Clutch pedal mods

-
gliderider06

gliderider06

FABO Gold Member
FABO Gold Member
Joined
Oct 21, 2011
Messages
2,479
Reaction score
1,695
Location
Delaware
Has anyone modified their clutch pedal from the 5-1/4" length to the 6" length for a faster actuating clutch. I have also heard that some people extend the Z bar 3/4" instead of the pedal. Has anyone done any of these mods and was it worth it? Thanks!
 
gliderider06 said:
Has anyone modified their clutch pedal from the 5-1/4" length to the 6" length for a faster actuating clutch. I have also heard that some people extend the Z bar 3/4" instead of the pedal. Has anyone done any of these mods and was it worth it? Thanks!
Click to expand...


i have never thought to modify the pedal itself but i have tried modifying Z-bars and tried different lengths of upper and lower clutch rods and i always go back to the factory dimensions..

to me, it seems that what your looking for has everything to do with the pressure plate ....if you get a centerforce or something like that, where you eliminate the pedal overspring, might get some mechanical advantage. the pressure plate is the main spring in the system and will determine a lot of factors with performance.

when i tried to modify my set-up, i wasnt really looking for performance as much as easy operation bcoz im 4'10" but just moving the seat farther foward and trying different pressure plate/clutches made a better difference than z-bar mods.
In an A-body the mods to the geometry are not as forgiveing as a bigger car ...i have tried a lot of different mods/ combos in a B-body with greater success

i think the principle is the same between ease of operation and performance
 
It appears that this mod will move the position of the z-bar down leg toward the front of the motor. That also means that the clutch rod will need to have enough length to adjust out the 3/4" that was added to the pedal. But a bigger issue for my Demon is that the down leg will hit my header pipe. Of course this is all based on my interpretation of what's happing with the linkage based on the mod described in the Mopar Muscle article.
 
hi, an easier method is to shorten the upper arm on cross shaft and lengthen lower arm. I shortened mine about 3/4 in on upper and lengthened lower 3/4 in. I had to use a pedal stop under clutch pedal to keep from over centering.
this made the clutch a toe tapper. very little travel is required. the clutch rod back to throw out fork still will be same length. I have ran this setup for last 30 yrs in my 340 duster. very simple setup. just food for thought
 
I have both. The 6 inch is a little stiffer but shifts like butter compared to the 5 1/4 . also goes into reverse without the normal clunk.
 
Yes that article is what I was refering to. I have also considered lengthining the lower Z bar by th 3/4". I was just curious to what has been done before I go ahead and do it to my car. If nothing else, it will give me something to do for a few hours.
 
Bear in mind that the further you go with this, the more difficlult the clutch will be to push. If you run a diaphragm clutch probably not a huge issue. Big 'ol BB, that might be an issue.
 
hi, if your running a 3000# clutch, true will be some what harder. I ran 2800 down to 1600 # clutches with this. I ran the B&B/long pressure plates, the ratio on those is way better versus B&B. by modifying both ends of cross shaft, it works better. I speak from practical experience. I been running clutch cars long time.
 
If you can find the earlier pedal assembly the 6 inch dimension is already there, plus the clutch pedal shaft rides in needle bearings instead of nylon as an added bonus.. Herb McCandless never modified the z bar back in the day, said it made the clutch a bear to push, lengthened the clutch rod attaching point on the pedal 3/4 inch instead, probably due to the stiff racing clutches they used to run. A modified z bar may not be as bad with a diaphram clutch.
 
Looking at it, to me, seems that the z-bar mod might be easier to do than pulling the pedal assembly out of the car and easier to change if it does not work well.
 
You do run into some clearance issues with some headers on the lower side. And the rod from the pedal to the Z rubbing the fire wall when doing the z-bar mod. Some pedals came that way from the manufacture so the rest of the car will accept the pedal mod easier.
 
hi, when I shortened the upper bar on Z bar, I had no clearance problems with firewall!! my headers are kind of close to lower arm, yet there is room.
btw, back in the OLD days , mopar racers used a 3400 # clutch, they were hard even with stock ratio linkages. I had a 3400# clutch in my 55 chev then, was a brute. just food for thought.
 
I shortened the upper arm and lengthened the lower 3/4" and it is hard to push, and it made my pedal hang closer to the floor making it harder for me to adjust. I guess I will be changing it back soon.
 
Ok, So I have tried the modified z-bar. Like I was pushing on a brick and to find out that I had the wrong bellhousing ball stud which was pushing the fork sideways instead of straight. Got the correct bracket, another stock Z-bar and it shifted smoother. I still have a issue going into 2nd. I get a pedal, lengthen it to 6", and it is hard to push on the pedal and it is close to the floor, but a bit easier to shift into second without it grinding. (brand new Passion trans) No matter what I have tried it is jerky in second. No smooth transition, at any RPM. it just bucks into it. 2-3 shift is smooth and 3-4 is butter. Am I missing something on adjustments or does everything need to break in some? Only 135 miles on motor/trans/rear. Am I doing something wrong?
Thanks!
 
You must log in or register to reply here.
-

Back
Top