After being a GRM reader for some 20 years now, I'm finally starting a Challenge build of my own.
Picked up this Triumph TR4 roller for the princely sum of $400. Couldn't believe my luck when it popped up locally.
Based on the pics, I thought I would be getting a bare shell that had been primed and sanded. But there are a ton of parts stuffed in there. The chassis is clean and the suspension has obviously been freshened up recently. Even the brakes look good.
This is an early TR4 with live-axle rear. I don't know much about them and have no idea how to make them handle (later TR4/5/250 models had IRS, with which I'm more familiar).
No point in taking more pics today because it suddenly turned dark and rainy the second we pulled the truck into the driveway (naturally).
For once in my life I might actually have gotten lucky with a project car that's actually better than advertised.
My initial plans are:
- Find an engine/gearbox combo that's small, light, free-revving, and (of course) cheap. I'm thinking 1.6L Miata for now.
- Cannibalize my stalled TR6 project for any missing bits and pieces.
- DIY tractor paint in Massey-Ferguson Gray. Maybe roller paint? Or cheap HVLP gun from Harbor Freight?
- DIY powder-coat the wheels in gloss black. I've never had wire wheels before and have no idea how to test them to make sure they're safe. Will need to figure that out.
That should pretty much do it.
Wire wheel test;
Lightly tap each spoke and listen.
Good spokes will "Ting", loose or broken spokes will have a dull sound or almost none.
Look carefully at the splines of both the wheel and the hub.
The tops should not be sharp, there should still be a flat crown at each spline.
You cannot just replace the wheel or hub, if either half is worn it will quickly wear the other.
You should probably plan to use solid wheels for this build.
Front suspension is virtually the same as TR6, rear live axle works fine until you lift the inside wheel which slows you down for your own safety. 
You will need to control roll for best traction and speed.
I may be interested in purchasing the wire wheel set-up if they are in good shape.
Live axle TR4 is a better car than a TR4A. That independent rear was only there so they could advertise an advancement over the competition. From lots of personal experience repairing them when they were new cars the best thing to do with wire wheels is scrap them. Usually the hub splines fail before the spokes, but bent or loose spokes are alarms. The best part of wire wheel Triumphs is that the hubs are the same as disc wheel cars, other than having shorter lug studs. Seriously the best car Triumph ever made. The final drive will take quite a bit more torque than your intended engine, but consider something larger and slower revving, cause the final drive ratio is kind of long, unless it was originally an overdrive car (doubtful). If you can find an original engine within Challenge budget it would be a totally awesome entry, and it was a pretty good engine, far more reliable than any Triumph 6, and an easy build. The gearbox, though, not so good....Others have indicated height concerns for bonnet clearance, but the short stroke of the Mazda probably compensates for the extra cylinder head height. Great catch!
In reply to LanEvo :
Oh man, what a great score! TR4 and TR6 are on my someday list.
AngryCorvair said:
In reply to LanEvo :
Oh man, what a great score! TR4 and TR6 are on my someday list.
Depending on how this goes, I might let my TR6 project go cheap.
LanEvo said:
AngryCorvair said:
In reply to LanEvo :
Oh man, what a great score! TR4 and TR6 are on my someday list.
Depending on how this goes, I might let my TR6 project go cheap.
I’m not even going to ask. Because MonZora.
AngryCorvair said:
LanEvo said:
AngryCorvair said:
In reply to LanEvo :
Oh man, what a great score! TR4 and TR6 are on my someday list.
Depending on how this goes, I might let my TR6 project go cheap.
I’m not even going to ask. Because MonZora.
I'll take seconds behind the hand model.
Wait, we've got TWO TR$s headed for the Challenge?
You guys are my heros
I just spotted that the front fenders are TR4A or TR250 parts. TR4 does not have the parking lamp up top on the fender, only in the grill.
Might be a solid axle TR4A, the best combination. I used to own his and hers '67 TR4As, solid axles, both with wire wheels. One was bought as a parts car, but it was too good.
I have a front swaybar that I bought for my TR3B racecar, that should fit. I also have an OEM TR4A/TR250 fender flasher, though not exactly Challenge-priced.
Could also be mixed-and-matched parts. I'll check the VIN and see if I can figure out what's going on there.
In reply to LanEvo :
Wow, nice purchase!
Do you know if this car ever lived in Connecticut?
LanEvo said:
Could also be mixed-and-matched parts. I'll check the VIN and see if I can figure out what's going on there.
Good idea. The TR4A frames are somewhat bell-shaped (versus straight). Pop out a jack hole plug in either footwell, and see if the frame has a notch and support for a jack.TR4As used the same floor panels (and jack hole plugs), but no provision for the little jack.
Quick glance under the car will confirm if this is a TR4 or TR4A. First picture is solid axle TR4A, 2nd one is a standard TR4
I won't have much to contribute, but will watch this with fond memories. A lot of my early years were spent watching dad fiddle with his various TR2 through TR6s. After that he was into RX Mazda's.
LanEvo said:
My initial plans are:
- Find an engine/gearbox combo that's small, light, free-revving, and (of course) cheap. I'm thinking 1.6L Miata for now.
One came into my buddy's shop for a Miata swap, it was there for 18 months. It won't go without major surgery, a cross member is iin the way of everything.
How is a Miata engine "Small"?
I recently disposed of a Miata and complete spare drive-train as I realized the Miata engine is too tall for anything I would have wanted it for.
They are actually the same height as an Alfa-Romeo 2.0 which required that I dry-sump it in order to get it low enough for my use.
It may seem paradoxical, but a V6 or V8 is an easier fit.
TR's and the Buick 231 V6 or Buick/Rover alloy V8 work very well together while easily avoiding all the ECU and other sensor madness.
914Driver said:
One came into my buddy's shop for a Miata swap, it was there for 18 months. It won't go without major surgery, a cross member is iin the way of everything.
That's what I was afraid of. I seem to remember seeing an old build thread a few years back where they were complaining about the height of the MX-5 engine in a similar application.
RichardSIA said:
How is a Miata engine "Small"? ... it may seem paradoxical, but a V6 or V8 is an easier fit.
I've seen a bunch of V6 and V8 swaps in TRs. BUt when it comes to a pretty roadster that's quite small and light, I feel like a smaller engine revving to the stratosphere is a better fit (at least for my tastes).
I'm still doing my research and considering some odd-ball options. I came across a Lancia V4 1.3L locally for $500. That would be badass (they sound amazing), but I've only ever seen them in FWD applications. A Mazda rotary might make sense. Some YouTube guys put a supercharged Yamaha snowmobile engine in a Spitfire.
Robbie
MegaDork
12/2/19 12:24 p.m.
Oh man. Loving this! I'll be posting my build thread today for a challenge build very similar...
Very cool! Can't wait to see what you do with it!
Wish I had back ANY of the TR-2's, 3's, or 4's I had "Back in the day".
The big TR's were never high revving, but they had more torque than any other Brit car that was not a Jag.
Your rear end ratio will reflect that.
So a high-rev engine will also mean an axle swap to avoid bogging off the line.
I have a TR-4 chassis build underway, slowly.
Cutting the rear of the frame and converting to a four-link to avoid the inside wheel lifting issue.
And a hot Buick 225 odd-fire V6 and close-ratio T-10 to keep it all "Period Correct" as a 60's "Could have been" build.
If I were doing yours I would be looking for a Buick/Rover aluminum V8.
The 215's are pretty short stroke and very free revving, but you do need to upgrade the rocker shafts for high RPM.
For an "Easy" modern donor a Camaro V6 and T5 should not be too hard to find.
Here's a blog of a guy putting a Miata engine in a Triumph TR3A....
https://ericsgarage.blogspot.com/2014/09/tr3a-to-miata-radiator-hoses-and.html
I won't pretend to know how similar or dissimilar the TR3 and TR4 are.
How about a Suzuki G13B (Swift GTI engine) with Samurai trans?
People have swapped them into Spridgets...
And Datsuns...
Seems like a compact package...
