So after getting the trailing arm rebushed on the drivers side I wanted to check the rake. The rake looks good. I checked for level port to starboard and I got a lean. Almost like the s10 lean when the big dudes drive around on them all the time and the springs get sad. Front is leaning too. So my question is - Will the rear suspension affect the front suspension in regards to balance? I realize if the driver rear is super low it will have some affect on the driver front, but its almost like a 1:1 ration where as I thought the front would not suffer as much.

Oil tank is on the driver side accounting for some of the additional weight. I was not in the car when checking the side to side level.

Rear springs are 100lb 914-6 ones two perches up on both. Front is an SC setup with a front sway bar.

Will new rear springs solve all my problems or do I need to investigate something else like adjust the front driver adjuster also?

At the donuts
Drv F - 4 & 7/8
Drv R - 5 & 7/8
Pass F - 5 & 7/8
Pass R - ~6 - hard to determine as there was console work done on that side and the donut was remounted at an angle

From those numbers it doesn't seem like the rear should have as much variation, but it does. The fender on the Pass R is about 2 in higher than the Drv R. Maybe the guy that put on the flares was careless

The lowest point seems to be the Drv F with 1 inch lower than the pass F and Drv R.
So maybe if I adjust the drv F and get that donut in line with the pass F then I can start to adjust the pass R down one notch to bring it even with the drv R. Is this logic sound? Where you at Phil?

I'm not a suspension expert, but a 1" difference between the fronts sounds like a lot. I would adjust one or both torsion arms until they are equal (or nearly so-you can account for driver weight). Pretty sure there are threads on here that give all the factory specs for ride height, angles, etc. I would start there.

Fine!!!!!

Valvolines for reference



DR


PR


PF


DF

You could try switching the spring/shock sides and see if that changes things.

and even out the front torsion bar adjustments. Disconnect the front sway bar when you do this.

I blame those springs you sold me Tom j/k

Hey, My car sat level.... But I'm a skinny dude.

I need to know more..... Eileen too.

I adjusted my adjustable shocks. Happen to remember this, cause I was under the 914 changing the gear oil last weekend. Right side is set about 5 notches higher than the left. But I still lean a bit.

What is causing it?

Check the obvious first, like springs not seated correctly etc. Drive it around the block to make sure the suspension has settled.

Otherwise, you'll need a corner balance. And yes, changing the height on the rear will also affect the front (and vice versa).

Take it to a race shop that knows old Porsche cars and have them corner balance and align the car.

Thanks Andy.

Anyone know who does balancing in Maryland?

“It was at this moment nditiz’ thread died”

And be aware that a corner balance will not yield a perfect symmetry of height from side to side.

Set your approximate desired ride height, then take it in.

Nick, try Taylor Chapman in Sterling across the river from you maybe?

Otherwise consider posting on Dorkiphus (if you haven't already). There's definitely a place in Merrifield / Vienna. Just not sure where close to you in Maryland...

I wouldn't measure to the lip of the flare. They could be off during installation and show measurable difference.

@Rick 918-s is spot on. When determining ride height, you'll want to measure from solid points of the chassis. These cars can have significant variation in them, particularly at the fender once flares have been installed.
On my car, which I had corner balanced at a reputable race shop, the tech specifically called out not to measure at any body line. At level (chassis-wise) I have a 1/4" height difference across my front flares.
And not that I'm the world's best flare installer but if you look at my build, you'll see they were installed pretty accurately in terms of fitting them to the body.

Ya' all are lucky -- some idiot installed my driver front fiberglass flare 3/4" too far REARward.

Totally agree with Chris and Rick -- don't measure ride height to flares!



Yes!

Sort of goes without saying . . . but . . . make sure you're on a level surface. My garage floor is not level. Is yours? Have you actually checked it?

In my original post I did measure from the Donuts. Is there a better spot than that I should measure from?

The floor is level to an extent. All garage floors have a built-in slope to ensure water moves away from the back per local code.

Let me play around with the front and rear adjustments and report back.

Doh!

Doughnuts would be fine.

Why not use factory manual for front? The problem is that spec is +/- 5mm and you are way beyond that.

Are you checking with full fuel? Fuel tank biases weight toward passenger side by design.

Have you moved battery and/or switched to light weight battery?

When I had my CB/alignment done, weights were put in the driver's seat approximating my poundage.

I do have an almost full tank.

The battery is a lighter PC680. I can throw a regular on that side to see what that does.

My 200 lb butt would only make the driver side worse

When I get everything to level spec, then I can add some kids and kitty litter to the driver seat and recheck.

Let me check the mans for correct height. I do have an SC conversion front end, but that shouldn't change the height specs.

I don't know if I can explain this very well in words but let me try.

I think of weight (and ride height) distributions as a 3 legged stool. It takes 3 points to establish a plane (i.e. the level ground the car is sitting on).

When balancing race cars you'll forever fight the 3 legged stool trying to get all 4 corners to balance perfectly.

Using the 3 legged stool analogy, you'll tend to find that two legs are carrying the majority of the load . . . the other two are more lightly loaded and the car is sort of "teetering" back and forth across the diagonal. One of the two that are more lightly loaded, one will be heavier than the other.

Picture:
Click to view attachment

H=Heavy L=Light

empty circle = lightest corner

So in top picture we would want to add weight to #3. #1, #2, and #4 are the 3 legged stool

But when we do that (bottom picture) you'll find that the diagonal bearing the weight can shift and all of sudden #3 becomes heavier than you anticipated and #4 is now too light and/or becomes the lightest corner. The weight sort of "toggled" or falls over to the other side of the two legs that were "tallest" . #1, #2, #3 are now the 3 legged stool

I'm not really doing this justice in words. I've just learned this 3 leg analogy from corner balancing a lot of cars and watching how the weights and ride heights shift in relation to changes corner to corner.


So in your case, with the driver side listing, with the car being lower in the front, I'd focus on bringing the driver front corner UP. That will move some weight to the passenger side and also will move some weight to passenger rear. However, you will get more weight transferred to the passenger side front (and lower ride height on pass side) with less of it going rearward to passenger rear.

If that doesn't do it alone, you might need to drop the passenger rear shock one detent. At that point, I wouldn't be surprised if you find the driver front too high, and then need to lower the driver front.

Interesting discussion

Side question: In the OP, there was a comment about the front suspension being an SC and the rear springs being 100lbs. Does the SC includes the SC A-arm and torsion bars? If so, aren't these stiffer than 914 ones? Is the 100lbs (~stock 914) in the back a good combo with front SC torsion bars?

I only know that the setup is SC for the front end from a brakes and 5 lug standpoint. I do not know if the A arms were reused from the 914. Does anyone know the characteristics to determine the A arms are different between 914 and 911?

People place Jacks under the donuts and bend them. Measure from the pivot bolt for the rear suspension and the bolts for the aft side of the front rack mount with the car on a level surface. Least likely to have been damaged over the years.

Did this on mine, measured from the tube on the rear suspension arm, and where the front a-arms bolt to the body.

I should have put weight in the car when I set the height.

I will next time.

There's some conflicting ideas that seem to be going back and forth here. You can either set the corner heights perfectly to your liking, or you can have a shop put your car on scales and balance the weight at each corner to optimize handling.

The compromise you have is that that the stock rear perches - unless you use shims to raise or lower the perch - cannot be finely tuned. Therefore, the shop will use the height adjusters in the front to balance the weight as best possible between the 4 wheels. You will end up having slightly different ride heights at each wheel.

You can tell if you have 911 a arms if by the torsion bar spline count - I don't recall the number difference, but you can't interchange them.

Sounds like this is a new setup, and you haven't really tried any of it out. If I were you, I would set right height, get an alignment only (or do your own), and drive the car to see how it handles. If you autocross or drive hard, take notes on what you like or don't like about it.

I would suspect with a sway (stock or aftermarket?) and the 911 front end (depending on size of tbars), you might get some unwanted understeer. You can play with the sway bar and see if you can tune it out, but you might need stiffer springs (like 165 progressives ) for the rear.

Regardless, I wouldn't spend the time/money on a corner balance until you know you dont have to make any big adjustments to springs/tbars.

I measure from the bottom of the longs (assuming they were never deformed by impact or some PO using a floor jack in the wrong place).

To determine if one end is affecting the other jack the car up at its centerline one end
at a time.
Do this on level ground and measure UP to a solid feature on the chassis.
To do this remove the front steering pan.
Measure and mark the center of the crossmember tube.
Lift the front of the car with a narrow piece of wood on the jack pad directly under the
center of the tube.Make sure the wood lifts only on the tube.
The front wheels only have to clear the ground.
The rear height difference can now be measured.
To check the front, lift with a narrow piece of wood across the rear rib of the
transmission. The rear wheels only have to clear the ground.
I've done this many times it does not damage trans mounts.
The front difference can now be measured.
Rake is measured with a level on the door sill.
Nose lower is WAY better

Go to Translog in York. He is the guy for getting good alignment done. And he will set it for your driving style. General road/AX/Track etc.

There are several shops that won't even try on older cars.

We live in an area with choices. If Tony is too busy, you can always call Steve at Aircooled Racing. And if he's too busy he will have more suggestions for you.
Zach

Thanks Zach, York is only about an 1.5 hrs away. I forgot about Steve, he would be better if he does balancing.

Thanks Rory, I'll check that out as well

no comments on the title of the thread ?
Who sang 'Come on Eileen' ?

What do you call a girl with one leg shorter than the other?

Ilene.

I am a retired Prosthetist. Old prosthetic joke.