Technical Borg & Beck Finger Height - Pressure Plate & Clutch Issue

G'day Hambers, wondering if anyone can help me with the specs of the finger heights for a 10.5" borg and beck pressure plate?

I have a full kit from Wilcap and I am having trouble getting the engine to disengage from the gearbox when trying to go in to first gear.

Parts:

• 283 SBC engine
• 1939 Ford 3 speed gearbox - fully rebuilt and working as it should
• Wilcap BH 307-350 MT bell housing adapter with correct pilot bushing
• Wilcap Borg & Beck 10.5” pressure plate (3 short fingers)
• Wilcap 10.5” Organic disk - 1 3/8 x 10 Early Ford Spline (installed correct side to flywheel)
• 168 tooth flywheel drilled for 10.5” clutch
• Correct throw out bearing for the application (part # 78-7580-A)

Issue:

• I cant select first without grinding the gears and I don’t have enough adjustment left in the throw out bearing as it will touch the pressure plate fingers. It feels as though the pressure plate fingers need to travel or be pushed more for greater clamping force but as I said, any more adjustment in the throw out bearing means it would be riding on the fingers constantly.

My thoughts:

• I know Wilcap did/do have a fantastic reputation for quality parts, but I have read a few posts about their pressure plates sometimes not being set up correctly in regards to the finger heights.
• The problem I have points me to finger height on the pressure plate possibly not being correct and not allowing enough clamping force.

Questions:

• Should I adjust the finger height on the pressure plate? I can back off the throw out bearing as I have a heap of adjustment in backing it off (away from the fingers) just don’t have enough adjustment in moving it forward without it being in constant contact with the fingers.
• What should the finger height be for my application? I am wondering if it was set wrong initially or if the fingers are not all the same height.

I am struggling to sort this issue out and have had the thing apart more time than I can remember trying to understand what is happening with no luck.

Thanks in advance.

 

Hopefully you are aware that those boxes are not synchronized in first. Sitting, shift to 2nd or 3rd then go for 1st or reverse, in traffic your going to be nearly stopped before getting into 1st floating
You’ll need to check how much air gap you have between the disc and pressure plate at full disengagement of the clutch

 

Yes, I’m aware it’s not synchronised in first. I’ve tried going from 2nd and 3rd and then in to 1st when completely stopped and it still struggles to go in to 1st without grinding.

 

What ch***is and pedals are you running?
The problem I had with a similar setup in my 40 was not enough adjustment on the threaded adjustment rod that runs from the pedal to the arm on the TO bearing cross shaft. That and a severely elongated eye at the end of the rod. Bought a new longer rod (5”)from Third Gen Auto and that gave me the additional travel I needed to move the T/O bearing and the arms in farther.

FWIW, The rpm’s have to be at idle speed to get it down in to first, or you will get gear clash. But you already know that!
I occasionally can double clutch it at a slow forward movement in second and get it into first, but it’s always fingers crossed. I’m ready for an automatic.

No more adjustment, ran out of threads. T/O bearing barely depressing the clutch fingers.


New rod from ThirdGen Automotive. Think that it’s a ‘41. 5” long

 

As @Wanderlust suggested you want to adjust your clutch for proper air gap, for a three finger B&B you want .050.

 

Adjust the throw out bearing so it’s an 8th away from contacting the fingers and have a helper depress the clutch fully while you measure the gap, if no or not enough air gap you’ll have to adjust the ****ons on the fingers to achieve correct distance, also need to verify that the shift rods are correctly adjusted as well

 

I have the same combination of parts on my 40 Ford and had the same problem you and "hot rod A" experienced and solved it the same way "hot rod A" did. I wouldn't mess with the clutch finger adjustment before checking/adjusting your clutch linkage first.

 

This thread has measurements
https://www.jalopyjournal.com/forum/threads/mercury-pressure-plate-question.1343189/

 

Thanks for the input so far.

It's a 1935 ford ch***is running 1938 pedal ***embly. The pedal ***embly was rebuilt and I installed new bushes when I re-did it. There is no slop or free play.

I have enough adjustment in my linkage with plenty of threads left on the rod in either direction. The problem I have is if I adjust it to where it needs to be to disengage the engine from the gearbox, the throw out bearing is riding on the pressure plate fingers constantly.

I tested this theory today by adjusting out all of the free play and I had the throw out bearing constantly touching the pressure plate fingers (by all accounts this is not how it should be set up or it may cause premature failure in the TOB). I took it for a drive and issue was gone, no grinding trying to get it in to 1st gear when stationary.

This tells me I don't have enough 'clutch throw' or 'travel' to disengage the engine from the gearbox if there is gap between the TOB and the PP fingers.

Now, my thought is that I have to increase the distance of the pressure plate fingers closer to the throw out bearing so that I can back off the adjustment of the throw out bearing to have an acceptable amount of free play between it and the pressure plate fingers. Also allowing the engine to disengage from the gearbox which is the root cause I believe.

Does this seem logical or am I missing something?

 

It's also possible that the clutch linkage geometry is not correct. Pedal goes to the floor without moving the TO bearing far enough. Lever length, position only needs to be off a small amount for this to happen.
Any way to post some pics of the linkage setup?

 

Another thought. Could the linkage be pushing the engine/trans forward? Fords of that era used anti chatter rods for that reason

 

Not sure about the geometry as it’s all pieced together from different years, 35 ch***is, 39 gearbox, 38 pedals, etc. The threaded rod with the clevis was bent to suit the lever arm on the gearbox. I’ve added a photo of it.

 

Yes, this is a possibility, not sure how to stop this from happening if it is. No anti chatter rods on my application as it’s 39 gearbox to SBC.

 

Have seen guys attach brackets to the bell housing bolts to hold the engine end of the rods.

 

Looking back on some old posts by the late Bruce Lancaster and **** Spadaro, it sounds like that with a torque tube, there is a possibility for enough pressure and flex in the mounts to need the anti chatter/torque rods.
Don’t know for sure as my trans is 41 pickup open drive.
It looks like you have the correct arm. Did it come on the trans?

(Image from Van Pelts)

 

Or, similarly, blown out thrust letting the crank get pushed forward in the block. I have a car doing that now. Watch the pulleys while someone pushes the clutch. Or, pry bar the crank back and forth. It only takes a little.
Is the flywheel flat or cup ? If it's a cup, the height of the step may have been ground wrong somewhere along the way.

 

What are you using for engine and transmission mounts ? Ford style biscuits?

 

I hope the following info from personal experience and Tom Monroe's '77 clutch handbook will be helpful.

Anti-chatter rods were used on '32-'39 Fords mainly because of clutch pedal forces directly acting on the transmission or bell housing release fork shaft. Pedal force times the overall ratio to the throw out bearing is more than enough to move the engine forward before/during clutch dis-engagement, which the rods control
Ford switched to a (modern) equalizer clutch linkage in '40 that transmits most if not all clutch release forces between the frame and engine, eliminating/minimizing forward engine movement, and the necessity of anti-chatter rods.

Ideally, you want about 3/8" total throw-out bearing clearance between the pressure plate and transmission, and an adjusted 0.100" max between bearing and pressure plate fingers. Any more clearance is wasted pedal travel and not necessary. Keep in mind the overall ratio between the pedal pad and throw-out bearing is usually +/- 11:1 ratio, which will result in the normal 1"-1 1/2" pedal "free play".

With the clutch pedal properly adjusted, there should be about '040-'050" clearance between the clutch disc and pressure plate at full pedal travel. With the pedal's release and full stroke measurements in the ball park, the clutch operation should be spot on.

I used a pre- '40 direct acting style clutch setup on my '32, and made "anti chatter" rods out of threaded rod, angle brackets on the transmission and spherical rod ends to the frame, containing forward engine movement, and pictured below.
On my '40, I made a modern style equalizer for the larger 5-speed and BBF.

One last item. The usage of obsolete Borg & Beck and Long pressure plates by many on here is, well, interesting, when a modern, much simpler, much more available and sometimes lower cost alternative is the diaphragm. Two other big advantages are no (needed) finger adjustments, and lower pedal efforts. Just curious.
Bob

 

@V8 Bob
Thanks for the specs.
So, in your experience do you recommend using the anti-chatter rods with open drive like in the picture?
Is that a T-5 adapted to stock 8BA bellhousing? Great looking setup!
Thanks!

 

Thanks for this, I have tried the 33-34 (40-7511), the 35-38 (48-7511) and the 39 (91A-7511) as I have them all in my stash of parts. The 38 one aligns with the 38 pedals I have but it wont clear the 39 gearbox without hitting the casing at full pedal as it doesn't have the correct angle. The 39 one works as it should on a 39 gearbox but this is also why I had to bend up the threaded linkage rod to align with the 38 pedals.

 

Yes ford style biscuits for the mounts which are new and the better quality rubber on the bushing with metal reinforcement within it.

 

Thank you @V8 Bob, this is very helpful. I'm aiming to pull it all out today and will look to see if I can do something similar with the anti-chatter rods. Your set up looks fantastic.

I had all the parts which I bought several years ago when I didn't really know about alternatives so I am trying to use what I have without spending more money. However, I am also finding it difficult to find a diaphragm style PP for my configuration as I would look at that as an alternative but I cant find what would suit what I have so persisting with what I have which are all essentially new items.

 

When I finished building the open drive '32 ch***is, I visually verified engine/trans movement during clutch dis-engagement, making "chatter rods" necessary in my case. I would at least look for movement when using direct linkage to know for sure if control rods are needed.
The cast iron bell housing is a one-year-only regular production '51 Mercury, with a '32-'39 clutch release shaft instead of the stock later style, and a custom clutch arm. ****** is an "off topic" 5-speed using a 1" adapter plate.
PM me for more details if wanted, and thanks for the compliment!

 

Update - I pulled the gearbox out today and found that none of the fingers on the pressure plate were of the same distance/measurement. The fingers were never adjusted by me or anyone else, I bought the PP new from Wilcap and never thought to check the measurements as I was told it was all set up for my application as I also bought the Wilcap adapter and clutch disc altogether with the PP. All the nuts were staked/punched so it looked like someone had 'set it up' prior to me installing it.
I couldn't really find measurements anywhere on the interweb on what the installed measurement should be for my application so I adjusted the fingers out another 3mm or 1/8. I used the finger which was closest to the TOB as the base and adjusted all others to match. Not sure if this is too much or too little but I will install everything back in and see what happens.

 

Take the clevis off the linkage find a fine thread bolt that fits the clevis put a nut on it screw it into the clevis and weld the nut to the clevis. This will give you another 1/4 in. of adjustment. Had to do this on my 1950 Ford F-1 truck it worked great no more grinding.

 

GOOD GRIEF!
Is WILCAP still in business? What do they say?
Your hands on approach may get you on the road quicker than a back and forth with them.
Good luck, hope that you found the fix. Let us know.

 

I would purchase another brand, I wouldn't waste my time trying to adjust the one you have. In the last year I have had 3 customers bring cars back after fitting Borg and Beck clutch and pressure plates. There appears to be a quality control problem. These were 3 different models. The distributors sent replacement parts however on closer inspection all the replacements had issues. Google Borg and Beck pressure plate problems, it appears to have been an issue for a number of years.

 

I think Wilcap is being run by another company now trying to keep the name going. I bought all of these parts years ago, so I will just try to remedy the situation myself. I hope this solves my problem.

 

@krazee - which alternative PP do you recommend? Do you have any part numbers? Thanks for the info, I have read other posts with people having issues with fingers on the borg and beck PP's.

 

Good luck, good to see you tackling it head on. Let us know how it turns oit.