coil on plug vs coil wires

Discussion in 'Mazda Rotary' started by slociviccoupe, May 29, 2011.

Help Support HomeBuiltAirplanes Forum by donating:

  1. May 29, 2011 #1

    slociviccoupe

    slociviccoupe

    slociviccoupe

    Well-Known Member

    Joined:
    Apr 1, 2011
    Messages:
    184
    Likes Received:
    0
    Location:
    Palm Bay Fl.
    anyone know of any coils that will snap on the end of the sparkplag for coil on plug use and not be a coil stick like what fits down tubes in the cylinder head of most automotive engines for coil on plug installations. ive searched google and found nothing. i know a mount and bracket would have to be made to support the coil, but really don't want to run coil wires for the chance of them breaking down, coming off, added resistance. just piece of mind if i could just put the coil at the end of the plug and make a bracket to support the coil.

    not wanting to run the ls1 coils as their not designed for the firing and timing of a rotary engine, great coils and cheap but have known to break down even on the engines it was designed for.

    my ecu can either run the coil directly or run a cdi. so coils can either be 2 wire needing an ignitor or cdi or coils with built in cdi's. the mercury marine coils are looking promising but don't know if they can be mounted on the end of the plug.

    here is the new mercury marine coils, don't know what they come on engine wise but looks promising.
    Mercury Marine coils now available!
    can be ordered by different part number with internal ignitor or without.
     
  2. May 29, 2011 #2

    jumpinjan

    jumpinjan

    jumpinjan

    Well-Known Member

    Joined:
    Oct 4, 2004
    Messages:
    313
    Likes Received:
    6
    Location:
    Dayton OH
    I think you sound a little confused. The Coil-Over-Plug (COP) or the Coil-Near-Plug (like the LS1 & LS2 coils) either have an "ignitor" (typically 4-wire) or not (typically 3-wire). I don't understand the CDI that you made reference to? Are you running a magneto ignition, but using an ECU? Very confusing to me. If you don't like the superb LS1 coils to run, how about the LS2 coils, that are good to 10K rpm? You can buy the whole LS2 coil pack assembly that bolts to the top of the valve cover.
    (By the way, if someone said that LS1 coils are not strong, and breaking down, it could be they didn't get the spark dwell set up right, and burn them up)
    Jan
     
  3. May 30, 2011 #3

    slociviccoupe

    slociviccoupe

    slociviccoupe

    Well-Known Member

    Joined:
    Apr 1, 2011
    Messages:
    184
    Likes Received:
    0
    Location:
    Palm Bay Fl.
    i want to run coil on plug, with no wires. as for coils there are many types. 2 wire coils with just a positive and a negative needing either to be saturated with 12v and triggered by the ecu switching to ground. @ wire coils like the pensil coil sticks that use a cdi ignition to up the output, these usually being 100:1 turn ratios. have used these with very good results on the honda's ive built switching to coil on plug. then get into the newer coils that range from 3-5 wires. some having a built in ignitor essentially an internal cdi module.

    im wanting a coil that will sit at the end of the spark plug supported by a bracket with no plug wires. and as for the coil i don't care if it has a built in ignitor or needs a cdi to run.
    ill be running a stand alone engine management system that can either drive the coil directly, can trigger an external cdi ignition box that fires the coils, or run a coil that has an internal ignitor no need for a cdi as the ecu is sending the signal to fire the coil.

    as far as the ls1/ls2 coils they have been proven to break down, and yes because of dwell time and the difference between a rotary and a piston engines time between firing. a piston engine has time for the coil to cool as it fires the plugs in the firing order. on a rotary every time that rotor face comes around for compression the plugs are firing. so it has more power pulses (stroke cycles) than a piston engine. through other rotary forums the gm coils have ben known to fail. not something im wanting to happen in the air. the other problem is load. the automotive based coild aren't always under constant load. they are meant for starting, idling, cruising, and emissions. the coil has to fit all those needs. also has to be able to keep plugs in the engine for the service intervals and not destroy plugs because the arc is soo hot. under constant load like in an aircraft situation the coils are taking a lot of amps to opperate to give the desired output continuously.

    its like a free rev or a light load situation doesn't require much spark or fuel, but a full load condition is where weak spark shows up.

    enough on my rant. there are tons of topic how roatries need a hot spark and a coil that can handle the many times it is fired compared to a piston engine and not break down , heat up, or fail.
     
  4. May 30, 2011 #4

    NickH

    NickH

    NickH

    Well-Known Member

    Joined:
    Dec 27, 2010
    Messages:
    101
    Likes Received:
    0
    Location:
    Portland, OR
    MSD make aftermarket coils,andmight have something that meets your requirements. I know they make LS1/2 compatible coils with hotter sparks and might be up for more abuse than standard.
     
  5. May 31, 2011 #5

    slociviccoupe

    slociviccoupe

    slociviccoupe

    Well-Known Member

    Joined:
    Apr 1, 2011
    Messages:
    184
    Likes Received:
    0
    Location:
    Palm Bay Fl.
    yeah, actually looking for a plug boot that converts a standard coil such as the ls2 coils or the mercury marine coils to coil on plug instead of coil near plug.
    the boot has a plug connector in one end and fits on or in the coils tower, then the rubber boot just insulates it from arcing where it shouldn't.
     
  6. May 31, 2011 #6

    Natty Bumpo

    Natty Bumpo

    Natty Bumpo

    Well-Known Member

    Joined:
    Aug 6, 2010
    Messages:
    73
    Likes Received:
    5
    Location:
    Respublica de Veridimontana
    They can easily be bought for Bosch coils for Mercedes etc.
     
  7. Jun 1, 2011 #7

    slociviccoupe

    slociviccoupe

    slociviccoupe

    Well-Known Member

    Joined:
    Apr 1, 2011
    Messages:
    184
    Likes Received:
    0
    Location:
    Palm Bay Fl.
    any info and or pics of these? what ends do they adapt to. say if the coil has a female terminal that accepts the end of a plug wire i would need to adapt to the end that snaps on to the spark plug in a short manner. or say the mercury marine coils that have a tower that looks like the end of a spark plug would have to adapt that to a boot that also clips on the end of the plug.

    if that makes any sense.
     
  8. Jun 7, 2011 #8

    GaryBuster

    GaryBuster

    GaryBuster

    Member

    Joined:
    Jun 3, 2011
    Messages:
    10
    Likes Received:
    0
    Location:
    Frankston, Texas
    I choose to NOT hard mount a coil on a vibrating engine... either remote or on the spark plug... I prefer to put the coils on a solid motor mount, and even then, out of the way of the belt's plane of travel.... I've even seen a belt come off and take out the spark plug wires when they crossed that plane!! Engine out!
     
  9. Jun 7, 2011 #9

    skeeter_ca

    skeeter_ca

    skeeter_ca

    Well-Known Member

    Joined:
    Jun 29, 2005
    Messages:
    1,026
    Likes Received:
    50
    Location:
    Yucaipa, Ca
    One question, What's the difference of mounting a coil onto a spark plug and mounting it onto the vibrating engine. Either way it's mounted on the engine!
     
  10. Jun 8, 2011 #10

    GaryBuster

    GaryBuster

    GaryBuster

    Member

    Joined:
    Jun 3, 2011
    Messages:
    10
    Likes Received:
    0
    Location:
    Frankston, Texas
    Skeeter... you missed it completely... I mount it on the motor mount... so it's isolated from the engine.

    N263GB
     
  11. Jun 8, 2011 #11

    skeeter_ca

    skeeter_ca

    skeeter_ca

    Well-Known Member

    Joined:
    Jun 29, 2005
    Messages:
    1,026
    Likes Received:
    50
    Location:
    Yucaipa, Ca
    But you wrote "or on the spark plug" which means you're mounting it on the engine!! Subjecting it to all the vibrations the engine can dish out.
     

Share This Page



arrow_white