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spark plugs

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Sesman:
On the original question, yes the HT leads do need to go on the correct plugs or you could be 180 degrees out on firing order.

K2-K6:

--- Quote from: Sesman on February 21, 2025, 01:22:40 PM ---On the original question, yes the HT leads do need to go on the correct plugs or you could be 180 degrees out on firing order.

--- End quote ---

It doesn't need that either.

Most fours being a "flat plane" crank arrangement, this with triggered input at crank speed, still not affected.

Every time any piston is at TDC (power stroke) there'll be a spark ready and waiting.  It's effectively firing ALL plugs at every HALF crank revolution.  That's from being installed with the two crank sensors at 180 degree to each other.

That'll catch every firing order combination wherever the leads go to.

K2-K6:

--- Quote from: McCabe-Thiele (Ted) on February 21, 2025, 08:09:20 AM ---So the Boyer ignition is firing not just on a cylinder compression, it also fires part way through the induction cycle. Would that not cause premature burning in a cylinder part way through the induction cycle of a four stroke engine, with the inlet valve open that would create a risk of fuel burning back into the carburettor. That sounds like serious built in pre- ignition.

An extra spark on the exhaust cycle, I can accept that as it's not burning fresh fuel.

--- End quote ---

It's the variance in conditions (compression etc ) that stops the wrong thing happening in the wrong place.

Even with a low compression (estimate, much below about 90psi) then a closed and compressed cylinder will have trouble igniting the predetermined mixture at expected ratio of fuel to air.  Little or literally no risk seems realistic in this "Boyer" scenario.

Pre ignition does agree with this when seen. IF there was hot glowing heat source (think old coked combustion chamber) then that too will only fire at pre ignition point as compression comes up to squeeze the volume and subsequently be set off prior to spark arrival by that combination of glow & compression at reasonable level being presented to the whole ensemble  :)

A friend's uncle had a really coked up (different meaning nowadays  ;D in the Henry Cole idiom ) Triumph Spitfire which would, on a visit to their house, have uncle dipping a rich tea biscuit into his first mug of steaming  tea before the car stopped chuntering away in the drive, after being switched off on arrival  :)

Also a risk in running engine on a dyno at extended load, if low number (in NGK terms) plug was inadvertently let to go over temperature, then glowing earth or tip can cause pre ignition, with subsequent piston melt experience  :o

K2-K6:

 " As the Boyer also does without the mechanical advancer it must be a clever box of tricks that also acts as it's own crank position sensor. "

Yes, that's correct Ted. The fixed final positioning has absolute and direct relationship with crank rotation, and no mechanical displacement at all when running.

Hence the need to accurately set it AFTER any internal timing has played out (rpm lifted above any internal set point to check) from the "retard" method within the electronic scheme in play.

The firing event would be in the following order:- timing point arrival (at maximum set advance) then added delay to that signal based on rpm scale below the maximum advance positioning.  This to give the designated start and tick over timing, then to move up that internal scale by monitoring the absolute rpm, to arrive at the "no interference" final mechanical position providing the desired ignition advance. This should be completely native and reliable to produce that figure for the most demanding load conditions.
It can also, does, also multi fire the plug under certain conditions to give best chance of combustion, from memory at very low rpm /start speed, in order to facilitate starting that may have sub optimal mixture present.

deltarider:
Before chosing, I would need a complete picture, so I'd like to know:
what the effective duty cycle (dwell) is,
how much amps that B&B kit draws with the engine running (OEM coils), both at idle and revved and
if more erosion at the sparkplug's electrodes is to be expected.
Is that info public? By B&B?

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