When I got my Pertronix module about 20 years ago I was somewhat suckered into buying a "flamethrower" 40,000V coil. The pair have served me well over the years and quite a few engines but I've always used the stock spark plug gap 0.6mm. That would mean I've never taken advantage, if there is one, of increasing the plug gaps for a bigger spark. I've been reading that higher compression engines benefit from this fatter spark and as mine was built with too high CR I was wondering if it would help. Probably not but you never know. Anyone
There was a 3 electrode plug been sold a few years ago - splitfire rings a bell ?? That may help but maybe just a fad , i can`t see increasing the gap would be massively beneficial ..
There you go , it`s now progressed into a FOUR point plug https://www.eurocarparts.com/search...MIoYO5naDc6gIVCLrtCh1I5wB0EAQYASABEgJZX_D_BwE I`ll leave you to shout the "OW MUCH " ......
The two three and four electrodes are not for better spark just for vehicles with extended servicing as the electrode wear is spread over the extra electrodes, some vehicles have an expected 100k spark plug service life, or a time interval change time, usually around 5 years, so they don't get stuck in the head. If you have electronic ignition and a higher powered coil you can up the gap to the electronic ignition gap of 0.7mm
It doesn't matter the coil voltage will only rise enough to jump the gap most coils can do that easily. CDI is only really a benefit for high revving or where spark plug fouling may occur (******el engines/2 strokes). Edit apparently you can't say Dr Felix W.a.n.k.e.l engines.
Because these are low revving engines , the Kettering ignition saturates the coil magnetic components at max RPM, so theres no more energy there with a transistor breaking the gap, than a contact breaker and a capacitor (condensor) With CDI you can drive in more energy as the input supply voltage becomes effectively much higher - the capacitor is pre-charged to the 'peak' condenser voltage of a contact breaker then released- you can easily double the energy as it isnt stored in the coil but in the capacitor, and the coil is really only acting as a transformer not an energy store. I had fun a while back with the Linear Technology LT Spice CAD application, simulating Kettering and CDI ignitions - if anybody wants the models I have them somewhere.
I feel ...... a bit dizzy after reading that , i like it better when you just make scones at Techenders ..
Not gaps, but how to read spark plugs for heat rating and jetting. Quite interesting but requires thrash and checking with no slow running between which is a bit tricky. http://www.wallaceracing.com/plug-reading-lm.html
Interesting reading but as the feature states , it`s based on a full racing plug chop NOT general running . You`ll see racing bikes coasting in after their session , they`re not broken , the rider had cut the engine under hard acceleration to get a good plug reading . Obviously not as critical on a four stroke but vital for 2 strokes as they`ll seize if too lean . Had mine out today as it happens ... They`re all like that but the pics shows 2 veiws of the same pair of plugs . I`d be happy with those on a race bike but too hot for a old aircooled methinks ...
That plug doesn't look like a "protruding" electrode, is it? More like a B6ES/B5ES type in NGK numbers. Should be a BP6ES/BP5ES I read.
Correct , look at the electrode projection on the pic i posted above , they`re BP5ES and slightly longer than the one in your pic Steve ...
B as you have now will work and isn't incorrect but BP is what you're after I believe, with the protruding centre electrode. This was what I put in my photo the other day in my spare cyl/head. As you said at the time, it could protrude an inch and not hit anything. I've got BP6ES in mine and will probably get some 5s to compare next. It makes sense to me to have the spark a bit further in?
