[Lonnie P]

Has anyone modified their clutch pedal for more travel when using a street twin? My clutch is grabbing almost against the floor & there is almost no freeplay at the top. It is making shifting very difficult. All linkage is very good & cross shaft is new.

It is the B&B Long pressure plate with an adjustable TO bearing.

Does anyone have a dimension for the relocated hole in the clutch pedal to make things work better?

Thanks in advance for any info you can provide.
Lonnie

[Dougs72Nova]

Possibly need an adjustable fork pivit ball?


http://store.summitracing.com/partde...5&autoview=sku

[Lonnie P]

Doug, Thanks for the info. I've used the adjustable pivots before to prevent interference with the fork/bell housing or pressure plate. I do not have this problem as I aligned everything with the adjustable TO bearing.

I have a lack of release travel where the clutch has no freeplay at the top & still releases very low at the carpet. I need to increase the ratio of the linkage to get more release gap on the clutch.

I originally installed the adjustable TO bearing so that there was 1/4" freeplay as recommended by McLeod. This made the clutch too loose & I could not get it in gear.

Afterwards, I tightened the clutch & removed almost all the freeplay. This was enough to be able to get the car in gear, but not enough so it could be shifted smoothly. I then removed the rubber stop under the dash so I could get more adjustment. This is better, but still not enough as the TO bearing is almost in contact with the pressure plate when released & it still grabs too close to the floor. I cannot get any more adjustment unless the pedal can move more or the ratio changes.

This is why I want to modify the linkage for more clutch travel. I unfortunately tried to drill my cross shaft to alter the ratio, but it is hardened & promptly ate a bunch of titanium nitride drill bits & only made a dimple in the steel. I fear the clutch pedal is also hardened.

The twin discs take more travel to release as you have to maintain a gap for 2 plates. I have done a bunch of Street Twins on LT1 & LS1 cars & they all require different slave cylinders for more travel. Now this setup is proving I need the same thing.

It is also discouraging that McLeod only has tech support on Fridays until 1:00pm Pacific time. It amazes me that a major manufacturer does not offer normal business hours for tech support.

[Dougs72Nova]

Lonnie. What fork are you using? I had a MCleod dual friction diaphragm style clutch and had the same problem you are having. I cut the upper clutch pedal stop down to where it was just barely there and the clutch started engaging right off the floor with the pedal all the way up and no play. That clutch made some bad creek noise so away that clutch went anyway. What i found out when putting the new Hays clutch in the car was this.... The previous owner had the wrong fork in the car. I bought a new gm unit and the gm fork was about 1 1/4 inch shorter. The long fork would make for an easier clutch pedal, but it will also require more travel of the linkage to get the clutch to disengage. I put my car back together with the gm fork and Hayes street/strip clutch and all is well. I have about 1 1/2 inches of play at the top of the pedal. The part number on the correct fork is 3892632. P.S.... Where does the clutch fork sit in the hole of the bell with the t/o bearing just touching the pressure plate? It still seems to me that a adjustable ball could fix your problem?

[Lonnie P]

I always assumed the fork was correct but have no idea if it is. It lines up with the rod pretty well. Unfortunately I would have to remove the parts to check the number. If I can get a shorter fork, that would be great. Do you have any dimesions from the bellhousing to the tip of the fork for reference?

It did work fine with the previous Hayes setup. I only had to push the clutch in a little over 1/2 way to shift it with the correct freeplay at the top. I just got tired of smoking clutches & ruining flywheels. Also the diaphagms were not happy with shifts much over 7000.

[JimM]

I agree with Doug, wrong fork. But...
Mark.L.W uses this same clutch. Shoot him a PM to get the straight poop.

[Lonnie P]

Jim,
Thanks, will do.

[Dougs72Nova]

Originally Posted by Lonnie P

I always assumed the fork was correct but have no idea if it is. It lines up with the rod pretty well.

Is the adjustable linkage that goes from the z-bar to the fork on the inside of the z-bar(linkage toward the engine) or the outside(towrad the frame)? This can tell you if you have the long fork or the short. If the linkage is on the motor side, you have the short fork. If it's located on the outside of the z-bar, you probably have the long fork.

[sc68z28]

I drilled a new hole in the Z bar.

About 1" lower got me another .080" to .100" more travel at the T/O bearing



---Bill.

[Lonnie P]

Bill,
Awesome..... now I just have to find someone to drill it. My cross shaft ate 6 titanium nitride drill bits & I only got a dimple in it.

I was trying 1" down as you show.

What did you drill it with?

The .1" at the bearing must be about 1.5" on the pedal, correct?


After a conversation with "Mark .L.W.", he stated that my clearance may be off between the front disc & floater. Mark, thanks for taking the time to help me out. I'm considering reshimming the floater for a little more clearance, even though it measured out OK.

As for the clutch fork... mine is 10.5" long to the push rod hole from the center of the bellhousing, as it is installed. Does this sound like the correct length? My lower rod is on the engine side of the z-bar & is straight with the fork.

Thanks for the info.

[sc68z28]

Originally Posted by Lonnie P

What did you drill it with?

The .1" at the bearing must be about 1.5" on the pedal, correct?

Lonnie,
I did not have any trouble drilling mine, just used a bit out of a set I bought at Kmart. My Z bar is a repop from Classic, probably just mild steel. Yours seems to be hardened .

My pedal ratio is now about 10 to 1, depends on where on the pedal arc you measure it. Every 1" at the pedal pad, moves the T/O bearing .1" . I have about 9" total pedal movement, and about .900" movement at the T/O bearing.

My clutch needs a min of .400" T/O freeplay, I have about 1/2 a pedal of travel before the T/O bearing touches the PP fingers.

I have an extra fork at home (I'm out of town right now) if you need me to measure it? I'll be home tomorro afternoon, let me know.

---Bill.

[Lonnie P]

Bill,
A measurement would be greatly appreciated.

I have a reproduction z-bar. I think it was Classic Industries that made it. You cannot even mark it with a file or center punch.

Thanks,

[sc68z28]

Originally Posted by Lonnie P

Bill,
A measurement would be greatly appreciated.

Lonnie, the total length of the correct fork is 10.25" long.
I also have one that is a universal type, (it's to long) total length is 11.1".

On the correct fork (pic below) measures 6.5" , from pivot ball center to push rod center.

On the one that is to long, it measures 7.25" , pivot to rod center.



---Bill.

[Lonnie P]

Taking measurements with the fork in the car is tough, but I came up with the following:

10.5" from the center of the trans to the push rod hole.
7" from the pivot ball center to the push rod hole.

It looks like the one in your picture.
I guess I'll be pulling the trans this weekend to be sure.

I never suspected the fork as it worked fine with a single disk clutch for the last 18yrs.....

[Lonnie P]

I found some tungsten-carbide bits that will supposedly drill through a file, so I'll try a new hole in the cross shaft first. I'm crossing my fingers on this one as I hate to pull everything back apart. Trying to remove everything without scratching up the paint is not easy.