The ongoing quest for MORE caster, 71 Road Runner

I've had good luck getting my Charger to steer and handle the way that I like, so I took what I'd learned and tried to help out a friend with his 71 Road Runner.
He is the original owner and has made small changes over the years, but nothing too drastic. He wanted a firmer ride and more responsive steering so we added the following:

1.0 torsion bars replaced the stock .90 bars.
MP XHD Hemi leaf springs replaced the stock 5 leaf pack.
Welded in 3x3 frame connectors.
upper Control Arms with offset bushings installed to increase caster.
Fast ratio Idler and Pitman arms.

The car sits at what may be considered stock height. I didn't measure it but it looks about where I've seen others sit. 15x7 wheels, 235-60-15 tires. He had the car aligned today. I went along to tell the man that he didn't want the stock 1971 alignment specs, I had the following:
0 to 1/2 degree NEG camber
2-4 degrees POS caster
1/8" toe in.

The alignment guy couldn't even get close to anything except the toe #. Why? the car has never been wrecked. The parts are all stock except the bushings in the upper control arms. The car came with 14" rally wheels but that shouldn't make much difference. I didn't get a copy of the sheet but the numbers I recall were almost zero caster on the left, something like 0.2 and about 0.8 on the right with slight positive camber on both sides. What the heck??? wouldn't adding some NEG camber automatically get you more caster? There is more adjustment left in the alignment cams, I could see that.
The owner said the car feels twitchy. I know that Fast Ratio arms with overboosted steering will make a car feel a bit funny but the car felt okay to me. The steering wheel returns to center after a turn. My Charger has the same basic setup as this Road Runner but mine feels rock solid. I had mine aligned at a different place and was able to get 4+ degrees of caster on both sides along with .75 NEG camber.
The obvious suggestion might be to take the car to a different shop. My first suggestion months ago was to go to the guy that I use. I'm just curious to learn if I did something wrong or if I missed something.
The bushings in the Upper control arms were pressed in so that the front side bushings had the thin spot toward the engine. The rear bushings have the thin spots toward the fenders. It seems that this should have easily resulted in getting the numbers we asked for. It was aligned 9 months ago at the same shop after he replaced tie rod ends. At that time it still had the stock UCA bushings. The numbers were not much better than what we got today.
The owner is not interested in buying tubular A-Arms. If he was dying of thirst he wouldn't spend $10 on a bottle of water.
I'd appreciate any suggestions on what else to try. I'd like to not only help this guy, but others in the future. Thanks, Greg

after tire pressure is checked and ride height is set.The way I start out with a chrysler product when I align them is the rear cam is to the outside (that pushes the rear of the control arm torwards the engine, this gives it negative camber but positive caster, then I use the front cam to fine tune my adjustments. both sides need to have as equal readings as possible,so It doesn't pull, I usually set up the driver side with slightly more camber to correct road crown 0.1/0.2.difference. sound like you might not have the bushings in correctly?

That is what worries me. Every time I rebuild a front end or reassemble one for any reason, I always adjust the cams to max caster. The rear cam is set to pull the arm in toward the engine and the front cam is adjusted away from the engine. I might need to take another look at it.

'71 Ply B-body, U-Code...


I did the following when I went through the car...


Urethane front-end 'components'...

OEM 'hard parts'...

Gas shocks...

One leaf added per side to OEM spring pack(urethane bushings)...

OEM rear sway-bar...


Alignment specs are OEM...


HAD 255-60's on stock 15x7's(w/radials)for many moons...

A handful with manual steering...


235-60's up front now...

I can two-finger it comfortably with no problem...


Haven't touched the alignment specs in 20 years, and 20,000+ miles of driving...

This is one of the control arms that I was going to use. The owner saw a defect in the ball joint sleeve area so we didn't use this one. It is the right side. The other one I used had the bushings installed this same way. The left side has the bushings in just like this. Did I screw up?

If they are in wrong, I am confused because they seem right to me.

Logically, it seems that the cam bolt hole should me set toward the engine if you want more negative camber or toward the fender if you want positive camber. Doing the way shown was supposed to gain some negative camber while also increasing positive caster.

which arm are we looking at?
I think you have the offsets reversed if this is the driver's side upper arm. The forward bushing should be offset so the arrow points to the outside of the car with the rear opposite. Positive caster is the upper balljoint to the rear of the spindle centerline. With the bushings installed the way they appear here, I can understand how the shop was unable to dial in any positive caster. I might have a few extra bushings if you need them.

I would not be too concerned about getting max camber. Get the caster you want first and just get the camber to the most negative you can get (evenly) after. You can always shim the lower balljoint to add negative camber if needed.

I thought I wrote that this is the RIGHT side arm. This is actually from your car!

" You can always shim the lower balljoint to add negative camber if needed."

I forgot about that! Rick Ehrenberg used to sell those but I bet a pair of 1/8" thick washers would be just as effective.

http://www.firmfeel.com/articles/MAarticle2012apr.pdf

The bushings installed in the A-arm as shown are correct for the right/passenger side of the car.

But you should mirror the installation of the bushings when used on the left/driverside of the car.

Not all cars will be able to achieve the ideal numbers, just production line tolerances from 40 years ago.

To whit: I've done alignments on 3 69 Roadrunners 2 stone stock and my own with offset bushings. The one stocker could only reach 2 degrees caster with camber approaching 1 deg positive. The other could barely get 1 degree caster. Mine I could get to 2.5 caster with 0 camber. All 3 had fresh front ends and nothing wonky about the cam placements to indicate accident damage.

Mopar was basically plus or minus a quater inch when assemnling the chassis.

Thinking outside the box here but why couldn't an adjustable or slightly shorter strut rod be utilized?
I noticed with mine when I rolled it around the shop without the strut rods on it that the lower control arm moves a small amount front to back. Its set up on a rubber pivot at the bushing so if it was forward a small amount it would help and not hurt anything else.

This was used years ago on the RF of a dirt car to achieve large amounts of positive caster in the RF only without noticeable suspension modification. There's no reason why smaller increments on both sides wouldn't achieve what your trying to do.

The adjustments works in this manor. look at how the cams are set and determine if there is more adjustment left, a different alignment shop might be in order.

the control arm in at the rear (to engine)will give you negative camber, positive caster.
control arm out in the rear (away from engine)will give you positive camber,negative caster.
control arm in at the front (to engine) will be negative camber and negative caster.
control arm out in the front (away from engine( will be positive camber,positive caster.

I have done a number of early B body cars and the offset bushings never got me much of anything. On a 62-3 you are lucky if you can get a true 1.5 degree of castor, offset bushings or no (and this is on 4 different cars). Most of these cars were 1 degree or slightly less. If you really want castor you have to go to some rod end upper control arms. I got a pair from CA somewhere and immediately got 5.5 degrees castor for a 62 Dodge I raced at Barona. Good luck with this, its a common problem.

My convertible had the same alignment results, and I had the Firmfeel tubular uppers, which tilts the upper control arm towards the rear of the car.

It wasn't until I installed the Hotchkis adjustable strut rods that I was able to finally obtain increased positive caster. I was careful to adjust them shorter than stock strut rods, so that there was no binding of the lower control arm movement throughout the entire arc of travel(torsion bar removed).

This essentially pulls the lower control arm slightly forward of the stock position. The effect is that the suspension is set-up more like a chopper and less like the front wheel of a shopping cart that twitches back and forth while traveling forward. I'm thinking that by cutting the shoulder on the stock strut rods a very small amount on a lathe, one could achieve the same result.

Now, my car no longer feels twitchy. It feels stable and planted. I can let go of the wheel on the highway and it wants to track straight down the road. It does make the car much more enjoyable to drive, especially on longer road trips.

Thanks guys!

The camber shims are still available. Mancini has them and so does Firm Feel.

"The camber shims are still available. Mancini has them and so does Firm Feel."



http://www.manciniracing.com/caspki.html

They show that these will add 2 degrees of NEG camber. Since the rear cams are currently all the way to the inside, there is the ability to move them out to reduce the NEG camber. If the front cams are at the other end of their range, these shims may only address half of the problem since any outward adjustment of the rear cam results in less caster.
Maybe the tubular A arms are the only fix.

Thanks again for that. I do have the bushings installed that way. Now it appears that the problem exists either due to an UNqualified alignment guy or because the car was built at the far end of tolerances.

Trust your alignment guy, why would he lie. Its the way the cars are made.

I don't think that he would lie, just that he might not be qualified. The addition of the offset bushings resulted in less than 1 degree of caster? Really? My 70 Charger is a shade under 5 degrees with essentially the same parts. I understand production line variances but that seems excessive.
The owner drives the car sparingly since buying a Challenger R/T in 2012. He may not care a whole bunch. I'm just curious about this because I've had much better luck with other cars.

A thought about production line tolerances: perhaps it has as much to do with the plant that assembled the unibody? Maybe some had jigs that allowed more performance oriented alignments?

And my thoughts on alignment specs here: for street driving, caster is far more important than camber. The reality is that youre more likely to notice the self centering afforded by caster than the extra grip from the camber. Racing is a different story, especially autocross.

To those that have a hard time achieving caster, is the rear ride height boosted over stock? Changing the angle of the car will affect caster, a lower rear ride height will improve caster.

Has anyone ever done away with the cams and lengthened the slots to allow more adjustment? The cams are strictly to ease adjustment, once the bolts are torqued they dont do squat.

Let me re-state my original post above, that is, I have never got more than another .5 degree castor with offset bushings. That's on 4 cars, two mine, two not. I do my own alignments and have done this for friends also. Cars with .5 degree castor seem to drive and ride fine, but we'd like more. If you actually have 5 degrees of castor from factory, that would be extraordinary, but of course entirely possible.

On the aftermarket upper arms I bought, without modification, max castor I could get was 5.5 degrees. That is, one rod arm out as far as safe, the other all the way in. AND, driving around on the street, although not much, you couldn't tell the difference from before. I would do about 95 in the 1/8 mile, and this was done for racing. What I didn't know at the time, is all of this castor was done to fix a car that wouldn't go straight because of rear tire run-out.

Somethings you find out a little too late.

Let me re-state my original post above, that is, I have never got more than another .5 degree castor with offset bushings. That's on 4 cars, two mine, two not. I do my own alignments and have done this for friends also. Cars with .5 degree castor seem to drive and ride fine, but we'd like more. If you actually have 5 degrees of castor from factory, that would be extraordinary, but of course entirely possible.

On the aftermarket upper arms I bought, without modification, max castor I could get was 5.5 degrees. That is, one rod arm out as far as safe, the other all the way in. AND, driving around on the street, although not much, you couldn't tell the difference from before. I would do about 95 in the 1/8 mile, and this was done for racing. What I didn't know at the time, is all of this castor was done to fix a car that wouldn't go straight because of rear tire run-out.

Somethings you find out a little too late.

Also, I have had to grind off the back inside of the upper control arm as with the cam turned all the way in board with offset bushing, the arm would hit the inside of the "shock tower".

Would some of the problem be with the k-frame to far back? How far moving it forward would it take to help the problem (elongated holes in the k-frame) just thinking out load here.

I'm thinking the deck is stacked against you when you are dealing with sub-par assembly tolerances from the 60's&70's. It doesn't help on the friday or monday cars that were put together by someone who was having issues at work that day and not being able to check fitment before pulling the trigger on the welder. I know even on newer stuff like the 4x rams, the mounts for the upper and lower control arms can be off like 1/4"+ which contributes to the famous "death wobble". You have to resort to adjustable arms to alleviate it as the stock stuff only allows for minimal adjustments. The adjustable arms and strut rods are a big boost for our old cars, but what do you do if you can't get enough adjustment to get you where you need to be? I'm wondering if in those instances, you will have to move the pickup points for the suspension mountings. Also, if you are off only a small amount at the arm or part attachment, with the stack up of other issues and that the defect is magnified the farther out it gets from the pivot or attachment point, you are going to have a fun time fixing things.

Great questions. I agree that caster is the main goal for a mild street type car. The problem that I am learning is that gaining caster means also gaining positive camber. I am still curious about some possible fixes. The owner called me to say while the rear cam bolts are maxxed out to the inside, the front ones appear to be near the middle of their adjustment range. When I had the car here, I had the fronts cranked to the outside and the camber was WAAAAY positive. This has me wondering if those spacer washers from Mancini would be a way to reduce the excessive positive camber. (In effect, resulting in less than the 2 degrees of NEG camber that they are advertised to provide)
The same alignment shop had trouble aligning my FrankenDuster in 2011. I had these same bushings in that car, installed the same way. I chalked it up to a shop being NON Mopar friendly or possibly just unwilling to work on an old car. The Duster was also "Baseline/Bonehead" aligned by me with the front cams out and the rear cams in. It tracked and steered great with no abnormal tire wear.

That is entirely possible. Incorrect positioning either by damage or incorrect placement of the frame mounted captive bolts would certainly affect caster. Incorrect placement of the UCA mounts would too.

If those were the arms out of my car, I got about 6.5 degrees positive caster with .5 negative camber with them with no other modifications but lowered ride height. They should be good to go....

The thing that sucks with doing Mopars is that most alignment places don't want to spend the time to get it really spot on which is why I ended up doing it myself at a friend's shop

I have an alignment gauge if you want to try and do it at home. Let me know and I can bring it to the meeting on Thursday

I do not find you to be annoying.
Also, the meeting is on Tuesday.
Can you hear me?

Today we tried shimming the power steering pump to reduce the pressure for better road feel. After reading several posts here and elsewhere, we agreed on a total of .125 thickness. I have read of some going as high as .140 with good results so I figured that .125 would be a good starting point. It turned out to be too much! Once rolling, the car steered fine but with the car sitting still, the steering wheel went about 1/3 of a turn then got too hard to turn without using both hands.
He plans to step back to .100 or so and reevaluate.

I've had mixed results using the offset UCA bushings installed a'la Mopar Action. Due to the exaggerated location points you can get with this set up I've found you really have to tighten the lock nuts much more to keep the cams set. Even then I hear a little popping and creaking out of the uppers. I've also found that A bodies seem to allow 360 degrees of rotation on the alignment cams, whereas a 70 E body seems to hit and limit you to 180 degrees. And this doesn't seem related to the offset bushings themselves, as that same limitation was there with stock bushings.They would hit while turned all the way in. I understand a 71 E and B body share front frame rails and might expect that same limitation on a B body of that age. With an A bdy I seem to be able to get the caster/camber I want with the bushings - not so with the E body. I suspect it's because of the lack of 360 degree adjustment. What worked for me on an A body was setting the camber first using the back cam, then adjusting the caster with the front cam and moving the camber back with east caster change.

Funny that you should mention the strange interference while rotating the cam bolts. I found the same thing with this car. Its as if the bolts have egg shaped washer/eccentrics. I had to back them out a bit, clock them, then drive them back to get full 360 degree spin. I don't recall having to do this on my 70 Charger or any A body that I have ever worked on.

Yea, they do act as eccentrics by placing the through bolt off to one side - that's what moves the arms in or out as they push against those raised areas that capture the eccentrics. I've seen the same set up on late 60's early 70's Mustangs but on the inboard lower control arm mount. I found the e body upper ctl arm hits at about the 10 to 8 o'clock inboard position on an E body.

This bind or noise is probably the rear part of the A arm rubbing on the shock tower. I mentioned this above that you have to grind/cut off the inside part of the arm to make it work. This will also keep the cams from making a full turn.

In all of this, without going any further, if you have 1 degree, I bet it will drive and ride fine! Try it. If it doesn't, you have loose, worn, or bent "stuff". There may be a ton of ways to compensate, but no need to do so.

I use offset bushings everytime for this exact reason. I've done alignments for over 40 years. Many times even with the bushings ideal caster is not obtainable. You also have to remember that any chassis rake effects caster, rear end up reduces it
Additionally think about what happens to the toe pattern when you add too much positive caster. It lowers the outer tie rod and can create an undesirable toe pattern. Personally 2.5 degrees seems about right. My 64 Belvedere drag car regularly runs close to 150 mph with stock parts and 2.5 degrees without issue. This was achieved with off set bushings in the front location and shortening the strut rods .375.
Doug

The other day I started thinking that to get where he wants to be, it will take a few tricks, not just the bushings. My current plan is to add the lower ball joint spacers to add negative camber, then adjust the front adjuster cams further out to gain caster. The strut rod bushings are urethane. I can shave 3/16" from the inner strut rod bushing and pull the LCA forward some. This should provide enough to get there.
I was either lucky before or the other cars I had were on the other end of the tolerances. I have been able to get the numbers simply with the special bushings.

[quote=Frankenduster]The other day I started thinking that to get where he wants to be, it will take a few tricks, not just the bushings. My current plan is to add the lower ball joint spacers to add negative camber, then adjust the front adjuster cams further out to gain caster. The strut rod bushings are urethane. I can shave 3/16" from the inner strut rod bushing and pull the LCA forward some. This should provide enough to get there.
I was either lucky before or the other cars I had were on the other end of the tolerances. I have been able to get the numbers simply with the special bushings. [/quote


just came to me about the spacers... Not the ball joint stud but the bolts that hold it to the spindles, right?

Yes, that is right. They tilt out the bottom edge of the knuckle/spindle. The ones from Mancini racing are said to result in 2 degrees of negative camber. They look to me to be around
3/16" thick. That is more that we need, so I'm thinking of using thinner ones, yet still grade 8 for strength. I figure if 3/16" is worth 2 degrees, the 1/8" ones I can get would result in 1.3 degrees. Since outward adjustment of the front alignment cams to gain caster also results in a positive gain in camber, I think it should work.

Being as your basically sandwiching them between the LBJ and spindle grade 8 may not be required as there is no shear force applied.

The problem is seldom getting enough negative caster. If you turn the rear cams all the way in and fronts all the way out to gain maximum caster the camber will usually end up in the negative range, The problem results if you desire 0 camber. Then the rear cam must be rotated out, to increase camber and reducing caster. It's a trade off of trying to get enough positive camber and caster. I have never seen much over 2.5 degrees on a B-Body after doing hundreds of them. I don't believe anyone obtained 5 degrees of caster without modifying the attachment points. The idea of shimming the lower ball joint will obtain negative camber but you still won't effect the caster reading much if any. To gain caster you must either move the upper ball joint rearward or the lower ball joint forward, if your out of adjustment then either the upper arm or strut rod need to be modified. Also as I stated earlier every degree of forward chassis rake reduces caster by a like amount. 2 degrees of chassis rake is not uncommon with lowered front end.
Doug

Currently, the front cams are about middle of their adjustment. My goal was to add in the NEG camber via the spacer washers, then some will come out when the front cams are adjusted out. In theory, (Ha-ha) this should result in a caster improvement as well as a slight negative camber. Curently the camber is slightly positive.

I cannot explain how I was able to get the 4.7ish caster #s from my car. It was around 2.4 to 2.6 with the urethane UCA bushings before swapping in the Moog 7103s. My UCAs are stock, the LCAs are stock but I do have urethane strut rod bushings. Maybe they are thinner than the stock rubber ones? This would have the effect of moving the lower ball joint forward a tad.

Are the rear cams all the way in?
Doug

Yes they are.

I haven't read the whole thing line by line but we installed FirmFeel UCA with the BallJoint placed on from them and the factory eccentric bolts on my buddy's 72 Roadrunner 440 4speed. They advertise an extra 4º of built in caster. I aligned it myself using a DIY wheel alignment kit I bought. Toe wasn't a problem. 1/16" of an inch each side for 1/8" total toe...I can't remember my camber setting on it though

I reread the entire post. What I don't see is where your specs are at now. One question I didnt ask. Does this car have late spindles like F body for a disc brake conversion? They add positive camber. I personally have never seen too much positive camber with the rear cams all the way in, almost always negative. Add to that it appears you have offsets in the rear location as well? Is that correct? If so and all are in the correct location something else is incorrect. Either strut rod bushings pushing the lower arm rearward, something bent, misassembled.
Doug

The Road Runner has the original Disc Knuckles it was built with in October 1970.
The offset bushings were installed to have the maximum caster. The front bushing installed as per the MOOG directions with the thin rubber sections close to the engine. The rear bushings are in the opposite way with the thin spots away from the engine.
I am a carpenter, used to inches and fractions. The alignment sheet is in decimals. Still, the camber is something like 0.6 degrees POS on both sides and the caster is less than a degree POS.
I've been wondering why I had such good luck with my car and he has not. I've been under the impression that we have the same knuckle/spindles, but mine are from a 75 Dart. Maybe mine have some camber & caster advantage???

These pictures are of the RIGHT side arm.

Your specs indicate the rear of the arm needs to go in further. Is the arm itself contacting the shock tower behind the arm preventing it's full inward movement? Is the lower arm being forced rear ward due to possibly a incorrect stack up on the strut rod bushing?
Doug

Good questions! I will have to look at the car closer when the owner brings it back.

I think I saw something from either CPP, Mancini or somewhere that had stock looking arms but the ball joint was moved some for improved alignments.