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Ray: FWIW it seems to work. Thanks. Where was the current measured? I have to wonder why the transistor ever gets hot? The maximum power would be 12v x 20ma (led current plus a couple more for the 5k and 1k resistors) or 0.25 watts (give or take). Are you sure the transistor is turned on...

I don't have any "sales" of my ignition driver. In fact I have built more than 20 of them and given them away. They are built and used by a lot of model builders on the West Coast and it was featured in Model Engine Builder Magazine as a DIY project. It's not an ignition "system" per-se. It's...

Ok. Thanks for the info. I'm not familiar that one. I wasn't aware that there were coils that had an edge triggered "module" (so to speak) inside. The typical multi-wire coils I am familiar with have a simple transistor driver inside. Which saves you from having an external driver. The input 5v...

Ray: That is not the output from a Tesla coil. It's a seriously wicked spark (as Steve indicated) perhaps 5/8" long. Have another look at the video. My challenge stands. SHOW us a similar output from one of your circuits. The only reason the module Steve has employed in his big spark plug...

Steve: Do you still have my coil driver I gave you? It'll be your best bet so far.

Ray. I'm not sure how "Smart" your smart coil is and also you say you have controlled dwell BUT. What happens when the engine stops with the points closed or the hall activated? It seems this circuit still puts the coil in jeopardy (energized continuously) if the engine stops in the right...

Ah Yes. I remember it well from NAMES. Thanks. I'll be looking for that kind of performance from 74Sprints circuit. BTW. What's the gap. Thanks

Steve: Show us a movie of your GIANT spark plug. LOL

Bearings Canada ships by Canada Post. That's about as cheap as it gets. For you - six bucks maybe. +/-.

Closer than I thought (to me). Such is shopping on line. I could probably stop by if they had a bricks and mortar store. I'll have to check and save the post. That's where I get my one-way bearings and other related items too.

Try Bearings Canada (online). https://www.bearingscanada.com/ (Not to be confused with Canadian Bearings - generally a rip off.) Great prices, good stock and just about anything you'll need. I've had great success with them. They might be up your way. Not sure if they have a store. They ship...

The trick, for TIG welding aluminum is: CLEAN CLEAN and CLEAN again. Brush it with a stainless wire brush (never steel), wipe it with Acetone, let it flash and weld it immediately after cleaning. Way more picky than steel in that regard. The throttle pedal is key.

Brian: You should consider using the Sprague clutch type starter. Or at least a curved slot in the hub. It is likely that the engine needs / wants to spin faster than the starter to run. Your direct connection starter will be holding it back. The clutch will allow it to speed ahead of the...

You'll have to make some attenuators for the input of that scope. Many things you'll measure in an ignition system are over 50v. No sense going by the way of your China coil with the scope.

Yes. That's great. I've been looking at schematics for 55 years so interconnection diagrams just don't completely do it for me. :) Your suggestion of the series capacitor would normally be a good one but if I understand the CDI unit operation it might mess with the advance feature since the...

Paul: Do you have a proper schematic of your finished circuit - rather than the interconnection diagram or parts laid out on a piece of paper. I'm having trouble figuring out exactly how everything is connected. Nice work. Seems a pretty simple solution to the problem. Thanks

Ray: Q1 only has a dc current gain (hfe) of 8 at 5 amps collector current. Therefore it's going to require about 600ma of base drive current to properly drive the coil. The CD4047 at best will supply only 6ma. You're going to need at least a couple of pre-drive transistors. How about this: As...

Ray: You show an option for an IGBT transistor for Q2. I don't see a Q2 in the schematic. Same for TR2. I assume they are replacements for Q1 and TR1? TR1(2) being ignition coils I assume.

Ray: If you simply choose to use the Q(not) output of the chip (instead of the Q output) the transistor (and coil) will be energized most of the time instead of off most of the time. (sort of an inverted dwell scenerio). That's going to be an awful load on the transistor and coil and a waste of...

Ray: LED1 is never going to light The voltage at the base of the transistor will never go above 0.7v. The led will require at least a couple of volts. Unless you have something going on with a negative supply at VSS (-) on the led cathode? But I don't see it on the schematic.