New clutch installed and bad wheel hop?

-
RustyRatRod said:
What are you saying here? That the Borg and Beck SHOULD release close to the top? I ask because that's what I have in the Valiant, since that's what it came with. It releases pretty close to the top and it's always felt fine.
Click to expand...


The lever ratios on all the different covers are different. I used to know the difference between the B&B lever ratio and the Long cover.

The Long cover has a quicker lever ratio than the B&B does. The quicker the lever ratio is compared to what the OE used then the more the clutch pedal acts like a toggle switch. The OE pedal ratios are designed with the lever ratio of the cover in mind.

Speeding up the lever ratio changes everything from the cover up to the pedal. I’ve never liked a toggle switch clutch and I got burned by that once.

I was racing a clutch car against all the automatic guys. I wasn’t even using a 2 step so I was at a decided disadvantage. Over the winter I measured everything, did all the math and rebuilt the entire clutch and throttle linkage.

The idea was to shorten up the clutch pedal and throttle throw. And with that, cut my reaction times down to be more competitive. Luckily, I made both the clutch and throttle adjustable.

The idea worked like a champ sitting in the shop. At the track...well...that was a nightmare. I never considered what a beeeeeeeeeeeeeeotch it was going to be just driving through the pits or even doing a simple burnout. With two flying toilets on a tunnel ram it was near impossible just getting to the staging lanes.

It took 1.75 inches to make the clutch go from the pedal stop to the top. The throttle was 1.200 from closed to WOT. So everything was super quick.

With the flying toilets it took about .100 butterfly opening to get 7500 RPM with no load. So I’m feeling real smart as I head to the staging lanes.

My dad said it looked like I was riding a bucking bronco. The clutch was either in or out. And the throttle didn’t have a sweet spot. The engine was either idling or blowing through the pits like my hair was on fire. Got my *** chewed by the track owner for driving reckless through the pits and pissed off a bunch of people who thought I was acting the idiot.

Then I couldn’t even do a burnout. Once the tires spun, the engine was either bogging down or running up to 8500. It was a complete disaster. So I aborted that first pass and went back and slowed everything down to where I could drive the thing.

So...I learned that what sounds good in my head and looks great on paper isn’t always good. Mostly it’s NOT good. I still run a Borg & Beck cover with Long fingers. So I have to change the pedal ratio so it’s drivable. And, when Cale at Black Magic clutched did the update on my junk he used levers that he designed. And they are a bit quicker than an OE Long lever so I had to modify the clutch linkage again.

There is a lot more to changing form a B&B cover to anything else if you want to keep the drivability like OE stuff. I had to learn it the hard way. I hate fighting the car just to get it to move. Or things like pulling into a bank parking lot with a locker and screwed up pedal ratios. That ain’t fun.
 
Are you sure it’s wheel hop and not clutch chatter ?
Also the clutch grabbing at the top is not great.
Wheel hop , as everyone has said is suspension , not clutch.
Following
 
LovetheA's said:
The clutch grabs about an inch from the top but can be adjusted to engage farther down not an issue. I think the first thing I should do is get the pinion angle correct. I don’t know if it is in between 5-7%. Then yes the front spring eye perch’s as well as the back of the springs are replaced with new bushings. The rear leave springs are the factory style that came in those BB 4 speed cars. I believe they are 6 leaves on each side. They may be even a little stiffer than original. The springs are about 15 years old but the car has only been driven about 10,000 miles so I wouldn’t think the springs are shot. I have new 3 way adjustable hotchkis fox shocks all the way around and they are new. I think those shocks should be adjustable to work for this car? Anyone else have any feedback on these shocks? There is a factory pinion snubber on the car but I also have the tall adjustable pinion snubber but don’t want to put that on for street driving as it clunks and bangs often. Based on this combination I think it should squat and go, not hop around like crazy. How do I determine if the rear leave springs are the problem?
Click to expand...
I don't think it should ''Squat and go''.
It should lift the back end and go.
If it's lifting the back end, the axle is moving down toward the road surface and planting the tires.
This is with a Mopar leaf spring car of course.
When you launch, the front end and the rear of the car should rise together if it's set up right.
The tires unloading and loading is what contributes greatly to wheel hop.
And the more power you have, the worse the wheel hop will be.

The basic idea is that the axle center line should be not in the center of the spring but biased forward, and the front segment between the body mount to the axle needs to be stiff, and the rear segment needs to be weaker and longer to allow the lift.
You also must take into consideration that the shock travel needs to be enough to allow the springs to move the maximum amount to achieve this.
If not, it will cause the wheel hop problem as well.
The Shock tops out and unloads the suspension, then relaxes enough to let the back end drop, then the car gets traction again causing the rear to rise and the constant loading and unloading of the suspension is what causes the wheel hop.
Some people have used the shocks from an Imperial or pickup to allow for the longer stroke that they need, and also the rubber brake hose between the body and the differential needs to be changed out for one from a pickup.
It's all about unrestricted range of motion, and the brake hose trick is so the brake hose doesn't rip off and make the brakes fail when the car launches.

Remember, this is the old technology taken from the Direct Connection book that was designed for cars with Super Stock springs and an adjustable pinion snubber.
Newer set ups like Cal Tracks and slide a links are a different ball game all together........
 
Last edited:
Put the adjustable snubber, or pieces of 2x4 to stabilize the pinion against the floor .
Give that a try, process of elimination.
If you haven't clamped ALL the front spring segments, it'll wrap that segment ! !
 
Might have bent the clutch disc and you are getting clutch chatter and not wheel hop.
 
LovetheA's said:
so I wouldn’t think the springs are shot. I have new 3 way adjustable hotchkis fox shocks all the way around and they are new. I think those shocks should be adjustable to work for this car? Anyone else have any feedback on these shocks? There is a factory pinion snubber on the car but I also have the tall adjustable pinion snubber but don’t want to put that on for street driving as it clunks and bangs often. Based on this combination I think it should squat and go, not hop around like crazy. How do I determine if the rear leave springs are the problem?
Click to expand...

I wouldn’t think the springs are shot.
How do I determine if the rear leave springs are the problem?
Stop thinking about it; the springs are telling you that they cannot resist the torque. The front segment is waffling.
I think it should squat and go,
And that also is Chevy thinking. Squatting is bad and leads to spinning the tires. What you want is for the rear of the car to rise a little. For this to happen simultaneous with power application the springs have to push up. Which is the same as you pushing down on the trunk. With 300pounds per inch springs, for each side to rise 1 inch, that is similar to pushing down with 700 pounds of force. That is a lot of traction aid, that you don't have to carry around cement bags to get.
Squat is bad. traction is reduced. Tires spin. Spinning ain't winning.
Additionally; the pinion has to be down, and the snubber in the saddle; that is what is gonna lift the back of the car. That is the second reason why it it needs to be 5 to 7 degrees nose down. The goal is for under power, for the angle to be near zero. So the more power you have or the softer the springs are, the more nose-down you will need.

On the street you need a heavy flywheel for a couple of reasons
1) it smooths the power application
2) it is easier to modulate engagement
3) it makes it way easier to take off with. Just blip the throttle to put some energy into the flywheel and (in mine) sorta dump the clutch and go.
4) it stores more energy on the shifts to bust the tires loose again, if yur into that sortof thing...... like I would be if I didn't already have enough power as it is,lol.
5) it smooths and stabilizes the Idle, so you can idle the engine down and hear the cam. My 11/1, 367 will idle AND pull itself at 500/550 rpm with a 10.97 starter gear; (with a 230* cam and a manual trans).
I always wanted to try a lightweight FW, but after I put this combo together, I said un-uh.

I am not advocating for SS springs on the street.
What I did was add a fat second main leaf, eye to eye, on each side and clamped the front section pretty tight (two clamps per side IIRC). I clamped the back loosely with one clamp per side only.
This allowed me to ditch the factory snubber completely, cuz my floor was too low for it anyway.
Read YRs post #14, again
 
Last edited:
So re-adjust the clutch linkage so that the clutch grabs farther down? Is the thinking if there is more travel to engage and release the clutch then it’s easier to let it out without having it grab too harshly? My only concern is that in my previous cars if things were set up correct there never was the severe wheel hop I have in my Dart. I should be able to simply side step the clutch and if I’m on the gas the car should just go. Meaning there would be noticeable wheel spin but car would still launch and move forward.
Thank you for all those that explained what is actually happening with the functioning of the rear leaf springs the correct pinion angle and what to look for to correct things. I’ll keep you all updated on how I solve the problem.
 
LovetheA's said:
So re-adjust the clutch linkage so that the clutch grabs farther down? Is the thinking if there is more travel to engage and release the clutch then it’s easier to let it out without having it grab too harshly? My only concern is that in my previous cars if things were set up correct there never was the severe wheel hop I have in my Dart. I should be able to simply side step the clutch and if I’m on the gas the car should just go. Meaning there would be noticeable wheel spin but car would still launch and move forward.
Thank you for all those that explained what is actually happening with the functioning of the rear leaf springs the correct pinion angle and what to look for to correct things. I’ll keep you all updated on how I solve the problem.
Click to expand...


Why are you “side stepping” the clutch? It’s the slowest way to let the clutch out and it’s death to the pedal stop.
 
Yellow rose just an expression. I should rephrase that as dumping the clutch and it grabbing solid and assuming the tires aren’t drag radials but street tires my experience has been tire spin but not damage to drive train at least with a healthy 8 3/4.
 
I’m using the factory big block cast iron bell housing. Shouldn’t that be adequate with an approx 450 horse engine? I’m not actively racing the car. It’s more of a street sometimes strip car.
 
I had the same issue, turned out the new clutch was no good, changed the clutch problem solved
 
Along with all the advice given to check and or correct the wheel hop issues which I thank you all for I’m hearing loud and clear if the mopar is wheel hoping something is not correct.
 
It is your pinion angle. Had this exact issue with a maybe 400 horse 383 4 speed in my 1968 Dart. Tried different clutches, springs, etc. Old 4 speed racer said get 4 degree pinion angle shims, place them in between the axle perch and spring. Angles your pinion down. I could barely pull out without my car shaking badly with wheel hop. I did the above. Problem instantly solved. Got the shims from Calvert racing.
 
You must log in or register to reply here.
-

Back
Top