Anti-Roll Bar

I managed to get around to fitting the front Anti-Roll bar to the car.  This includes two drop links fitted with Rod-Ends linked to a bar that goes across the chassis mounted with plastic mounts.

I screwed the rod ends into the supplied drop links with around 1-2 threads showing above the lock nut.

The anti-roll bar was fixed to the chassis using the supplied plastic mounts and 6mm high tensile bolts to rivnuts in the bottom of the chassis.  Note:  Ensure you use hex head bolts since you can't get an allen key in for the upper wishbone.

I jacked up the front of the car and allowed the wishbones to drop down at full droop.  The rod ends were then bolted to the anti-roll bar and wishbone as follows to permit the softest setting:

Anti-Roll Bar - Hole Furthest Out (Furthest from pivot point)

Lower Wishbone - Hole Nearest Centre of Car (Nearest to pivot point)

Once bolted together the car was lowered.  Job done!

Front Suspension

After I set the bump steer, I re-fitted the front shock absorbers and loosely bolted them up in position.  I still have to fully tighten the track rod ends.  I packed them with washers just to save the nylock nuts just in case I had to take them off again while checking the front toe.

Front Suspension Geometry

With the rear geometry finished, I started to the front.

I opted for the adjustable front wishbones which are connected to the chassis with front and rear rod ends.

I used a length of wood (planed straight) and two plumb bobs to project some lines down to the floor.  I drew a parallel line to the centre line so that I could ensure that the hubs were pointing directly ahead.  I then drew on two lines 20 degrees from the centre point to setup the caster.

I straightened the hubs and then measured the camber.  I made sure both rod ends were screwed out the same distance before starting.  I then screwed them in / out to suit.  I found out the following:

1 turn of the rod end alters the camber by 0.3 degrees.

I then used the following method to measure the caster using my digital camber gauge.

On the left hand side:

Rotate the hub to the left by 20 degrees using marks on the floor and the plumb bob.  Rotate the digital gauge to vertical.  The camber angle measurement is then noted (eg. +1.1)

Rotate the hub to the right by 20 degrees using marks on the floor.  Rotate the digital gauge to vertical and take the camber reading (eg. -1.86)

Since one of the readings is negative camber, and the other is positive then these numbers should be added together (ignoring the + & - signs - eg. 2.96

Since I used 20 degrees as the angle of rotation, this number needs to be multiplied by 1.5 to give the caster angle. (eg. 4.44)

Repeat the above for the right hand side.

I did have an instruction manual describing this in detail - I will attach it when I can find it again!

To adjust the caster, depending on which way it had to go, each rod end has to be screwed opposite to one another to maintain the camber angle.

This was a little more trial and error and I didn't seem to have an exact figure for 1 turn of movement.  Although roughly it seemed to be 1/2 turn on the rod end altered the caster by 0.3 degrees.

Once I connect up the steering arms then I can set the front toe.

The settings I aimed for at the front are:

Front toe: 5min toe in to 5 toe out to suit conditions and driving style.
Front camber: 0.75 to 1.5deg to suit track – check for even tyre temp.
Front caster: 4 to 4.5 deg neg to suit driver.

I need to think about how to set the bump steer.......

Rear Suspension Geometry

Apologies for not updating the blog as I go.  I have been steadily working away.

I was trying to get the geometry setup for the suspension as close to what it should be.  Once the car is on it's wheels and bedded in, I will take it to a garage and put in on laser alignment system.  I put in place some steel bars to simulate mid travel of the suspension.

I started off using my brother in-law's Bosch GLL-280 laser level.  I marked centre lines on the chassis, and drew a line on the floor using the laser as a guide.  I then drew two more lines perpendicular (front & rear) exactly 4m apart.  This would then allow me to use trigonometry to calculate the toe angle.  I then strapped the level onto the rear hub which I believed would be the best option to show the toe and camber.

After playing around a bit with moving the rose joints in and out, and the turnbuckle, I have worked out the following:

1 turn of the Upper Rod End (Rose Joint) alters the camber by 0.25 degrees.  It has no effect on the toe.

1 turn of the Lower Rod End alters the camber by 0.16 degrees.  Note: The turnbuckle needs to be rotated by 1/2 turn to maintain the toe angle.

I used the following specification for the rear setup:

Rear toe: 10min

Rear camber: 0.5 to 1.0 deg (to suit track)

I screwed the upper rod end fully in, and then out 2 complete turns which will allow for an alteration of 1 degree without having to alter the toe angle.  To alter the lower joint, the shock absorber has to be unbolted and is a little fiddly with washers etc.  I have seen a GD rear wishbone that had a separate shock mount, so I could maybe upgrade in the future if I regulary track the car and require frequent adjustment.  

I altered the lower rod end and turnbuckle to suit the specifications.  I used a digital camber gauge to measure the camber.  I also checked using the laser and trigonometry.

Once I was happy and within a nearness, I moved all the equipment to the other side.

I then transferred some of the measurements of wishbone length and turnbuckle length to mirror the setup.  When I switched on the laser I discovered that the setup was miles off!  I couldn't understand it.  I double checked measurements and almost came to the conclusion that the chassis was wrong.

I then carefully looked at the laser level.  Although the side is nice and flat and appears to be parallel to the laser, it is not.  The laser sits at a slight angle and over a 4 metre length was off quite a bit!  Also, the laser had to be mounted the opposite way around on the other side, so it was even further off.

Back to the drawing board.  I then used some string and a spirit level and re-adjusted the setup.  This took a bit of time since I had to do the adjustment, then plumb the level against the string at the rear of the car and measure from the centre line.  I then had to move to the front of the car to do the same.  I input the figures into an excel spreadsheet which automatically did the trigonometry calculation for me.

I finished both sides and then moved to the front.......

Suspension Setup

I spoke with Andy at GD and he said to set up the suspension it was best to move it into the midpoint position.  Andy said that the front shock length would be 11-11.5" and the rear would be 12-12.5" (roughly).  I had lengths of steel made up with a hole in each end to simulate this.

The front ones are 11.5" long and the rears are 12.25".

I have ordered a dual axis camber / castor gauge which will hopefully come in the next few days.  This will allow me to get the geometry relatively close to what it's supposed to be.

Front Suspension

I have managed to assemble the front suspension.  I opted for the rose jointed wishbones, as I felt I would prefer a more adjustable set-up to future proof the car.  Probably once set, they won't be adjusted again!

I had to get my dad to help put the spring on the shock since I couldn't quite manage to compress the spring.  I could have used spring compressors, but it just needed a little bit of persuasion.

A fairly straight forward install, however you have to make sure that the hub with the left hand thread nut (kindly marked by Andy at GD) is installed on the right hand side of the car.

The lower ball joints were pressed in using a hydraulic press, but I have no photos of that.

I am hoping to start installing the brake lines now that I have received my tube benders.  I have the rear callipers and discs, but I don't have the AP racing front brakes yet.  I have asked Andy for the aluminium mounting blocks for the callipers so at least it the hub assemblies can be fully bolted up for the moment.

Rear Suspension

I have loosely assembled both rear quarters now.  I will make up the brake pipes before putting in the diff and driveshafts.  I am waiting on my new tube benders before doing this, so I will be moving on to the front suspension.

Poly Bushes Fitted

Since the wishbones have been painted also, I started to assemble the suspension.  The polyurethane bushes were pressed into each wishbone using a G clamp to help - they weren't too tight though....

The stainless bush inserts had to be trimmed to fit my chassis.  This was done on a small Sealey lathe which did the trick.  They bushes started off at 38mm long, but I required approx 34.5mm long to fit.

Some of the wishbone lugs on the chassis had to be opened up using some threaded rod and a couple of nuts.  The holes also had to be cleared out to 1/2" to accept the high tensile bolts.

Once the bushes had been turned down, I pressed them in using the vice to give a helping hand.

Again they weren't stiff to go in.

I then loosely bolted the wishbones in place - I will properly tighten once on the ground.

I bought some rubber boots for the rose joints to see if this will help prolong their life.  I covered the ends in grease, and pulled the boots on.  The only one I didn't put on was the inner rod end on the rear turnbuckle since the covers have bits that stick out and the wishbone didn't really have enough clearance to get the cover on.  The boots were bought from McGill Motorsport - http://www.mcgillmotorsport.com/