Category Archives: 5. Triumph TR4

Ecotec Powered Triumph TR4

This is my cousin Jim’s Ecotec Powered Triumph TR4. Currently for sale on Bring a Trailer – CLICK HERE.

Jim passed away about a year ago. He was a machinist and built many cars in his shop in Greenville, SC. This was his personal car, having built it about 14 years ago. The car weights 2100 pounds – read more HERE. The odometer in the speedo states 21,784 miles. The speedo was brand new when installed at the time the car was restored (zero miles). The paint scheme was inspired by the 1959 ex-works Sebring Sprite – Jim owned a Bugeye Sprite back in the day, and he used to talk about it a lot!

The body shell was locally sourced in Greenville SC and was for the most part rust-free. The body was stripped, primed and painted in Jim’s shop. Bad spots were fabricated and repaired then welded where needed. The hood and the trunk lid are all aluminum, formed with an English wheel in his shop. The hood and trunk lids both have custom fabricated stays. Finally, a custom hardtop was also made from aluminum. The car does not have the convertible soft top frame nor soft top.

Inside, the car has a roll bar mounted to the frame. In addition to the hard top, the car comes with an “Alumakini” that can be used instead of the hard top (read more HERE and HERE). In the nose of the car is a custom aluminum air dam, stainless mesh, and aluminum front grill. At the rear, the bumper is custom made from aluminum, as well as the tail light bezels. All body panel fit is consistent and there are no big gaps between body panels.

The car rides on a set of 185/55R16 Firestone FR740 tires mounted on Panasport 16″ wheels – read more HERE.. Wheels are free of scars or curb rash. The tires have code “V698 ADR 2820″”; no cracks on the walls; no cracks on the tread. The 2820 date code indicates these tires were manufactured in the 28th week of 2020.

Jim made a new frame from square steel tubing to match the dimensions of the original frame. The frame was designed to hold Triumph TR6 IRS front suspension components, TR6 steering rack, Aldan coil overs (front and back) and a modified rear axle. The rear axle housing is a narrowed 8” Ford with Motive posi-traction and a 3.80 to 1 ratio. Axles are special order Moser. The rear end is held in place by a 4-link design. Once all was fitted, it was taken apart and painted black and re-assembled.

The frame was also designed to hold an LE5 2.4 GM Ecotec 4-cylinder motor. The motor and transmission came from a 2006 Pontiac Solstice. The engine/gearbox was purchased from a lot of engines/gearboxes sold by Mallet Cars. Mallet at the time was doing LSx conversions on Solstice/Sky cars, and we bought 3 “take out” motors with almost zero mileage. The engine and transmission in Jim’s car originally had less than 20 miles on it. The engines came with the Solstice harness, and that was later modified at Jim’s shop to fit the engine compartment of the TR4. The gearbox is an AISIN 5-speed, as fitted to the Solstice/Sky. The engine did not come with an ECM, so an ECM from a 2.4 Cobalt SS was used instead. Using HPTuners, the base Solstice 2.4 tune was downloaded to the ECM as a base and then, further tuning was performed. The E67 ECM fits inside a custom aluminum box in the engine compartment. Various relays, circuits and main fuse panel can be found there. The Ecotec has variable-valve timing (VVT) and it is noticeable when accelerating.

The engine is for the most part stock. However, the Solstice intake is too big so a custom aluminum intake was fabricated by Jim. The new intake was mated to a GM sourced flange that matches the intake ports. Four aluminum runners were welded and the new intake made to match. The original fly-by-wire electronic throttle was adapted to the new intake. Due to space restrictions, the headers were fabricated from stainless steel and welded to a GM sourced exhaust flange, including provision for an O2 sensor. This was welded to a low restriction muffler and a single stainless pipe exiting at the rear of the car. Just because we wanted to be different, the end holds two Supertrapp diffusers with removable rings. All this gives the TR4 a very distinctive exhaust note. The driveshaft is custom-made by a local manufacturer and adapted to fit the AISIN 5 speed gearbox and narrowed Ford 8″ rear axle.

The E67 ECM has been set up by a local LSx tuner. He set the mapping based on several hours of real-time driving; the TR4 was never put on a dyno. We used HPTuners to remove VATS and also to set the engine mapping. The Solstice was originally rated at 177 HP and with the new intake, exhaust and tune, the tuner estimated it would be good for 200 HP. Perhaps this can be improved with more tuning/dyno time.

Engine cooling is handled by a Griffin Thermal Products aluminum radiator. It has a custom-made shroud holding a SPAL curved blade high-efficiency puller electric fan. The fan is controlled by a temp sensor that has a potentiometer that can be dialed in for whatever temp you want to set – this is inside the aluminum box housing the E67 ECM. At the time we put the car together we did not have the fan figured out to run with the ECM. However, with a little work, this can be achieved.

Due to the fuel requirements of the Ecotec, Jim made a new aluminum fuel tank for the TR4. This tank is fitted in the trunk and holds a modified GM LSx electric fuel pump. There is also a fuel regulator mounted in the trunk for dialing in the correct fuel pressure. If you look at the frame pictures, you can see all the stainless tubing for fuel lines and brake lines held in place with special brackets. The tank holds approximately 15 gallons.

As stated previously, the Solstice engine harness was modified to fit. The rest of the car’s wiring was made at Jim’s shop. All wires, relays, switches and breakers were sourced from Waytek. All joints and connectors were soldered and shrink wrapped. Gauges are all VDO and are fully functional. Lights all work, turn signals work and brake lights work (see video). The instruments are mounted on an engine-turned plate on the wood dash. The VDO speedo has a problem with the LCD for the odometer in that it goes blank from time to time, although to the best of my knowledge the counter continues to work. This seems to be a known issue with VDO speedos and there is a fix available on youTube – CLICK HERE for the video. I have contacted AK Speedo and they have told me their repair kit will work with the VDO speedo.

There is a fuse box mounted in the passenger’s side dash area. The master switch is on the wood dash, with a key. There is a momentary on/off toggle switch next to it, and that starts the car. There is also a switch mounted on the dash for the turn signals. Mounted underneath the edge of the dash (out of sight) is a horn push button, light switch, windshield wiper switch (with low, fast and intermittent settings), heater switch and fuel pump switch that acts like an extra security because the engine won’t run without the pump running. To turn the car off, just turn the key back to the “off” position. I provided a video that explains all this too.

There is an adjustable steering column! This is controlled by a small lever that unlocks the mounts and allows free travel up and down. The four spoke steering wheel is custom made and hand stitched. The shift knob came from brass stock, and was turned by Jim on his lathe. This compliments the very short-throw shifts by adding a little more mass to the shifter. Installed is an aftermarket street rod heater. Jim made several trap doors that are manually operated to help distribute warm air to either passenger side or driver side or defrost to the dash. The headlight high/low beam is controlled by an old-school foot switch, mounted vertically on the side because there is no room on the floor. You can press it with you left knee. There is also a lever near the heater that opens/closes the air scoop on the dash. There are factory openings behind the dash that allow air to come in.

Brake calipers are Wilwood Dynalites in the front and Nissan in the rear. The rotors are TR6 in the front and matching Nissan on the rear and they are not vented. The hand brake mechanism was fabricated and it engages he rear brake pads – however this might need to be adjusted. The brake master cylinders are Wilwood with two reservoirs and a balance bar on the pedal, so this allows bias adjustment. The clutch master cylinder is also Wilwood. Also to note, there is no power booster and as such, requires a bit of pedal pressure to stop the car. The pedal box is also Wilwood. There are pressure residual valves on both front and back brake lines. This provides a constant minute pressure reducing the amount of pedal travel. A keen eye will notice the VIN plate is not where it is supposed to be: in the area where the Wilwood pedal box is currently installed. The VIN plate has been relocated to the driver’s side door sill.

The bodywork was all done at Jim’s shop. The body was primed, sealed and painted with single-stage automotive paint in Gulf sky blue. The aluminum top is painted in gray, and has a small crack on the passenger’s side. Overall, the paint is not show quality. It has aged, shows some orange peel (mainly on the top) and has a faded patina. Perhaps in the hands of a professional, the look could be improved. There are several small cracks in the paint and there is a damaged spot on the passenger’s side door. There is a small ding on the hard top, but since it is aluminum that can be repaired with a hammer and dolly.

The aluminum top was shaped to resemble the hardtop on a TR6. The side windows do open and have a fabricated latch that allows the window to swing and lock in the closed position. The side and rear window are all acrylic, and while the side windows are still clear, the rear window is very foggy. The rear window can be replaced by removing screws holding it in place.

Jim fabricated the aluminum bomber seats. The bottoms have a rubber insert with springs around it, reminiscent of old Jaguar seats. The back-rests are held by screws. All the upholstery was made by a local automotive upholstery shop. The seats currently in the car are “version 2”: they have a longer seat cushion and are very comfortable. Included with the car will be the “version 1” seats; they have a shorter bottom cushion and different backrest design. Lap seat belts are provided and are bolted to a post extending from the frame. This is the same post that the roll bar is bolted to. There is a small box in the back deck between the roll bar posts for holding registration papers, etc. This small box is made of aluminum and has a lock, however I don’t have the key for that lock. The carpet throughout the car was sourced from a local upholstery supplier and was cut and shaped to fit.

The fuel tank is made of aluminum with an in-tank fuel pump accessible through a bolted cover. The tank holds approximately 15 gallons. The tank sits in a recess in the trunk so the bottom of the tank is not exposed. In the trunk area is a separate small fuse box that controls the rear lights as well as the fuel pump. Inside a fabricated enclosure sits a red-top Optima battery. The fuel tank has a spout with a custom turned aluminum knurled top that screws on. The trunk lid does not have a key, instead there is a small cable that extends underneath the back bumper, that when pulled, opens the latch. Closing the lid requires very little effort.

In summary, this car is a blast to drive! As shown in the photos, the car has room for improvement aesthetically. There is a lot of TLC but the mechanical systems and quality is absolutely first rate. The car has not been driven much over the past few years, and the underside could benefit from cleanup and paint to get rid of the surface rust. I have several ignition keys. The car has a clean South Carolina title and is in my name.

Finally: There is more info in the TR4 section – there are several articles about the TR4 there as well as a ton of information about my Ecotec powered Triumph TR6.

We built my TR6 first, and after Jim saw how much fun it was, he built the TR4 for himself. If you want even more information, you can read about the the TR4 and the TR6 in this blog. The details of the construction of my TR6 are very similar to the TR4 since they have the same basic frame, engine, gearbox, rear-end. The TR6 of course is a bit different but you get the idea.

If you have any questions, feel free to leave them on this page and I’ll do my best to answer them.

Triumph TR4/TR6 Wheel & Tire Sizing

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A few days ago, I received an email from a reader (thank you Richie) asking to know more about Triumph TR4/TR6 wheel & tire sizing as fitted to our cars. I thought this might be helpful for others so I decided to take a few pics and show you what we have installed.

My Cousin’s TR4 Wheels and Tires

The email from Richie mentioned he had never seen a TR4 with 16″ Panasport wheels as in the case of my cousin Jim’s TR4. The wheels are Panasport in the “standard” size for a TR6: which is 16 x 7 inch, zero offset as indicated by the following picture from taken from one of the boxes.

Richie also mentioned in his email that this wheels size would be too wide for a stock TR4 because the wheel would make contact with the leaf spring. I suppose this is correct, however in our case this is not an issue because the rear suspension on my cousin’s TR4 is using coilovers instead of a leaf spring. As seen in the following picture the wheel/tire package fits very nicely without the need for any sort of wheel spacers. On closer look on the picture below, the rear wheel looks a bit “off” but that is just because of the way the surface is below the tire. There is a dip in the driveway ahead of the concrete pad.

Here is a picture from the back of the car just to show the profile. It is a little dark – sorry about that, I took this with my cell phone – but you can see the tires don’t stick out too far out from the fender edges.

So now lets talk about tire size. My cousin decided on a set of Bridgestone Turanza 185-55 R 16 as show below, on all four wheels. They are a little narrow, but they work well. If I am not mistaken, these tires came from a local Discount Tire store.

bowtie6‘s (TR6) Wheels and Tires

I have the same wheels as fitted to the TR4 on my TR6. However, the tire sizes are quite different. My first attempt was a set of matching Kumho 215-55 16’s. This worked very well and gave bowtie6 a very aggressive look. However, the front tires in this size were just too wide and on cornering I heard the edges of the tire digging into the front fenders. I did not want to push my luck and have further problems so I bought a set of matching Kumho 205-55 16’s for the front.

This is what the 205-55 16’s look like on the front:

Here are the rear 215-55 16’s:

And finally, what this combination looks like showing the profile:

The Kumho’s have been very good and have lasted about as long as you would expect from a “summer performance” tire. When new, these tires were very soft and sticky, however after almost 18,000 miles they are now showing quite a bit of wear. They are also much harder and need replacing. More than likely I will be ordering a new set of BFGoodrich tires, just like the ones I recently bought for my Honda S2000 and they were sourced from The Tire Rack. They are also “summer performance” tires and I anticipate good service from them.

Just as in the case with my cousin Jim’s TR4, my frame has coilovers and clearance is not an issue. Finally, bowtie6 does not use any form of wheel spacers.

What about size for the next set of tires? Well, I have been struggling with this a bit. The staggered 205/55 front and 215/55 rear gives the car just a tad of rake that I really like. The downside is not being able to rotate tires. So the question is whether to go for the staggered look or just buying four 205/55 16’s for all corners. Stay tuned, I’ll have an update when I make up my mind! 😉

Final Thoughts and Considerations

Please keep in mind as you study these pictures that we have custom made frames under out cars. The frames and suspensions were specifically designed in order to give the necessary room for clearance between the wheels and all other components without having to resort to dreadful spacers.

As a side note though, I did use the staggered setup along with the Panasports on my TR6’s factory original frame before it broke. In the front though, the upper “A” arms had to be trimmed just a tad in order to clear the wheel weights on the front wheels. The rears though, fit perfectly with the stock TR6 trailing arms. So a 16 x 7″ Panasport will fit on a TR6.

Another trick that is not easily visible is the way both TR4 and TR6 body shells are mounted on our frames. You see, we made spacers in order to adequately raise the body just a small amount in order to make things line up properly. This required a little “thinking outside the box” but the end result turned out very nice indeed.

And there you have it. If you have any questions, suggestions or comments they are all welcome. Just fill in a comment below and I will be happy to elaborate some more.

Update:

More info about tires on a TR6 here: Yokohama ADVAN Neova AD08 on a Triumph TR6

Details About an ECOTEC Powered TR4

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After the success we had with bowtie6, my cousin Jim and I had many conversations on improving the concept. I remember countless hours of discussions next to the space heater in Jim’s well equipped shop several winters ago. We quickly zeroed-in on the engine: the Ecotec as fitted to the Pontiac Solstice mated to the Aisin 5 speed gearbox would supply a powerful and reliable drive-train. It would also offer a PCM that we could tweak with a laptop. We also decided a Triumph or MG would be a good platform for the Ecotec. Finally, we would subscribe to the ideas that Anthony Colin Bruce Chapman based his designs upon: keep wight at a minimum.

Eventually, we got word there was a local fellow with several cars in his basement that had to be sold Needless to say, Jim and I quickly grabbed our gloves and jumped in the shop-truck and headed out to this fellow’s basement. Sure enough. We found a 1964 TR4 as well as a Datsun 2000 roadster. The Datsun was our first choice since it is the more “exotic” of the pair however it was missing entirely too many parts. Jim decided the TR4 would be the best choice. A few days later we arrived with a trailer and brought the TR4 home.

I could write about all this for hours but I think you want to see pictures and not a bunch of words, so let me fast forward to the present and show you what Jim’s TR4 looks like today. Unfortunately I cannot cover the entire car in one article; I’ll break this up into several. Today, I’ll start with the outside. After all, beauty can’t be only skin deep, right?

As you can see in the picture above, the nose of this TR4 incorporates many subtle changes. For starters, the turn signals are gone. They are now hidden behind that hand-made aluminum grill. The front bumper is also gone and the oval air inlets below the grill have stainless mesh behind them. Finally there is a hand formed “air dam” with two “nerf” bars on the roll pan. Jim likes his “nerf” bars – Steve if you are reading this, I am sure you will agree with me. 🙂

The picture above shows the new bonnet. When I mean “new”, I mean this piece was formed entirely from aluminum. If you look closely, you will see the “bulge” is missing – I guess it is a matter of choice but this is the way Jim decided to build the bonnet. The trick to making this bonnet was piecing together several sections. They were all carefully formed on the English wheel and TIG welded together. The following gallery shows what the back of the bonnet looks like.

But… Before you start clicking on all these pictures take a look at the first one of the set. There is a small recess, wide enough for two fingers to be used to lift the bonnet once the latch is released. Pretty cool, huh?

Next you can see the backbone of the bonnet. This backbone is also made from aluminum and is not welded, instead it has been bonded to the backside of the bonnet with automotive epoxy glue. Finally, take a look at the third picture. If you look close enough, you can see some of the hammer marks left from when Jim formed the headlight bulges. Yes, all this was carefully welded and shaped just like it in the glory days of hand formed bodies.

The next gallery shown above, displays the hard top Jim made for the TR4. This top is entirely made of aluminum and just like the bonnet, is extremely lightweight. Again, many pieces formed by hand and on the English wheel, TIG welded and carefully finished. If you look at the surface of the top (see second picture) you will see ridges formed by Jim’s Pullmax machine. These ridges are there to add strength and to prevent the top from oil-canning. Finally, to keep weight down Jim used thin Plexiglass in the windows instead of glass. Oh and the side windows open; Jim made special hinges to allow the side windows to pivot. The following collection of pictures shows what the top looks like from the back and from the sides.

The back third of the top has a small taper. It is also formed in such a way to give the rear glass a curved look. At first, one would think this would hinder visibility but the seats are very low in this car, and outward visibility is excellent. I think it looks very cool!

Finally is this picture from the back of the car. The bonnet is also different from stock. Yep, you guessed it. It is also formed from aluminum. Jim made a similar backbone frame for it and it is extremely lightweight. As if that were not enough, take a look at the rear bumper. This one is not as wide as the ones Jim made for bowtie6, but is just as lightweight. This bumper also is different from mine in that it’s finish is made by simply wiping it with ScotchBrite. This gives the aluminum a muted, matte finish.

I hope you have found this interesting. I’ll have more about Jim’s TR4 in future articles, so stay tuned! 😉

Alumakini on the TR4 – Part II

Triumph TR4 Surrey Top – modified –

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Well – here’s a new one for you…

There is the concept of a Surrey top for a TR4/250. OK – they are nice but they are hard to find. They have glass and they are heavy. They do offer a removable centre section and yes, they are pretty cool. But here is a variation on the theme…

My cousin Jim’s TR4 has been an awesome car so far. The ECOTEC has been magnificent providing plenty of power and lots of fun. However summer is upon us and it gets a little hot to go topless the whole time. What to do? Order a canvas top and look like any other TR4? Nah. How about this:

Jim’s TR4 has a rollbar bolted to the bespoke frame on special mounts. Off the hoop, there are two tabs offering a way to mount the hand-made aluminium “bikini top” shown on the picture at left. The three “ribs” have been formed on a Pullmax machine. All total this top is not heavy at all, maybe a couple of pounds. Not exactly “stock” or “original”, but what the hell. Jim is a master craftsman and this car is indeed unique.

Here is another shot of the new top. It shows the mounts on the rollbar. The front attaches to the factory mounts on the windshield frame. Two bolts will hold that in place. Jim has made this in such a way that the side glass can be rolled up and it will be perfectly aligned with the edge of the new “top” – and by doing so, the car could be driven with light drizzle and this would prevent one from getting soaked. This is the inspiration to the new “top”. Granted, this is not everyone’s cup of tea but what the hell. It certainly looks trick!

I realize the top looks a little “crude” – it was only made today and has not been totally finished yet. We were kicking around the idea of fully polishing this top – after all it is aluminium. The idea would be to make it as shiny as chrome. Then again, it might just get painted either body colour or some other contrasting shade. We were also kicking around the idea of covering it with some convertible top canvas to give it a faux look. One thing we can be certain of: take a look at the following picture:

Check out the little tab… That is a small proof-of-concept: yes, the top is going to have a mild NASCAR “wing” on it. This will not only look good, it will provide some downforce at high sped. And believe me: the TR4 needs it. With the extra pop of the ECOTEC, the car certainly can use a few free pounds of downforce. After all, all the pressure would be transmitted to the rollbar, mounted directly to the frame right above the rear axle… Pretty cool, huh?

the bowtie6 blog

For this Triumph TR6, the road goes on forever and the party never ends…