Club Cobra - Kirk! We're under attack!! Suspension help.

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- - Kirk! We're under attack!! Suspension help. (http://www.clubcobra.com/forums/classic-roadsters-ii/137021-kirk-were-under-attack-suspension-help.html)

Just to correct above, I have the toe in measurements front and rear reversed. The front is 50 7/8 and the rear is 50 15/16, this is the +-1/16 toe IN.

Didn't want someone to catch the way I wrote it up actually being toe OUT.

My ooops.

Quote:

Originally Posted by cycleguy55 (Post 1404472)

In no way was I suggesting "simple" also means "easy" - sometimes it's far from easy to find and fix.

I found the upper half of my rear main seal installed backwards and, to continue the theme, the side pipe muffler inserts were installed in opposite directions (one with the louvers facing forward, the other facing back). The emergency flasher wiring was cut off under the dash and the brake lights were wired so they'd only work when the ignition was on. The gas tank was installed without a vent to the filler tube and was not only slow to fill but a b**ch to do so without spilling gasoline all over the bodywork. Oh, I almost forgot - the rollover check valve on the tank was installed backwards.

Okay now I feel better, lol.

You know the thing that really sticks in my craw is that I could have done most if not all of this myself. Having a commercial general contracting business and three little kiddos and of course my wonderful wife, time is short so I entrusted these guys to speed things up.

What I got was a helacious bill wich I disputed and a good 5 weeks of lost drive time.

Live and learn I suppose.

Quote:

Originally Posted by rbgray1 (Post 1404493)

Redhawk,

Just getting ready to weld in my supports for my new Heidts front upper and lower A-Arms for coil overs.

I decided to ditch the strut bars and go with full lower A-Arms.

Anyway, I took numerous measurements with the stock Ford Arms and Strut rods and then mocked up the new Heidts arms. Since the Heidt arms use 5/8 inch bolts and the factory uses 1/2 in bolts for the lower arms, I used a 12 in long piece of threaded rod to temporarily attach and make all the necessary measurements with the new Heidts arms.

Long and the short of it, even though the new Heidts arms are straight at the ball joint while the factory Ford arms angle up about 7 degrees at the upper and lower ball joints, the actual spindle face measurements are EXACTLY correct to the stock Ford stamped arms. I even kept my tie rod settings EXACTLY the way they were with the stock Ford arms and the spindle tracking (toe-in) is exactly the same from factory to Heidts.

I have two sheets of measurements from the before and after measurements, please let me know if you would like me to forward them to you so you can measure yourself or have a shop do it.

I measured the following before and after, these are critical:

Front of Spindle face at spindle center side to side (Ford 50 15/16", Heidts 50 15/16")
Rear of Spindle face at spindle center side to side (Ford 50 7/8", Heidts 50 7/8")
(This is basically Toe-In as the spindle face aligns with the wheels/tires) Above is approximately 1/16+ of toe in at the rim.

Rear axle center to spindle center (measured at the face/base of the spindle where the spindle meets the "flat" portion) (Ford 94 7/16, Heidts 94 1/2") the 1/16 difference may be due to the upper arm in a very slight different position than the Ford OEM or just a variance in tram measurements. This is close enough and can be adjusted during alignment with the position of the upper arms on the T bolts.

Length from rear side pipe hole on the frame to spindle face center (similar to above, just an additional point) (Ford 77 1/4", Heidts 77 1/4")

Diagonal length from side pipe mount to opposite spindle center. (Ford 92 3/8", Heidts 92 1/2") 1/8 difference same as above, definitely within adjustment range) This measurement is critical and should be EXACTLY the same to ensure the car doesn't "dog track", meaning the tires do not track in the same horizontal plane when driving. Another way to spot this is to wet a portion of the road near your house and slowly drive from a wet road to dry surface with the steering wheel straight. If correct, the tire patches should have even overlap when you look at the wet tire contact patch on the street, however this is a rough measurement only.

Side to side face of spindle center to face of spindle center. Ford 50 29/32 +/- 1/32, Heidts 50 29/32 +/- 1/32) exactly the same.

Side to side Spindle Tie Rod hole to spindle tie rod hole. (Ford 47 7/8", Heidts 47 7/8") This measurement was done AFTER spindle faces on both sides were set to 1/16"+ toe in again)

A couple of questions/ suggestions to check:

1. I'm supporting/welding the new Heidts Lower A-Arms in different method than what your shop did. The Heidts lower arms require that you drill out the lower a-arms holes to 5/8 of an inch, weld on support tubes and gusset appropriately. I'm not sure how the previous shop would screw this up, but you may want to check if this was done "off center" from the factory holes. I can provide this measurement (from lower a-arm attachment bolt side to side, front of A-Arm and rear of A-Arm) to you if you need it, it will just be a few hours before I can measure this on my car.

2. Check your measurement from tie rod end to tie rod end. This can be done with a tape measure fairly easily. Measure at the top of the spindle tie rod knuckle where the tie rod attaches to the spindle arm. Most accurate is on the top of the steering knuckle right where the tie rod comes out of the knuckle from the bottom at the tie rod nut. This should be close(+/- 1/4") to 47 7/8" from center of tie rod ball joint to center of tie rod ball joint!!!!

3. Did your shop make any alterations to the front of each Spring/Perch tower? If not, take a very close look at this! The new Heidts Lower arms will contact the front of each spring tower, just above where the boot of the steering rack is during suspension travel. If there is any contact from the lower a-arm with the spring tower during fully compressed suspension travel, this is very dangerous! I'm personally going to cut a 1.5" slit in the front of the angled portion of the spring tower, bend the 1/8" steel inward to provide clearance and the re-weld the tower. If you shop simply beat this area in with a hammer, the strength of the steel may have changed your lower geometry, doubtful, but something to check anyway. Take a look at the front portion of your spring towers and see if this area looks like it was beat on with a BFH.

I wish you the best of luck and please let me know if you need any additional measurements or photos.

BTW, my car is a CR1 and based on your car if it is a CR2, some of the measurements may be different because I understand that Don Scott made some modifications to the frames from the original CR1.

Holy smokes Rbgray1 you are dialed in! I have a lot to do to go through your check list. I have a busy week, but will try and take measurments as you suggest and will take pictures too and post.

Thanks!

I thought I would post a video from one of the the last times I was at the SHOP that did the stellar work on my car.
http://viralgifs.com/wp-content/uplo...ver.gif?fb43fe

Redhawk,

See the picture below, this is where the Heidts lower A-Arms will contact the Spring Perch/Tower. This MUST be addressed as it is within the travel length of the shock. At full suspension travel, the lower A-Arm must be able to travel up an additional 1.75 to 2" from this position.

Redhawk,

Thought you might like to see the result of the work on the rear suspension on the CR1.

Just need to re-install brake lines and new wilwood e-brake cables.

If anyone is interested, these are the brackets (see picture) that I had made for the rear coil over mounts. I took these templates to a local metal fab shop and had two of each made (one set for each side) from 3/16 CRS. The longer bracket is for the upper mount and the shorter is for welding onto the rear axle bracket. My local steel fab shop charged me 25 bucks for all 4 and they did it in 1 day. I would recommend to not bend these yourself using heat as heating CRS changes the molecular makeup of the steel and makes it harder/more brittle, not a good thing on a critical suspension component.

The reason for the upper and lower length differential is to provide for clearance of the coil over and to maintain factory shock angles.

I also welded each of these brackets completely to the upper frame and lower rear axle area making careful measurements for placement, this keeps the rear geometry the same as stock. As well as welding them in, I also gusseted each bracket on the top or bottom and the upper frame mount in two places with 3/16 CRS plate (side and top, see pictures) to provide additional strength. Bolts would probably work, I just feel better knowing these are welded in solidly and constructed from 3/16 CRS, and rock solid. You may not need to gusset the frame, I just think this adds a lot of strength and will make me more comfortable on hard launches or at 100mph.

Thank's Rob, for posting these pictures, as per our conversation last night I believe this is the correct way to go with mine before the body is bolted down. As always thanks for your help buddy.

Quote:

Originally Posted by Alfa02 (Post 1404614)

Thank's Rob, for posting these pictures, as per our conversation last night I believe this is the correct way to go with mine before the body is bolted down. As always thanks for your help buddy.

Thanks Tom.

One thing I forgot to mention, when you weld on the strap or gusset on the lower shock mount, leave a small gap near the base (about 1/4"). This is due to the angle of the lower mount and the gap will allow water to drain out of the lower mount and not collect in the bracket causing premature corrosion. See the picture from the ground up of the lower mount, I know it's hard to see clearly.

Here are some pics of new A-arms and tower fabrication.

Redhawk,
Can you take a close up photo of the front mount of the lower a arm and the rear of the lower a arm?

You also just confirmed the upper shock mount issue for me.

Lower control arm braket and rear brake setup

Rbgray1 also look at rear brake. Does this look right? I remember you mentioning all the different set ups for wilwood.

Redhawk,

The rear rotors are missing the center rotor indexing bushing. This is an aluminum bushing that slips on the axle before the rotor is slipped on. This bushing centers the rotor on the axle helping to reduce/eliminate runout while braking, otherwise only the threads of your lugnuts are controling runout. Runout during braking may create a chatter effect during hard braking. Take a look at your rear brake kit instructions, if you don't have the instructions I can forward you a scanned copy. You'll see these on the top of page 2 of the instructions. One size came with the kit for the most common Ford Axles. I had to order a set from Wilwood as my axles were not the most common size. They only take 2 mins to install and I would definitely order or install the correct ones. Take a close look at the picture I posted previously of the side shot of my Wilwood install. The silver ring around the center of the axle at the rotor is the aluminum rotor indexing bushing.

Also, not sure why your toe-in is wrong, but looking at your previous pics I can see you are way in on the tie rod threads. I have over 1.25 inches left on each side of mine.

Difficult to tell from the pictures, are there 2 sleeves welded on that the A-Arm 5/8 bolt runs through?

Make sure these support sleeves that came from heidts with the lower arms are there. The sleeves are installed to put the arms in lateral compression (squeezing in from side to side). The rear bracket they made and installed is great, however only limits the a-arm lateral spread, not compression.

Take a look at the center of the crossmember where the A-Arm bolt runs through, is there a sleeve (about 1" diameter) welded in between the crossmember?

The heidts arms come with 2 sleeves for each arm, a shorter one that gets welded between the crossmember mounting and a longer sleeve that is welded on between the rear of the crossmember and the rear mounting point. These are important as they provide for constant compression of the lower a-arm and keep the mounting points stable.

Without these sleeves the rear bracket they installed only limits outward travel of the A-Arm pivot points and does not limit or provide for inward compression of the bushings. Also, these sleeves place the bushings in compression making the A-arm more stable.

I'll send pictures later today.

Quote:

Originally Posted by rbgray1 (Post 1404804)

The picture of the rear rotor was at their shop so until I pull wheel off which I will do not entirely sure if they did it right. Something tells me they probably didnt.

Also I need to see pictures of the sleeves your talking about because although I think I understand what your saying Im not 100% clear.
Can you tell me more about negative effects of not having sleeves as you have mentioned. Safety etc...? Should I be driving this car?
Thanks! You have been a huge help. Love your garage too with vette hiding in the background.

Quote:

Originally Posted by rbgray1 (Post 1404608)

Redhawk,

Thought you might like to see the result of the work on the rear suspension on the CR1.

Just need to re-install brake lines and new wilwood e-brake cables.

Rear suspension looks nice!

You should consider installing a Panhard bar on the rear end while you have the body off. That addition made quite a bit of difference on my car.

Joel,

Does a 4 trailing arm setup benefit from a panhard bar?

Can you send me a pic of your setup? Would be very easy at this point.....just not sure Panhards and 4 trailing links go together.

I do know you want the panhard as long as absolutely possible, to create the largest arc possible.

Quote:

Originally Posted by rbgray1 (Post 1404875)

The biggest problem with a Panhard bar is the axle will move in a slight arc - with the arc being reduced through as long a Panhard bar as possible. While there is certainly some compliance in the bushings of a 4-link rear suspension, this is not ideal.

You may want to look at a Watt's linkage ( https://en.wikipedia.org/wiki/Watt%27s_linkage ) - you get the lateral location benefits of a Panhard bar but the axle remains centred. While there is still some lateral motion, it is significantly less than a Panhard rod would produce.

A very thorough assessment of suspension including 4 link suspension and Watt's linkage. It touches briefly on Panhard rods but discards that design due to the issues of arc travel of the axle. https://eprints.usq.edu.au/3971/1/Parkin_2007.pdf

So it may be time to end this thread

Decided to take the car for some auto cross fun even though car isn't ideal yet. A lot of work has gone into getting car righted after getting back from the SHOP.

I wanted to test suspension and play around with dual adjustable shocks. First run was with everything at its stiffest setting. After crappy times and one high speed near corner washout I found a setting that got me times within 3 seconds of the fastest guys and gals out there running slicks.

On my last run I had throttle loss on take off but it came back on. I think it was my old vapor lock enemy, but not sure. Time to check fuel pressure among a whole bunch of other things.

It was a beautiful day in the rockies and car had no problems with hour trip to and back from road course.

Upward and Onward
RedHawk out
*poof*

Quote:

Originally Posted by rbgray1 (Post 1404875)

Does a 4 trailing arm setup benefit from a panhard bar?

That all depends on how the upper control arms are positioned.

If the upper arms are positioned parallel (or near parallel) to the lower arms, then a panhard bar will definitely help with lateral positioning in a solid rear axle car.

But, if the upper control arms are angled in, so that they converge near the center point of the rear axle (forming a triangle), then the control arms themselves serve to keep the axle located laterally, and a panhard bar would be redundant.

Given the angling of control arms on the CR1, the main lateral movement comes from control arm bushing displacement. If you have "solid" bushings, no or very little displacement. If you have rubber bushings, then there will be displacement under load. Under load is when you really don't want the displacement.

Is a Watts linkage better than a Panhard bar? Yes, but it's more complicated and thus likely more expensive.

Can a Panhard bar be setup to minimize the amount of arc? Yes, through length and setup. On mine, it's length it about that of the distance between the frame rails. For setup, it goes slightly downward from frame to rear end at normal ride height. So when the suspension compresses, the Panhard bar first goes to level and then to slightly upward. Given the amount of rear suspension travel on a CR1 (not a lot) and this setup, there's very little arc introduced by the Panhard bar. And besides, when you're cornering hard it's usually on a fairly flat surface, in other words not a surface with large undulations.

I didn't have a chance to jack up the car and take pictures over the weekend as I was busy welding new mufflers into the side pipes. Let me know if you really want some pictures and I'll try to find some time to take them.