AZDoug

So far I have been told:

Traction Masters still hop with enough tire/HP/sticky track,

caltracs are not available for C1,

I have found:

Slapper bars are not available (at least taht I ahve found) that allow the use of the rear sway bar (otherwise I would have put them on 30 years ago.

So, that leaves me with building my own lower link system.

This will obviously have to be a double rod end link to allow the axle greater freedom in movement.

I have seen in the past, C1 drag cars that had lower links that went dang near to the front of the car, why did they extend them so far forward?

My though is that a flush mounting pad, welded to the frame, just about where the front leaf spring hanger is, with a 5" drop tower (for rod mounting) below the axle mount pad,and some 1" heavy wall 4130 tubing with adjustable rod ends would provide about the right geometery. This of course would angle the rod up toward the frame

However, i am not a suspension engineer, and I still want to keep the factor upper radius rods,and a leaf spring is involved, rather than coils.

Would I be better off with a lower link that is parallel to the upper radius rod?

Or, use the angled up lower link as I originally suggested and remove the factory radius rods? I do not mant a binding issue.

Anybody know of any technical websites about this stuff?

Thanks,
Doug

Vogie

I don't know your experience level and don't want to insult you. If the geometry is not correct, and the link and spring don't work together, you will experience spring bind. For example with leaf springs and ladder bars, the differential must be able to move on the spring and rotate in the mounts. Take care.

I have known of people that built their own system by borrowing from the CalTrac design. If you have the resources, I would recommend you do that or talk CalTrac into helping you. They are good people.

MikeM

You don't need all that crap with reasonable tires. If you can't get slapper bars on there, or don't want to temporarily remove them to accomodate slapper bars, put the 50-50 shocks on the rear and clamp the front halves of the the leaf springs in several places. The clamps will tend to keep the spring from winding up, unwinding, etc. That's how you get the hop. The shocks will do the same. Your stock radius bars will help. It would also help to install poly bushings in the leaf spring front eyes.

DZAUTO

I have a set of original Traction Masters on my 56, which came with the spacers and longer U-bolts for 60-62 cars. When I acquired them (about 20yrs ago), the U-bolts and spacers were rusted so bad that I felt they were unsafe, so I replaced them. I also ordered a set of poly bushings direct from TM.
The TM bars work great for my 56!!!
It is my understanding that TM has started manufacturing the bars for the early Vettes, BUUUUUUUUUT the ends are a little different from the original cast ends. THERE IS A DIFFERENCE BETWEEN THE ONES FOR 53-59 AND 60-62. The 53-59 TM rear brackets fit right up against the bottom of the spring plate. The 60-62 version must use spacers between the TM rear plate and the spring plate to allow them to clear the bracket for the 60-62 rear sway bar. You can just barely see those spacers in this picture.

I have upgraded my 56 with the 59-62 radius rods and 60-62 rear sway bar as well as the heavier 60-62 front sway bar.

Vogie

I have seen folks clamp the front of the leaf springs, but not in years. It works with relatively low power applications by effectively converting the front half of the spring into a rigid trailing arm. The back half of the spring does all the work. The slapper bars allow the spring to work but limit wind up and pinion angle rise. Once into ladder bars and four links, you begin to work with weight transfer by suspension action and geometry. I would suggest you go to some street legal drags and see what the "stock suspension" classes are running. You will see a lot of CalTracs and similar systems that will allow preload of the leaf spring and limit wind up and pinion angle. I would use whatever system you could find that limits spring wrap and wheel hop, controls pinion angle, and allows weight transfer. A lot of this discussion is limited unless you have an idea of power levels, suspension, tires, and performance expectations. The folks on the Drag Racing area of the forum might be of help. Good luck.

Plastic Pig

Doug , I didn't forget you. I'll dig the SSM bars out tomorrow and get you some pics.

vetrod62

Doug, This set up works.
Remove strut rods, store for next owner

add extra rear leaf

buy a set of comp engineering snubber bars for 67-69 camaro #2101

cut bar length so that snubber lines up with the spring eye bolt

re drill hole for snubber

attach snubber, double nut and loc-tite it

cut off J-bolt brackets

throw away J-bolts

get new .500" U-bolts made to proper length (Most places that re-arch or re-manufacture leaf springs can make them and supply the proper nuts)

attach shock to existing bracket

weld in grade 8 .500" to above bracket

fabricate rear sway bar bracket ( My car sits high, so the bracket is on top of housing






If you get it right, you should be able to do like the car below, with out any wheel hop, which has the same set up. Details of this car... Nothing special engine, 1977 350 junk yard short block--NOT REBUILT--1969 302 stock heads--NOT REBUILT-- L-79 cam used, M-21 trans, 4.56 gears, 5000 rpm launch. ET this trip 12.80



The BAD NEWS is once you get your traction problem solved and if you running the stock type chevy rear, you will surely break it.

vetrod62

63 340HP

The cut down (modified mount) Camaro slapper bars work (buy extra snubbers to cut and tune the pinion angle under load).

The 1/2-inch U-bolts are safety insurance.

The leaf spring pads welded on top of the axle tube for the sway bar brackets are available at most spring shops.

I am not a big fan of welding grade-8 bolts due to the resulting brittle steel properties (grade-5 is less prone to weld induced embrittlement). You can also purchase bolt-in shouldered shock bolts from the spring shops that sell the spring pads, U-bolts, and other small pieces.

The axle in the photos has been trussed, a valid improvement for the ET's reported & slicks shown.

If desired I can e-mail an excel file that allows you to plug in the axle & frame mount 4-link pin coordinates and tire diameter, and it calculates the IC, roll center, roll axis, and anti-squat % (etc.) as the axle is cycled through it’s range of travel. The program was written by a fairly recent BSME graduate from Cal Poly SLO and it works, but it’s kind of a work in progress. Knowing what to do with the resulting data falls back on practical experience (and what fits under the chassis, and a correct pinion angle, and ... testing with controllable data). It gets overwhelming and unless you have something like a clean sheet chassis to begin with most of the "ideal" set-ups will not fit.

An effective alternate is to build a ladder bar with an inverted shackle as the front chassis mount to isolate and control the pinion angle, and not bind the suspension. The shackle is under tension under load as the ladder bar chassis end is rising (as the car launches) keeping the pinion angle parallel to the transmission tailshaft, and the hinged movement allows the axle and ladder bar to move forward and back to follow the leaf springs true length. A crossmember is needed to locate the chassis mount, and it takes up space (and thought to make it fit and tune). It's a more permanent fixture than John Calvert's Caltracks bar design, and does not work as well with soft leafs or monoleafs, but it is a less expensive alternative to a 4-link.

My recommendation is KISS with the modified Camaro slapper bar. It’s easy to tune the pinion angle with a snubber change, spring rate can change with adding or removing spring leafs, and they make the most out of the exiting leaf spring mount locations available instant center. Twenty years ago when I worked on a SS396 Camaro in competition with John’s 428CJ Mustang we ran mid-11-second ET’s on 29x9 slicks with slapper bars and the factory 12-bolt. Tire & traction upgrades (14” wide rubber & the shackled ladder bars) helped get us into the low 10-second ET’s, but we shattered the 12-bolt R&P and overworked (broke) every other part of the drivetrain to get that extra second. The ET’s and trap speeds of the modern LS6 & LS7 Corvettes make it look so easy, because the chassis and suspension evolved as much as the engines.

Good Luck!

AZDoug

Thanks for the advice and great pics!

I already have 5 1/2 leaf springs on the car, and I installed a narrowed 12 bolt posi 25 years ago. The 12 bolt should handle a SB engine w/o problems, i think.

I am not trying to do wheelies, just get rid of spring wrap.

Doug

AZDoug

Vetrod, what are teh forged steel eyebolts on the back of the slapper bars for? Trailer tie downs?

Doug

knight37128

Stiffer springs will help.

If the springs are 25 years old also they may have lost there stiffness.

AZDoug

Springs are 6-7 years old. car hardly moves up or down.

Doug

Vogie

They were the shock mounts for the Camaro installation. I'd bet you guessed right on the tie down.

vetrod62

Doug you and Vogie are both correct. The eye bolts are for the tie downs. I have 2 more up front attached to the old tow bar brackets. They work very well for a quick, strong, safe hold down in my trailer.
vetrod62

Plastic Pig

OK Doug Sorry for the delay here is what I have.

South Side Machine lift bars. These attach to the very front of the spring and shims can be added side to side to set pre-load.












While going through the parts I also found these off a another '62 I used to have. These might be the same as what vetrod and vogie are describing as they have been modified. I got them from a guy that raced a '58 in the 70's. These will eliminate wheel hop as well. I was able to knock down consistent 1.6's on drag radials. I took them off when I tubbed the car and went to a 4 link. Just found them when I was digging the other ones out.

Plasticman

Here is a picture of the spring clamps I use on my 62. They are effective, and do not affect ride quality if properly adjusted. If too tight, they will still prevent spring wrap up (and resulting wheel hop), but ride quality will suffer. If too loose, then wheel hop returns. I have 2 of these clamps on each front half of both rear springs. They are retained in position by the lip on the shorter leaves as shown. Need to adjust (tighten) periodically. A quick burnout will tell you if they are in need of adjustment, so do it often.

Cheap to make, and effective with street tires (and a very healthy 350 SBC and used with both a 4.11 and 3.55 rear gears).



Note that a few years ago (before adding the spring clamps), I determined that I was getting side to side wheel hop caused by the rear anti-sway bar (hooked up a video camera underneath the 62 so that while making a burnout I recorded the wheels hopping sided to side). Taking the bar off helped quite a bit, but since I added the spring clamps, I have been able to add the bar back on with out any hop. In other words, try taking the bar off - it should help.

Plasticman

Plastic Pig

More info.

AZDoug

I put a calipers on my U-bolts and they are about .480" OD, which is essentially 1/2".

was there another size U-bolt used?

I will probaly get new 1/2" U-bolts from Jegs or Summit anyway and put new nuts on them as long as it is all off the car anyway.

Thanks,
Doug

K2

Most u-bolts have rolled threads and therefore the shank will measure undersize. As the threads are rolled the thread diameter expands giving you the required thread diameter.

vetrod62

Clamping the springs can stop spring wind up, but will do little to improve traction. The slapper bars or SSM bars do more than stop wheel hop. That is why SSM calls them Lift Bars. Basically, for lack of a better description, the bars act like a primitive 4-link. The spring is the upper bar and slapper or SSM bar is the lower bar. When tuned correctly it puts the instant center where it belongs, about 40% of the wheel base in front of the rear wheels, thereby increasing the load on the rear axle.

I ran traction bars for decades and was perfectly happy with them until my buddy with the green '61 installed the snubbers. What a difference. By-by traction bars, hello snubbers. The best I can figure the instant center with traction bars is some where behind the car, thereby lightening the load on the rear axle.

If most people look at the picture of that car posted earlier, they see air under the front wheels. When I look at that picture I see the the rear axle carrying the entire weight of the car and driver (3350 lbs) AND the gap between the rear tire LARGER than when the car is at rest.

If a car that has a rear end weight of 1500 lbs, and it squats on a launch, the instant center is probably too far forward or to far to the rear. Your 1500lbs rear weight on the tires now has changed to some thing less, say 700lbs. The same car with the instant center in the proper place, that 1500lbs on the tires could turn into 3-4000 lbs for the first few feet. Which will mean a great 60' time or lots of smoke. On the car pictured, those bars are working.
vetrod62