car talk

HA! Never do what you're told. I like the COP modules for their integral driver. Saves a lot of design and power issue transporting spark coil power around....

So I yanked the rubber boot off the end of the toyota COP module... aaaaand it turns out that it's shape is nearly identical to a distributor cap tower socket. Aaaaaand a regular spark plug wire fits it. Instant coil near plug...

Now I know these things are designed with very thin margins... and I'm not sure if the module will tolerate the added cable (inductance and resistance). So at the least I'll set one up on the bench with a "long" plug wire and run it for a few thousand cycles and see if it bursts into flames or something. (likely death will be a hole punched in a silicon barrier and... silent death).

20 bucks each and driver built in and available at autozone on the road....

OK I rummaged around in search engine and RockAuto.com and found some cheap, common Toyota coil on plug modules for which I can get connectors too. And bought one. The issue is (see photos) this is an old pushrod OHV motor, cam in block, and all COPs are designed to fit down through the valve cover etc. So it dangles. This is a really small car, and even if I make brackets to support them, it's bust. I'm not relocating the battery (umm low center of gravity was not ever considered...) so this scheme won't work.

I think coil-near-plug as a smart Volvo fan suggested is the next thing to look at; I'd ordered this part before that post. I'll post on that when I find one to examine.

In the mean time here are photos of failure, lol. Projects like this are failure every step of the way through success.

Plug side of the motor. It's a very small car, same wheelbase as a Yaris (within 5mm). Tiny engine compartment especially for 1960.

COP on plug #2. Immediately obvious to me not gonna work. Simply too tall. Cyls 1, 2, 3 maybe, but 4, 5, 6 are under the battery and I'm not moving that (again). Too cluttery.

Lifted by hand to in-line with the plug.

Here's the module itself. Lovely thing! Coil and MOSFET driver right in the sealed unit. I lurv this new shit.

Last post today: the distributor (no photos yet) is a typical old Delco Remy, they're OK, but all of them are worn out after 60 years, shafts wobble, etc, and new ones don't exist and no one rebuilds them any more (I do my own).

The plan is to replace the distributor guys with an optical coder that gives absolute position so the first cylinder fire position reached actually generates a spark -- [EDIT:] 60 degrees of crankshaft rotation, not 720 etc. Pertronix II needs a full rev to determine angle and another I think to work out coil dwell.

I use MegaJolt/e with EDIS-6 on one of these engines in my sports car, but that stuff is old now, I dislike the single-source Megajolt now, 10 years later. With COP it;s just some logic drivers, sensors, and a spark map. I'm running two fuel maps now for the carb (AFR and enleanment feedback) so spark will be easy.

Here's a distributor stripped to the housing, shaft, and drive gear. The mechanical advance was stripped out of this one, but for fail-back purposes the one that goes in the car will have the advance junk retained, just pinned to disable, so in theory the contact points could go back in.

Welp, things change.

I'm likely not gonna continue with this project, now anyway, for the simple reason that putting electronics inside a distributor, even if it's as little as IR sensors and LEDs, is too unreliable. (Pertronix modules have a tiny micro in them, and are quite reliable, so maybe I'm being too conservative here. But is it commercial temperature range stuff? No idea.)

It's easily 200F/95C in there, inserted into an engine block at 195F/90C+ operating temperature. Low reliability is the LAST thing I want.

The overriding reason for a modern ignition system was to get control over spark timing (advance) so that I could take advantage of the leaner mixtures I can controllably get with the electronic carburetor. Not necessarily a lot more advance, just control over it.

For the short term I've switched to a different distributor I've had for sometime, an old contact-points distributor someone hacked to take a Ford Duraspark type variable reluctor driving a GM HEI module. They did a poor job mounting the coil square to the moving pole, so I spent a day (aargh) fixing the bent "points" plate and got the gap to be a solid .015" and square. It was angled, < .010 at the top and .020 at the bottom and spark was a bit erratic. Seems solid now, when it cools off I'll put the oscilloscope on it and see how much it jumps around.

The engine turns so slow (RARELY does it spin even 3000 rpm) that a dumb old single coil is adequate.

I cobbled up code for a distributor with optical position sensor, but given how much of an overall PITA distributors are I'm at this point more likely to scrounge up some EDIS-6 stuff and bolt a wheel to the harmonic balancer, even though that gear is from the 1980s.