Disabling the alternator on a car

The "and wait" means another thought. The injection requires more electricity than the ignition. Dead stop. And wait - New thought. A magneto IS really just an alternator or generator - and it takes power as well.

Which has a "retard start" but does not controll timing across the RPM band. IIRC it retards the timing 10 degrees for starting. The retard was triggered by grounding the "R" pin - which was only on SOME of the GM modules (called EMR if I remeber correctly). The standard 990 4 pin module did not control the timing. There was another 4 pin variant that automatically retarded the timing, I believe, 4 degrees on start. These were used in distributors WITH mechanical advance. CCC didtributors with no built in advance required full computer control.

etc. being done internally.

running, probably since there are no permanent magnets in it disconnecting with the engine stopped may/might/probably be safe.

If you're bent on doing this experiment... Measure the peak battery voltage fully charged while charging. Decide how low you want your battery to discharge. Subtract the two numbers and put enough diodes in series to make it happen. That's a fail-safe that keeps you going. The diodes won't cost you any power when not charging. Probably have to do something about powering the field with only one wire so the alternator can start up. Maybe some reverse diodes or a resistor.

Just spinning an alternator takes energy. I once tried to build a 120VDC generator from a lawnmower engine and an alternator. Took all the engine power just to spin it up under no load.

No, that schematic shows how the electronically controlled low voltage 'stuff' interfaces to the high voltage. jsw

regulation etc. being done internally.

running, probably since there are no permanent magnets in it disconnecting with the engine stopped may/might/probably be safe.

Then you were definitely doing something wrong. The drag of 2 ball bearings and a pair of 1/4 inch brushes and a 4" low performance cooling fan is pretty negligible - even for a 2 or 3 HP lawnmower engine.

Under load would be a different story. 6 HP will give you ABOUT 30 amps running at 3600 RPM set up to give 120 volts DC. Used to run

120DC alternator kits on my Dad's old Dodge work trucks for running drills and saws roughing in houses (he was an electrician)

You replying to me or the previous poster? I didn't look at the diagram shown (which has nothing to do with controling the spark timing ) -it shows a simple 4 wire HEI system schematic, and it is incomplete and inaccurate as it does not show the battery or other primary power connections.

You really seem to have a problem understanding English, don't you.

The "as well" refers to the previous subject, the need for electrical power.

But given that you have this problem understanding, what I would call, simple English there isn't much sense in prolonging this conversation as I'm sure you will demonstrate further problems with comprehension if we continue.

Your illustration shows a distributor with both mechanical and vacuum control for ignition timing :-)

But I don't see why an additional 4 degree electrical retard for starting if the distributor already has a mechanical advance mechanism.

You would need to compare the actual advance curves that the centrifugal and vacuum mechanisms produce with the optimal measured values. I don't have them and couldn't release them if I did, since I signed an NDA when I worked as a test engineer for GM engine and brake controls. jsw

John - I have no problem understanding what I wrote. It was ME who wrote it. anf I DO understand how magnetos work, having worked on them on old farm machinery 50 years ago, and on current aircraft engines as recently as last summer. I also understand how much (electrical) power electronic ignition and electronic fuel injection take to run, and how much physical power it takes to produce that electricity in an automotive environment, having been a licenced mechanic since 1971.

Not my diagram. and the actual purpose of the 10 degree retard was for emission control reasons (on the 5 terminal units) - but it makes starting a high compression engine easier and allows an otherwise unmodified distributor to provide more total advance for performance and fuel economy - while not breaking the nose off the starter or striping the drive gear when starting. I cannot remember the application of the 4 degree automatic advance module or the purpose of the 4 degree advance. I DO know that they were often replaced with the non-advance units without any serious effects.

Yes of course. I was only commenting as various other engines have gotten along with mechanical and vacuum advances over the years.

Yes, they were 'good enough' for cars, but not optimum. The controls for late 1940's large aero engines are better examples of what could be done mechanically to maximize performance and economy, though they didn't have to consider the lower end of the power band or emissions.

"Cruise fuel consumption could be as low as 0.40 lb/hp/hr." This is 243 g/kW-h, not much worse than a TDI Diesel:

I recently removed the catalytic converter on my 12 year old car. There was NO soot in the pipe ahead of it. jsw

I never worked on the 3350-compound engine but I did work on the 3350 fuel injected engine and I did talk with guys that worked on the compound engines. From what I could see, the engine came too late in the period that reciprocating engines were used and the maintenance costs of the compound engine were not only higher then the injected engine but higher then for the R-4360 engine.

regulation etc. being done internally.

running, probably since there are no permanent magnets in it disconnecting with the engine stopped may/might/probably be safe.

Wrong, many have exactly one wire.

regulation etc. being done internally.

running, probably since there are no permanent magnets in it disconnecting with the engine stopped may/might/probably be safe.

Give me a list of five models that use a single wire alternator from the factory. Any less than 5 is not "many".And if all 5 models are from one manufacturer it still doesn't count.

Many cars have a full-throttle alternator cutout circuit. I would try to determine if your Mazda came with such, and try to insert manual control in that circuit. There may be other conditions that trigger alternator cutout from ECM control. You may be able to fool the ECM into seeing those conditions.

regulation etc. being done internally.

is running, probably since there are no permanent magnets in it disconnecting with the engine stopped may/might/probably be safe.

Yeah, I'll get right on that.

Tell you what. I'll make it easy for you. Give me TWO from different manufacturers.