*** Update with photos *** Burnout and tire hopping remedy?

[fairlaniac]

Ok, I don't make a habit of doing burnouts in the street but occasionally it happens. My '66 Fairlane used to have a mild 390. I still have "Cal-tracs" and KYB gas shocks on the car from those days. The occasion street burnout seemed ok. Now I have my 427/484 stroker and the other day after I left a car show I found a secluded country road surrounded by cornfields to jump on it. My street BFG's didn't hold much traction and I blew through first, second and third rapidly but each gear was wheel hopping. The marks on the road are about 18 inches of rubber, a foot of space and more rubber. It looks like two dashed lines on the road. I don't want to shake the shit out of my car and break things. If I'm going to do a street burnout I'd like a nice and easy smooth patch. I have the Cal-trac adjusted to just touching the spring. No pre-load. Are the gas shock junk for this? I have basically stock leaf springs and have no need or desire for mono-leafs. Any idea on how to tame the wheel hop? I never got the hop from the 390.

thanks!

[My427stang]

First, don't do it anymore until you fix it.  That rapid loading and unloading breaks all kinds of stuff from the front to the back of the car

I would look at your pinion angle first, it may need to be more nose down to counter the stock spring wrap-up.  I do believe Caltrac preload could counteract it to some extent, but still need to see, if it goes over-center it will always try to snap back

[fairlaniac]

First, don't do it anymore until you fix it.  That rapid loading and unloading breaks all kinds of stuff from the front to the back of the car

I would look at your pinion angle first, it may need to be more nose down to counter the stock spring wrap-up.  I do believe Caltrac preload could counteract it to some extent, but still need to see, if it goes over-center it will always try to snap back

Thanks Ross! FYI - None of this was done from a standing stop, no launches, rather I'm rolling along and nail it while in first then through the gears.

[shady]

maybe clamp the springs.

[My427stang]

Just be careful, think of the acceleration and load changes when that car was airborne, which it is when it gave you no rubber marks.  Engine goes from pushing 3000+ lbs during acceleration to free wheel, then back to a shock load.

Ironically, the hoppiest car I have ever worked on was a 67 Fairlane.  I was young and didn't know much back then, as Shady said, we clamped the springs and added slappers, (not inferring Shady's advice is bad, but just a reference to me back then) and it was good enough for a healthy small block, but I think the real issue is the long-ish front run of the spring and pinion angle changing as that spring wraps on a stock setup.  We had never known to measure though

Easy to measure pinion angle on 4 jackstands or a  4 post lift, but where it should be to prevent wheelhop  is a bit of a technique and trade-off.  If you have bendy springs (technical term LOL) you need more static pinion angle, but that means when they aren't wrapped, you may have dissimilar planes from tranny to pinion, at extreme cases that causes vibration or u-joint wear. 

I know you didn't want them, but that's the beauty of the Calverts.  Beefy leading front section, and flexible rear section prevents the total wrap up but still rides nice.

I'd say get some numbers, it's all relative angle, crank centerline/tranny, driveshaft, and pinion all together will tell you where you are. 

[machoneman]

Could also be those '66  springs, now what, 57 years old have given up the ghost. Still OEM or.....

[fairlaniac]

Could also be those '66  springs, now what, 57 years old have given up the ghost. Still OEM or.....

Springs are 5 year old Eaton's.

[MeanGene]

Can you run a tight pinion snubber with Cal-tracs? I used to have one that was built up about 3 inches on my Galaxie, ala the old Mopar setups, and it worked pretty well. The Gal has 7 leaves (up from the 406 6 leaves) and clamps

[fairlaniac]

Just be careful, think of the acceleration and load changes when that car was airborne, which it is when it gave you no rubber marks.  Engine goes from pushing 3000+ lbs during acceleration to free wheel, then back to a shock load.

Ironically, the hoppiest car I have ever worked on was a 67 Fairlane.  I was young and didn't know much back then, as Shady said, we clamped the springs and added slappers, (not inferring Shady's advice is bad, but just a reference to me back then) and it was good enough for a healthy small block, but I think the real issue is the long-ish front run of the spring and pinion angle changing as that spring wraps on a stock setup.  We had never known to measure though

Easy to measure pinion angle on 4 jackstands or a  4 post lift, but where it should be to prevent wheelhop  is a bit of a technique and trade-off.  If you have bendy springs (technical term LOL) you need more static pinion angle, but that means when they aren't wrapped, you may have dissimilar planes from tranny to pinion, at extreme cases that causes vibration or u-joint wear. 

I know you didn't want them, but that's the beauty of the Calverts.  Beefy leading front section, and flexible rear section prevents the total wrap up but still rides nice.

I'd say get some numbers, it's all relative angle, crank centerline/tranny, driveshaft, and pinion all together will tell you where you are.

Ross,
Here is a sketch showing my angles. The car has a front to rear rake/angle of 3*
Crank is 3.5* to the floor
Driveshaft is parallel 0*
Pinion is 1.5*

Sketch, front is to the left.
http://www.fairlanet.com/images/pinion-angle-fairlane.jpg

[machyoung]

Can you run a tight pinion snubber with Cal-tracs? I used to have one that was built up about 3 inches on my Galaxie, ala the old Mopar setups, and it worked pretty well. The Gal has 7 leaves (up from the 406 6 leaves) and clamps

Didn't the higher performance Mopars also have a longer supporting leaf or additional leaf on the pass side

[MeanGene]

Yep, they had it pretty scienced out

[427Fastback]

Yep, they had it pretty scienced out

Yes..they called them super stock springs..Put lots of them in my brothers Darts..I believe it was 6 leaves one side and 7 on the other side

[Rory428]

The nice thing about the MoPar leaf springs, was they were designed with a short, stiff front section, ahead of the center bolt, with long section behind, which kinda acted like a built in traction bar. That said, most modern Stock Eliminator MoPars are now using the Calvert monoleaf springs with Cal Tracs.    Concerning your Fairlane, does it still have the factory rubber "ISO clamp" setup that has rubber pads between the housing spring perches and leaf springs, with a metal surrounding them? If so, I would remove that stuff, it was meant for a softer, smother ride, but are not a good thing for performance. I am having a similar situation with my 428 CJ 4 speed 59 Ford 2 door sedan, it will wheel hop pretty badly with street tires, even with new stock style leaf springs, and a set of Lakewood "slapper" bars. In both our cases, I believe the stock type springs are too soft and "flexy" on hard acceleration, so I am going to try some clamps on the front section of the leaf springs, and see if that helps. Not sure if gas shocks are as good as an old style hydraulic shock for this style of driving. I can say that this is the first time that I have heard of a car wheel hopping with a set of CalTracs, although I believe that they are designed for use with the Calvert mono leaf springs. But I have no personal experience  with Cal Tracs. On my 59, at the dragstrip, it will wheel hop badly with the street tires, (275/60R15 BF G T/A radials) as well, but not with a set of drag slicks, which I assume is due to the thinner sidewalls and lower air pressures, which better absorbs the impact of sudden throttle, but that is more of a crutch, and obviously not a solution for your street only car. Have you tried lower tire pressures, to see if that helps at all?

[6667fan]

Doug, you won’t get to have all the possible fun with that car if you don’t commit to the rear end components. The engineering Calvert put into their systems is proven over and over. I tried fresh factory springs with their bars and had mixed results. After switching to the split mono it was a new car, ( at the track)   . On the street the leaf set up is noisier than stock as the insulators go away. So as always there is a trade off.
I have a fresh set of the Caltrac rear leafs. I bought a second set with more arch in them for tall tire clearance and to raise the rear end for the look I like. You would just need the front sections. I don’t know if they sell the fronts separately.
As far as your immediate problem you could experiment with tire psi. I have seen old, hard, rubber behave like that too.


Oh yeah,  you’ll have to buy new shocks for the rear, and then new front shocks, and then new front coils, and then, etc, etc.

[Tunnelwedge]

I'd toss the KYB's in the bin. Stock original oil dampers are better than KYB. Great marketing though.
QA1 adjustable are an excellent choice as are Viking.
Koni has some nice shocks.