made in its lifetime. I read on this forume that for US SC's these spacers were added. Not sure whether I have them because the car was a Europen Delivery. I think the only way to find out is to discoonect the front shocks, as if they need to be exchanged, and look for that spacer on the top of the schocks.

I found this thread:

When did US ride height spacers start?

[Alan L]

if you disconnect the front shocks you will need a front end alignment. I don't know anything about the US spacers, but would imagine you should be able to see them at the top of the shocks. Normally there is just a thin plate there to butt up on the rubber mount in the alignment unit.
That price is ridiculous. I just fitted a rear sway bar, lowered and corner balanced a mates car in a morning. That also included adjusting the rear and front torsion splines.
There are threads here on all this stuff, but at that price you could invest in a bit of the gear you need and do it all yourself. The main issue is to make sure you don't screw up your alignment and corner balancing when fiddling with this. You can cheaply do the corner balancing by buying a Speedway checker unit (that is what I use).
Wheel alignment I usually pay for, but can do camber and toe relatively easily myself.
depends how far you want to get into it.
Alan

[cgh911sc]

I can't find a Speedway checker unit on the internet. Do you have a model number
or more info so I might look it up?

[Alan L]

Try this - this is what I bought from them. Works excellent.
Hydraulic Wheel Load Checker - Speedway Motors, America's Oldest Speed Shop
You may also want to buy the floor level tube system - about $30 - you want the car on dead level surface. I use pads of lino to adjust, altho currently I have a dead flat purpose built pad, which helps.
If you are so inclined to spend the time, you will find it very useful. I have the front susp out of my track car at moment. Simple job to get it all back correctly.
Lots of threads on setting your suspension up, but with that gear you can make sure you have the balance right. After all that, you only need to pay for a wheel alignment if you have made major adjsutments.
Alan

[Alan L]

If you JUST want to raise/lower the front, you can do this simply, by marking the adjuster bolts with a marker pen. Rotate each side exactly the same amount. eg 2 turns up will raise it somewhere between 10-20-mm. You will not have affected the balance of the car. If on the other hand you are going to fiddle with the rear spring plates as well, then this would be a good time to get involved in setting up the suspension balance in the car, if so inclined, for a modest outlay in the required tool.
Alan

[nameisbauer]

I think this has been glossed over slightly, and for someone who has never "re indexed" before, it seems like a bigger task than it is.

The Adjustment screw is very simple to understand, and has been covered. But if you have to re index, everything I have read makes it seem like a difficult job. Taking torsion bars out, etc.

It is SO EASY, it gets glossed over so I took some pics to help the noobs (myself included in that statement.)

If you have the adjustment screw maxed out, so the Torsion Bar Adjustment Lever is bottomed out you need to re index to go lower:



Back out the Adjustment screw all the way. Adj Lever can come off now


The Adjustment lever just comes off, Toward the camera in this photo,


This is your Torsion Bar. Leave it!


Re Index by simply moving the Lever down a spline. Think about it maxed out. If the lever could continue up, it would go lower. You step it down, so it can in theory, continue to go up. I went one spline(by feel). If you car going from Safari Rally height to Slammed low rider, you would probably need to go 2 splines.


Re Install Adjustment screw. Will look like this until to re weight the car, drop it on the wheels. This was too low to me, so I needed to raise the car, via screw. Now at less that halfway in the lever.


Hope this sheds some light, Hope what I did was correct!

[rbogh901]

Nicely done Jim. Thanks.

[Walt Fricke]

When setting ride height, one really ought to use Porsche's method. It is easy to measure the distance between the CL of the torsion bar, and the CL of the axle, and use that. Just turn the wheel out, lie down on the ground with a tape measure, and measure to the ground for each, then subtract the one from the other. I measured a friend's car, which seemed lower than mine, and used his measurements as a kind of safe harbor. Got the car down about an inch more than it was, and no bottoming.

The fender height method will vary with your tire diameter (I'm using 225/40/15s up front now, mainly to get the car lower). And I have no trust at all in fender locations, especially in the front where it is easy to replace.

So measure your ride height the way Porsche does - the difference in height between the axle and the torsion bar. Easy to do with a tape measure and a bit of eyeballing to get in the eyeball park.

For an SC, this difference at ROW (Euro) ride height is 108mm, +/- 5mm. I found I was at 156, but a buddy was at 185 and had no bottoming issues. I figured I could lower an inch (25mm or so) and still be OK.

I measured the distance from T bar axis and ball joint at about 300mm. I measured the torsion bar adjuster effective length at 53mm. This meant I needed to loosen the adjuster about 4mm (close to 6 to 1 ratio) to get a 24mm drop in ride height. Thread looked to be M8x1.25, so three turns of the adjuster should be close at 3.75mm. It was, and I came out at 178 and 181, the difference side to side being from previous corner balance adjustment.