Issues with clutch linkage on #782 (Bob?)

[DanEC]

Yesterday the car actually moved under it's own power for the first time but I could tell the clutch needed more adjustment as the transmission would not go into gears easily while running and release was right at the end of the pedal travel.

Today I carefully adjusted the slave cylinder until there was about 1/16 inch freeplay with the piston bottomed out in the cylinder and reinstalled the spring to the fork. I also adjusted the pedal to where the face is about 7-3/4 inches from the end of the footbox. I'm getting every bit of 3/4 inch movement of the end of the clutch fork when the pedal is depressed, a little more actually. Here is a video of clutch fork movement.




I have the seat set back to about 1 or 1-1/2 inches from the bulkhead due to being 6'2" and having a 34 in inseam. The pedal face is 23 inches from the edge of the seat cushion.



This was a step in the right direction as the clutch will disengage cleanly now and the transmission will shift fine to all the gear positions with the engine running. But, it's disengaging probably about a half inch to an inch off the floor (footbox). I have to completely extend my leg out and stretch out in the seat to get the clutch all the way in. The upper position of the clutch is not bad but 23" + 7-3/4" is requiring full extension and then some. I really need a little shorter clutch pedal cycle.

My clutch is a bent finger McLeod and I have a spacer on the slave cylinder to get everything in alignment.








I also noticed that the 3/4 inch Tilton master had a little fluid on the rubber bellows and I pulled it off to see that it has been leaking a little. I also noticed that the rod seems to hav been rubbing on the housing and had scrapped the shaft pushing up a burr on it. I took a hobby file and smoothed the burr off of the shaft.



All in all, does this sound like maybe I just need to insall a 1 inch Tilton master which is mentioned in the manual as an options??

[DanEC]

I guess I should add that moving the seat up isn't a real great option. I can barely fold my legs and feet in through the door opening as it is.

[ERA 778]

What transmission, bellhousing, clutch, etc. are you using? I used a Quicktime bellhousing and McLeod clutch and diaphragm style pressure plate hooked up to a Richmond Gear five speed. I had to go with the aluminum spacer on the slave and a 1" master cylinder to get adequate travel. Even now I sometimes think about going up in master cylinder size again since the move into reverse is still marginal. At first I was concerned about pedal effort, but that has really not been an issue.

[patrickt]

I have the 7/8" Tilton, Lakewood bell housing, Centerforce clutch, and use the little block of aluminum as a spacer. My pedal is pushed back because I'm 6'4", and it works just fine - beautifully, in fact. If you would like me to measure anything I'll be happy to do so.

[patrickt]

Here is a video of my slave/fork in action.

[strictlypersonl]

We usually use a McLeod diaphragm pressure plate, which might require less motion. If your current effort is light, consider going to a larger master cylinder. You might now have a 3/4" or 7/8" master. The size is cast into the side.

[DanEC]

Patrick - if you don't mind, what is the distance from the clutch pedal face to the seat cushion (nearest point) on your car? And the face of the clutch pedal to the footbox?


ERA 778 - mine sounds like your setup except I have a toploader - Quicktime, McLeod diaphragm clutch, spacer. Thanks for the cmts on the 1 inch Triton


Bob - it's a 3/4 Titon. I looked at it while under there. I think this one might be toast anyway with some leakage and the scored shaft?? I wouldn't call the pressure light but it's not bad. Does a 1 inch one sound right? By area increase that should shorten the pedal stroke about 40%.

[patrickt]

Originally Posted by DanEC

Patrick - if you don't mind, what is the distance from the clutch pedal face to the seat cushion (nearest point) on your car? And the face of the clutch pedal to the footbox?

The face of the clutch pedal is six inches from the end of the footbox. The face of the clutch pedal is 26 inches from the end of the seat cushion that is closest to the pedal. The face of the clutch pedal is 45.5 inches from the seat upright backrest cushion. That measurement is directly back from the pedal, the inward curve of the back of the seat looks like there might be one more inch or so to the very "backest" part of the seat, which is in the middle.

[DanEC]

Originally Posted by patrickt

The face of the clutch pedal is six inches from the end of the footbox. The face of the clutch pedal is 26 inches from the end of the seat cushion that is closest to the pedal. The face of the clutch pedal is 45.5 inches from the seat upright backrest cushion. That measurement is directly back from the pedal, the inward curve of the back of the seat looks like there might be one more inch or so to the very "backest" part of the seat, which is in the middle.

I have 42 inches to the off-center back of the seat cushion from the pedal. It sounds like I may have my seat about an inch forward of where yours is - I have an inch clearance to the bulkhead. I suspect yours is against it. I may have my seat located a little too far back for my height and leg length. Possibly moving it about 1/2" forward and going to a 7/8 master cylinder would be a good compromise.

thanks

Dan

[ERA 778]

Bob says that they usually use the McLeod diaphragm plate like mine, but there was no way I could get the 3/4" cylinder to work. Maybe the Quicktime bellhousing creates a different geometry. I know ERA usually uses the Lakewood units. This might explain the difference. I've got over 4,000 miles on my car now and other than the occasional issue with reverse mentioned above, mine works great with the 1" cylinder. (The reverse issue may just be my legs; I'm slightly height challenged at 5'-8" and have to move the seat up almost to the end of the travel for the adjustable mounts to comfortably work all three pedals effectively.)

[DanEC]

Originally Posted by ERA 778

Bob says that they usually use the McLeod diaphragm plate like mine, but there was no way I could get the 3/4" cylinder to work. Maybe the Quicktime bellhousing creates a different geometry. I know ERA usually uses the Lakewood units. This might explain the difference. I've got over 4,000 miles on my car now and other than the occasional issue with reverse mentioned above, mine works great with the 1" cylinder. (The reverse issue may just be my legs; I'm slightly height challenged at 5'-8" and have to move the seat up almost to the end of the travel for the adjustable mounts to comfortably work all three pedals effectively.)

It sounds like I need a different master - I guess I just need to figure out whether to go with a 7/8 or 1 inch. Compared to my 427 Corvette with a McLeod diaphragm clutch and especially to my late model Mustang GT (may have a dual-disc clutch) this clutch is already somewhat heavier than I expected. I assume this is the same clutch package Keith Craft sends out with most of his Kirkham motor packages so it shouldn't be anything unusual. A 1 inch master sounds like what I would like in terms of shorter travel but I'm not sure about in additional leg effort. So the 7/8 may be a good compromise. I need to make sure I haven't overcompensated for my heigth and entry/exit to the car by positioning the seat back too far. Although pretty tall, I typically sit closer to the dash and steering wheel than a lot of people who are shorter than I am.

Thanks

Can someone verify that the Tilton Model 74 series is being used for the clutch on ERAs? From memory that is what it looks like.

[ERA 778]

Yes , they are series 7400 kits. Summit Racing has them.
Let us know if the 7/8" unit does the job!

[DanEC]

Originally Posted by ERA 778

Yes , they are series 7400 kits. Summit Racing has them.
Let us know if the 7/8" unit does the job!

Will do. I figure if it shortens the pedal stroke inversely proportionally to the increase in piston area - and assuming the pedal stroke is about 6.5 inches now (?) - I will end up with a 4.8 inch pedal stroke. I think that will work.

Thanks

Dan

[DanEC]

Reporting back.

Went with a new 7/8 inch master cylinder. Although my clutch seems surprisingly heavy to start with after carefully adjusting the clutch pedal bellcrank assembly (I think I put it back together a little off) it's still heavy but about the same as before after adjustment and with the bigger master.

I have the bellcrank set to where it is pretty much hanging straight down and rotates back and up as the pedal is depressed. Before I had the bellcrank positioned forward quite a bit and depressing the clutch required it to go down and then overcenter in going to the rear. I think that sort of amplified the pressure plate effort although it minimized pedal throw.

I double checked the McLeod clutch and it checks out as a regular street/performance diapraghm clutch and organic disc set advertised to be light in operating pressure. Same thing as in my 427 Corvette that I always though was so light in pressure.

I noticed the ERA bell crank on the clutch pedal has another hole on it closer to the pedal axle. Using it would provide more leverage but result in a lot longer pedal throw or require a really big master cylinder. Nothing in the manual that discusses it.

I will fire it up today since I'm going to change out the break in oil, and see how the overall action is now. As long as the pedal stroke is a little shorter it will probably be OK.

[DanEC]

Well, my fiddling around with the clutch pedal bellcrank more or less defeated going to the bigger master cylinder as far as pedal throw is concerned. So I moved the bellcrank back to almost where it was before and now the range of clutch engagement seems more normal. I still need to do some more adjusting of the pedal heigth and seat location.