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> Calling on all Engineers: Better way to raise/lower rear of the car?
SirAndy
post Apr 19 2008, 07:07 PM
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here's what i have:

- yellow konis with threaded collars and adjustable perches ...

here's the problem:

- while i had the car on scales today, i tried to finetune the rear height to corner balance the car.

ideally, i would like to do this with the car on the ground (scales) but the weight of the car prevents me from turning the perches.
i had to jack up the rear, turn the perch, lower the car, roll it off the scale, back on the scale, measure and start over. (IMG:style_emoticons/default/headbang.gif)

what a royal pain in the ass! (IMG:style_emoticons/default/barf.gif)

and yes, i did use the "monkey wrench" that fits in the recess of the perch ...
there's no way that thing will turn the perch while it's loaded with the weight of the car! (IMG:style_emoticons/default/bs.gif)


this really sucks! anybody got any bright ideas on how to make this easier ???
(IMG:style_emoticons/default/idea.gif) Andy

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r_towle
post Apr 19 2008, 08:11 PM
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A better nut setup that will allow you to use an impact wrench somehow...or a long pipe on a wrench...but the nut needs more meat to grab so you wont slip.

Seems the Nascar guys do this on the fly...
Look at those types of systems.
Rich
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charliew
post Apr 19 2008, 08:14 PM
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Can't you just jack the car up on the scales to where the weight is off enough to turn the nuts? You might try some silicon spray lubricant also.

Charliew
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Spoke
post Apr 19 2008, 08:18 PM
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I think nascar uses spring rubbers to change stiffness (and height to a degree) although the car is on jacks. They have a ratchet access in the rear window for what I think is a track bar (sway bar).
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swl
post Apr 19 2008, 08:52 PM
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deleted dumb idea
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SirAndy
post Apr 19 2008, 09:14 PM
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it's just that the front is so much easier ...

11 mm nut and ratchet and up and down she goes.

i lubed the threads, didn't help. problem is, with the car down and on the scales, there's barely any room to get the wrench on the perch anyways, let alone room for any sort of leverage.

and to make things even worse, the threaded part rotates on the shock!
(IMG:style_emoticons/default/dry.gif) Andy
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SirAndy
post Apr 19 2008, 09:16 PM
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QUOTE(charliew @ Apr 19 2008, 06:14 PM) *

Can't you just jack the car up on the scales to where the weight is off enough to turn the nuts? You might try some silicon spray lubricant also.


problem is, once you unload the suspension, you have to roll the car to get it to settle again ...

(IMG:style_emoticons/default/headbang.gif) Andy
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Joe Bob
post Apr 19 2008, 09:24 PM
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yeah...it's a pisser. Same problem on my 911 and I have easily adjustable (Sway Away) torsion bars on the rear. I've never seen any shop NOT have to roll the car to settle it out.

I know a guy who tried doing it on a rolling smog dyno and he took just as long....MAYBE saved a few minutes....
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Borderline
post Apr 19 2008, 10:08 PM
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those yellow swing arms would look good on my car!
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RJMII
post Apr 19 2008, 10:16 PM
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could you use a spring compressor, and some sort of stop that would rest the weight of the car elsewhere while you adjust a little?

This would unload the tension on the height adjuster nut, the car would settle a little to find the stop, then when the tension was reapplied, it would go up, instead of having to settle...
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RJMII
post Apr 19 2008, 10:18 PM
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QUOTE(Borderline @ Apr 19 2008, 10:08 PM) *

those yellow swing arms would look good on my car!

I think black would look better. That way you'd have some contrast rather than blending all of the parts together with one color.
They really are a nice color of yellow, though. They match the Koni's quite well.


Andy, where'd you find the paint to match the shocks? I have the same shocks and want to paint stuff to match.
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J P Stein
post Apr 19 2008, 10:35 PM
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Humm.....No problem turning the perches with weight on the tire here.

I used grease on the threads tho. Just stick a drift in one of the holes & push/pull. Gotta back off the locking allen screw first, of course. There is a rubber bumper in the hole that actually sets up against the threads to protect them from the allen screw. My perches are a bit different than yours.
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SirAndy
post Apr 20 2008, 12:24 AM
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QUOTE(J P Stein @ Apr 19 2008, 08:35 PM) *

Gotta back off the locking allen screw first, of course.


Ya'think? (IMG:style_emoticons/default/shades.gif)


tried the luby thing, didn't help ... maybe my car is just too heavy ...
(IMG:style_emoticons/default/rolleyes.gif) Andy
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effutuo101
post Apr 20 2008, 12:33 AM
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Why don't you put jack stands under all 4 corners. Then you could adjust the suspension without having to roll the car off the scales. You have seen those niffty little wheel stands that bolt onto the studs at car shows.
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PeeGreen 914
post Apr 20 2008, 02:06 AM
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They make wrenches for this sort of thing. They go onto the groove in the collar to move it. I haven't had a problem using them.
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byndbad914
post Apr 20 2008, 02:59 AM
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Andy, search around the net and I think you could find the large diameter needle bearing rollers that are out there. They go between the spring and the perch; you have a nice roller to remove the friction. I know they exist, but don't know where to specifically buy them or what size springs you have. McMaster-Carr probably has something too with the right ID to match your spring size.

Needle bearings can handle a lot of load without crushing. I bet you may need some sort of race (think hard steel shim) on the alum perch to keep from digging in.
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messix
post Apr 20 2008, 03:12 AM
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QUOTE(Spoke @ Apr 19 2008, 07:18 PM) *

I think nascar uses spring rubbers to change stiffness (and height to a degree) although the car is on jacks. They have a ratchet access in the rear window for what I think is a track bar (sway bar).

nascar uses spring rubbers to change the effective spring rate, not ride hight, corner weight is effectively changed from the change in spring rate, and this is done on the front only.

the rear uses jack screws to alter the spring to body mount position.

and nascar does not use coil overs.
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McMark
post Apr 20 2008, 03:27 AM
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The bearings are a great idea. They're called Thrust bearings and McMaster has them in large sizes, but I'm not sure of the dimensions so you'll have to look at it yourself.
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byndbad914
post Apr 20 2008, 03:38 AM
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QUOTE(McMark @ Apr 20 2008, 01:27 AM) *

The bearings are a great idea. They're called Thrust bearings and McMaster has them in large sizes, but I'm not sure of the dimensions so you'll have to look at it yourself.

thanks Mark... it is 2:30AM here, I am about half crocked off pear flavored Vodka (yes I drink girlie drinks but am all man otherwise (IMG:style_emoticons/default/blink.gif) ) and could NOT remember what they were called (IMG:style_emoticons/default/laugh.gif) Used 'em all the time is Chevies for thrust bearings, you'd think I would remember the name. You put a race between the block and bearing, then the bearing rode against a 2nd race against the cam drive. In this case, I suspect you would only need a race against the soft alum, but get a pair to be safe.
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J P Stein
post Apr 20 2008, 07:31 AM
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QUOTE(SirAndy @ Apr 19 2008, 08:14 PM) *


and to make things even worse, the threaded part rotates on the shock!
(IMG:style_emoticons/default/dry.gif) Andy


If that is the case (and the same thing happens to me, I just reach up & hold the "threaded part") friction at the spring/collar is not the problem.
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