Gearbox Throw-out pin and gasket question

[kkaa]

Hey hey boys, couple gearbox questions..

How the he#^$% does the throw-out bearing PIN work for this throw-out bearing? This ones CRUSTY and before we tangle, i figured i'd ask. It is pulled? The manual I have doesnt say...

Also, check out the pick for the "racetrack gasket" for the gearbox. It doesnt come with the AHspares master gasket kit. Does anyone know what its called and or can i make one out of gasket paper?

And, last but not least.. When i rotate the input shaft, the gearbox feels tight and smooth. I dont feel any bearings "grinding" but i do have new bearings. Is this a case of "leave well enough alone"?

 

[Bob_Spidell]

The pin is a tapered pin that locks the fork onto the shaft (the pic is misleading, it actually should be shown with the shaft). You can just make out one end of it in your second photo; it has to be drifted out--I don't recall which way--if you need to replace the bushes on the shaft. When I did this I couldn't knock it out so drilled it and, IIRC, I put a roll pin in. This pic shows it better; it's #16:

https://mossmotors.com/clutch-100-6-3000

The 'racetrack' gasket is called, I believe, a 'buffer.' Its job is to keep the shift rails from going too far forward which could cause the gears to possibly get stuck in a gear. A cut-up gasket would work, but I think it's better to use leather or hard rubber/soft plastic of the same thickness as the one shown (wouldn't hurt to glue it in).

I'm not sure about the third question; did you just put bearings in without putting new synchros in? It's pretty much SOP to put new synchros in when you have a gearbox out since they're a wear item but, if it was shifting good when you pulled it out and don't intend to put a whole lot of miles on it it should be OK.

Edit: I got to thinking about it--again--and wondered why they didn't just make the oval-shaped recess a little less deep, but I think the buffer is also there to give the shift rails a little less 'hard stop,' and to protect the bellhousing. It was probably supposed to be replaced as SOP when, say, synchros and bearings were replaced.

 

[kkaa]

Bob, your AWESOME! Couple years back you helped me and the kids with another full restore and everything you suggested works PERFECT!

Great idea on the gasket, i'll make something up out of something rigid like you said, plastic, leather, something.. You can for sure see the witness marks that its helping take shock out shiftigng.

The pin, im wondering if its in i should just change the release bearing and call it a day? The bushings are in, do have some play, but not sure how much play new ones have?

On the "leave well enough alone" question. We bought the gar as a roller, not runnign frozen engine etc. The engine we rebuilt and finishing now, but the gearbox, we pulled the cover and all the teeth seem to be on the gears and there was no metal pieces in the bottom. In fact, as HORRIBLE as it looked, it seemed to change gears well and when spinning the input shaft, i dont feel any drag.

So, should we pull it apart and replace the bearings with new ones i have in hand, or, would you suggest leaving well enough alone?

Thanks again!!

Kurt

Build pics.... Bottom are the most recent.... https://photos.google.com/share/AF1...?key=TnF4R2dIR0Jva3p2TDNXb1dwT1F5dV90WVp3QlB3

The pin is a tapered pin that locks the fork onto the shaft (the pic is misleading, it actually should be shown with the shaft). You can just make out one end of it in your second photo; it has to be drifted out--I don't recall which way--if you need to replace the bushes on the shaft. When I did this I couldn't knock it out so drilled it and, IIRC, I put a roll pin in. This pic shows it better; it's #16:

https://mossmotors.com/clutch-100-6-3000

The 'racetrack' gasket is called, I believe, a 'buffer.' Its job is to keep the shift rails from going too far forward which could cause the gears to possibly get stuck in a gear. A cut-up gasket would work, but I think it's better to use leather or hard rubber/soft plastic of the same thickness as the one shown (wouldn't hurt to glue it in).

I'm not sure about the third question; did you just put bearings in without putting new synchros in? It's pretty much SOP to put new synchros in when you have a gearbox out since they're a wear item but, if it was shifting good when you pulled it out and don't intend to put a whole lot of miles on it it should be OK.

Edit: I got to thinking about it--again--and wondered why they didn't just make the oval-shaped recess a little less deep, but I think the buffer is also there to give the shift rails a little less 'hard stop,' and to protect the bellhousing. It was probably supposed to be replaced as SOP when, say, synchros and bearings were replaced.

 

[Jack T]

Kurt, by all means leave that pin in the clutch fork alone unless there is a lot of slop in the shaft bushings. It is not designed to be easily removed, as for the rest of the 'box, I would at a minimum install new synchro rings. You'll kick yourself if you put it back in the car and have grinding when shifting into second. The layshaft is prone to wear as well. Since you already have the bearings, do the full rebuild including springs for the shift hubs and rods. Overall it's a straightforward job without the need for special tools.

 

[Bob_Spidell]

Jack's right, the shift fork shaft bushings are a PITA to replace. But if you do let us know, I have some suggestions. A little side play is not a problem; in fact, when I showed my late father--a very experienced mechanic--the little bit of play I had he said: "Yeah, they'll only last you another 50,000 miles" (and my box had about 200K miles on it at the time). By all means replace the release--Brit for 'throw out'--bearing if it's got less than a quarter-inch of 'meat' showing.

Jack's also right about the synchros; should be done when the box is out unless they're pretty new. And the layshaft usually has wear on the ends from the needle bearings; Denis Welch has an 'uprated' shaft, I put one in my last rebuild but I can't vouch for its superiority. I didn't replace the main bearings last time; I'd replaced them once years ago and they seemed perfectly good. They're pretty rugged and bathed in clean oil so don't seem to wear too fast.

Magnus Karlsson has an excellent video on reassembly of the main shaft: https://www.youtube.com/watch?v=9rz6b8ZWXfc

 

[kkaa]

You guys are AWESOME! Thanks for the recommendation and on moss now for parts, thankfully they reopened! Throw-out and syncro-rings...

I'll l post a vid of the bush slop and get your view on it. Hopefully we can leave it, looks super crusty and a fight...

Question on flywheel, clutch and pressure plate... This car was a roller and had a replacement engine and gearbox frozen in it. Its a bn-7, didn't originally have an OD, but lucky the replacement does!!

The throw-out that came off was 4inch end to end, thats what i know.. There was a flywheel in a box that was re-surfaced and measures 13 1/4 inch end to end.. . How can i tell if that flywheel works with this car and and pick the right pressure plate and clutch? All the other parts im replacing, so master etc...

When i look on moss site, its not giving throw-out size and allowing me to back in a spec and also they dont have flywheel specs. The one thing i did check was that the hole pattern on the crank does work for the flywheel....

Ideas?

 

[Jack T]

You guys are AWESOME! Thanks for the recommendation and on moss now for parts, thankfully they reopened! Throw-out and syncro-rings...

I'll l post a vid of the bush slop and get your view on it. Hopefully we can leave it, looks super crusty and a fight...

Question on flywheel, clutch and pressure plate... This car was a roller and had a replacement engine and gearbox frozen in it. Its a bn-7, didn't originally have an OD, but lucky the replacement does!!

The throw-out that came off was 4inch end to end, thats what i know.. There was a flywheel in a box that was re-surfaced and measures 13 1/4 inch end to end.. . How can i tell if that flywheel works with this car and and pick the right pressure plate and clutch? All the other parts im replacing, so master etc...

When i look on moss site, its not giving throw-out size and allowing me to back in a spec and also they dont have flywheel specs. The one thing i did check was that the hole pattern on the crank does work for the flywheel....

Ideas?

I can't offer any answers about the flywheel right now, but speaking of the clutch one word of caution assuming the gearbox you have is a sideshift. Both my car and one I bought for parts came with gearbox / overdrive units from 100-6's. The swap for both must have occurred back in the 60s when there were plenty of dead 100-6's being parted out. Nothing really wrong with the 'boxes themselves as far as I know, but they came with a bell housing that would not accommodate a 10" clutch for a 3000. Hard to tell the difference when they're side by side, and the rubbing on the inside goes away once the pressure plate wears the inside of the bell housing. (Don't ask how I know this).

The number cast on the 3000 'box is AEC 3415, while the 100-6 is AEC 3174. Internally, the gears are cut at the opposite angle, but unless you have them side by side you won't know which is which. The laygear in a 100-6 box has the teeth for first gear at the very end of the gear, while in one for a 3000 there is a bit of a 'nose' that extends past the first gear teeth. I think that was meant to take the load off the very end of the needle bearings.

The good news is that the bearings, synchro rings, springs, etc. are interchangeable between the 'boxes. And if you do have a box / overdrive from a 100-6 the even better news is that it probably has a 28% overdrive. That, along with the 3.54 rear end that came in a non-o.d. car like yours gives you the best of both worlds for highway driving.

 

[kkaa]

Great callout Jack and thanks for the info!

Wheew, looks like we lucked out, this ones from a 3000 looks like, 3415..Also looked at my engine tag and it is a BN-7 ending in H 3156. I've got a message into this seller of a borg kit and hopefully he can help me see if the flywheel we have works..If it does, well clean it up and hopefully be one step closer.



https://mesg.ebay.com/mesgweb/ViewMessageDetail/1/125680101431

I can't offer any answers about the flywheel right now, but speaking of the clutch one word of caution assuming the gearbox you have is a sideshift. Both my car and one I bought for parts came with gearbox / overdrive units from 100-6's. The swap for both must have occurred back in the 60s when there were plenty of dead 100-6's being parted out. Nothing really wrong with the 'boxes themselves as far as I know, but they came with a bell housing that would not accommodate a 10" clutch for a 3000. Hard to tell the difference when they're side by side, and the rubbing on the inside goes away once the pressure plate wears the inside of the bell housing. (Don't ask how I know this).

The number cast on the 3000 'box is AEC 3415, while the 100-6 is AEC 3174. Internally, the gears are cut at the opposite angle, but unless you have them side by side you won't know which is which. The laygear in a 100-6 box has the teeth for first gear at the very end of the gear, while in one for a 3000 there is a bit of a 'nose' that extends past the first gear teeth. I think that was meant to take the load off the very end of the needle bearings.

The good news is that the bearings, synchro rings, springs, etc. are interchangeable between the 'boxes. And if you do have a box / overdrive from a 100-6 the even better news is that it probably has a 28% overdrive. That, along with the 3.54 rear end that came in a non-o.d. car like yours gives you the best of both worlds for highway driving.

 

[British_Recovery]

Make sure you use the correct release bearing for whatever clutch you end up using. They have different back spacing, but all fit the release arm. Wrong one will either put too much force on the clutch, or not enough.
Bob