67 1600 'simple' EFI conversion

[polkadot]

After 2 and a half years, I drove my Datsun home today!
in August of 2021 I bought a rust free - nearly complete - not quite runnning - 1600 off marketplace a short 4 hour drive away.

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It looked pretty good compared to all the other cars I'd looked at, minus some interesting color choices (red hightlights on the wheels and hardtop? one door black, one blue? hood and trunk done in TEXTURED grey???) I was told 'the webbers are junk' but the engine was recently worked on, whatever that means. I got it home and the next day dug into 311s.org to find out what on earth i was looking at.
I cleaned the SU carbs, replaced the aftermarket fuel pump (the mechanical pump's rocker arm was snapped off), the starter motor, and the water pump. It started and ran, tho pretty rough. I did drive around the block, possibly the first time it had been on the road since its last registration in '85.

After very little time tuning the carbs I decided it would be a fun project to convert the car to EFI. This was dumb.

I will briefly mention my goal with this project is not to hide what I've done, but to keep a period appropriate look. This means I try to make choices that may not look original, but look good as a whole. I dont care about power, and I hate wasting parts that are still useful, and when possible I try not to put more holes in original parts.

I thought it might be possible to use the SU carbs as throttle bodies and mount injectors in the original intake manifold, so I bought a microsquirt and all the sensors I thought Id need to get the job done. I then shelved the project for over a year. I have a little workshop in Santa Clara that I moved the car to in July 2023 thinking id get this all wrapped up in a couple months.

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This was my first attempt at modifying the intake manifold. Siamese ports with big split fire injectors mounted in bungs welded as far back as possible in the manifold (meaning id lose the water passage and its cool looking heater system fittings) and it worked pretty well! For various reasons (mostly bad assumptions) I bought a second manifold and modified it to hold 4 injectors, mounted as far forward as possible.

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I had to make a new exhaust header to clear the fuel rail, and added a bung for the wideband o2 sensor (innovate lc2)

I welded a toothed wheel to the back of the crankshaft pully, and made a little bracket to mount the crankshaft position sensor using a couple of the bolts on the timing belt cover.

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I also decided to use the microsquirt for ignition timing. I took the points out of the distributor and welded the weights in place so all advance would be taken care of electronically. I added a single channel ignition module to fire the stock coil with the logic signal provided by the microsquirt.

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After chasing down one inexplicable splice in the engine bay loom I ended up replacing every inch of wire in the car minus the steering column.
I haven't looked at the rear differential, the transmission or anything on the engine besides checking valve lash (perfect!) and the timing chain (perfect!). The only rust on the whole car was the entire exhaust, so I made a new one mostly following what I think the original did. I bought a rebuild kit to fix a leak from one of the front brake pistons, and now it stops on a large dime. Replaced the shocks with some cheap KYBs, Converted the taillights to LED. I was given some Holly retrobrite headlights, which I modified with the glass from some old Marchals that look pretty good. And somewhere in there i realized the alternator didnt work so I replaced it with a 1 wire alt that looks very out of place, but works for now.

I've been ignoring aesthetics trying to focus on getting the car running, but I did spend a lot of time fixing up the dash, and I had some metallic blue paint I tried on the hood and trunk, but eventually I'll be going back to the stock sora blue.

This all brings me to today, when I finally got the courage to take it for a real drive. I had done a few test drives around the parking lot at my shop trying to get a little tune on the controller, but today was nine miles down El Camino, grinning like an idiot, waving to anyone who looked at me for more than two seconds. It was glorious.

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Tons more to do before I get to bodywork and paint, but for now Im thrilled with my roadster.

[Nissanman]

Very interesting journey you have had!
I am impressed with the conversion to EFI, nowadays it can be so simple.
So, how is the driveability/economy/fun factor?

[drieseck]

Impressive EFI, good photos. I have many memories of grinning like an idiot. Keep us posted how it runs. Dave

[Daryl Smith]

Welcome to the EFI club!
I converted years ago and was really impressed with how it ran, the improvements in overall power and the milage increase.
I am going to suggest you see about a better heat shield, there will be a lot of heat on those injectors/fuel rail if they are still on the underside of the manifold.
I understand having it 'look' original, but, since you have the crank wheel, if you decide later to dump the dizzy, it is really easy to convert to the VW 'smart' wasted spark coil (logic voltage triggered). This is what I am using, mounted where the dizzy used to be.

[polkadot]

I am going to suggest you see about a better heat shield, there will be a lot of heat on those injectors/fuel rail if they are still on the underside of the manifold.

I was pretty worried about that, but after wrapping the exhaust I haven't been able to record a temp over 120F at the closest injector/wiring harness. I'm sure my measurements are sloppy but I'm a big believer in the fiberglass wrap.

I understand having it 'look' original, but, since you have the crank wheel, if you decide later to dump the dizzy, it is really easy to convert to the VW 'smart' wasted spark coil (logic voltage triggered). This is what I am using, mounted where the dizzy used to be.

I hadn't heard of that system before but it looks pretty neat! I'm just not sure what advantage it offers, plus I plan on adding a little tooth wheel inside the distributor as a poor mans cam position sensor, in aid of adding a knock sensor at some point.

As for power, I cant say how it compares to stock as I only drove it around the block, scared out of my mind with zero brake fluid and no exhaust, but I am shocked at how much grunt the little r16 has!

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Thanks everyone for checking it out!
Id also like to give a huge thanks to Mike Young for his expert advice, kindness, and inadvertently making EFI sound like a good idea. Also to Gregs672000 for being a patient trove a knowledge and experience, as well as being a sounding board during this weird process.

[Daryl Smith]

"I hadn't heard of that system before but it looks pretty neat! I'm just not sure what advantage it offers, plus I plan on adding a little tooth wheel inside the distributor as a poor mans cam position sensor, in aid of adding a knock sensor at some point."

Main advantages:
1) Timing accuracy - timed directly off the crank, none of the gear/chain slop encountered in getting to the distributor
2) 2 coils in system, more dwell time and 'spark' power available - tho to be honest on a stock engine it wouldn't make much difference.
3) No moving parts to wear out. No replacing the distributor cap or rotor.
4) Coil wires go direct to the spark plug. Shorter wires. No power losses at the distributor. Once you've done it, you'll never have to worry about getting the wires in the right order ever again.
5) If mounted on the engine, that space on the firewall where the coil and ballast resistor used to be is now free. Tho if you are using the dizzy for other timing info, the coil would likely go in the original location....I wonder if it might be easy to fit a later 'sensor' only type 'dizzy' for that?
I had considered a sensor at the fuel pump lobe of the camshaft, but don't feel the need anymore.

This is the EDIS system I first installed, but the coil position is the same.
http://www.311s.org/pmwiki-311/pmwiki.p ... ssIgnition

[funkaholik]

I love everything about this, but most especially the blue Adirondack chair as the "back seat".

Seriously, though, hats off to you for building your own EFI system. Very, very cool. Did you modify the SU carbs to use them as throttle bodies, or just remove the fuel lines and add a TPS?

[Gregs672000]

Ya baby! Woo hoo, love It! I was just thinking about sending a PM to see how things were coming... looks like it's coming along just fine! And you will find Daryl a great resource. I have followed in his footsteps, and if he's suggesting something it's because he's been there or is there. I agree with him on converting to a crank-fired ignition. I don't know what you were required to do in regards to the toothed wheel positioning, but I do know that the missing tooth needs to be in a specific position on the crank pully so be sure to research that if it was not required before (at least, this is what is required using a Ford EDIS). I would also consider mounting your crank sensor to a more rigid plate (?), as any vibration can cause signal loss. It so happens that the alternator or air pump triangle metal plate that's used to mount them to the engine bolts perfectly to those two front cover bolts... There's one shown in the "assorted 68 2000 parts" for sale list going on now if you need one. That's what I used and I've never had an issue with signal loss, and that can be a common problem from what I've read. Would also be happy to discuss timing maps, acceleration enrichment etc. after you're able to get some time for autotune to start making a fuel table. To that end, be nice to her, check your ignition timing, and take your time. If you don't already have it, download Megalogviewer to help analyze your data logs. I can help you reduce sensor signal noise and help you trouble shoot wiring problems using data logs when/if needed.

So cool man, very excited for you. I have this great image in my head of you driving down the street and waving like an idiot... I can relate!

[polkadot]

1) Timing accuracy - timed directly off the crank, none of the gear/chain slop encountered in getting to the distributor

the microsquirt is timing directly off the crank, the distributor only exists to vaguely point at the right plug wire for when the ignition event occurs, but point taken, there are a LOT of extra moving parts and things to go wrong by preserving what I have.
Also I love the idea of picking up cam position from the mechanical fuel pump lobe. Definitely gonna check out turning the old broken fuel pump into a sensor housing.

Did you modify the SU carbs to use them as throttle bodies, or just remove the fuel lines and add a TPS?

I pretty much removed the fuel lines and pistons, plugged up one hole and Im using the other for intake air temp. I originally had the TPS mounted to the throttle linkage on the manifold, but moved it to the side of the throttle body so I could theoretically use the choke knob in the future as cruise control.
When I see that Adirondack chair in the picture it looks almost normal size, but I build it for my 18 month old daughter :p

The missing tooth needs to be in a specific position on the crank pully so be sure to research that if it was not required before (at least, this is what is required using a Ford EDIS). I would also consider mounting your crank sensor to a more rigid plate

The Microsquirt has an offset number to adjust how far from TDC the crank is when the toothed wheel lines up with the sensor, I checked it with a timing light and I think Im within a degree. I did remake the sensor mount on your recommendation out of 16ga steel, still a bit of flutter on tunerstudio's tooth logger, but its very consistent, just the toothed wheel not completely co-planar with the crank pully (or a bent crank!)

Im incredibly excited to start working on the timing and fuel table in earnest, but life is in the way for the next couple weeks. Torture!

[mojorising84]

Woohoo! Great to see that you have things running! I'm excited to follow your EFI journey and will definitely have to ask you some questions along the way. I'm afraid my journey with the EFI conversion has stalled due to life things for the moment but I'm hoping to be able to carve some more time out soon.

On a similar note of the cam timing wheel, I stumbled across a YouTube video of a guy also doing an EFI conversion. He had mentioned that he was working with JT (don't quote me on who it was!) and he showed a modified distributor body with what looked like an optical sensor mounted inside. The sensor itself looks similar to the Cam Angle Sensor found inside a 300zx v6 NA. I think late 80s early 90s. It looks like a really nice fit and I believe that it gives a simple square wave output. It may be the solution you are looking for with regards to cam timing.

If it was JT that made it maybe he can chime in? I will see if I can find the video tomorrow and I know I found the sensor spec somewhere too.
Cheers,
Dave

[mojorising84]

OK, I found the link to the video from KR Motorsports.

https://youtu.be/fLUFyh7v2Tg?si=cEDNCERIqQSRGn4X

I have the sensor spec which I THINK it might be on another computer. Will have to find it tomorrow.
Cheers,
David

EDIT:
This may be useful...
http://datsun1200.com/modules/mediawiki ... ptical_CAS

[Gregs672000]

Yes,I 've seen the YouTube videos and heard mention of JT. I believe the distributor is the 123 Distributor which is an interesting and more drop in solution vs crank fired/toothed wheel. May not be quite as accurate but for the vast majority of engines a little gear "slop" is no big deal and does not require modifying and welding the crank pully, a significant installation advantage. Disadvantage is the 123 costs money, but many would probably farm out the weld job like I did, so $ regardless. I was already crank fired before EFI so for me it was a natural progression.

The most economical part is the Microsquirt V3 itself... compare its price and operation to any other controller not specifically designed for the V8 crowd and $315 bucks or so is an absolute steal. It works great for simple engines like ours that don't require emission controls or a bunch of add ons (thought it's capable of doing a lot more than what I ask it to do). Setting the parameters correctly and good wiring/sensors does become much more critical to engine operation vs a carb and points... a carb will accept a lot more "garbage" than a computer! NO exhaust leaks are tolerated if you want a good and consistent tune. No bad or weak grounds or questionable wiring connections accepted!

For example, the other day I did some adjusting on my ignition parameters in TunerStudio after reading some. I uploaded it and forgot about it. Next time I fired up the car, all of a sudden it didn't want to warm up like normal and would drop idle and die. It's NEVER done that. Just seemed like the idle was set too slow, so I increased it and things were fine... but why? I kept thinking about it, and a few days later went back over the manual and found I'd used the wrong info/parameters for my system. Set back to what it was and everything was happy again. I like control, but you have to take CONTROL!

You're doing great! Looking forward to your continued success!

[Daryl Smith]

"Definitely gonna check out turning the old broken fuel pump into a sensor housing. "

Might be easier to just get a fuel pump block off plate (thick one - not hard to make) and a long sensor from the wreckers. Back when I was considering this I found some sensors which I thought would be long enough.
I will say, I don't know if this will work as easy as it sounds, but have heard it mentioned elsewhere. Have not seen any working examples.

Search brought this up:
https://turbobricks.com/index.php?threa ... er.366262/

[redroadster]

Does the system have a shut off to the fuel pump from a link to the alt. Like in a wreck where the ign is still on but the engine got stopped ,if not the pump still runs . You could pull the coil wire to see
VWs 80s CIS FI system there's no timing to the valve opening on the engine , it will time its self to the optimal sequence within 5-10 sec.

[polkadot]

Like in a wreck where the ign is still on but the engine got stopped ,if not the pump still runs

oh I assure you, if theres a wreck where I cant turn off the key, burning alive is going to be my parting gift to myself.