LT1 and a T56 in a 55 Chevy

Ran into another problem with this clutch setup....
As I mentioned earlier this '93 Camaro 6 sp tranny uses an unusual "pull" type clutch setup...
So I had to re-install the clutch release bearing in the clutch pressure plate from the motor side:
55HTclutch13s_Feb2019.JPG

55HTclutch21s_Feb2019.JPG


The procedure is to "retract" the clutch release arm, as shown here....
55HTclutch18s_Feb2019.JPG


And after the tranny is reinstalled, I'm supposed to "relocate" the clutch release arm to this position, engaging the collar of the clutch release bearing...
55HTclutch19s_Feb2019.JPG


So yesterday I got it all assembled, my "new" cover fitted nicely back on the floor, and tried to "shift" the clutch release arm into position on the clutch release bearing, and it won't go !

I should have "trial fitted" that fork on that bearing collar before I put it all together, and I didn't...
Something is wrong, the collar is to big or the fork is too small for that collar...

The fork is the original one out of the '93 Camaro LT1/T56 setup, but the clutch release bearing (and collar) is internet aftermarket, NAPA does not even list a release bearing for this application, which I find pretty strange, no listing for a 6 sp '93 Camaro ??

There is absolutely no access to this setup to see what the problem is, I'm guessing it's what I described above, as I laid under the car for quite awhile yesterday fiddling with it, and the fork just will not fit onto the bearing collar !
55HTclutch11s_Feb2019.JPG


So I have to pull the tranny again, and check out why the fork won't go...
But I'm sure tempted to cut an access hole in the bell housing where I could get access to where the fork fits onto that collar, and fab a cover plate for it, but decided against that !

Yes, bartender, pour me a double scotch !
 
Set the Clutch release fork into a VERTICLE Mill Bridgeport with an Endmill. Size to Fit Willy.
Or less accurate use an air grinder.

The High end pro mod cars with Lencos have a removable Scattershield cover topside. Floorboard comes out Dezus fasteners.
Put an access hole in the T56 Topside bell.
Be best to verify working correct.

Not your Super charged 425 Olds 55 Gasser.
It's A-Ok.
Street Toy here.
 
Maniacmechanic1 said:
Make sure the hole is full round.
Or oval retangle.
Nice Radius corners.
Click to expand...
One way I've done it in the past with a rectangular hole/plate is to drill four holes, like
1/2", in the corners and then cut between the holes to leave nice, rounded corners with
no sharp spots where stresses can concentrate, am still thinking about it for this setup...
 
2Loose said:
One way I've done it in the past with a rectangular hole/plate is to drill four holes, like
1/2", in the corners and then cut between the holes to leave nice, rounded corners with
no sharp spots where stresses can concentrate, am still thinking about it for this setup...
Click to expand...
Anything to make the job easier Willy.

It was done factory GM in the 1950's To about 1959 on Chevy V8 and Pontiac V8 on 3-speed and 4-speed Cast Iron Bellhousings.
Access plate at 12-O'clock. 2 screws held the Tin cover on.
 
Pulled the tranny, removed the clutch fork, measured it, measured the clutch bearing collar,
and found that I had 0.025" clearance, so don't know why it wouldn't go, test fitted the fork
on the collar, no problem, so, what the heck ??

Put the tranny back in, but stopped about 3/4" short of being "home", shined a light up in there
while I fiddled with the fork, and it popped into place on the collar !!
Shoved the tranny all the way back in and bolted it up, put the tail shaft support and
driveshaft back in, all bolted up, and went back to look at the setup some more.
The front of the fork looks awfully close to the outer rim of the pressure plate housing to me,
not possible to get a pic of it, but it just doesn't look like there's enough room to fully
depress the clutch and disengage the pressure plate without hitting the fork against the
rim of the pressure plate assembly.

Two things I can think of, this pressure plate assembly is larger than the stock unit, bringing
the rim of that housing closer to the fork, and/or the release bearing and collar is longer then
the stock design, pushing the inner end of the fork toward the rear, and the outer end of
the fork closer to the pressure plate rim.

Wish I had some good specs of what that clearance between the front edge of the fork
and the outer rear rim of the pressure plate should be....
The fork pivot assembly has a rectangular mounting base that fits snugly into a
rectangular slot on the front of the tranny housing, that I could machine if needed
to move the pivot point rearward, allowing more clearance between the fork and
that pressure plate rim.
I wonder where I might find that kind of information... ?

This sketch below I posted earlier showing my thoughts on one way to engineer the clutch
linkage shows a max movement available at the slave cylinder of 1", with a hydraulic
pressure available at the slave cylinder of 5.5 times my foot pressure at the pedal.
Looking at it as closely as I can through the slave cylinder opening, it looks like the
clearance between the fork and the pressure plate housing is only about 1/2", if that!
Guess I'm going to have to figure out a way to try to pin down how much clearance
is actually available in there, and try to find out how much I need!

Bartender, just leave the bottle....

55HTclutch05s_Jan2019.JPG
 
2Loose said:
Pulled the tranny, removed the clutch fork, measured it, measured the clutch bearing collar,
and found that I had 0.025" clearance, so don't know why it wouldn't go, test fitted the fork
on the collar, no problem, so, what the heck ??

Put the tranny back in, but stopped about 3/4" short of being "home", shined a light up in there
while I fiddled with the fork, and it popped into place on the collar !!
Shoved the tranny all the way back in and bolted it up, put the tail shaft support and
driveshaft back in, all bolted up, and went back to look at the setup some more.
The front of the fork looks awfully close to the outer rim of the pressure plate housing to me,
not possible to get a pic of it, but it just doesn't look like there's enough room to fully
depress the clutch and disengage the pressure plate without hitting the fork against the
rim of the pressure plate assembly.

Two things I can think of, this pressure plate assembly is larger than the stock unit, bringing
the rim of that housing closer to the fork, and/or the release bearing and collar is longer then
the stock design, pushing the inner end of the fork toward the rear, and the outer end of
the fork closer to the pressure plate rim.

Wish I had some good specs of what that clearance between the front edge of the fork
and the outer rear rim of the pressure plate should be....
The fork pivot assembly has a rectangular mounting base that fits snugly into a
rectangular slot on the front of the tranny housing, that I could machine if needed
to move the pivot point rearward, allowing more clearance between the fork and
that pressure plate rim.
I wonder where I might find that kind of information... ?

This sketch below I posted earlier showing my thoughts on one way to engineer the clutch
linkage shows a max movement available at the slave cylinder of 1", with a hydraulic
pressure available at the slave cylinder of 5.5 times my foot pressure at the pedal.
Looking at it as closely as I can through the slave cylinder opening, it looks like the
clearance between the fork and the pressure plate housing is only about 1/2", if that!
Guess I'm going to have to figure out a way to try to pin down how much clearance
is actually available in there, and try to find out how much I need!

Bartender, just leave the bottle....

55HTclutch05s_Jan2019.JPG
Click to expand...
There is nowhere else online to look that I know of.
Have a one off problem.
This is the most advanced group here on Grumps place.
Some Drag Race groups on FB...But no T56 is used.
 
I see the Orange Paint Willy.
I say Grind Mill the Clutch Release Fork to clear plenty.
Means taking out the Reinforce webbing.
Then go back Re Engineer and make the fork resist bending torsional loads.
Fishplate Weld in Bracing on the Fork.
 
I found your Centerforce Dual Friction clutch on Summit Racing .
Holy Crap its expensive. Way more than the Centerforce 11.000" clutch I use in my Old TA with a Muncie 4.
Just not sold on Overdrive.....too much money.
I just want to drag race & win. Need just 4 gears me.
 

Read the Comments on his video.

hey guys sorry no video. i solved my issue with the clutch fork by grinding about 3/16 of an inch off the area that was rubbing against the pressure plate.
 
The first time I put it together, I wasn't paying attention to the fact that is was a pull type
setup, and just shoved the release bearing on the tranny snout, and put it together...
About the same time, I ran the battery cables up from the rear, connected 'em, and
jumped the starter relay and spun the motor over. In the process, the fork arm rubbed
against the pressure plate cover, hence the orange paint...
(look at the pressure plate pix above, I was quite embarrassed by that...)
I'm going to try to get some measurements, and am leaning toward modifying that T-stand
the fork pivots on to get more clearance. If I do that right, I shouldn't have to modify
the fork at all.
 
2Loose said:
The first time I put it together, I wasn't paying attention to the fact that is was a pull type
setup, and just shoved the release bearing on the tranny snout, and put it together...
About the same time, I ran the battery cables up from the rear, connected 'em, and
jumped the starter relay and spun the motor over. In the process, the fork arm rubbed
against the pressure plate cover, hence the orange paint...
(look at the pressure plate pix above, I was quite embarrassed by that...)
I'm going to try to get some measurements, and am leaning toward modifying that T-stand
the fork pivots on to get more clearance. If I do that right, I shouldn't have to modify
the fork at all.
Click to expand...
Ok Willy.
I read one guy modified his pivot stand.
Unclear exact how he did.
Bench grinder I think.
 
Yup, I think that's the direction I'm going in...

This is what my '93 Camaro six speed clutch release fork looks like...
That T-stud and bolt is what it pivots on...
Chevy also had a 5 speed option for the Camaro,
it is the "old style" clutch setup...
fork1.jpg


A view of the back side...
You can see how it slides in and out to engage the clutch release bearing collar
during assembly/installation...
fork2.jpg


By carefully milling the base of that T-stud to shorten it,
I should be able to locate the fork away from the pressure plate
where it can function correctly....
fork3.jpg


Now I need to figure out how to measure the existing "clearance" between the fork and the hub of the pressure plate...

And here's another good question, how much movement do I need at the clutch release bearing to get complete disengagement of the pressure plate ??
Hmmmm.....
 
Wished you 'd paid attention in math class a little better, huh. An access hole and a bore scope would work nice in your circumstance. 1 inch hole would work and not risk having a big cover plate like suggested earlier and no scatter shield. A small patch that would swivel on a rivet or screw.
 
Yeah, good idea, have been thinking about getting a bore scope anyway...

Pulled the tranny and started taking measurements....
55HTclutch37s_Mar2019.jpeg


Getting faster, only took 30 minutes to get it out of the car this time...

Probably getting more measurements than I really need....
55HTclutch38s_Mar2019.jpeg


But by milling off some of the bottom of this "Tee Stud" that the fork arm
rides on, I can move the fork back away from the pressure plate...
55HTclutch39s_Mar2019.jpeg


I went online and found a spare "tee stud", so now I have
a backup on the way just in case I mess this one up....

Later....
Willy

More pix here....
 
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