Throwout bearing length explaination needed
 

So this is the second 67 Tempest that I am swapping over to a manual.

Can someone please tell me WTF is up with the TO bearing? I mean, all transmissions that I would use Sag, Muncie, T10 would have the same measurements INSIDE the bell housing right?

So why no matter which clutch set I order, the TO bearing needs to be longer or an adjustable fork ball installed or both.

Does everyone here with a 67 manual need to order an additional TO bearing every time they order a clutch?

And this can ONLY be TO bearing length issue. Z bar throw and transmission dimensions cannot be changed, nor would it make a difference...

Thanks in advance..

Dave

I feel your pain! I think the problem is that the listings are wrong, or at least that's been my experience. What changes you ask, well, in some cases, the pressure plate, which can have a direct impact on the TO height.

Now it could be that the bellhousing is different than the listing/app is calling for.

Just as a reminder, the fork where the rod touches, should be 90 degrees to the centerline of the crank/driveline.

Or are you just venting!?! Heh-heh!

.

Maybe a tad. But I have had 3 different TO bearings and I cant believe that they are all wrong for application..

New one should be here middle of next week.. I need to drive it soon. I am trying to get it road worth to make PY show in June!!!

If you have a pressure plate with many "Fingers", Typical diaphragm style, then you need a throw-out bearing with a rounded contact face/ outer edge.

If you have a pressure plate with a 3 "Fingers". Typical Borg & Beck style, then you need a throw-out bearing with a FLAT front surface/ and slightly rounded outer edge.

So now if you have that deal figured out then the next question is: Did you cut the factory cast iron flywheel? Did you install an aftermarket flywheel? A Lakewood scattershield?

If you have an aftermarket flywheel then the throw-out bearing might be in the wrong location vs the factory pivot ball location. Same deal if you installed the flat shield in front of the scatter shield.

So we need a lot more info about what you are actually doing.

Tom Vaught

Some use long release bearings, and some use short ones. The type of pressure plate you are using does make a difference. The diaphragm type is the stock type of setup, with the many flat fingers which are relatively flat to the pressure plate housing, so it uses the long bearing. The "performance" 3 finger type have fingers that are more raised outside the housing, so use a shorter bearing. So, if you have diaphragm type of pressure plate and it won't release, you obviously need the long bearing. There's even an adjustable length release bearing available for odd situations.

I have an aftermarket OEM style flywheel with a Pontiac bell housing with a stock style z bar set-up. The engine mounts are in the correct loaction (factory) I welded the z bar bracket dead nuts to where the z bar is on a good perpendicular angle. No sway or engine rocking.

I have the HD style clutch rod. Although it was too long and needed some messaging on the grinder. Works great now.

Stock-ish set-up and I got no separation from flywheel and disc.

Readjusted clutch rod for ZERO gap to see if that would make any difference. I got a little marcal movement, but not and separation.

I have a diaphragm style clutch with the TO bearing that it came with.

Same thing happened on last Tempest. I ordered National PN# 1377C. Should be here in a few. Ill swap it out then.

I'm just curious as to why all of these short bearings don't move the PP away. I mean if you JUST changed a clutch in a 67 from original you would run into this issue wouldn't you???

The TO bearing on left came with clutch. 1377 in the middle..

I was putting a clutch in a 57 Chevy for a customer. He had bought the parts from Summit, which included a scattershield, flywheel, clutch, diaphragm pressure plate and short release bearing. The 57 was set up with original clutch linkage. I knew a 57 uses a long bearing. I told him the short bearing wasn't going to work. He said it's all supposed to work together, so I didn't argue and put it in and of course, it didn't work. So, he had to pay me to take it back apart and put in a long bearing which is now working. I don't know why the parts places are putting short bearings in with these clutch kits. I don't see how it can work without different geometry in the clutch fork and linkage.

Maybe that is my point. I think the longer bearings are needed..