[flat-bill]

I am setting up the engine and trans in a car I am building. I bought a Hayes 10.5/11 inch flywheel and an 11 inch LUK clutch kit. The pressure plate is a diaphram type unit. I have the stock aluminum bellhousing. I am using a Saginaw 3 speed overdrive trans. I have not run any of this yet but it looks like there is no freeplay room for the throwout bearing. The throwout bearing appears to be about 1 1/4 inch thick. I think that this is actually the shortest of the various throwout bearings available. While this MIGHT work to start out I am sure that as the disk wears the pressure plate fingers are going to press more and more on the throwout bearing until the unit starts to slip.

Am I looking at this wrong and missing something or is there some solution to this? Thanks, Billk

[flat-bill]

I should add that this is a '69 400 although I don't think it matters. Thanks, Billk

[ID67goat]

How are you checking the free play? Are you checking it with the transmission and clutch installed minus the clutch fork and looking in through the side of the bell housing?

From what I remember, that is the shortest throw out bearing. You definitely do not want the throw out bearing riding on the fingers of the clutch all the time.

I just looked up those 3 speed overdrives and they definitely seem different....is it physically different than a Muncie 4 speed or T-10 where it mounts to the bell housing and that's why it won't work?

[TAQuest]

Originally Posted by flat-bill

While this MIGHT work to start out I am sure that as the disk wears the pressure plate fingers are going to press more and more on the throwout bearing until the unit starts to slip.

Am I looking at this wrong and missing something or is there some solution to this? Thanks, Billk

On your wear theory, factor in that the difference in thickness from a new clutch plate and a used up one is about the thickness of a dime.

[flat-bill]

I will check for differences between the Saginaw and the muncie trans input bearing retainers.

I THINK that even though the thickness difference between a new and a worn clutch disk is small, the movement of the diaphram finger tips is much more because of the ratio built into the assembly.

[TAQuest]

Originally Posted by flat-bill

I will check for differences between the Saginaw and the muncie trans input bearing retainers.

I THINK that even though the thickness difference between a new and a worn clutch disk is small, the movement of the diaphram finger tips is much more because of the ratio built into the assembly.

If it works new it will be fine. Not much difference in the movement of the pressure plate as the plate gets used.

[TedRamAirII]

I doubt the bearing retainer has anything to do with anything, as long as the TO isnt resting against the back of it? Is the correct clutch fork installed? is it bent? correct ball pivot height? Is the Pressure Plate the same height as stock? Flywheel same as stock? with AM parts, its always a crap shoot.

[flat-bill]

All this is a new assembly. Has not ever been together before. I need to check again but my initial impression is that the TB is resting on the bearing retainer and right up at the clutch fingers. Let me check again and I will repost. Thanks. Billk

[Sirrotica]

Originally Posted by flat-bill

I will check for differences between the Saginaw and the muncie trans input bearing retainers.

I THINK that even though the thickness difference between a new and a worn clutch disk is small, the movement of the diaphram finger tips is much more because of the ratio built into the assembly.

That's correct, the ratio of pivot point to end of fingers makes the fingers move towards the transmission as the disc wears, it is more than the thickness of dime between new and down to the rivets after you factor in the leverage ratio of the pressure plate fingers.

The Saginaw you're speaking of more than likely came in a late fifties, early sixties chevy (just guessing here). If it's the one I'm familiar with it will not last long behind even a stock 400, they're notoriously weak. That being said if you have trouble finding a throwout bearing you might try getting one for the original application for what car the transmission came in. The interchangeability between chevy and Pontiac transmissions was pretty good. I have many times used the 3 speed chevy Saginaw into a Pontiac, longevity was rather dismal though. A warmed over 283 would shatter parts in one of those early transmission in a heartbeat.

That being said the Pontiac clutch linkage, bellhousing pivot , etc. will have to be very near to it's stock specs for the linkage to work properly. Back in the day when GTOs were daily drivers those linkage pieces wore in 50,000 miles, and many times I have had to either weld up wear points, or replace linkage with new parts to get everything in proper relationship again to work together. Throwout forks wear out first usually and cause headaches with disengagement, followed closely with clevises and bellcrank/crosss shaft parts, and rods where they pivot. The pivot that screws into the bellhousing for the throwout bearing also can be changed or adjusted to different pivot points to get it closer or further from the engine to keep geometry correct for different applications.

Pontiac was famous for using the Borg and Beck beehive style pressure plate, which was usually shorter than a 3 finger pressure plate, could be the parts aren't correct for what you're attempting to do.

As you can see everything needs to be in it's correct relationship for it all to work as designed.

[flat-bill]

The trans I am using is not the '55 to mid '60's 4 bolt side cover trans. This is the 7 bolt side cover trans that was used from about'67 on up. It is much beefier than the early version. I am not racing anyway and the car weight is about 2500 pounds.

[Sirrotica]

The 3 speed that came behind OHC 6s? I wasn't aware that they had OD available, but you have it in front of you, so if you say it's OD that's something else I didn't know.

Muncie and Saginaw as far a bearing retainers more than likely won't interchange, they shared some of the same dimensions as far as fitment to GM bolt patterned bellhousings and length to make it physically fit within the floor tunnel. Parts interchangeability would probably be slim to none. You might be in for a trip to the machine shop if you need a longer step on the throwout surface of the bearing retainer.

[flat-bill]

I can machine the TB holder by walking across the basement to my lathe. My concern is if there is enough metal thickness to retain enough strength.

I am trying to attach a picture of the trans so you will know what it is. It has the standard bolt pattern and rear mount as a Muncie. Hopefully see attached.

I think the 3 speed in the OHC 6 was probably the Ford trans as was used in my dad's '66 tempest custom. That trans used the alternate bolt pattern in the aluminum bellhousing.

Mine is from late '60's Chevy's cars and PU's.

Billk

[Sirrotica]

Light duty 6 cyls and small V8 chevy novas and camaros is what the net says they came in, not mentioned is an OD but you have a picture. Supposedly there was a Saginaw for a 69 Chevelle with OD so that clutch complete should bolt in there and work.

There should be a throwout bearing for what ever application the transmission came in that can be used in a Pontiac bellhousing. GM made their stuff interchangeable so it would fit all divisions without special parts designated to only one division. If you know the original application of the transmission, all the parts should fit into the Pontiac bellhousing. Mixing up Borg and Beck parts with 3 finger pressure plates is useless and you're going to have trouble making it all work. If it's out of a light duty chevy application get all the parts for the OEM application.

[Doug]

Originally Posted by flat-bill

I am setting up the engine and trans in a car I am building. I bought a Hayes 10.5/11 inch flywheel and an 11 inch LUK clutch kit. The pressure plate is a diaphram type unit. I have the stock aluminum bellhousing. I am using a Saginaw 3 speed overdrive trans. I have not run any of this yet but it looks like there is no freeplay room for the throwout bearing. The throwout bearing appears to be about 1 1/4 inch thick. I think that this is actually the shortest of the various throwout bearings available. While this MIGHT work to start out I am sure that as the disk wears the pressure plate fingers are going to press more and more on the throwout bearing until the unit starts to slip.

Am I looking at this wrong and missing something or is there some solution to this? Thanks, Billk

It appears that you haven't assembled any of this yet so I have some advice.

I note that you bought a LUK clutch disc kit which I assume included the throwout bearing.

I will share that I bought a RAM kit (pressure plate, disc. pilot shaft and throwout bearing. I bench assembled it on a 67 428 with new PRW flywheel, clutch fork and a 67 bellhousing. I mounted it all as a unit in a car and it sat in a car for a couple years, never started.

When I got ready to start the car I went to adjust the clutch linkage and started adjusting the clutch fork pushrod for freeplay. Something was wrong.

When I looked closer, the throwout bearing had come apart. That is, the back (retractor) ring of the bearing had come loose and was hanging on the input shaft housing.

Attached are a few photos showing throwout bearings. The first photo shows (left to right) shows a side view of a "long" throwout bearing about 1 3/4" thick, a short ( 1 1/4") bearing and a third short bearing. The third bearing is the one that came with the RAM kit.

The second photo is a top view of the bearings. You will note that the middle bearing retractor ring is a flare built into of the inner collar whereas the other short bearing has a separate ring piece that is attached by flaring out the inner collar, a very, very poor design which failed.

Other photos are of the short bearings and one is of the failed bearing installed.

When I went to local parts stores they told me that the failed bearing had a history of failures of coming apart.

I suggest that you look at your throwout bearing to see if it is of the failed bearing style.

Likewise, since you are at the early assembly stage, I suggest that you install an adjustable clutch fork ball stud to give you more flexibility in clutch adjustments.

Good luck!

[flat-bill]

As you might see in the picture that I posted there is not a lot of room between the frame rails to inspect. What I need to do is pull the engine and trans and get it where I can really see what is going on.

Thanks for the info and the pictures of the throwout bearings. Billk