EFI, engine swaps, reliability...

Forgive my ruminations. Winter wears heavy on New York City.

In the middle of researching NA Miatas I realized something—I don't want a Miata! I just want my '65 Sprite to always work! Yes, yes, part of the car's character and charm is in its delightful quirks, but it's not my only needy toy, and never will be. The effective result is that I have a car in a valuable garage spot that I've put roughly 50 miles on in five years, despite it being the most fun one I have to drive. I'm no collector. To me this is a tragedy.

What I am is rather pragmatic (if ignorant) engineer. What good is a charming car that you don't drive? This has since led me down even crazier avenues than the Miata...

Pathway into Darkness - Imagine an LBC with a 1.0L Ford EcoBoost. A turbo 3-cylinder motor that puts out 120hp and weighs less than any motor BMC ever put in a car. I get giddy imagining it. I do not get giddy imagining what it would be like to mount this motor in a Sprite, mate it to some or other transmission, and see what it does to the rear diff. I also wonder about gearing and the general perils of owning a Sprite that could reach 100mph. I'm just dumb enough to see what it's like.

Back to the Future - Across the pond, in a strange imperial land, these 50-year-old motors continued in production right up to the cusp of the 21st century. I wonder greatly what it would take to install a Rover 1.3i motor in place of my 1098cc motor. Weight and power would not improve much, but that's fine. What it would buy me would be glorious modern fuel injection. Is this a bolt-up operation or are these motors way more different from their predecessors than I'm giving them credit for?

Enhance - Modern EFI kit to bolt onto my existing 1098cc? I've never messed with MegaSquirt, et al...

A Bland Rational - I could, of course, try and fix whatever is causing my motor to run rough and stall out at temps above 180°F and plod along as per usual, hoping for the best. I just have this feeling that I'll never get to turn-key reliability from any carburetor, even with an electronic ignition. I've owned too many motorcycles. Yes, yes, your SU carbs are extremely reliable if you just get them adjusted perfectly, keep everything clean, adjust the points every season, and try to avoid moist air, stopped traffic, and disagreeable temperatures...I have enjoyed months of (somewhat) trouble-free operation, but California has that effect on classic cars. We now reside in a ruthless area, and the result is unfortunate confinement.

If the motor never gave me another issue for the life of the car, it would still have plenty of charm left in the suspension, defrost, lighting, wheel bearings, transmission, final drive, et al...So. How crazy am I in my desires?

You're not crazy at all -- driving these cars is why we have them, they are fun! If you're struggling, then they're less fun. Or no fun.

EFI is certainly an option. Patton Machine has a kit that looks interesting: https://www.pattonmachine.com -- but will require some work to make function. Engine swaps can be incredibly fun to drive, but require some serious engineering. There isn't a bolt-in easy swap for a Spridget, so you'll have to do a bunch of engineering work to make it all function properly. Probably to include a new transmission and rear end.

A rebuilt set of SUs should be quite reliable. You can also swap to a single SU that makes things even simpler. For more power, a 1275 drops right in and there are lots of speed parts for it. Your 1098 should be okay, though, if it's working right.

Were it me, I'd start with the ignition and make sure it's all in top shape. Have the distributor rebuilt (Jeff at Advance Distributor is a go-to guy) and convert to electronic ignition if that's your thing (I'm a fan of points). Next, make sure your SUs have been rebuilt and don't have any air leaks. The shaft that connects the 2 is often a wear point. Good condition SUs should be dead reliable. I've not had trouble with ones in good condition even here in Utah with pretty crazy elevation swings (from 4500' to 10,000').

You can also do a supercharger...

Good luck, and we're here to help get that little car running well!

The cheapest option would be to move back to San Francisco. The Ecoboost sounds really interesting. But a swap of a modern efi motor involves a lot of work, not only in installing the motor but also in figuring all the wiring, ecu, sensors, fuel system today's engines require. You'd also break a lot of axles with that kind of power, so plan on a rear end swap while you're at it. Not saying it can't be done, but I think people underestimate how much work is involved in even a "simple" engine swap (here's mine: https://forum.britishv8.org/read.php?13,8264) Unless you're really committed to all the work and expense involved in a swap, I'd start with Drew's suggestions ... a rebuilt dizzy with Pertronix, rebuilt SUs. New plugs (I like NGK BP6ES on my Sprite with a 12G 295 head) plug wires, points, distributor cap, rotor and condenser. Throw in a new coil while you're i there. I'd also make sure your fuel lines are clear and your tank is clean. Make sure your fuel pump is up to snuff, too. It's not like the A-Series motor is rocket science and with good functioning electrics and fuel there's no reason it can't be made to run reliably at far less expense than some of the other ideas you have in mind.

BTW, nice looking Sprite!

and exactly how wealthy are you? (if you live in SF or NY, you're either fabulously rich or starving, trying to pay the rent).

We have a bug-eye with a 948 cc engine, a Weber 40 DCOE (we never have recalibrated the distributor), and a recently installed Datsun 5 speed (we used the Rivergate kit; Gerard et al offer other choices), and no other upgrades. It hasn't had a lot of miles on it the last few years due to problems (my fault) with the tranny install, but it should be 100% reliable this summer - back in the 70s, it was our only car for a year or two (including winter in Calgary - home of the 1988 Winter Olympics). Complete with SUs. Key thing was buying a battery the same size as the engine......
We have a second BE getting assembled. It'll have a 1275 cc engine; Rivergate 5 speed, and probably a Weber 40 DCOE as well as front discs. And probably go Pertronix and get someone professional to match the distributor to the carb.
Now, if you're wealthy: have a look at Specialist Components Twin Kam conversion in the UK whereby you modify your (new to you) 1275 cc block and then bolt on a BMW motorcycle DOHC EFI cylinder head and induction system. They'll also sell you a supercharger system for over 200 hp.
Regards Megasquirt: my son has a 1973 round tail light FrankenBMW with 271 hp (low boost) at the rear wheels, courtesy of a 2.5 litre BMW six that the previous owner installed and converted to Megasquirt and added a turbo. Having someone to discuss the Megasquirt installation & tuning is very helpful, but not critical. Note that you've only got two intake ports feeding four cylinders; I understand that the latest Megasquirt system can handle siamesed ports, but I don't know that for sure. We've also got a normal BMW 2002 roundie that I'm looking into converting to EFI (Simple Digital Systems or Megasquirt), but using a pair of junk Weber DCOEs as throttle bodies so that it'll look visually period.
IF Megasquirt can handle the siamesed ports, think about a gooseneck manifold with the injector bosses welded to it and a junk DCOE acting as a throttle body. Trigger wheels etc. etc. are commercially available - and I'm guessing you'd be looking at two grand or so for the conversion, without the manifold/junk DCOE.
Probably the best bet is to pull the SUs and put a rebuild kit into them and pay someone to change the points and check the timing.
Next best bet is what you described: slap in the Pertronix; buy a manifold and downdraft Weber from your favourite supplier, change the oil and brake fluid, and enjoy!
Life is too short to muck about trying to do it all: get it running; enjoy; and contemplate further improvements! Good fortune, Doug

The biggest issue with a motor swap is the limited space for a transmission.
Ive waffled with the idea of engine swaps but at the end of the day the old tech serves its purpose well. Maybe you should just install a rebuilt 1275 and 5speed.

Trevor Jessie said:

The biggest issue with a motor swap is the limited space for a transmission.
Ive waffled with the idea of engine swaps but at the end of the day the old tech serves its purpose well. Maybe you should just install a rebuilt 1275 and 5speed.

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Or the 1275 and 3.55 rear gears.

Sadly all the modern engines are in front wheel drive cars and finding a good trans to couple them up to is going to be a big challenge. The Ford ecoboost seems very interesting. One I'd like to do is a Rotax 800 e-tec. 160hp from an engine that probably doesn't weight 100#.

Kurt.

While my first inclination is to go for making what you have reliable - there are some other options - https://forum.britishv8.org/ is a good site to chack - some engines. There are some interesting options here - mostly because the swapping kit is readily available - and the engines bolt up to RWD transmissions - https://www.hotrod.com/how-to/additional-how-to/0812rc-gm-quad-4-ecotec-ford-zetec-duratec/ - I would also add rotary engines to the mix - small and regularly done - and, while a Miata engine is a tall engine, they are available and cheap. The Mite is an example - https://the-mite.com/mite1.htm

Given that you only did 50 miles, recognize that a new engine will keep the car off the road for some time - and will take time to fettle. Given that these cars are really only 50 mile drive cars anyways, I would take the time to make it reliable - even if you have to pay someone it will be cheaper and easier.

Or, well, let me just put this here:

https://www.coupers-cars.com/sprite_restoration.htm

Build a 1275 for the most torque it can make. Forget the engine swap foolishness.

AN5Sprite said:

Build a 1275 for the most torque it can make. Forget the engine swap foolishness.

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As an owner of a '65 sprite with a Mazda 12a I can honestly agree with building up a 1275. If I had stuck with the 1275 I would be out enjoying my car right now. Im close to being done with the 12a swap but it certainly has increased the amount of time it has taken to get the car back on the road.

SBC

anarchy99 said:

SBC

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Well, yes, if you try hard enough anything is possible! How about Bill Young's V6!

Kurt.

Seriously, a built 1275 is NOTHING like a built to outrageous specs 948/1098.... It's so much better....If reliability is the issue there's no reason to look beyond a fresh/stout 1275. I've never been stranded by mine...

My 1500 is Megasquirted. It has taken me years to work out all the bugs. Now I have a rather reliable car, but it was a long journey getting here. You can shorten that journey somewhat with the Patton Machine kit. Rick is a super great, very knowledgable guy. He helped me with my set up.

Honestly... you will get more bang for your buck using stock parts vs. efi. Unless you are a mad scientist like myself and cannot help yourself, it may not be the path for you. That said. You will learn a lot and gain a huge sense of satisfaction if you got the efi route. Also, I will share what knowledge I can should you decide to bite the injector.