1972 Triumph TR6 looking for a purpose

More fun with bearings. The pinion depth gauge is finished. I welded it up in an extra diff with a 0.032" spacer so the pinion depth can be measured with a feeler gauge. Here it is in the diff being rebuilt.

According to this, I'm dead on where it should be, maybe 0.001" closer to the carrier. So now I should be able to just set the backlash. Unfortunately, I bent the cage on one of the inner carrier races when the jaw puller slipped off. I forgot the shims don't allow the jaws to really grab the race unless you notch the shims. From now on, I'm using the separator/puller as it can't slip and doesn't seem to distort the cage. A replacement inner race was only $35 from Amazon, so no big deal.

My carrier end float measurement was a little off. I ended up putting all the shims I had on the carrier and it still just drops into the case without the spreader, although it's really close to zero end float (with no pinion). I'll order another 0.005 and 0.003 shim to get some preload. Right now, I have almost zero backlash. so the ring gear needs to move away from the pinion. And the guessing begins...

I pulled apart another diff to get extra carrier shims. Before setting backlash the pinion preload was verified. The factory manual calls for 15-18 inch-pounds of torque to turn the pinion. Len Renkenberger used 12 inch-pounds. I don't have that light of a torque wrench. The HF 0-60 inch-pound torque wrench would cost more and probably be less accurate than the method I used.

That's a one pound bag of water hanging 12 inches from the pinion center. If the bag was moved just 2 inches to the right, the pinion would turn. The outermost mark is at 18 inches, or the upper torque limit. I'd call this good. BTW, the bearings were lubed with gear oil before final assembly and the pinion torqued to the upper limit of 120 lb-ft (to line the castle nut up with the safety wire hole). This pinion is tighter than any TR6 diff I've felt before, but they all had over 40k miles on them. In theory, the new bearings will wear in quickly and end up loose. But I'm a little worried this is too tight. Then again, it's way too loose if a single 0.003" shim is added.

Next, I added a 0.005" shim to the pinion-side carrier bearing so that 1/2 turn of the spreader nuts just allowed the Quaife to drop into the case. Checking backlash, it was at 0.008" on average. The spec is 0.004" to 0.006". I moved a 0.003" shim from the pinion side, and checked backlash again. After torquing down the bearing caps, the backlash closed to 0.003". Then I realized I forgot to torque the bearing caps on the previous attempt. Reversing my shim change and torquing the caps put backlash at 0.006" with less than 0.0005" variation at 6 different points around the ring gear. Good enough.

Painting some prussian blue on the ring gear face to check gear mesh didn't give me a clear indication of success.

I might do better reading tea leaves. Maybe I'll try to find some different, easier to read gear mesh paint. It's hard to tell from the picture, but the residual dye from the second pass of the pinion on the ring gear appears to have left a mark centered radially and just a bit closer to the tooth tip than the root. Edited: High contact means the pinion is a little too far from the ring gear.

If it doesn't make noise or explode, it must be OK.

I ordered some "Genuine GM Fluid Gear Marking Compound" from Amazon. Best to be sure of the gear mesh. I just really hope the pinion doesn't need to move, because that would be some work. I can easily swap a 0.005" and 0.003" shim side-to-side on the Quaife to tighten up the backlash.

The engine block went to the machine shop last week and the #3 main is slightly out of line, but can be line bored. Otherwise, it's good. They started on the rest of the engine parts this week, so I should have a short block within a month. A completed rolling chassis by the end of May is still a possibility.

Today was blasting and powder coating the differential flanges and seal holders. After dinner, I checked the gear mesh with the new GM marking paste. Wow, yellow is a much better color for this.

This is the drive-side gear face. Since these are used gears, the pattern is supposed to be toward the toe/inside of the ring gear. With this paste, the pinion depth looks spot on. The coast side looks good as well. So at this point, it should be fine unless it makes noise. With that done, the side drive shafts were assembled and the case buttoned up.

Damn it feels good to have that done. Tomorrow I'll mount it on the frame.

The diff is mounted on the frame. Tonight's job was assembling the halfshafts.

I like the Neapco u-joints that Richard Good sells because they put the grease fitting on the bearing cup. This leaves more room for a larger bearing surface and a thicker spider. It's also just easier to get at. You don't need long grease fittings. As a bonus, they're made in the US.

The only problem I had was that one of the needles fell into the bearing cup when I was inserting the spider, so it was dented when the cups were driven in. These u-joints aren't too expensive. I've seen them for $20.

You're patience with setting up this rear end is inspiring. Nice work.

I bolted up one half-shaft today and put the brake parts on the backing plate. Last night I found a forgotten box labeled "Brake parts" that contained Lucas-Girling rear brake adjusters and the hardware for mounting the shoes. This stuff is at least 25 years old, and was probably several years old when originally purchased. I had bought the same stuff new recently, so had a chance to compare and use the better parts. From first impressions, I thought the newer adjuster (on the right) would be better.

The Lucas part was made in the UK, and the newer in Taiwan. The Lucas part appears to be a sloppy casting job. Then I pulled them apart to look at the internals pieces.

The cylindrical wedges on the Lucas part were much smoother. The Lucas adjuster screws were also cleaner and the threads felt/turned smoother. It also has a longer squared end. This is important because when these damn things rust up I'll need that to break it loose. I should have checked the material hardness, but didn't. Also, there was some machining swarf left in the body of the newer adjuster. So I put the Lucas part on the car. While the newer part would work, it just isn't as good where it counts. Lucas for the win.

I cleaned/painted some new brake drums to replace the finned aluminum 240Z drums I'm taking from my other TR6. This will save a few pounds of unsprung weight, and they cool better.

The steering rack was taken apart and cleaned up. The only problem I found was a slightly bent inner tie rod. I have two spare racks and grabbed another from those.

The rack I'm rebuilding didn't even need to have the right side bushing replaced. These usually run dry of grease and wear quickly. So the entire rebuild cost two nylon sockets (<$10), some grease, and a few hours. Well, and some new rubber gaiters that came with the car/pile of parts.

I've been cleaning stuff up in preparation to mount some wheels on the chassis this weekend and get it off of the jack stands. This will be helpful as I need the stands to change all of the fluids on my Miata. I pulled the aluminum brake drums off my other TR6 and cleaned them up. They needed a little bit of scuffing with some sand paper, but shouldn't need to be turned. There's less then 10k miles of wear on them.

The next non-enviable task was cleaning and polishing a set of lug nuts. There's a joke there somewhere.

The steering rack is ready to mount as well. When I bolted up one of the half-shafts, the inner U-joint got quite a lot tighter. The shaft or diff flange may be warped, so I need to look into that.

The original '72 cam I wanted to use is more worn than I originally thought. The machine shop said it was worn through the case hardened surface and wouldn't last very long in addition to being slightly pitted on a few lobes. I could have it reground and nitrided, but I'd rather spend money on a new cam. Unfortunately, the one I want to use (Richard Good's GP2) violates street prepared rules. I have a good '74 stock cam that actually has more lift (0.372 vs 0.350) and more duration (256 vs 240) than the '72 cam. Everything else in the block is basically the same, so this shouldn't matter for street prepared rules. I can call it effectively a '74 short block. The head, however, is from an early car ('69 or '70), and the '72 cam was legal with that head. Looks like I'll either clean up a late head or live with a known rules faux pas. Hey, at least it's to my advantage.

TR6 cam comparision

Much good was accomplished this weekend.

First, I finished fitting the half-shafts. The tight U-joint was caused by some high spots (only a few thousandths) on the flange under the yokes. This distorted the flange enough to bend the yoke and tighten the joint. These Neapco U-joints are a bit close on tolerances.

It's been a while since I fitted brake shoes so I forgot how much I hate doing it. Remembering the right order to fit the springs took too long, but it's done. The trailing shoe was upside down on my first attempt, and that was corrected. Oops. I just didn't take a picture of it the right way around.

Next I powder coated the steering rack, engine, and gearbox mountings. Then the steering rack was bolted up. With that, the front and rear suspensions are done.

I'm down to bending some 3/8" fuel lines and mounting up the engine/gearbox, then hanging the exhaust.

I'm sort of in a holding pattern on this project. The engine is the main issue, as the machine shop is backed up and hasn't finished work on the block. I'm also lagging in putting the gearbox together. I did run into the paint guy I want to spray the body at a car show, and he's booked until at least the end of May. So it looks like I'm going to enjoy a break during the next month. Time to recharge the batteries.

I really need to decide on a paint color. The two leading candidates are the original Triumph colors Sapphire Blue and Damson. I'm leaning toward Damson if only because a beige interior would look nice with it. With Sapphire Blue, black is the only reasonable interior IMO, and that will just be to hot for an autocross car.

Damn, where did that last month go? All I accomplished was mostly rebuilding the driveshaft and bending/mounting fuel lines to the frame. Time to get motivated.

The machine shop is slowly progressing with the engine. It's almost ready for line boring the cam bearings. After that, I should soon have a complete short block and can start bolting parts on that.

I'm diggin' it

nice job

Some progress was made this weekend in spite of a fun but energy-draining autocross on Saturday. First, I finished the drive shaft. I should probably have the balance checked.

I've been looking for dust caps that fit the front hubs for months. They are a weird size, and the stock ones I had weren't deep enough. The castle nut rubs on the inside so they won't go on all the way. I ordered others that were deeper, but the bore size was too small. So I cut the flange off the stock ones to make a ring, stretched the metal to fit over the deeper ones, and ground down the ring to fit the hub. Little details like this can be real time sinks.

Finally, the gearbox internals were laid out to make sure I have everything needed for the rebuild. I'm using two NOS synchronizer rings that I've had for years along with a new 1st/2nd gear synchronizer unit. I also have a new set of shift forks, all new bearings, and a new layshaft. This should get put together sometime this week.

I got distracted by working on our club's autocross timing system. Configuring new computers (Raspberry Pi 3s) and compiling/testing code can suck up large amounts of time. Then there are the software modifications...

Looks like I need to have a talk with the machine shop. It's been three weeks of waiting for the crank to be balanced and fitted. They've had the engine since late March and have done most of the other work, but I'm getting impatient and spending money to not work on the rest of the car. If it comes down to it, I'll get it balanced elsewhere and assemble the damn thing myself.

In the mean time, I'm going to prep the body for paint. There are a few little jobs that need doing such as making a dead pedal that will also hold the high beam switch. I also need to make some aluminum spacers for the roll bar mounts so that when the tub is painted it can be final bolted to the frame before bolting on the loose body panels.

I'm still considering what color this thing should be. I prefer dark colors on a TR6 for some reason, but don't really want a drab color. The current favorites are Sapphire Blue...

...or another factory color Damson.

As something different, I really like the blurple color Ford has on Focus STs.

That might just be a bit too eye-stabbing for a TR6.

This project is lurching into motion again. Today I finally got around to assembling the gearbox. Everything sat on the bench long enough that it needed to be cleaned off again. I had previously checked all of the tolerances and had all of the correct shims lined up. So theoretically, this should have been easy. It was until it was time to engage the layshaft gears. You need to drop the laygear down to insert the input shaft. The pain of this is keeping the thrust washers in place between the laygear and the case. If you remove the layshaft, they can fall into the bottom and the mainshaft gears block access to the laygear to put them back. So you pull the rear main bearing, remove the mainshaft, and try again. For some reason, the laygear was tight and wouldn't turn. I also couldn't get the layshaft all the way through the case. I'm starting to get fed up when I notice the reverse gear shaft had slid forward (no keeper plate yet) and was contacting the laygear, putting just enough tension on it to cause trouble. I had to pull the layshaft back out and push the reverse idler shaft back, and managed to not drop the thrust washers. If I did this more often, I'd remember these little lessons better. The J-type overdrive still needs to be bolted on and the top cover rebuilt.

Even better is that I'm finally picking up the engine block tomorrow to take it for line boring the cam bearings. After that, it's just cleanup and assembly.

This thread continues to educate and amaze me.

Yesterday I took a field trip up to Richard Good's shop to have the block line bored for cam bearings. Having read enough of Peter Egan's wisdom, I took the road less traveled where you see cows instead of traffic jams. It was a nice drive, but unfortunately the block would not easily nor safely fit in a 2-seater.

Richard made his own device for doing this job. He basically turns the block into a mill and pulls a cutter bit through it using a gear reduction transmission that runs off a drill. Like this...

It's brilliant, and I now have cam bearings. Thanks, Richard.

Now for the less good news. The machine shop didn't knock out the freeze plugs when the block was hot tanked. That left quite a lot of rusty sludge towards the back in the water jacket. It was nearly 2 inches deep along the back, and the drain plug was blocked. It wasn't when I delivered it, so I assume the tanking freed up rust and it settled in the back. After nine hours of driving and line boring, I spent the rest of my day scraping and scooping sludge as best I could, then sprayed water through all of the coolant passages until it ran clear. Then I sprayed the block down with WD-40, wiping and blowing it dry. Not perfect, but all of the loose sludge is gone. I also ran a tap into all of the threaded holes.

I'll talk to the machine shop about what should be done now that the cam bearings are in place. Another hot tanking may damage the bearing material. At a minimum, the oil passages need to be cleaned out somehow.

JoeTR6 wrote: Yesterday I took a field trip up to Richard Good's shop to have the block line bored for cam bearings. Having read enough of Peter Egan's wisdom, I took the road less traveled where you see cows instead of traffic jams. It was a nice drive, but unfortunately the block would not easily nor safely fit in a 2-seater. Richard made his own device for doing this job. He basically turns the block into a mill and pulls a cutter bit through it using a gear reduction transmission that runs off a drill. Like this... It's brilliant, and I now have cam bearings. Thanks, Richard. Now for the less good news. The machine shop didn't knock out the freeze plugs when the block was hot tanked. That left quite a lot of rusty sludge towards the back in the water jacket. It was nearly 2 inches deep along the back, and the drain plug was blocked. It wasn't when I delivered it, so I assume the tanking freed up rust and it settled in the back. After nine hours of driving and line boring, I spent the rest of my day scraping and scooping sludge as best I could, then sprayed water through all of the coolant passages until it ran clear. Then I sprayed the block down with WD-40, wiping and blowing it dry. Not perfect, but all of the loose sludge is gone. I also ran a tap into all of the threaded holes. I'll talk to the machine shop about what should be done now that the cam bearings are in place. Another hot tanking may damage the bearing material. At a minimum, the oil passages need to be cleaned out somehow.

You don't paint a very flattering picture of your machine shop and/or machinist.

NOHOME wrote: You don't paint a very flattering picture of your machine shop and/or machinist.

No, I guess not. These guys can do good work, but I'm having my doubts. I'll hang on to the block over the weekend to decide whether to give them another chance or just retrieve the parts and assemble it myself. The original plan was for them to build up the short block. All of the machine work is done. I've never fitted bearings or gapped piston rings before, but have always wanted to learn how.

JoeTR6 wrote:

NOHOME wrote: You don't paint a very flattering picture of your machine shop and/or machinist.

No, I guess not. These guys can do good work, but I'm having my doubts. I'll hang on to the block over the weekend to decide whether to give them another chance or just retrieve the parts and assemble it myself. The original plan was for them to build up the short block. All of the machine work is done. I've never fitted bearings or gapped piston rings before, but have always wanted to learn how.

No fitting to be done on the bearings, just get some plastigauge and follow directions.

Rookie mistake is to have oil on the backside of the bearings. You want the backside of the bearings to be immaculately clean and dry.

I go through a case of brake-clean and a couple rolls of paper towels getting the inside of the block washed out and parts cleaned. Paper towels are not ideal cause lint, but it is what I have used.

Need a ring grinder if you are going to do the ring gaps. Easy to check gaps as you just use the piston to push the ring square in the bore and measure with feeler gauges. Get a ring expander so you don't break the rings when installing on pistons.

A dial indicator and magnetic base might also be a good idea for checking crank and cam endplay.

Note that if you are only ever going to do this once, the cost of the tools will be about the same as what the shop charges to do the assembly. Comes down to who do you trust?

Good to know. Thanks for the wisdom. I could buy a ring grinder, ring spreader, and piston ring compression tool for not too much. I have a dial indicator, and was already planning on installing the cam and timing gear myself. Supposedly the crank bearing clearance and end float are done, but it wouldn't hurt to check. The inside of the engine case and bearing caps are quite clean, probably from being line bored. Replacing the freeze plugs is another matter. I've been told that leaving the original plugs in place is better if they aren't rusted from behind. There are no signs of leakage, and they look clean from the outside. OTOH, getting the rust out of the bore holes and putting in new plugs with epoxy seems like a good idea to me.

Finish it up and bring it out on Saturday! See you there!

CrookedRacer wrote: Finish it up and bring it out on Saturday! See you there!

This is for my project TR6. We'll be driving Ed's tomorrow. If you're at the autox on Saturday, I'd love to get a morning ride-along.

How hard can it be to mate up a J-type overdrive? Pretty hard when the oil pump drive ring is bent.

The drive cam in the middle is supposed to just drop into the ring connected to the overdrive oil pump. You can see light on the right side. It will press in, but it's pretty tight. Of course I didn't learn this until I had already prepped the gasket with some sealer, so that's toast.

I tried tapping the ring with a drift to bring it close enough to round, but no joy. I see two possible solutions. Remove the oil pump drive and hone it (I don't dare in situ as this thing needs to stay very clean) or pull one from a spare J-type (from a Volvo 240). Since either involves removing the oil pump drive, I may as well try the honing first.

Maybe this is a sign that I should just stuff a 4-speed into this thing.

Another small victory. I removed the oil pump drive ring what I thought would be the easy way. Rather than remove the sump cover and oil pump body, I drove out the pin holding the ring to the plunger. Almost a huge mistake. The pin was secured with a roll pin hidden on the end of the plunger. Good thing it split in half and I recovered all of the pieces.

After some careful honing and polishing, the cam fits quite nicely. That little assembly is $100, but at least it's still available. To refit it, I had to grind off a small bit of the swivel pin so it would clear the case. There's no way to insert the roll pin with the plunger in the pump body otherwise.

After attaching the overdrive, I was looking at a parts diagram and saw that there's supposed to be a spring clip holding the cam in position on the mainshaft. I didn't have this clip, so will order a new gasket, clip, and anything else needed to fit the overdrive to the frame. At least J-type overdrives are easy to fit on the gearbox. A-types are a huge pain in the butt.