TR4/4A TR4 gearbox dimension? Handbrake lever spare?

[Alan_Myers]

Hi all,

This evening I've been test fitting a new exhaust system on my TR4 frame and I have a request. Would anyone be able to measure - without too much trouble - the distance between the very bottom of the gearbox bellhousing and the bottom of the outer frame rails?

The reason is that my engine is still on a stand, awaiting flywheel and clutch balancing and a few dozen other things. But I've temporarily bolted just the gearbox/OD back onto the frame to check clearance. The exhaust is running *very* close to the overdrive. I'm hoping the dimension, lowest point on the bellhousing to lowest point on the main frame rails, is around 1.5" or more.

On the subject of exhaust, has anyone installed an exhaust system rigidly, without all the rubber hangers? I will be using a flex fitting between the header and the rest of the exhaust, so engine torque wouldn't be a problem. The reason I'm asking is I remember the loud "clang" my old exhaust used to make every time I went over a bump. Besides engine torque, and perhaps some additional resonant noise inside the car, and concerns about dragging low parts of the exhaust, are there other reasons most systems are rubber mounted in some way?

Unfortunately, I found a problem with one of the handbrake actuating levers in my car. The pivot pin in the lever (which passes through the rear drum backing plate and pushes the shoes to engage the handbrake) is normally press fit, but I've discovered one of mine is loose and slowly chewing up the inside of the hole. I tried to drill a hole at 90 degrees, to drive something in from the side and trap the pin in place. It worked drilling through the lever, but even a cobalt drill won't make a dent in the pivot pin. Must be incredibly hardened! I'm attempting to weld the pin in place, then grinding & file everything back into usable shape. But I sort of doubt I can get it into good enough to do the job. I've checked TRF and they don't stock replacments. Does anyone have a spare?

Other progress: I've got many the brake lines run, all the fuel line anchor points are ready and awaiting AN6 line to arrive. Front suspension is nearly complete, awaiting new Konis that are on backorder. The front calipers are both rebuilt, freshly painted and reinstalled, although I'm awaiting brake pads. The steering is back in, complete with a rebuilt rack that I'm adjusting and new tie-rods.

A quick check of the modified front geometry looks like I'm managing to get the half to one degree of negative camber I was trying for, caster and toe-in appear close but all three will still need to be confirmed with a proper alignment once the car's all back together.

Rear axle is now stripped out of the old frame and getting cleaned up and checked out. There's a limited-slip unit for the diff sitting on the shelf, but awaiting a 4.1:1 gearset before tearing it all apart.

I'll be test fitting the rear axle/diff with the exhaust, too. Looks to be a close fit there as well. New rear springs are on, although I plan to swap out the rubber shackle bushings for a poly set that arrived today. One lever shock has been gone through and tested okay. The other will get it's 40 years of grease and road dirt removed in the next day or so, but seems to be working fine.

The remaining rear brake parts I needed arrived today, except for alfin brake drums that are promised soon. The old drums are surprisingly good, though, and can serve in the meantime. The only "glitch" is the parking brake lever mentioned above.

Both rear axles look excellent, although seals will all need to be replaced and I'll certainly go ahead and install new bearings at the same time. Drive shaft is ready to go with new u-joints installed, new high tensile bolts and all-metal locking nuts arrived today (6 of the 8 old bolts I removed didn't even require a wrench, their nylock nuts had given up completely! Scary!)

Oh, and an oil cooler take-off with integral thermostat arrived today. Fits great and that's another item checked off the "to do" list. Now for the plumbing!

Whew! Still loads to do! But it's sure fun when things start to come together and it actulaly starts to look vaguely like a car again!

Cheers!

Alan

 

[Simon TR4a]

Sounds as though you're making good progress, Alan, you are ahead f me, but most of my mechanical assemblies will just need cleaning and painting before reassembly, just the odd bushing or mounting clip to replace.
What colour is your car going to be, and what sort of paint?
I am thinking of polyurethane not the ultra-shiny base/clear that a lot of cars now have.
Simon.

 

[Simon TR4a]

Just realised I didn't answer any of your questions;
1) I will try to measure this and reply on Monday.
2)Exhaust system needs flexible mounts so it does not get subjected to stresses which might cause it to leak fumes into the car or even fracture. Likely also not to transmit vibration and cause noise in the car.
Hope you have overdrive with that diff ratio, acceleration should be great!
Simon, again!

 

[Geo Hahn]

I am not sure where the rubber mounts you refer would occur. Mine is solid mount except for the rear-most hanger, it has a non-metal strap that is very rigid -- probably does reduce noise transfer though.

 

[Alan_Myers]

Hi Geo,

On my car, the front mount exhaust hanger (at the gearbox/motor mount) is solid. The side mount, behind the cruciform and strapped to the frame just under/forward of the axle/LH shock, has a rubber insert, and the rear hanger has a rubber insert.

One reason I asked is that I've got a solid metal strap that's a perfect fit at the rear, with the new exhaust system, and positions the muffler just about perfectly, as close to the tubular cross member of the frame as I'd dare. I wouldn't want that close with a flexible mount.

Thought I was done with it, but I found I have a little more welding to do on my frame, in this exhaust fitting process.

The frame I'm using is slightly earlier than the original and previously the only difference I'd only noticed was that it lacked the gussets from the steering mount ears to the inner/lower trunnion bracket (I added two gussets, using the original frame as a guide, and rewelded the steering ears at the base where they had cracked! I can see why the factory added the gussets mid-production.)

When fitting the exhaust and comparing old frame to new, I just discovered this earlier frame also doesn't have the side exhaust bracket. It's not broken off, just was never there. So, I'm guessiing that might have been a mid-production change, too. Without it, the exhaust would only have three mounting points: the header, gearbox mount and rear hanger for support. I've already fabricated a bracket and will be welding it on soon.

By the way, I'm going to use a stainless steel flex coupling in the exhaust system, just after the header. This is one of the changes recommended by Kas Kastner in his TR4 tuning book.

Thanks for the info! I still haven't totally decided whether or not to use flexible mounts as original, or solid mounts throughout.

Alan

 

[Alan_Myers]

Hi Simon,

Thanks for checking on that, at your convenience.

Eventually I plan to return the car to its original colors: Spa White exterior, Midnight blue leather interior. My BMIHT certificate just arrived today confirming that information.

But, I'm not a total stickler for originality. I plan for a pair of blue Le Mans stripes and other non original paint trim. I have a TR4A grill, Raydyot mirrors, and will be adding a hard top, just because I like them. I haven't really considered yet the type of paint I'll be using. There are several good possibilities and part of that may be determined by the shop that does the job.

The car is currently red, 20 coats of hand-rubbed lacquer that I sprayed myself after stripping to bare metal and straightening every inch, back when I did that sort of thing. It really looked luscious when fresh in 1978 or 79, and still looked very good in 1986, the last year I drove it. But, over the subsequent "neglect" years in storage, it's cracked quite a bit and needs a lot of work (My nephew's Rottweiler like to sleep on top of the car!)

When I first bought the car in 1976 or so, it was bright orange with a black interior and freshly retired from a modest racing career. It had been in one accident that I know of, but was reasonably well repaired. After driving it for a couple years and doing a few more things on it, I was rear-ended by a drunk in a full-size pickup truck.

That little incident set off a flurry of work to repair the damage (technically the car was totalled) but I'd grown weary of the orange anyway! A number of body parts had to be replaced in a "body on" restoration. I took the opportunity to do some improvment on the older repairs at the left front, too. In 1978/79 it wasn't easy to find parts or even info on Triumphs in Colorado! TRs were pretty uncommon. It's soooo much easier today, with the Internet and online catalogs, discussion groups, etc.

This time around, it's a true frame-up restoration. I've been pleasantly surprised how much is in really good condition on this car. I don't know how many miles it's actually gone, the odometer quit working at 96,000 miles and I drove it for at least another 4 or 6 years after that.

I give myself a small pat on the back for proper maintenance and previous repairs to the car. But, there is also the amazing durability of these old cars, and good fortune that it spent much of its working life in what is, for all practical purposes, a desert region. Plus there is the propensity for the early TR2s, 3s and 4s to undercoat themselves with their open crankcase breather circuit. My original gearbox had 1/2" of oil/road grime, but when that was cleaned off, is absolutely pristine without even a hint of rust on any bolt.

Still, much of the critical stuff is being replaced. Many brake parts are new. Much of the front suspension/steering is new. I can actually think of only one fastener that is being reused, so far (the big, special bolt at the handbrake pivot). Every other nut and bolt has been replaced, most upgraded, especially in critical areas. For all practical purposes, this will be a "new" TR4 by the time it goes back on the road, with a few carefully selected, special tuning mods!

Yes, I do have an early A-type OD going into the car. The original 4-speed had it really revving at about 75-80 mph, but got there very quickly in spite of the 3.7:1 rear end! That was because the car had wide 14" wheels with low profile tires. It took a lot to break loose a tire in a corner, though!

By the way, the Group 44 racecars were built with non-OD gearbox and 4.1:1 rear, but those were high rev, carefylly balanced engines that got rebuilt often. They only proposed using overdrives on 4.3 and 4.5 ratio rear ends (all of which are still available in England).

Up front the car has a .125 milled head, is getting oversize valves, porting/polishing/matching, 40 DCOE Webers, "D" grind camshaft, 87mm AE Hepolite pistons, camshaft hardened, conrods lightened, aluminum flywheel, TR4A diaphragm-type clutch, Mallory ignition & coil (might add an MSD unit). The jury is still out on whether to use a harmonic balancer. It might be necessary with the lightened flywheel. The engine rebuild is still ahead of me, although I've stockpiled most of the parts already.

As it goes back together, I can't help but get a bit anxious to put this car on the road! That is probably a year away, though, realistically. That would be about right... the last license plate is dated 1986... so next year will be 20 years exactly since it last was on the road and about 30 years since I first bought the car.

Like I said, I am not a real stickler for originality. This car had seen a lot of modifications when I bought it. I do try to use "period correct" modifications and accessories, though, except with safety related issues.

Cheers, and thanks again for any info you can give me about the relative position of the gearbox in your car.

Alan

 

[Geo Hahn]

[ QUOTE ]
...The side mount, behind the cruciform and strapped to the frame just under/forward of the axle/LH shock, has a rubber insert...

[/ QUOTE ]

That is the one I don't recognize. The Moss illustration doesn't show it and neither of my TRs has it -- but I have seen what looks like a bracket for it welded to the frame. Makes sense as a (sideways) hanger there would keep the rear muffler from fouling on the diff I think.

I doubt that a solid rear mount will give you a problem if that saves it from banging at the cruciform.

 

[Simon TR4a]

Alan that's going to be a great car when you get it done!
I tried to get the clearance you asked about, not sure if I really understood the question.It seemed from the flange of the bellhousing to the exhaust was about 1.25 inches and the pipe is right up against the frame; the starter is removed on my car at the moment and would be close to the exhaust too.
Regarding the exhaust hanger you mention, I'm just guessing here, but some TR4s were made with a single transverse muffler instead of the more common "y" shaped system. Could the bracket be to mount that type of muffler?
Simon.

 

[Geo Hahn]

The twin vs transverse were variations in the 4A... Alan's 4 has basically the same exhaust system as the TR2-3. There may have been some undocumented variations is how the brackets were fitted, personally I think I will fashion a sideways strap hanger for the bracket by the LR shock to help the system stay put (and quiet).

 

[Alan_Myers]

Hi Simon,

The dimension you gave may help. I'll check it.

I might have partially answered the question myself, too. I looked at the engine motor mounts and drew an imaginary line back through the lower starter bolt (it's mounted on an engine stand right now), think I have the gearbox pretty well situated.

Here's how I measured. I've got a 2x4 laying across a pair of jack stands and the frame is sitting on that. I positioned this support just under the front edge of the gearbox, the lowest point or the flange of the clutch bell housing. The gearbox is bolted in normally at the rear, with a new mount.

Initially the gearbox sat directly on that support (i.e., even with the bottom of the main frame rails), but that's lower than it would normally be positioned. So I set an additional, small piece of 2x4 (1.5" thick) on top of the support, propping up the gearbox with the front tilted slightly upwards, more as it would sit if it were bolted to the engine and the engine/gearbox combo was fully mounted in the car.

What I was looking for originally was that 1.5" dimension above. In other words, if you placed a straight edge of some sort up under an assembled car, pushed up against the bottom of the main frame rails (much like the support my frame is sitting on), positioned under the leading flange of the gearbox/bell housing, how much space is there between the bottom edge of the gearbox bell housing flange at its lowest point and the bottom edge of the main frame rails (or the top of the support they are sitting on, in my case)?

Fiddling with the position of the exhaust pipe (which are really easy to work with when the car is frame-off like this) it appears there will be enough clearance. But, not a lot by the overdrive! I still have to make up a collector pipe/flex fitting between the main exhaust pipe that runs back to the muffler and up to the header at the front. I plan to set up something slightly long that can just be trimmed to the correct length and slipped into place, once the motor is completely back in the car.

Working on this I do see one thing that concerns me a little. The newly installed brake pipe leading from the five way connector at the right front to the hose at the rear axle runs pretty close to the exhaust pipe before it passes through the right/front cruciform frame rail. I think I'll put one of those heat sleeves on it, just as a precaution.

I've also test fitted the rear axle/diff to see how it works with the new exhaust. Again, no room to spare, but I think it will be fine. I've moved all the exhaust slightly rearward and am figuring out my alternatives for rear exhaust hanger mounts.

Speaking of the rear axle/diff, it's surprising how good shape it's all in. The crown wheel and all the innards of the diff all look super. The axles look like they just came off the assembly line. The outside was all covered with about 1/4" of oily road grime, but a couple hours cleaning got rid of most of that. A little more cleaning, degreasing and it will be time for a fresh coat of black paint.

I found a lot of places around the rear axle and the hand brake mechanisms that appeared to have orriginally been quite thoroughly covered with Waxoyl or something similar, probably right from the factory. It's now a fairly solid coating, but comes off with brake cleaning spray (regular cleansers/degreasers don't touch it). Under the Waxoyl, parts are like new. So it did it's job! I would guess it was sprayed on thickly at the base of the handbrake lever, all over the compensator, on the hand brake cable ends and all around the differential itself, both to seal against dirt and water, and to provide some lubrication for the moving parts. Looks like it works! Most are fine, would be usable, but I'm replacing all brake items with new stuff just as a safety precaution.

Simon, my car would originally have had the "TR3 style" exhaust, one pipe which should have a muffler just ahead of the axle and a resonator just behind. Early on (1977?) I installed a header and replaced the old exhaust that the previous owner installed, with had a Ford muffler and a 2" pipe front to rear. That actually worked pretty well for homemade, except it made a loud "clang" when going over any significant bump. Now it's getting a stainless steel sport system that is a 2" pipe leading to a single muffler that sits pretty far to the rear, has a short tail pipe coming right out of the muffler.

Geo, if you have rattles or "clangs" the side mount near the axle/left Armstrong shock would definitely help. This whole assembly is like a "sideways" hanger that keeps the exhaust system positioned. You're right, Moss doesn't show it. TRF sells a kit, but you could as easily put something together from off-the-shelf "universal" items available at most parts stores.

The OEM setup is a fairly standard exhaust clamp that also holds the joint between the muffler and the resonator, and a strap that attaches under that clamp by a metal L-shaped tab on the end. There is a rubber flex piece between that metal tab and another piece of strap metal, which bolts to the bracket welded to the frame. The welded-on bracket is 1" wide steel, protrudes 3" from the frame, and has a 3/8" hole drilled centrally, about 3/4" in from the end, to attach the exhaust hanger. The TRF kit is too long for use with this weld-on bracket, so must have been sized to a car with something shorter (or an exahust system that differs from mine).

At the frame end of the weld-on bracket, there is an L-shaped tab for welding to the frame. Pretty simple really, I just made one up from scrap metal, copying the original on the old frame.

On my old frame the bracket welded on just about where the factory welded the angle into the frame, i.e. where the main rail starts to sweep upward to the rear of the car. The weld-on bracket is positioned about 1/2" down from the top of the large frame rail, actually parallels pretty close to the axle. Let me know if you need photos, I can snap a few and email them to you.

I did find one problem with the rear axle assembly. The pads that locate on the leaf springs have an approx. 1/2" hole in the center, that receive a "button" that protrudes from the spring in the center, to positively locate the axle. On one side, it was obvious the car had been run with this mis-positioned, or with clamps loose enough to allow the pad on the bottom of the axle to get bent upward, to the point were the "button" would no longer fit into the hole. This could allow the axle to slide around, forward and back or side to side, relying on only the big u-bolts to keep it positioned. I tried a number of things to straighten the mouinting pad, finally had success carefully heating it cherry red with a gas welder and hammering a big old screwdriver sideways in the hole, acting as a wedge between the mounting pad and the main axle tube. It took several goes with the heating/screwdriver to get that heavy piece of metal to pop back close to the proper shape, but it should work now! I'm sure the neighbors enjoyed the show, and maybe learned a few new words. I now have a big old screwdriver with an interestingly curved blade, too.

Thanks for the help!

I'm beginning to think I may actually get to drive this car again, some day! Well, there's a little work to be done yet, so I'd better keep plugging away at it!

Alan