Flywheel/pressure plate combo on '50 Merc block

[Jack 34pu]

I still did not get a good answer - probably because I did not ask my question correctly. Here goes again.

The flywheel on the '50 Merc has 6 evenly spaced mounting holes for the pressure plate on an approx 11 5/8" dia circle. The clutch surface is approx 8 7/8" dia - then a shallow groove - then pressure plate mounting surface. Most catalogs show a pressure plate with three sets of closely grouped mounting holes and 3 lever actuators rather than evenly space mounting holes and a diaphram actuator.

Could this flywheel be from an older motor? It looked like it had been on there a long time and was not easy to remove.
This is going into a 28pu @ about 2,400#, so a 9" clutch would be fine - right?

[Bruce Lancaster]

'49-53 Mercs used the flywheel you describe. It use Borg and Beck diaphragm/Belleville type pressure plate, not the Long type used in various sizes on Fords 1935-53 with the grouped pairs.

[Bruce Lancaster]

It would be fine for your use...there were two pressure plates, 49-50-very early '51 and '51-53. I assume you are using an early Ford trans, which absolutely requires the '49-50 type due to the large early throwout and matching finger spacing.
These are getting rare and I think are only available as rebuilds...find someone who has the last several issues of Hot Rod Deluxe magazine. They did an article maybe 5 issues back on '39 trans to SBC Chevy, a swap traditionally employing the Merc plate, and they provided ordering info for a modern plate assembled with early type finger spacing.
You cannot use the later plate or a regular '55 Chevy ones as fingers are too close and will interfere with collar when they move.

[George/Maine]

You must have the later pressure plate the early one had a 10" surface.As i said in your other post,I now have one on the bay
#320650765178 its 10" PIC and uses the 32 thur 48 throwout bearing.

[rotorwrench]

I've been farting around with the 8CM type Mercs since I was a pre-teen (my first hand me down car). They have the Borg & Beck 10A7 type pressure plate but they are standard three finger release. The fingers aren't skinny like the Long type pressure plates and the adjustments for the fingers are done at reassembly of the cover only. There are no external adjustments to the three fingers after the locknuts are peened into the screws. The PP covers can be identified by the stampings around the inner ring where the fingers are. The early 1949/50 ones are stamped 0988 and the later 1950/early 51 ones & replacements were stamped 1310 but most likely are mixed and matched from repeated overhauls over the years. These number are B&B model numbers specifically for the Mercury 8CM applications.

The 48 thru early 51 Mercury models used the B&B Spring Flex 10-inch clutch driven plates for B&B PP covers but I think you can use the Ford Torbend 10-inch disk that was used with the 10-inch Long type comercial and police application clutch used up to 1953 but I haven't compared them to see if that's true.

Bellville type diaphragm set ups came much later and at least one aftermarket manufacturer makes one for the early Ford 1 3/8" 10-spline transmission input shafts but I don't know if they will fit the evenly spaced bolt hole pattern of the B&B 10A7 or not. I think they may be a 9 1/2" size. I was always under the impression that the flywheel would have to be drilled to work with the new type clutches.

Kerby

[Jack 34pu]

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Rotorwrench,

Thanks for good info. That sounds like the one I need to use with the older trans input shaft sleeve and throw out bearing.
Any idea who may have a B&B 10A7 on their shelf that does not have to be rebuilt? I put an old 9" clutch plate on the flywheel and it matched the mating surface so a 10" clutch would not work - at least I think not - still learning. Ha!

Jack 34pu

[V8 Bob]

Bellville type diaphragm set ups came much later and at least one aftermarket manufacturer makes one for the early Ford 1 3/8" 10-spline transmission input shafts but I don't know if they will fit the evenly spaced bolt hole pattern of the B&B 10A7 or not. I think they may be a 9 1/2" size. I was always under the impression that the flywheel would have to be drilled to work with the new type clutches.
Kerby

The Merc B&B bolt pattern is a common diaphragm size , and is used by Centerforce on their flathead steel flywheels, and possibly also by others. The CF clutches are 10.4" for both early and late flathead applications. I know because I've had both. The local clutch shop matched the CF plates to a common and cheaper Chevy PP, so switching to a modern diaphragm clutch is very easy, and with several benefits; low cost, easy to find, and lower pedal efforts. There are also some diaphragms that replace the Long pressure plates, with their bolt pattern. Considering diaphragms have been the design choice for over 30 years by all the major brands for cars and light trucks, it makes sense to ditch the antiquated, costly and hard to find B&Bs and Longs for a diaphragm. JMO

[rotorwrench]

V8 Bob: I too agree that the CF clutch set ups are superior in every way but the snag for me has always been the necessity to replace the flywheel with their part. At some point my old wheels will be boat anchors but I think I'll keep running the original stuff till its broken.

Jack 34pu: To the best of my knowledge, there is no source for new, off the shelf parts for the old Mercs. The other alternative besides going the new Centerforce route is the Ford pick up 10-inch Long type clutch. Both of the 10-inch clutches will work for adapting an 8BA type engine block to any early Ford V8 center shift transmission but you have to match the clutch to the flywheel. If a guy was going to drill an 8BA wheel for an old 9-inch Long type Ford clutch, at least you would be getting a clutch that is easy to get parts for. I find good B&B Merc clutch cores on e-pay all the time but they will have to be taken down to the local clutch shop for rebuild. Fort Wayne clutch is a good source for rebuilds and a lot of folks on here use them as a rebuilder of all clutches for Fords.

Kerby

PS: I checked the measurements for the type 2 flywheel pattern on the Center Force web-site and it measures the same as the Mercury Borg & Beck and has the same size bolt holes so it may in fact work on the Mercury flywheel with the P/N CF365222 pressure plate and the P/N 381870 disk. The CF flywheel is lighter and may have a slightly different mounting distance on the clutch face side but it might work on there. It would be nice to know if it would anyway. Since the early flathead V8s and the Mercs use the same throwout bearing at least back to 1937, that should be covered.

[jdl]

Here are some pictures that might help... Flywheel is a 8BA Merc. pressure plate is that # 1310 B&B if you need more measurements let me know.

[V8 Bob]

rotorwrench,
I talked to CF about why they state their clutch should only be used with their flywheel, and the answer was simply to keep any mistakes from happening. I'm using a generic diaphragm on my CF flywheel with no issues. One problem I had using a CF clutch was the disc springs are large and can come very close to the flywheel bolts. I had to get special bolts from ARP that solved that problem.
The advantages of the CF steel flywheel are lighter weight (about 11 lbs over a stock cast iron wheel), new ring gear, both Long and B&B/diaphragm bolt patterns, factory balanced, and SFI certification. By the time you have a stock flywheel crack checked, machined, new ring gear and balanced, you're not far away in price from a CF wheel. JMO.

[rotorwrench]

V8 Bob: By the term generic, do you mean a late style say Chevrolet/Chrysler type pressure plate (one that just happens to fit a lot of different models). If so, can you give an easy example of the fitment, say a specific model or engine type. Also what type of transmission are you running (clutch plate fitment). If you would, I'd appreciate it. I'm always curious about this stuff.

Thanks
Kerby

[Dick Webber]

Is the 49-50 Merc flywheel the same as F series truck?

[V8 Bob]

Originally Posted by rotorwrench

V8 Bob: By the term generic, do you mean a late style say Chevrolet/Chrysler type pressure plate (one that just happens to fit a lot of different models). If so, can you give an easy example of the fitment, say a specific model or engine type. Also what type of transmission are you running (clutch plate fitment). If you would, I'd appreciate it. I'm always curious about this stuff.

Thanks
Kerby

I wanted a lower pedal effort than the CF plate required, (don't mean to knock CF but their's is overkill for my needs and my overall ratio is on the low side) and decided to change clutches while the tranny was out for repair, so I went to our local clutch rebuilder with my flywheel and T/O bearing and had them match the finger height of the CF diaphragm plate and finger shape (bent finger in this case ) for the '51 mercury T/O bearing I'm using, to a diaphragm plate that can handle a flathead. The plate they selected is good for 300 HP and is a common GM application. I'm using a Mustang T-5 with a 1 1/16" X 10.4" disc on a steel CF flywheel.


Here's a picture of the new setup.








Here's the '51 Merc bell housing and stock T/O bearing that I'm using.

[V8 Bob]

Originally Posted by Dick Webber

Is the 49-50 Merc flywheel the same as F series truck?

No, Ford cars and Lt. trucks used Long clutches up until the late 70s/early 80s.

[Jack 34pu]

V8 Bob,

Any part # available so we don't have to reinvent the wheel. There are no 'clutch type' shops out here in the boonedocks.

Jack 34pu

[V8 Bob]

Originally Posted by Jack 34pu

V8 Bob,

Any part # available so we don't have to reinvent the wheel. There are no 'clutch type' shops out here in the boonedocks.

Jack 34pu

I'll contact the shop Monday and try and come up with a number/application.

[rotorwrench]

Since that is a 10.4-inch, I wonder how well it would work with the Center Force 10.4 disk with the 1 3/8 " 10-spline hub. If it does, that would be the hot smokin combo for all the early Ford conversions to 8BA type blocks while still using the old 3-speed center shift gearboxes and the Merc/truck half bell. The only problem may be the throw out bearing. The later 51 Mercs that had the Ford passenger style transmissions may have used a different (smaller diameter) throw out than the earlier Mercs & full bell V8 blocks of the 30s & 40s. If thats the case the fingers would have to be matched to the older "78-7580-A" style 3 1/2" throw out bearing & "48-7561" style hub.

Thats a damn good combo for the T-5 set ups for sure.



Kerby

[V8 Bob]

Originally Posted by rotorwrench

Since that is a 10.4-inch, I wonder how well it would work with the Center Force 10.4 disk with the 1 3/8 " 10-spline hub. If it does, that would be the hot smokin combo for all the early Ford conversions to 8BA type blocks while still using the old 3-speed center shift gearboxes and the Merc/truck half bell.

Low pedal presure would be the hot ticket.

Kerby

CF has you covered. Here's the pressure plate and 10.4" disc for the 1 3/8" inputs. The plate is "straight fingered" and allows the large '32-'48 Ford/'39-'50 Mercury and Ford truck T/O bearings. I got these in a trade and sold them last year.
The CF clutches are brutes and can handle lots of HP, but the efforts are a bit more than standard diaphragms as a result. Most stock clutch linkages will be fine as the overall pedal effort lessens as the clutch is disengaged, vs a B&B or Long, whose efforts increase during disengagement.

[Jack 34pu]

V8 Bob,

Thanks for your efforts. The bigger trans sleeve and throw out bearing will have to be checked against this item - also the distance from the flywheel surface as I was, and most use the original clutch linkage.

Fordbarn is the best!!

Jack 34pu

[V8 Bob]

I spoke to the local clutch shop today about the setup (above) in my '32. The pressure plate they sold me is a common bent (or curled) finger GM part, with their # 361675 stickered to it, and will work with '49-53 Ford car/'51-'53 Mercury T/O bearings. It has the same bolt pattern/circle as the '49-'53 Mercury Borg & Beck. The item # is MU 1675 2PC on my invoice. One application would be a 1975 Camero 350". The MU 1675 refers to the bolt circle. The actual clutch diameter is 10 3/8", although the PP measures 10 7/16". The disc# would depend on spline size and count. I would contact them with any questions, as they are very nice to deal with.

South Bend Clutch
709 W. Jefferson Blvd.
Mishawaka, IN. 46545
1-800-988 4345