plugs and gap
- Thread starter 69DARTS
- Start date
-
moe7404
moe7404
a real Capacitive discharge ignition like the old Delta mark 10B. can work with as much as .060-.080" gap.
they will even fire a fuel fowled plugs. once i had 1957 dodge P.U with the old flat head 6. my friend had a set of fuel fowled plugs from a race 383. i put some in my 6 cyl and it fired right up
they will even fire a fuel fowled plugs. once i had 1957 dodge P.U with the old flat head 6. my friend had a set of fuel fowled plugs from a race 383. i put some in my 6 cyl and it fired right up
moe7404
moe7404
on the chrysler electronic ignition i have used . i used .045" . but not sure it was better. the old Delta mark 10 was a kit. it all so has switch to from C.I.D to std. i got mine from Radio Shack. my first time soldering electronics. back in the early 70s. you can sometimes find them on E-Bay.
67Dart273
Well-Known Member
I wish (I knew) of a good definitive comparative article. This should be easy to compare on a dyno.
But there has GOT to be a (practical) limit
Bigger plug gaps require lots more ignition voltage and power. Voltage and power is different. Power is power, wattage
Bigger plug gaps at some point must surely get 'so hard' on other components as to be impractical.
RFI......The rf electromagnetic interference caused by high power pulse, IE high power spark
This can be manifested in interference to "it's own system" IE causing misfires, multi-fires and timing glitches due to interference in the trigger mechanism.
It can certainly cause disruption in OTHER systems, including charging and instrumentation
AND it can even cause FAILURE of sensitive systems
Cross firing from one tower to unwanted "other places," including destruction of the rotor (punch through) carbon tracking, actual arcing to ground from various places including the plug terminal itself, or even penetrating plug wire insulation.
But there has GOT to be a (practical) limit
Bigger plug gaps require lots more ignition voltage and power. Voltage and power is different. Power is power, wattage
Bigger plug gaps at some point must surely get 'so hard' on other components as to be impractical.
RFI......The rf electromagnetic interference caused by high power pulse, IE high power spark
This can be manifested in interference to "it's own system" IE causing misfires, multi-fires and timing glitches due to interference in the trigger mechanism.
It can certainly cause disruption in OTHER systems, including charging and instrumentation
AND it can even cause FAILURE of sensitive systems
Cross firing from one tower to unwanted "other places," including destruction of the rotor (punch through) carbon tracking, actual arcing to ground from various places including the plug terminal itself, or even penetrating plug wire insulation.
mguner
How many is too many?
I used to have an old AC-Delco sparkplug testing machine. You had chambers that you could pressure up and fire the plugs with a constant power source. It was very interesting to see the difference in spark from variations in gap and pressure...
Bulldozer
free ice cream sandwiches
Eddie wants to know what spark plug and gap you all are using with your MSD, not how to time travel to Pluto to figure out the range of pressure a collapsed O-ring will take before the ovalommeter explodes at 140,000 volts and cause the imploding of the navigators cranium over the course of 700 lights years at 2,578 miles per hour holy crap
67Dart273
Well-Known Member
So, I guess you don't know either?
If I ever get mine back together (before I die) I might do some testing. Buy a performance meter. Make some test runs. Hire a dyno.
Otherwise, gap 'em anywhere from 35 to 60 and forget 'em.
Bulldozer
free ice cream sandwiches
lol , if it were me , I would run NGK's with a .045 gap. the same I use with the HEI ignition. ive had a couple MSD boxes , but I decided to stick with what I have.
famous bob
mopar misfit
KitCarlson
Well-Known Member
I have found that when you buy plugs for an application they are often pre-gapped for the given electrode length It is important to keep the electrode and ground gap parallel for good wear life. If the gap is increased significantly, the ground electrode becomes short, and the gap is a wedge shaped. So if you buy a plug that has an original gap of 0.040", going to 0.060" may be a detriment.
As the gap is increased the spark duration decreases because energy consumes faster with increased voltage. MSD CDI has a short duration to begin with, that is why multi spark happens at lower RPM.
As the gap is increased the spark duration decreases because energy consumes faster with increased voltage. MSD CDI has a short duration to begin with, that is why multi spark happens at lower RPM.
EL5DEMON340
Well-Known Member
My 360 with MSD 6al and SS coil is at .045 if you go to NGK site they state the regular plugs should not be gaped more than .045 if you want to run more you need a race plug. Opening up a standard plug much more than .045 will cause the electrode to not be squared up to the strap.
moparmat2000
Well-Known Member
I used to gap em at .035 in the points days. I guess with electronic you can open em up wider. I will prob try .040, .045
-
