Clutch question for Y-block Car guys

[Ross F-1]

I have a diaphragm style clutch I bought at NAPA for my flathead truck. The clutch worked fine but the truck clutch linkage didn't seem to have the right throw for clean disengagement.

The old-timer at NAPA told me it was a Y-block clutch, but since I bought it, NAPA has stopped carrying them, so I can't confirm (and the old-timer retired).

Can any of you confirm this is what Y-block cars used? It's a 10" clutch and the bolt pattern to flywheel is same as the Long clutches on a flathead.

 

[Kahuna]

I can't help with the Y Block clutch, but I can tell you that an 80's Mustang GT uses the same Diaphram 10" pressure plate and it bolts to a Flathead flywheel.
I use one in my Flathead powered 32.

 

[Ross F-1]

No problems with the PP fingers clearing the release bearing and sleeve?

 

[Tinker]

I can confirm its a modern version anyway, my clutch plate was the old 3 arm version. worked okay.

that might require a longer throw...

 

[grumpy don]

Common problem back in the day if the flywheel has been refaced. They used to sell shims to go between the crank flange and the flywheel to keep the flywheel the original position. Its a matter of clutch linkage geometery.

grumpy don

 

[Ross F-1]

The bearing retainer that the release bearing slides on/over is larger diameter on trucks (1-3/8" splined shaft) than for cars, is my understanding?

 

[V8 Bob]

What you have is a diaphragm replacement for a Long PP. Normal diaphragms have an evenly-spaced bolt pattern, like the Borg & Beck. Ford didn't start using diaphragms until the '70s.
Your bent finger style release fingers are normally used with smaller od T/O bearings, while the straight finger design is for large T/O bearings, like 1 3/8" truck/older Ford/Merc inputs. It's possible the ends of the fingers were contacting the trans bearing retainer during disengagement.

 

[Ross F-1]

... It's possible the ends of the fingers were contacting the trans bearing retainer during disengagement.

It was mighty close to that, enough that I wasn't comfortable with it. A shame too because it was soooo smooth compared to the Long.

 

[V8 Bob]

Ross,
A straight finger diaphragm Long replacement is probably available, most likely from a clutch supplier/re-builder.

 

[Ross F-1]

I was wondering if that would be the case, Thanks, I'll give that a go!

 

[frank long island]

I like the tail light flashing on your avatar nice touch

 

[V8 Bob]

Another option is using a '49-'53 Mercury flywheel. These are drilled for a B & B pressure plate, which has the same evenly spaced bolt pattern as many common OE and aftermarket diaphragm plates. The stock Ford flywheel could also be re-drilled.
Steel aftermarket flywheels are available, like the Centerforce I'm using. They comes drilled for both Long and B & B/diaphragm, are balanced, SFI certified, and about 10 lbs. lighter than a stock cast wheel.

 

[Alaska Jim]

V8 Bob, are you saying that the early Merc. (49-53) flywheel can be used on a Y-Block? If It does, that is good info to know. I never have compared the 2 to see if there was a difference. I have a lot more Flathead stuff than Y-Block stuff. Finding either up here is a bit difficult. most have sold for scrap back in the late '90's.

 

[V8 Bob]

Jim,
Ross has a flathead in his F-1. The Y-block and flathead flywheels are not interchangeable, but both came with Long style clutches, with common Long bolt patterns.

 

[Ole Don]

If it is still together, peek up inside with a very bright light and a mirror while someone presses down on the pedal slowly. You may see that a different TO bearing will work.

 

[Ross F-1]

No, it isn't still together. I had watched thru the inspection hole and could see the fingers were real close to the bearing retainer tube, and appeared to ride on the inner race of the TO bearing at fully depressed. Can't use anything but the stock retainer with the large input shaft on trucks.

 

[Alaska Jim]

V8 Bob, Thanks for that clarification , I did not think they were the same, but I did not have one of each to compare. That is what I like about this site, there is a wealth of knowledge here. I learn something almost everyday here on the Barn.

 

[40cpe]

If you can get the throw distance worked out, the flat area where the throwout bearing makes contact looks long enough to have a few thousandths machined off the ends to clear the TO bearing retainer.

 

[Ross F-1]

I may take it to the local clutch shop and see if they can replace the diaphragm with a straight-finger one that clears.