G11 – Dealing with the Tiger’s Front Suspension

by Chuck Ingram in the November 2003 RootesReview

The Ackerman Problem

We have all heard and know about the Tiger’s front suspension. The original Alpine front suspension with a rear steering arm geometry was modified by simply turning the steering arms to the front without modifying the geometry. This means something was compromised in our Tigers and it was the Ackerman angles. Many have found this to be acceptable in a stock Tiger and I’m one of them. My stock ‘65 is just fine the way it was built. Saying that however does not go for my Spirit of Lister. (Ed. Note: See RootesReview December 2000 for an extended look at the Ingrams’ Sunbeam-Lister.)

Since the Tiger started life as a ‘64 Alpine, it had many modifications. I’m not sure how much is due to the extra weight or the conversion of the Alpine steering arms or what, but I am sure of one thing and that was the steering was not what I wanted. This brings me to what I have done to hopefully remedy all the problems.

I started by contacting Brian Norquist at MacGyvers, located in Lloydminster, Alberta. With a few phone calls and E-mail diagrams, we considered it possible to mount tubular A arms, to the Sunbeam crossmember. These A arms are available as aftermarket replacements for improving Mustang II suspensions. The similarity to the Sunbeam is quite remarkable.

The lower A arm bracket had one hole that bolted to the original Sunbeam lower A arm mounting and was welded solid to the crossmember. The upper arm was mounted by removing the Sunbeam shock tower and welding the Mustang shock tower in place. This also required some of the crossmember to be removed for spring clearance as the Mustang springs are fitted with a slight bend to them.

The rack was attached using the Mustang insulated mounts. This was accomplished by welding a 1/2” plate to the back of the front plate and then drilling and threading it to accept the bolts that hold a Mustang rack in place. As I mentioned, I did remove 1/2” from the back of the mounts and cut the Mustang insulator mounts 1/2” as well. This helped the clearance greatly and I do not think any strength in the mounting was lost.

Modifying The Cross-member

I started by stripping all the parts off the crossmember. An extra bottom plate was added and extended beyond the stock plate. Two pieces of 3/16” by 1.5” steel were then shaped and added to extend up to the spring openings. With a bit of grinding and lots of primer it was sent to MacGyvers. Brian, who owns Macgyvers, did all the initial work in design and adding the A arms to the crossmember. It was then shipped back to me. The springs, rotors and calipers were then added. Next it was on to mounting the Mustang rack and pinion.

The mounting took five attempts to get it to the point that I was happy with. Each attempt however was only slightly different than the first one. This was one of those times where I couldn’t cut without measuring and I couldn’t measure without cutting. I then boldly, and with more confidence than I should have, cut into the crossmember. Now at least, I had a reference point and I could measure and cut some more.

All modifications were done using 3/16” plate. I basically cut a fitted plate to extend to the back of the crossmember internally and it was welded solid. I must be getting better at this kind of stuff as I only burnt through 4 times. Internal bracing was added. Where the crossmember was cut at the top, I also added a 1.5” x 3/16” wide extra piece internally for strength. I did have to cut a bit into the internal bracing that I had added to allow some space where the mounting bolts for the Mustang rack would extend into the crossmember. This could have been avoided by double-checking before the bracing was welded in but it was a “do as you progress” job.

The front plate was then added with 3 extra gussets from the bottom plate to the faceplate. I did need to heat and bend the front plate to flow into the lines of the crossmember. This took a lot of welding, shaping and grinding but it looks good. It was necessary to add some protection where the new faceplate was dropped to accommodate the lower mounting position of the rack.

I cut and welded a 2” ID pipe in place for more strength. On the back of this I added a fairing to smooth the line. The Mustang rack was finally mounted but I didn’t like where it was sitting. I thought that another 1/2” closer would be better. This was accomplished by removing 1/2” of the inside of the rack’s mounting brackets and cutting of the insulating rubber to match. It definitely looks better now.

Hooking Up The Tie Rods

Now it’s time to hook up the tie rods to see where we are at and I suddenly encounter another problem. The Mustang steering arms have the tie rod ends mounting from the bottom. This is not good as the angles are too large. The solution was to have bushings made and drill the arm slightly undersize to receive them with an interference fit. To make sure that the hole would be exactly straight I made up a fixture that clamped to the steering arm. It took longer to get that right then drill the hole to size. I had to heat up the arm to accept bushing and insert. When it cooled, it was solid. The tie rods were attached with the use of a washer on the bottom of the tie rod just in case. Now things looked better.

It looks good on the stand and the Ackerman angles don’t look bad at all. This, of course, is with no weight on the suspension. The heavier sway bar was mounted by slightly changing the angle of the rod to match the angle of the Mustang A arms. This was mounted by using some very simple brackets.

I used my transmission adapter bolted to the big floor jack with an extra piece of steel bolted on to the adapter to be able to balance the unit. The adapter also has a tie down chain that helps a great deal. One must still move this around nice and easy. I dropped a small rod with a bend on one end down the front mounting holes to help make lining up the unit easy. At this point, I found a couple of problems. The first problem was that the mounting holes were off a bit. No problem. I remedied this by removing a minute amount from each hole.

I found a second problem. Although the narrowest measurement was the same as the original, the width of the A arms was not and therefore made the unit narrower by a small amount due to the angle of the A arm. This I did not consider, nor did Brian at the time. The frame needed to be massaged by removing some of the flange. I also had to make a good sized dimple. After welding the frame solid, it was still a very tight fit. Brian at MacGyvers thinks this can be overcome by modifying the upper A arm and/or the shock tower a bit more. This would need to be exact to keep everything in line.

Adapting the Brakes

Next the brake hoses presented a problem. I could find a banjo-type of mounting brake hose but not a proper bolt to attach the hose to the caliper. I solved this by using a brass T fitting and a plug. It took a bit of fooling around to get the opening tight and facing exactly where I wanted it. Also the brake hoses do not mount in the bracket as the Sunbeam brake hoses do but use a clip through a groove. I drilled the mounting hole large enough to have the Mustang hose fit the bracket and made up some clips that are pressure tight. These are then held in place with a retaining screw.

After the wheels were installed and the weight of the car was on the suspension, another problem showed up. The front end was now too high. I thought I could cut the coil without removing it but there was no way I wanted to remove the Mustang spring to do this.

Now I’m expert at something. I’ve removed the front wheels quite a few times so I’m rather fast at it. I then removed the shock and compressed the spring. A couple of metal shields isolated the rest of the coil and other parts so I could cut one full coil. I may need to cut a bit more but I was being cautious. The coils should settle about 1/2 inch after they are worked a bit. I hope that is a correct assumption. The horizontal angle of the tie rods are now close to what I think they should be. This is more or less in a straight line.

Now that the suspension was mounted it was only necessary to hook up the steering wheel shaft to the rack. I already had ordered the longer shaft to fit from the one universal to the other. By the way, all U-joints for the steering shaft are Borgenseon. I couldn’t believe how exact this was, as I only guessed at the length before I even started on this project.

The next easy step was to bleed the brakes using that “one-person” system. After numerous attempts and still seeming to have air, I went to the “two-person” system. Out comes my wife, the second person, and she pumps the pedal. Hey the pressure is getting better. Only one more wheel and she howls that the pedal went straight to the floor. The brake light switch was leaking through the leads and boy, did the reservoir empty fast. I guess it was sucking air in but didn’t leak without any real pressure.

After I fixed the switch I did indeed find out that it was my fault. I had somehow mounted the calipers wrong. The left was on the right and the right on the left. They were almost identical but they left room for a bit of air at the top of the caliper. I guess I’m entitled to one mistake.

Alignment and Test Drive

Now it’s time to put the wheels back on and put the weight on the front end. The front wheels were lined up to the rear using a laser level and measuring tape. This worked quite well other than using up a lot of duct tape to hold the level on the wheel. The next step was to adjust the camber and toe in. Camber as it sits right now is as close as I could get it to 0 degrees. This was done using a level and a level car. After that it was easy to set toe in at 1/8”.

I drove the car twice [90 feet] on my driveway and I was impressed. It was like I added power steering. It was quick and responsive. I can turn the wheels with one hand at a standstill. The plowing effect is no longer noticeable. The braking distance should be shorter as the brake pads have about 1.5 times more area than the Sunbeam and the disks are vented. Now the car is on the floor and if it settles 1/2”, the height will be perfect. It is good right now and the car is slightly lower at the front than the rear.