Aligning the suspension. How accurate?

[lal Naja]

I'm the final stages of setting up the suspension and I've set the car up on a perfectly level work surface. Frame has 5 1/2" ground clearance all around.

Wheel Camber on all four wheels is dead on.

Wheel Base measurement on the left is exactly the same as the right, exactly!. But the diagonal measurement for the four measuring points are off 1/4". So the four points make a parallelogram not a perfect rectangle. I Plan on finding out where the misalignment is and correcting it.

What have you guys found to be an acceptable tolerance?

This is my first Cobra build and I want it to ride and go where it's pointed. So all advice is respected and welcome.

Thanks,

Arthur

I just edited the above. I typed track Instead of whee base. Oops!

[mickmate]

Hey Arthur you're pretty darn close. Remember if you're getting 1/4 on the diagonals that's actually only 1/8th as you split the difference. That seems a little high for the ground clearance, most I've seen run lower on the front end. Is the wheelbase good on both sides?

[Excaliber]

Generally speaking you do want a bit of a "rack", lower in the front, higher in the rear. BUT, the Butlers are not your typical replica so the basic rules may not apply to them.

[SoTxButler]

Arthur,

My car is 1" lower...4.5 all around on level ground.

Russ

[lal Naja]

Originally Posted by mickmate

Hey Arthur you're pretty darn close. Remember if you're getting 1/4 on the diagonals that's actually only 1/8th as you split the difference. That seems a little high for the ground clearance, most I've seen run lower on the front end. Is the wheelbase good on both sides?

Is the wheel base good on both sides? Mick, I don't understand your question. Please explain further.

5 1/2" It may be a little high. My bell housing hangs almost an inch lower than the frame and I'm installing skid plates on the frame to prevent an impact on it. We have many speed bumps here in the city of Chicago. After I drive the car awhile, I may feel more comfortable lowering it if I've not made major contact. I've got needle thrust washers with custom machined thrust bushings on the coil-overs and that makes adjusting shocks/ride height a breeze.

Arthur

[mickmate]

Wheels pointing straight ahead measure centre to centre front to back on both sides. Most cars and the originals are 90" WB (wheelbase).

[lal Naja]

Originally Posted by Excaliber

Generally speaking you do want a bit of a "rack", lower in the front, higher in the rear. BUT, the Butlers are not your typical replica so the basic rules may not apply to them.

I think a rack gives it a good stance. My car may end up with one in time. But for now I'll test the 5 1/2" (4 1/2") at the bell housing & chassis skid plates. If I clear most road hazards I'll be free and clear to lower it.

Thanks for the comment.

http://www.photoshow.com/watch/Mc7rt2Mu

Arthur

[lal Naja]

Originally Posted by mickmate

Wheels pointing straight ahead measure centre to centre front to back on both sides. Most cars and the originals are 90" WB (wheelbase).

Yes Mick, Wheel base is perfect on both sides. I was having a senior moment and I typed track instead of wheel base in my opening statement. It is now corrected.

Arthur

[lal Naja]

Originally Posted by SoTxButler

Arthur,

My car is 1" lower...4.5 all around on level ground.

Russ

Russ I like 4.5" and I may end up there some day. Have you ever hit anything at that height. Sloping aprons to a driveway? Speed bumps, etc.

BTW how is the Fast Cars front suspension performing?

Arthur

[Excaliber]

5 1/2" is a good call for the street, speed bumps, parking lot ramps, man hole covers, yeah, it's a good call.

Have you cut the bottom off your bell housing? That is generally the lowest part of the car. I broke my trans mount from hitting speed bumps with the lower portion of the bell housing. Since I cut off an inch or so it makes a BIG difference!

[lal Naja]

Originally Posted by Excaliber

5 1/2" is a good call for the street, speed bumps, parking lot ramps, man hole covers, yeah, it's a good call.

Have you cut the bottom off your bell housing? That is generally the lowest part of the car. I broke my trans mount from hitting speed bumps with the lower portion of the bell housing. Since I cut off an inch or so it makes a BIG difference!

Good idea, I had not considered it before. It is a McLeod Steel unit and cutting off some of the bottom flange should not be a problem. I think I'll loose one bolting hole if I do.

I'll check this later today when I get to my shop.

Thanks,

Arthur

[Jerry Clayton]

Arthur

It is common practice to cut the bottom of those straight acroos the bottom--I try to leave just a little of the curve at the bottom and you can gain at least an inch

[Jerry Clayton]

Arthur

I may have a Lake wood From my old pro stocker here--if so I'll take a pic and email it to you

Jerry

[MaSnaka]

Cut the bell housing flange flat across the bottom as was already said, but still go over stuff slow.

John

[SoTxButler]

Arthur,

Haven't hit anything yet at 4.5". Of course I do take drive aprons, etc. at an angle.

The Fast Cars Suspension is beyond my expectations....I love it.

You are making great progress....lets get that car on the road soon.

[lal Naja]

It's been a while since I've tackled the alignment. I set up measuring strings. One string down the theoritical center of the frame. One for the IFS and one for the IRS to make sure front & rear suspension is at right-angles to the string and parallel to each other. And I have found the following:

1: Front suspension was off center 1/8" too far to the left. And a little askew, Right axle a little forward and left axle a little to the rear.

2: Rear suspension is a little Askew too. Right axle too far back, and left too forward and 1/4" off-center to the right.

I machined up some custom screws that screw into the grease nipple holes in the bottom of the Jag hubs and two into the grease ports front wishbones of the IFS. I can run sttrings from these and they give me a positive latching point for my tape measure.

I hope the JAG grease holes are an accurate mirror image. It seems like all indications show mine are very close.

[mdross1]

Never measured mine in the diagonal,but did get alignment specs from a long time Cobra racer,and also had the car scaled.Very important thing to do.The car handles like it's on rails!!

[mreid]

Definitely trim the bottom of the bellhousing. Gives you some piece of mind, plus your car will settle a bit as you drive it and you may find that without any adjustment you find yourself at 4 1/2" ride height over time.

[lal Naja]

Originally Posted by mreid

Definitely trim the bottom of the bellhousing. Gives you some piece of mind, plus your car will settle a bit as you drive it and you may find that without any adjustment you find yourself at 4 1/2" ride height over time.

I took a look at trimming the bell housing, but unfortunately, the bottom of the sump/oil pan is at the the same level. So trimming is out of the question, as the sump would then take the impact. That would be bad news as it will distort the seal area too.

I am installing sloping rubbing blocks to the frame. In an event where I bottom on something the frame/rubbing blocks will just glide over without impact to the sump. Providing the hump I'm going over is reasonable flat. LOL

Arthur

[lal Naja]

Finally done! Diagonal measurements are just under 1/16" longer on one side (Right back to left front) or shorter by 1/16" on the other side if if you prefer. Correcting this required more elongation of holes and I'm accepting this good-enough.

Have no idea how this compares with other Cobras or in cars in general.

At some point in time, I will have alignment checked on proper alignment equipment.

I trust that I will not have to make any changes to move anything, as IRS/IFS is dowel fit to the frame.

Arthur