In another post on this community, partially just trying to generate a conversation, i asked about adaptable coil-on-plug modules. A couple folks were helpful, but it’s still thin on the ground here, that’s cool, it’s all new, etc. Here it is: https://lemmy.world/post/1263808 (not much).
But I’m serious about designing and building a new ignition system for this ancient, forgotten engine that I’m kinda expert on by now (that expertise plus five bucks buys me coffee at starbucks). I’ve got two cars with this engine now, it’s just barely tenable to drive now, parts are extremely scarce (eg. timing chain setups).
Anyway this engine, the Rambler 195.6 cubic inch inline 6, has roots back to the 1940’s, AMC slapped a shitty OHV head on the old flathead engine, introduced a number of reliability problems, then solved those just as they introduced the brand new design engine, the 199/232/258.
It’s got a once-conventional distributor, contact points and coil ignition. There’s a Pertronix in there now. It works fine, but I hate them – the distributor has to crank two rotations before it fires the coil, so the engine cranks for over a second each time, instead of firing right up on the first contact-point opening. I WANT THAT BACK.
So I’m gonna make new electronic guts for the distrib, drive some form of coil-on-plug, and do software spark control in the computer I’ve got already running the electronic carburetor.
ITT is chat about research, photos, etc. I’ll make a web page for the project like I usually do. My Rambler Lore website is https://www.ramblerlore.com/index.html
Here’s the page on this engine: https://www.ramblerlore.com/AMC/195.6ohv/index.html
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.