1936 Ford - Axle Wrap Problems - Parallel Springs

I am finishing up my 36 coupe and I am having some issues with axle wrap. I am running a 8BA Flathead with a T-5 Transmission - open drive line to a 9" ford rear end. I have installed Ch***is Engineering parallel springs on the rear to mount the 9". I also had 3" lowering blocks to get it down low enough. I had some pretty major axle wrap when going from a dead stop. I figured it may be the blocks, so I removed them and the axle wrap was gone. Problem is, the car sits like a 4x4 with out them.

I decided to cut some 2" square tube about 10" long to use as a lowering block. I figured the longer length would help distribute the torque. It is a bit better but it still has quite a bit of hop and vibration only when taking off from a dead stop. There are NO vibrations when running down the road or in reverse.

Aside from installing a torque arm / traction bar etc... I'm not sure how to cure this. The car sits WAY too high without the blocks.

Anyone else have this problem??? How did you fix it???

 

I installed the same kit in my 36 and was way to high. I took my springs to a spring shop and had them dearched 3". worked great, check out my album.

 

The original torque tube and the arms going to forward to the center underside of the car were responsible for eliminating axle wrap. Unfortunately you have eliminated the eliminators...

You will need to instal some sort of reinforcement in the name of a 4 bar link (just as you suspected).
There is no strength in the springs alone in eliminating axle wrap.



Nice car btw, 36's are a favorite here
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Very nice 3W Fred.
I thought about having some springs made with a reversed spring eye in front. But it is just that I see 100's of these 35-40 Fords w/ ch***is engineering parallel springs and lowering blocks... They can't all be having axle wrap issues.

I called CE and they said I should not need blocks b/c their kit sits very low out of the box... I guess most people are running a lower profile radial instead of the tall 700-16 Firestones that I am running.

I checked my pinion angle and it is at -2 deg. I am considering making some wedge shims to see if the pinion angle changes anything.

 

I don't see how anyone could have run them as high as mine set right out of the box. But the rearch is no big deal, and there is no need for four bars

 

Tramp bars may be the solution here.

 

I used the CE springs on my 35 and also had to use lowering blocks. God help ya if you tried to launch it, axle wrap and rear steer like you wouldn't believe. Fabbed up a set of Traction Master style bars, problems solved. Launches nice and straight, bites pretty hard.

 

what 36 Fred said==CE kits always sit too high from my experience and blocks create wheelhop --just de arch and problems will subside--have had to do it on every 40 I've done--ususally 2 1/2 inch dearch

 

The springs have almost a negative arch already... When you de-arch them an additional 3" is the ride affected?

 

You can run one "top bar" on each side running forward like a factory '62 Corvette. Sorta like a 4 bar without the bottom bar, the leaf spring would take the bottom bars place. Idealy the top bar would run forward and hook up inline with bottom spring front center bolt ..................................... if there is no floor clearence issues.

 

Dan, that's not a drag race kit, parallel leaf springs are notorious for axle tramp. The use of a tall lowering block acts as a lever arm under torque and rolls up the spring during acceleration. As you found out by removing the lowering blocks the axle tramp diminished. As noted by other posters the easiest way to control your spring wrap issue upon heavy acceleration is the use of some kind of traction control rod. This will keep the rear spring from wrapping under torque loads and will slightly stiffen the ride. You should keep the control rod in parallel to the rear spring to maintain axle position and make it as long as possible to eliminate any bind. Changing the pinion angle will have only a minimum effect on the situation that you are incurring.

 

Thanks for the input ****. But I should clarify... This is under light to normal acceleration. I do not plan on racing or having any hard launches in this car.

I am running your clutch with a 10" pressure plate. I have a Dwight Bond adaptor w/ an 8BA. We first thought it was clutch chatter, I think my dad even called you for suggestions. We originally had an 11" pressure plate, so we changed it out and redrilled the flywheel. I am still having the issues so we narrowed it down to axle wrap once we removed the lowering blocks.

 

Get a kicker shock for a mud truck. It lays on its side a lot like a steering stabilizer and goes from the axle to the spring eye above the spring.

 

Now wait, the story changed, Do you have a clutch chatter issue or a wheel tramp issue? Under normal acceleration the spring setup will not tramp. Start over and describe the symptoms.

There appears to be something out of alignment, by removing the lowering blocks the problem lessened. This would bring the alignment of the pinion and drive shaft more into alignment of the transmission. Shoot a picture of the undercarriage for starters could be something like the U joint out of phase. Before everybody starts a guessing game a simple picture might point out something.

 

****... Here are the additional pictures.

In first gear I can slowly let out the clutch and the front of the springs shimmy and shake until it gets rolling. Once I'm going, there are no issues. I am using a Ford 9" from an early Ford Bronco. The pinion on this rear end is not centered. It is slightly off to compensate for the transfercase on the Bronco.

The engine is an 8ba mounted with truck water pumps in the stock holes. Transmission is mounted with a modified Pete & Jakes split wishbone crossmember. I extended the crossmember and I am using a TH350 style stock rubber transmission mount.

We are building an identical frame / suspension set up for my dads 35 Cabriolet (except he is running a sway bar). I have included pictures of that as well. Would like to get this straightened out so that he doesn't run into the same problems.

My Dads Frame:




Under My Car:

 

Great the pictures make this a lot easier. Question 1, is the rear end centered on the case or centered on the pinion shaft? Question 2, does the pinion point up hill, down hill or straight ahead to the transmission. Question 3, if you place the car on jack stands so a 4 of the tires are off the ground at equal height and you start the car put it in 1st gear and engage the clutch to rotate the tires , do you hear any odd noises?. Question 4, with the car up in the air and repeating question 3 procedure, how far off the floor is the clutch pedal before the tires begin to turn? I'll stop here for answers.

 

I'm pretty sure that that would do it and the advantage of that method over using a conventional traction bar under the spring is that it doesn't hang down looking ****y and out of place. It's up high and out of sight, instead. And I don't think it would have as much effect on the ride, either.

 

You can build the same setup I did.

Without my pics this will be difficult to explain but it looks alot like that tramp bar. Only mine runs right with the springs, not below or above it.

I ran from the front eye parallel to the spring to the rear of the drop block. There I took a 4" piece of 3/16 wall tube with a 3/4 id. Two threaded rods and 4 heims, just like the lower bars on a 4 link. Longer bolt for the front spring eye and one long enough for the new mount and heim for the rear.

No wrap and no drag. I set them loose in the neutral position with the car on it's wheels so the weight was there. Keeps my pinion angle set right where it is.

Night and day difference.

 

Dan,
I had the very same setup you had in my 37. With a 5.0 / C-4 I never had enough poop to wrap the springs. What the hell kind of flat head you got?

More to the point, my 37 didn't sit low enough for me with the CE blocks.. So I even added some strap spacers to lower it even more. 6 months later I had to take them out... the springs will sag. Trust me. All the CE stuff does. Sooner or later, the springs got a sag in them so bad I thought something was really wrong. CE said no, not to worry, the "work" regardless of the upward arch in them ok. Everyone I ever talked to about the sag said they had it too. I'd drive it for awhile before I tried new springs or other options. Gary

 

Just another thought, do you have chatter rods to the bellhousing? just wondering if lack of fore-aft engine control is contributing to what you are feeling. stock trans mounts are often pretty soft, and allow this movement.

 

He shouldn't be feeling much fore-aft engine movement with that open driveline. Ford used them because the rear axle/Torque tube pushed directly on the trans/engine. This rear axle pushes on those leaf springs...

 

Is your rear end sitting at the same angle as the motor and trans, sure looks like the yoke is pointing downward, maybe an illusion?
Nice looking ch***is, if it were mine I would angle cut the front and rear rectangle tubing and cap off for a cleaner look JMO

 

Dan, FWIW, I was looking at a 40 p/u a couple of weeks ago with the same setup that you have, trying to get a feel for what we'll need on dad's 36 p/u. He had no lowering blocks, his springs were actually reverse arched and looked like they would fit just right in you setup with the blocks removed. He was running an auto, so less potential wrap or chatter problems, but he did say it rode good.

 

1) The rear end punkin is pretty well centered between the frame rails, which makes the pinion slightly off to the p*** side due to the offset design of the 3rd member. The drive shaft is not perfectly straight from the trans to pinion.

2) When the car is sitting flat on the tires, the pinion angle is pointed down 2 degrees.

3) I have not tried this w/ the front off the ground, but w/ the rear end jacked up enough for the tires to clear, there are no odd noises or wrap up issues when there is no load on the tires.

4) Will check tomorrow... With the car on the ground, the clutch releases nearly at the end of the clutch throw. (I am running stock 39 pedals and linkage)

I do not see any provisions for anti-chatter rods on this 8BA motor. I considered this also, but the open driveline should not require these rods.

The engine/trans angle down to the back of the car 2 degrees. The pinion angle is pointed down 2 degrees as well. Most of the ch***is builders I talked said it should point down slightly???

The lowering blocks are just temporary to see if the smaller height and longer length would help the axle wrap. From my experience with offroading jeeps we would fabricate long spring perches to help eliminate axle wrap. Just though I would give it a try. Seemed to help, but still not gone.

 

Interesting read ........... http://tractionmaster.com/

"The engine/trans angle down to the back of the car 2 degrees. The pinion angle is pointed down 2 degrees as well. Most of the ch***is builders I talked said it should point down slightly???"

I think they have it wrong!
I also don't think you are positioning your degree wheel rite but I don't have the words to describe it the rite way, maybe someone could draw the relationship of the center of crank and center of pinion?

If your front hub is higher than your trans yoke, than the rear end pinion/u-joint need to be higher than the imaginary line drawn threw your rear, hows that!

 

Dan, based upon your latest post I am forming an idea that your problem is centered around your drive shaft. I am not in favor of running laterally skewed drive lines because the angles change drastically when the suspension works. This is a very basic kit with wide market acceptance..

In your case the more you lower the ride height of your car the more problems. By returning your car to stock CE design the problem diminishes. If you check the center line alignment side view you will see that as the center lines of the trans tailshaft housing and the center line of the pumpkin yoke are closer to the same plain the problem occurs. Remember the pinion rotates upward upon acceleration and as you add lowering blocks you bring the pinion axis closer to the central axis of the transmission tailshaft. If the tailshft axis is below the pinion axis when the pinion rotates up under acceleration and spring flex you now place a bind in the ujoint, causing the shutter.. You should also check the ujoint phasing if you have a homemade drive shaft.

It seems to me that when you drastically add lowering blocks the operating angle the drive shaft is going into some kind of bind which is transfering to the spring and therefore it appears to be a spring issue but really is not .

In regard to your clutch adjustment I would favor the linkage to be adjusted so that full contact is made at about 1/2 + pedal travel out.

Anyway go back and check out the driveshaft angles that is where I believe your problems exist.

 

Also another thought not to "pig" this thread but when the pinion is lower than trans yoke apon excelleration you are pushing the drive shaft into the trans. How much play do you have in the yoke to trans?

 

As **** said you should check the clutch throwout bearing for freeplay.

What you described suggests to me that the adjustment probably isn't right. At the pedal you should have about 3/4"-1" of free travel before the throwout bearing comes into contact with the fingers on the pressure plate. If the throwout bearing is riding then the clutch will slip and could easily cause the chattering particularly if its been in there a while as you could have oil migrating to the lining surfaces and it will chatter.

 

From the posted pictures I only count 3 leaves. My setup had 6 leaves with a very short one. I took this one out because the stackup was too much for my U Bolts. Now has a total of 5 leaves. I also reinforced the spring retaining plates. My plates were bowing from the force exerted from the U Bolts. If you look at most factory plates they have the edge turned/formed for reinforcement. I added flatbar to my plates.

 

Well, what's the verdict?