1973 Isuzu Bellett: Refresh

As you all know, I absolutely adore driving my Bellett like a complete hoon. She’s not fast, pulling 0-100 km/h in about 13 seconds, but she’s one of the most hilariously fun cars I’ve ever owned. But, she’s still more than 45 years old, which means things break. As of late, the carburetors were begging for a clean (which makes sense because I stupidly don’t run a fuel filter) and the brakes were feeling atrocious – pulling hard to the right with a spongy pedal. On top of the that, the springs in the driver seat bottom had given way, giving me a terrible backache if I drove the car for too long. So, I knew it was time for a refresh, but I was putting it off and putting it off because I had other projects I was in the middle of.

What finally made me decide to start the overall refresh was the picture above. After searching on and off for a few years, that set of carbs and manifold showed up on Yahoo Auctions and I jumped on it. Finding a pair of Mikuni Solex 40 PHH carbs isn’t all that rare in and of itself, but finding them attached to a manifold for the G180SS engine is super rare. Once I finally got the carbs back to the US, I pulled the Bellett into the garage and got to work.

Not wanting to have a massive clutch fan obscuring the sweet, sweet noise of those Mikuni carbs, I took the opportunity to change over to an electric cooling fan as well. Which meant it was time to clean up some wiring in the engine bay. First, I built a panel that would hold two relays wired up to two 10A circuit breakers (instead of fuses) to run the e-fan and electric fuel pump. This panel would mount just below the battery and tuck nicely out of the way.

A lick of paint and she looks good installed!

Next up it was time to address the electric fan. I built these two x-brackets to hold the electric fan in place using the radiator mounting bolts.

I’ll show a picture of it installed a little later, but I don’t want to spoil the carbies just yet! While we’re on the topic of electronics, there was one more little problem I wanted to deal with. The alternator was woefully underpowered and would struggle to keep up with the fogs, headlights and high-beams on all at once. Throw in an electric fan and I was afraid I’d overtax it. Fortunately, since I’m in the middle of a Miata engine swap on the 117 Coupe, I had a spare alternator hanging around that was about a 15A upgrade. It didn’t mount up super easy peasy though. First, I had to figure out the wiring, which after a bit research led me to making this guide:

The space between the mounts was about 6mm too small for the alternator to slide onto the Bellett mount. So, after a lot of measuring, I found that the distance from the inside of the front mount to the center of the belt was the same between the two alternators, which meant all I had to do was chop about 6mm off the back mount. It had plenty of meat on it and I had a milling machine at my disposal, so chop chop and it fit perfectly! Just like the e-fan though, I’ll point that out after I get to the carbies.

Which I guess I should go ahead and show! Before cleaning anything up, I went ahead and slid them on to the engine just to make sure I could indeed make these work. Everything seemed to line up pretty well, so off they came and I stripped them completely.

While stripped, I cleaned up the body and manifold to make them look brand new. Then, a full rebuild kit went into the carb and on it went! Only, it didn’t. The manifold fought me tooth and nail the entire time. There must have been some subtle differences between the engine this manifold was designed for and my engine. It was still clearly for an Isuzu G-series counterflow head engine, but some of the tabs were off just enough to make it a bear to install. After some shaving here, grinding there, swearing over there, it finally slipped on and bolted down.

Even with just one carb clean, it looked absolutely brilliant! I set about rebuilding and cleaning up the remaining carb and tossed it on as well. Then, I had to do a few supporting mods to make sure the engine could keep up with the carbs. First, was a fuel filter. I ordered an SA22C RX7 fuel filter and clamp sized specifically for it, then made a little bracket and bolted it in place.

Next up was the ignition. I wanted to upgrade to a point-less type ignition, but you can’t exactly order an Isuzu Bellett conversion. Fortunately, after popping the distributor cap off and taking a look at the points, I could see they were actually a set of Nissan points.

After some hunting, I came across the Hot Spark 3HIT4U1, specifically for Japanese made Hitachi 4-cylinder distributors. After a bit of measuring, it was a perfect fit. I don’t have a picture of it installed, but check out their website linked above for more info.

With the ignition and fuel sorted, it was time to start buttoning up the engine bay!

Good god they look amazing! Other things to note in those two pictures are the 117 Coupe alternator installed just below the carbs and the electric fan tucked up against the radiator. Also, a little harder to see is a completely new ground cable that ties into the chassis at three different points along with the engine. With the carbs installed, it was time to give the old girl a start.

Yeah, that’s amazing! The throttle response is out of this World and the engine seems so much more lively than it ever did on the SUs. And keep in mind, in that video I have done zero tuning on the carbs. However, I can’t run it too long because the exhaust fumes would kill me and there’s still a lot of problems to take care of before I can move the car outside. First up, is the brakes.

After taking the front calipers off and taking a look at the caliper pistons, one major problem was immediately evident. They were so rusted and pitted, it was a miracle they even built pressure at all. Again, it’s not like I can just order new pistons, so it was time to get creative. First up, measure.

Even in those measuring pictures you can see how pitted they were, and I used the cleanest piston I had to get accurate measurements. After a ton of searching on the internet, I discovered there was nothing out there even remotely close that could work. So, I was left with essentially two options. Make new pistons or swap to different calipers. While mulling it over (and even holding an S30 caliper up to see if I could make it work), I looked over at the lathe and got to brainstorming.

I didn’t need the right height, I could fix that on the lathe, all I really needed was the right diameter. And, as it turns out, 350Z base model, single piston calipers use the same diameter. I ordered four seal kits and brake pistons for the 350Z (two pistons per caliper on the Bellett). They were obviously about two times too tall, but that can be fixed with carbide bits. On my first test, I destroyed the piston, which was expected, but I wasn’t smart enough to order spares. I then promptly ordered spares. My next trial was a total success, as seen in the picture above. The piston on the left is the 350Z piston, the piston on the right is the stock piston, the piston in the middle is my modified 350Z piston. The next attempt after that destroyed another piston. I was having difficulty because even though all the pistons I ordered were from the same manufacturer and for the same car, it turns out they were made of different materials. Some cut super easy, some were a right pain. Finally, after about eight pistons in total, I came up with four that would work.

I decided to get the rotors turned as well, which required pulling the hubs off. I’m not sure what wheel bearing grease I used when I built the car, but it was the wrong type of grease. The grease had turned black and wasn’t doing its duties as grease. Time for new wheel bearings too. With those ordered and installed, I put the whole brake system back together and started the arduous process of bleeding.

Unfortunately, it just wouldn’t build pressure. You’d give the pedal a few pumps and it’d firm right up, but wait 10 seconds and the pedal would go right to the floor again. I thought I was just crap at bleeding and went through two full bottles of brake fluid trying to get it to bleed, but it just wouldn’t. I figured it had to be a bunk master cylinder, so, out it came. Interestingly, when I built the car about 10 years ago, you could still get new master cylinders, and this was a new Isuzu part. But after dismantling it, I could see it was leaking pretty profusely.

A brand new master cylinder kicking it in under ten years is just… frustrating. Not wanting to go through the rigamarole of trying to get another new one from Isuzu Japan and get it shipped here, if they even still had any, I decided to start the hunt for something could work. After a couple trials and errors, I settled on a proper racing brake master cylinder from Tilton.

Unfortunately, this isn’t a dual master cylinder, so the entire brake system is now on a single circuit. Which means if I get a leak, the entire system loses pressure. That’s why they call it an “emergency” brake, right? The upside is that it was almost a direct bolt-in upgrade. I had to enlarge the mounting holes on the Tilton master by 1.5mm and I had to remake a few of the nasty Bellett hardlines, but that was it. I even was able to reuse the Bellett push-rod. Also, I bumped up in master cylinder bore diameter from the 3/4” of the stock master to 7/8” on the Tilton. This should give a firmer pedal that I can really lean into.

And boy did it deliver! After a single round of bleeding the pedal was the most affirming and brilliant brake pedal I’ve ever felt in this car! Before we could go for serious test drives though, there were still a few more things to tackle. First, the seat.

I ordered this OMP Silverstone seat slightly used off eBay and ordered an OMP seat rail off Amazon. Interestingly, the factory Bellett seat mounting holes were so close to the OMP seat, that all I had to was enlarge the Bellett holes by about 3 mm and the seat bolted right up. It’s super weird that I’m having better luck with bolt-ons for a car from the 70s than I ever had on cars from the 80s and 90s!

It is super comfortable! I would prefer for it to drop down about another half-inch and slide back another 2 inches or so, but that would require a fairly large amount of cutting on the Bellett. So, we’ll drive it like this for a while and see how I like it.

Some of the more astute viewers may notice in those seat pictures that I’m missing a shift lever. Let me tell you a story about how I’m an idiot sometimes. While working on the car, I noticed that there was an alarmingly large puddle of trans fluid forming underneath it. After climbing around I could see that it was coming from where the speedo cable goes into the trans. Not too surprising, the speedo has been having trouble for a while now and a shot cable was on my list of suspects. After some research, I think I’ll change over to a GPS box that spins an electric motor with a short cable to turn the original speedo, eliminating the need for a new cable. I pulled the old cable out, and dumbly didn’t realize that it was below the fill line of the transmission. A ton of fluid came out, dropping the transmission fill level to about half. Okay, that’s a problem for future David, first, let’s make a plug for the speedo hole.

God, I love having a lathe in the shop. I popped my new plug in, tightened it down and set about refilling the transmission with fluid. Except, I couldn’t get the fill plug out. Throughout the years it had been stripped, broken and beat to hell, and I remember the last time I filled the transmission that I hoped I never had to fill it again. It was so stripped I could not crack it loose, and with the transmission tunnel in the way, there was no space to get vice grips or anything on it. So, I started looking for other potential places to fill from. I tried dropping the drive shaft and filling from there, but that was a no go. Then I noticed just above the fill spot there was a small bolt holding a plug in place. “Sweet, it’ll overfill, but I’ll just be careful” I thought. I undid the bolt, slid the plug out and promptly discovered that it wasn’t a plug at all, but rather a pin for the shift linkage. Hmmm, that meant there was only one direction to go from here:

Yup, transmission out. Fortunately, the shift linkage was all on top and easy to access once out of the car. With the pin back in place, I ripped that crappy fill plug out.

It was properly gone. I measured it up and ordered a new one, so now I won’t have this problem again hopefully. While I was messing about with the shift linkage, I decided to address the sloppy shifter. Upon closer inspection, it was clearly sloppy because the original bushing had exploded into a million tiny pieces. Welp, time to spin that lathe up again.

Transmission got thrown back in, shifter with new bushing thrown in, and the whole car buttoned up. It was time for a proper test drive. My God it’s a different animal. After some idle tuning and playing with ignition timing, I’ve got it set pretty close. The jetting on the carbs feels pretty close too and the plugs look good, but I need to get a proper tune done on a dyno to make sure I’m not leaning out anywhere. The brake feel absolutely amazing, they’re the best feeling brakes of any car I’ve ever owned. Thank you Tilton! The seat is ultra comfy with fantastic support. The fan kicks on when it’s supposed to and keeps engine temps perfectly in check. It’s just an absolutely wonderful car to drive now!

Here’s the “Too Long, Didn’t Read” list of all the changes that went down:

New Mikni Solex 40 PHH carbs and manifold
New electronic ignition
New fuel filter (from SA22C)
Upgraded alternator (taken from 117 Coupe)
Electric fan (with thermo switch in bottom radiator hose)
New breaker and relay panel for e-fan and fuel pump
Tilton brake master cylinder
Modified 350Z brake pistons to fit Bellett calipers
Turned brake rotors
New wheel bearings
New OMP Silverstone seat
New shift bushing

Thank for reading!

1973 Isuzu Bellett: Repair Manual

Download it here: PR90 FSM (78 downloads)

This is something that has been a massive help while working on my Bellett! Although, it’s not specifically for the 1800GT, it has gotten me headed in the right direction many a time.

Download it here: PR90 FSM (78 downloads)

Hopefully this can help someone out there trying to keep these beautiful machines on the road!

1991 Honda Beat: DFW Kei Car Meetup

My two Kei car brethren from the Magazine shoot we did at the end of last year have a mutual friend who recently got his hands on a Suzuki Alto Works RS/X. And, he knew another gentleman with a heavily modified Alto Works, so they asked if I wanted to come on up to Dallas for a Kei car meetup!

I, of course, said absolutely, because it sounded like a good time, but it was also serendipitous because I just got my hands on a DJI Osmo Mobile 2 smartphone gimbal, and I wanted to give it a real World test. Also, it was a great chance to meet a fellow online acquaintance who had recently moved to the area from Canada with his utterly awesome Autozam AZ-1.

I only took a little bit of video and the low light conditions were playing havoc with my phone camera, but the result isn’t bad! Check the quick music video I put together below!

Also, check out the Usagi Motors YouTube channel for more videos: https://www.youtube.com/c/UsagiMotors

1978 Isuzu 117 Coupe: The Swap Begins

When we last left off, I had just gotten the new Mazda Miata 1.8 twin-cam engine – read up here for more info on how we got to that point.

First things first, I laid the Miata transmission side by side with the 117 Coupe transmission and the Miata transmission was a bit longer, meaning the engine would need to sit a little further forward than the stock 117 Coupe engine. This actually tuned out to be a very good thing for reasons that will become apparent later.

I measured up the engines next, or rather the lengths of the oil pans, since they are a pretty good indication of overall engine length. Here are the measurements:

117 Coupe pan: 545 mm

117 Coupe transmission: 755 mm

Miata Pan: 460 mm

Miata transmission: 820 mm

117 Coupe total length: 1,300 mm

Miata total length: 1,280 mm

As you can see there’s just 20 mm of overall length difference between the two!  Awesome, this plays well into my overall ethos, which is to get this swap done with zero modifications to the 117 Coupe. So, the next step was to just lift the transmission into place for an initial test fit. For now, all I did was line the shifter up, jack the transmission roughly into place and pop a jack stand under it to see how it sat.

So far so good! The first major problem in this mad experiment soon showed itself. The 117 Coupe uses a ball-nut type steering setup, which necessitates the use of a center sump oil pan. The sump rests in between the crossmember and the steering linkage. The Miata engine uses a rear sump oil pan, which normally wouldn’t be too much of a problem to modify, except the Miata oil pan is aluminum and structural, meaning it also bolts to the transmission.

You can see here that the Miata oil pan is resting on top of the steering linkage, so the entire pan needed to be modified extensively. It was time to call upon my favorite fabricator, Dashbuilt Performance.

All I did was give him a printout of those dimensions with a general idea of what I wanted to achieve and he got work!

The results are stunning!  I actually had to send it back for a revision and the pictures above show the revised pan, but that was because my measurements were off.  That adage of measure twice cut once should be modified to measure 50 times and still have to cut twice. However, the new pan now lined up perfectly, so I slapped it on the motor and lowered the engine into place. After some fiddling and fighting with it, I got the transmission bolted up so I could start locating things properly.

Of course, it doesn’t always go super smoothly. The Cam Angle Sensor located on the back of the cylinder head is just too large and was butting up against the firewall.

In order to keep the transmission optimally located as well as keeping the pan from running into the steering linkage, that sensor will have to be removed. This means I can no longer run the factory ECU, which isn’t necessarily a bad thing. I was planning on running a set of ITBs in the future, which would necessitate the use of a standalone ECU, so this is just moving that idea forward a bit.

Once I was happy with the engine position, the first step was building a transmission mount. Using the factory body mount locations, I built the above piece to run from left to right and hold a factory Miata engine rubber mount. The bottom half of the Miata engine mount bolts onto the piece I made above and the top half bolts onto a piece that connects to the transmission using the factory bolt holes for the piece that connects the Miata trans to the diff in the Miata.

With the transmission located right where I wanted it, it was time to work on engine mounts. I reused the factory 117 Coupe engine mounts to assure that the entire drivetrain is rubber isolated. Then I built adapters that go from the factory engine mounts to the block.

Now, all the mounts are going to come back out and get reinforcing braces welded to them where it counts to make sure everything is plenty strong. However, for the time being, the engine and transmission are in!

With the engine in its final location, I could start work on the next major hurdle I had to overcome. The 117 Coupe uses a cable operated pull clutch while the Miata uses a hydraulic operated push clutch. I tossed around a lot of different ideas of how to overcome this issue, which was compounded by the fact that I refuse to cut the firewall to mount a clutch master cylinder. Ultimately, I decided to build this contraption.

This piece mounts in the front driver side area of the engine bay and uses a lever to operate a BMW 325is clutch master cylinder with the stock cable. The reason it’s shaped so… elaborately, is because it mounts through bolts and holes that were already on the body (for the crossmember, condenser and headlight). I haven’t tested it fully yet because there’s no clutch or flywheel on the engine right now, but I’m quite happy with it!

The Miata slave cylinder uses a 3/4 in. bore size and the BMW master cylinder also uses a 3/4 in. bore size, so we get a 1:1 movement ratio out of that. Through various reading, it seems that the Miata uses anywhere between 15 and 20mm of travel at the slave cylinder, which means we want to aim for 17mm of travel at the master cylinder. The 117 Coupe factory clutch cable has about 30mm of travel. So, the cable is placed 90 mm from the pivot and the master cylinder is placed 50mm from the pivot. Since these draw two different arcs, it means that for about 30mm of travel at the cable, the master cylinder travels 17mm. Of course, I made this whole thing with a sawzall, drill press and an angle grinder (save for the two round pivots I machined on the lathe), so there’s going to be a little inaccuracy, but it should be close enough.

That brings us up to speed. The garage is quite full at the moment, so it may be a while before I get back into the 117 Coupe. In the meantime, keep an eye out for upgrades to the Bellett!