Upper control arms - more caster?

davelacourse · Poncho Master!

Upper control arms - more caster?

eeluddy · Uber Guru

Seeing that you have spent this time figuring out the fabrication, i say go with #3

cdnpont · Canadian Poncho Superstar!

Nice drawings Dave!

Was the alignment (at least the caster) on a 56 not done entirely with shims anyway?

Shim in as much positive as you can get...find another set of arms on top of your spares, and start on your geometry project. Drive the car while you take your time working on the new arms.

davelacourse · Poncho Master!

Yes shims alone for caster and camber adjustment, they have been tweaked as much as possible, still a lot of negative caster and no camber. (Toe is set by adjusting tie rods.)

The alignment guy said "Just lower the rear" and I said "That is not an option" since I like the stance and also it's the only way those big tires will fit in there without cutting the wheel opening in the rear fenders (and I like the factory lines).

Thanks,
Dave

427carl · A Poncho Legend!

davelacourse wrote:

Well I drove to the alignment shop, and he put the 56 with all new/rebuilt front suspension on the fancy computerized/laser-guided machine, and ... cannot get anywhere close to the factory specified 1 degree postive caster, and cannot get any positive camber either (toe-in of course is not a problem). Reason: very little adjustment built into these early cars, and I have dropped the front end 2 inches and raised the rear end about 4 inches, introducing over 3 degrees of negative caster into the front end.

Steering is OK driving down the road, turns really easily, BUT the return-to-center feature we are all accustomed to is gone - I have to crank it back to straight. So I have 3 choices:

1. Live with it. Drives OK except for the missing return-to-center feature which is kind of weird. But it does drive OK, no wandering, no pull, no twitching.

2. Buy a pair of tubular upper control arms Easy bolt-in, cost about $350. Ouch
The alignment guy can easily add shims to bring the caster and camber into line with specs with those control arms.

I am not a big fan of tubular control , but I could live with them.

Buy the tubular ones LATER you can't make them for less than 350.00 Its a Hot Rod not a show car... tubular are cool and professionaly built

2drpost · Uber Guru

uummm, upper arms aren't on their wrong side are they? confuse

davelacourse · Poncho Master!

69 belair wrote:

uummm, upper arms aren't on their wrong side are they?

Whoa! That would have been really freaky, eh? Would have resulted in about 7 degrees negative caster, can't imagine what handling would be like then!

Yep, they are on the correct side - I even went out to the garage just now to double-check

Although that would have been a REALLY quick, cheap fix, eh?

Dave

tc · Guru

Had a similar problem with a 61 Pontiac Tempest wagon I built a couple years back. Altered the upper control arms, relocated ball joint [Used Chrysler screw-in style] was a massive pain in the ass. In the end I went over to McColls racing products [London] and got off the shelf uppers [Cascar Tubular] and was done with it. It turns your problem into a no-brainer!!

sixtywagon · Uber Guru

HMMM, Unless it really bothers you to have to "return" the steering to centre , everytime you make a corner, I'd leave it as is...Maybe purchase the tubular ones later on, if you feel nessesary

My 2 cents

Ken

davelacourse · Poncho Master!

Thanks for all the input, guys - I decided that I wanted the alignment done right, so even though I could live with it, I will change the upper control arms. And I decided to go with powder coated tubular upper arms from Eckler's - their Halloween sale was 15% off so I got them for $305 US, they have 5 degrees positive caster (mine is now 4 degrees on one side and 4 degrees on the other side, both negative caster - so adding 5 will allow both to be shimmed to the specified 1 degree positive), 2 degrees postive camber (mine is now a tenth or two negative, so this will allow shimming to the specified 1/2 degree positive).

Ecklers control arm.jpg

Thanks again, I did take into account everything everybody said.

Dave

427carl · A Poncho Legend!

EXCELLENT! although I gave you, permission to buy them later like next year wink

davelacourse · Poncho Master!

It's my early Happy New Year present to myself

Dave

427carl · A Poncho Legend!

davelacourse · Poncho Master!

Update - finally got around to installing them, here's a comparison shot (original driver's side and new passenger side):

and here is before (passenger side) and after (driver's side) pictures.

Have not yet made it back to the alignment shop, overheating problems again ...

Dave

427carl · A Poncho Legend!

VERY NICE JOB!!

Living in Florida, you really should get air conditioning, That will keep you from having heating problems confuse

rabbit64cs · Canadian Poncho Superstar!

an old rodders trick on the 55- 57 is to cut the welds on the rear side of the mount for the upper, then tap them up against the frame rail and re weld. This corrects the castor. If you look at the last picture , you can see how this would work. I got this tip from a friend who ran an alignment shop for years, and drives, races, breaths 55 chevy's.

sorry for coming to the party late !!

The tubular looks real cool , nice and clean !!

59poncho · Poncho Master!

great, now you have me really worried!! I just dropped the whole car about 3 inches all around, and from what i have read i knew it would mess with the car a bit, probally go through tires faster, and might not handle as well, but is it dangerous?? I have not driven the car yet so im not sure how it handles. I just figured i would have to watch for potholes and big bumps!

davelacourse · Poncho Master!

59poncho wrote:

great, now you have me really worried!! I just dropped the whole car about 3 inches all around, and from what i have read i knew it would mess with the car a bit, probally go through tires faster, and might not handle as well, but is it dangerous?? I have not driven the car yet so im not sure how it handles. I just figured i would have to watch for potholes and big bumps!

The main reason I had a problem with front end alignment is that I changed the rake of my car substantially. The calculation is as follows (and here you thought trigonometry would never be useful in the real world, eh?):

The wheelbase of a 1956 Canadian Pontiac is 115 inches. For every inch of rake (done by either raising the rear end or lowering the front end, or both in combination) the caster changes by the tangent of 1/115 = 0.5 degrees. In my case, I lowered the front 2 inches and raised the rear 4 inches so I added 6 X 0.5 = 3 degrees of negative caster. Hence my need to make some other major change to get alignment within spec, since there was not enough range of adjustment built into the car by the factory.

Since I used stock height front springs (the front end lowering came via dropped spindles) there should have been no other changes in geometry that affected my allignment.

In your case, you lowered both ends equally, so you did not change the rake, so you will not have the same problem I did.

Good news eh?

However, you still should consider the following.

Given no rake change, the only impact lowering the rear on a solid axle car like yours should have is (1) less suspension travel over bumps (as you know) and (2) in theory, slightly better cornering at speed since you have lowered the center of gravity. Maybe a somewhat harsher ride, too, since coil springs are designed to operate with a given length.

In the front, you should have the same as above, plus whatever changes in geometry resulted from the drop - my guess is that you would have significant change in camber (because most independent front suspensions are designed to have camber change during cornering when one wheel will drop and the other rise due to weight transfter), which is not good - for sure front tires will wear out fast (unequal wear) and handling will be adversely affected. Take the car to an alignment shop (if you are like me and do not have the [expensive] tools to do it yourself) and find out. Hopefully the alignment shop can shim enough to get your car in spec so you will not have those problems. Otherwise you will have the same dilemma I did - live with it or fix it somehow. I do not know enough about the 59 Chevy chassis to know about possible fixes.

You probably have introduced a change in caster when you dropped the front, since you have changed the static location of the lower ball joint compared to the upper ball joint. I don't know the geometry and measurements for a 1959 front end (similar desingn but not interchangeable parts compared to 1956) so I can't do the trigonometry again to find out - but the same trip to the alignment shop will give the answer.

Good luck Trevor!

Dave

59poncho · Poncho Master!

thanks dave, math was not my strong subject plus i dont really know how everything works as far as the suspension camber, toe in, and all that stuff. Reading this post and what you were saying made it a little clearer though, thanks. After march the cars going in to tinys for the alignment. I love the rake on your car, looks awesome.

davelacourse · Poncho Master!

59poncho wrote:

thanks dave, math was not my strong subject plus i dont really know how everything works as far as the suspension camber, toe in, and all that stuff. Reading this post and what you were saying made it a little clearer though, thanks. After march the cars going in to tinys for the alignment. I love the rake on your car, looks awesome.

And the 3 inch lowering job on your 59 looks great!!!!

If shims won't get the job done now on your front end with the cut coils, maybe do the best you can and then when you have the cash to do the dropped spindles (and new stock springs) do the alignment again, is what I would suggest. And put cheap used tires on the front until then

I would also suggest that you go to power disc front brakes when you do the spindles - you can get spindles specifically designed for the calipers without extra brackets, and disc fronts plus the power booster make for WAY better stopping - the improvement on my 56 was amazing. When the time comes, let me know, I can fill you in on where I got mine (direct from manufacturer, complete kit including all the bolts/hoses/dust caps, no extra trips to the parts store).

Dave

59poncho · Poncho Master!

sounds good. When i was looking at the droped spindles i figured i would get the disc brakes as well. When i sold my trans am i kept the brake booster so i could use that, i was actually thinking ahead for a change!!

dualquadpete · Canadian Poncho Superstar!

Dave, good choice on tubular arms, I think the re worked ones would have worked, but in the back of my mind I'd be worried all the time "is this going to break" I also "love " the RAKE look!!!

unburt · Guru

Hey Trevor the 59 looks soooo neat lowered and the brake upgrade is probably one of the best mods you can do. That car is a heavy weight and discs will give you way better performance and safety. The suspension geometry has changed when lowered and Tiny is the man to make it right.

59poncho · Poncho Master!

its going to tiny for sure, same with my PT Loser, needs some front end work as well. With the car lowered it looks more hot rod/custom, which is what im going for, cant afford an original looking resto, plus thats not really me. is the T/A ready for the summer? You have to take me for a spin, i miss mine a bit, that part when you let the foul barrel open and get pushed back in the seats is what i miss the most. The 59 is a slow and now low rider!

unburt · Guru

Well Trevor i had a camshaft let go ,1 lobe and lifter ground to dust. This happened the last week in August and i was to say very ticked.
The motor has been out for 3 months and i stripped it down (bare block) and it is at a machine shop.
I decided to go with a complete rotating assembly from British Columbia , company is called SD Performance.
I am going all in with a stroker kit ,this will take me to 464 cubes. The owner Dave Bisshop is a very well known pontiac engine guy and we talked for a long time about the parts industry and the problems camshaft makers are having.
I have decided to go with a full roller cam and this also has made me get into full roller rockers and diffferent springs.
I am getting everything shipped this week and hope to get the parts to the shop friday.
The motor is going to be a monster torque producer and i cant wait to fire this thing up down the road.
I will for sure give you a ride when its done.