Front suspension experimentation

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gregcon

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I found a good deal on a Wilwood disc kit for the 68 Valiant....so the trusty 9" drums had to go. While I had the car apart for that, I decided to also rebuild the front end as it was the all-original 55 year old pieces....still working well.

With all the talk about caster, I decided to make some upper arms to allow me to add more + caster. I wanted to stay with the small upper ball joints - because they are smaller and lighter - and I also used spherical bearings instead of bushings.

I think the 11/16" tie rods ends are unnecessary but they were half the price of the smaller originals so I used those and made some 7075 aluminum sleeves. The strut rods are pretty much a copy of the ones being sold by the aftermarket but I made my own as I think the aftermarket versions 'cheap out' by eliminating the tapered fit in the LCA.

The new UCA's allow me to go to about 6-1/2 degrees positive caster while still hitting 0 degrees camber. This also means that if I dial them back to 2-3 degrees positive caster, the cam bolts are positioned about midway which I think is better than having them maxed out.

For shocks, no one makes a good non-gas shock that I've found....I had the old Monroe Matics which still worked well but I also bought some Sachs gas-filled shocks to try.

So....I tried a bunch of different alignments with the camber at 1/2-3/4 degrees negative and the toe-in at 1/16".

1) I don't see a ton of difference in how the car drives as long as there is 'some' positive caster. Up at 6 degrees, you can feel the steering gets a bit harder, but I left the car at 3-1/4 degrees positive and everything seems OK. But it's not markedly different than 1 degree or even 1/2 degree.

2) The UCA uses spherical bearings that are Teflon lined....this probably adds some 'accuracy' to the suspension but hitting things like road reflectors is notably more noisy. The bearings are super-strong, over 50,000lbs load rating. But when you remove rubber from the suspension, it comes with a price. As for all guys who use polyurethane bushings (the worst of all IMO) for 'performance', all I can say is there's a reason Vipers and Corvettes come with rubber bushings.

3) The Wilwood discs are lot lighter than the 73+ factory discs but about the same weight as the 9" drums. I set them up properly, including bleeding until the pedal is rock hard. The pedal feel is less enjoyable than the drums, but I do like that I can do a hard stop from 60MPH without my hands on the steering wheel and the car will stop in a straight line and with more confidence.

4) The gas shocks work OK but raise the nose of the car by about 1/2" which I don't like....I want the torsion bars doing the suspension and the shocks doing the shock absorbing. I wish someone still made a good non-gas shock.

My final verdict is .... the stock suspension in good shape is pretty hard to improve upon for the average car. Maybe the mods I did (which seem to be "must do's" within the hobby are beneficial at the outer edges of competition but I don't drive like that and I doubt many do.

spherical bearing.jpg


UCA 2.jpg
 
Are you still using the 9" spindles?
I have lost two of those both on street driven 6-banger cars. In both cases it was the right side and both on slow-speed right handers, and off the brakes.
It's like they just went on vacation; snapped off at the spindle-nut and the wheel took off into traffic
I'll never use a 9" spindle again for anything other than wall-art.
Both were Barracudas one a 69 the other a 68
 
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Yes, the Wilwood kit is made for the 9" spindles. In 40+ years of driving these cars I have never seen one break. We used to off-road the old 65 Barracuda back before using trucks became popular....hit bunches of potholes, etc. Never had an issue. But now that you've said it....it'll probably break lol
 
That is excellent suspension work. I believe you are correct that the 6 positive is really only needed for high speed stability. Did you trim the control arm bushing bra kits on the frame for additional clearance? Do you have a lot of nice easy suspension travel? I would imagine so with the rod ends. Nice job.
 
Nice work! I didn't know the aftermarket strut rods were not tapered at the control arm mount, that's a bit dissapointing considering the price.
The gas shocks work OK but raise the nose of the car by about 1/2" which I don't like....I want the torsion bars doing the suspension and the shocks doing the shock absorbing. I wish someone still made a good non-gas shock.
What about Koni's? They are an oil shock with adjustable rebound.
 
Yes, the arms travel up/down very smoothly and easily....that's one reason I used them as I knew I would be doing a lot of alignments and with bushings it's sometimes tough to get good repeatability.

Yes, I had to trim the mount bracket a little....if someone is opposed to this, the arms can be made to exit the bushing area at 90 degrees which negates the need for trimming. I wanted to keep the bend in the front leg less severe so I did it this way. With the jig I made, there are a lot of options that can be produced.

I haven't looked at Koni's but they're out of budget anyway! I like to use 'daily driver' level parts when it comes to shocks.

yeah....the strut rods they sell don't have the taper where it fits the LCA, seems kinda cheap.

strut rods.jpg


uca jig.jpg
 
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