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TR2 & TR3 Forum

Just to be sure I got it right

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TR3driver Randall Y
Confusion, Los Angeles, USA   USA
My memory is a bit fuzzy (was a long time ago for me), but there is at least one bolt hole that does go unused. They added a "dowel bolt" to the TR6 setup for better locating (I guess) and the TR3 block doesn't have the hole for it. What I can't recall for certain is whether there is another unused hole over near the starter.

Two more look unused, because they hold the locating dowels. On the TR6, these were replaced with "dowel bolts", which are bolts with precision diameter shanks that double as locating pins.

Barry's photos do show bolts in place of the studs; probably because that's what his PO used. Probably work fine, if you get the bolt length just right. But the holes are blind, and as I recall, not overly deep. So if the bolt length isn't quite right, you'll get either too few threads engaged in the block, or the bolt bottoming in the hole instead of clamping the gearbox flange to the block. The studs seemed preferable to me.

Here's a shot of mine, where you can see the empty hole, and the 3 studs across the top. The apparently empty hole lower down has a dowel in it (retained with a drop of Loctite).




Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

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Jacad Avatar
Jacad Gold Member Barry Shefner
Montreal, QC, Canada   CAN
1959 Triumph TR3A "Loose Wheels"
1976 Triumph TR6 "The Tweetster"
Ah so that is where the 3 threaded studs are supposed to gosmiling smiley, the parts book does not show the stud locations and the original studs were not present on my engine block, probably because as Randall said a PO must have discarded the studs (which were too short due to the thicker TR6 gearbox casing in favor of hex bolts.) I'm not sure why Triumph used a threaded stud over hex bolts (perhaps it helped locate the tranny to the block???) but there must be some logical explanation .... (of course it is Triumph and sometimes there are strange quirks so who the heck knows)



Barry
59 TR3A 0TS57675LO - "Loose Wheels"
76 TR6 CF54266U - "The Tweetster"
Website: Triumph TR2-TR3-TR4 www.trtriumph.com/ (sorry for not keeping it current for the past couple of years)

TR3driver Randall Y
Confusion, Los Angeles, USA   USA
There's a photo on E10 of the workshop manual where you can (barely) see the studs peeking out of the block.
https://drive.google.com/open?id=0B2H2NJt34OffYWZiN2VlZGMtNTkxMi00NGUzLWE4NzMtMGRkODRkYzU3MDU1



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

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Attachments:
E10 Fig 5 Aligning clutch with mandrel.jpg    58.2 KB
E10 Fig 5 Aligning clutch with mandrel.jpg

chris Avatar
chris Platinum Member Chris Roop
Pendleton, OR, USA   USA
So there are supposed to be some studs and some bolts? This thing has been apart for 17 years.



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TR3driver Randall Y
Confusion, Los Angeles, USA   USA
Right. 3 studs across the top, a locating dowel on each side, the rest are all bolts. The two starter bolts (which go through both gearbox and engine block) are 3/8" diameter; the rest are 5/16"



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

chris Avatar
chris Platinum Member Chris Roop
Pendleton, OR, USA   USA
Randall, did you use the TR6 mounting plate for the slave cylinder of the TR3 one? And I'm guessing you used the TR3 slave?? What is mounting it TR6 style? Thanks!



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TR3driver Randall Y
Confusion, Los Angeles, USA   USA
In reply to # 1523527 by chris Randall, did you use the TR6 mounting plate for the slave cylinder of the TR3 one? And I'm guessing you used the TR3 slave?? What is mounting it TR6 style? Thanks!
Nope, still TR3 mounting plate. Honestly I didn't even realize the TR6 is different, not sure what the difference is.

On the TR3-4 (with Girling hydraulics), the mounting plate goes on the rear of the transmission flange, and the slave cylinder bolts to the front of the mounting plate.


On the TR6, the mounting plate goes on the front of the transmission flange (actually on the front of the engine rear plate IIRC)



To do that on a TR3-4, you would have to either beat flat the lip on the clutch cover, or switch to one of Joe A's flat alloy covers.

Not a very good photo, but this gives some idea of how much thicker the TR6 gearbox is in that area




Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

chris Avatar
chris Platinum Member Chris Roop
Pendleton, OR, USA   USA
Thanks for the detail! The TR6 plate is roughly football shaped while the TR3 has a dip taken out of the transmission side. Maybe because of this difference in mounting. This is based on pictures, since I have only so far found a TR6 plate. smiling smiley Also, you can still buy the one for the 6.



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chris Avatar
chris Platinum Member Chris Roop
Pendleton, OR, USA   USA
Another question; which push rod did you use? the TR6 or the TR3? I found the TR3 slave mounting plate in the first box I looked in, AND found out that I had ordered a new slave. All I have so far though is the TR6 pushrod. Up above, someone mentioned cutting the pushrod?
So far, it is 3 flywheel and clutch, A type 6 o/d trans with the short cover plate from the A type, 3 clutch slave and mounting bracket.



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TR3driver Randall Y
Confusion, Los Angeles, USA   USA
I made up a new pushrod from scratch, but could have cut down an old one instead. It's just a length of mild steel round rod (5/16" galvanized from Home Depot IIRC) with one end rounded and the other end threaded (5/16 NF again IIRC).

The TR6 pushrods are normally not adjustable, so they need the TR6 slave arrangement, which has a spring to extend the piston and take up any slack. That means the TOB runs all the time, and the TR6 TOB is a special free-running type. When I initially installed the TR6 gearbox, I was still using a TR3 clutch, and so I wanted to keep the return spring and adjustment feature. (The TR3 setup uses an external return spring to pull the TOB back away from the clutch slightly, so it only runs when the pedal is depressed.)

Then later, when I installed a TR6 style clutch (actually from a TR4A), I just kept the slave arrangement, since it had been working well for me.



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

chris Avatar
chris Platinum Member Chris Roop
Pendleton, OR, USA   USA
Well nutz! I have a TR3 TO bearing on a TR3 carrier. All that is here that I've found so far is the TR6 pushrod. So, I use the return spring and mount the clutch slave and mounting plate TR6 style? Sorry for being so dense, I just don't want to screw this up.
Edit: And if I do have to cut the TR6 pushrod, how long do I want the shaft to be??



Used parts are negotiable; they look better on your car than in my shop.



Edited 1 time(s). Last edit at 2018-04-04 06:32 PM by chris.


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Jacad Avatar
Jacad Gold Member Barry Shefner
Montreal, QC, Canada   CAN
1959 Triumph TR3A "Loose Wheels"
1976 Triumph TR6 "The Tweetster"
Chris,

I know that you are putting in a setup similar to my own (TR6 Tranny with a TR3 Engine) so FWIW here is what my pushrod looks like. https://www.triumphexp.com/phorum/read.php?6,1478457,1478502#msg-1478502 Also FYI my mounting plate is TR3. From the photos of both TR3 and TR6 clutch mounting plates they look fairly identical in terms of hole locations. If you cut the curve (what you described as football shaped) on the TR6 plate using the Tranny as a template it should work.



Barry
59 TR3A 0TS57675LO - "Loose Wheels"
76 TR6 CF54266U - "The Tweetster"
Website: Triumph TR2-TR3-TR4 www.trtriumph.com/ (sorry for not keeping it current for the past couple of years)

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Attachments:
TR3 slave mount.jpg    7.2 KB
TR3 slave mount.jpg

TR6 slave mount.jpg    3.8 KB
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chris Avatar
chris Platinum Member Chris Roop
Pendleton, OR, USA   USA
Thanks Barry. I have now found 2 TR3 mounting plates in addition to the 1 TR6 plate. I will use the TR3 plate. There is only the one TR6 pushrod though. So, length of push rod and which side to mount stuff on are the questions. You guys have been good to me sharing your info. If that length will work, then it is just a matter of which side to mount the plate on. It seems that Randall was saying in front of the engine, but I want to be sure.



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TR3driver Randall Y
Confusion, Los Angeles, USA   USA
IMO, if you are using a TR3 TOB & clutch, then you pretty much have to have an adjustable pushrod. There has to be some free play at the pushrod, but not too much. The free play gets multiplied and added to how far you have to push the pedal down to release the clutch. So it needs to be within a fairly narrow window.

Furthermore, the free play goes down as the clutch wears in service (hence the need to periodically adjust it). If it goes to zero with the piston bottomed in the slave, then not only does the TOB turn all the time (which may lead to rapid wear), but it starts to hold the pressure plate partially released, which can lead to a slipping clutch, burnt facings and so on.

I've never tried mounting the bracket on the front of the gearbox flange myself; just seems like it should probably work.and might remove the need to shorten the stock TR3 pushrod. So best I can say is to bolt it up and try it. If you can get the adjustment within range, you're good to go. Otherwise something has to change.



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

chris Avatar
chris Platinum Member Chris Roop
Pendleton, OR, USA   USA
There must be a couple of apple boxes of parts that have gone mia over the last 17 years. I remember all of the fussy little parts for the clutch linkage, can't find them, so it is all on the way from Moss. The plan is to follow the advice of bolt it up and see what works. smiling smiley
As for slotting the mount holes at the rear, do you oblong the front or rear of the holes? And I'm guessing you do it to the mount itself instead of the frame or trans?



Used parts are negotiable; they look better on your car than in my shop.



Edited 1 time(s). Last edit at 2018-04-10 10:27 AM by chris.


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