MSD Kill switch for pro mag 44

Discussion in 'PSI Superchargers Tech Questions' started by willy200, Jul 8, 2014.

  1. willy200

    willy200 Member

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    We are going to use a Pro Mag 44 magneto on a Top Alcohol Funnycar and I see several different style and brand of Kill switches on the market,
    What do most teams use in this situation and where do they mount the switch, was thinking of putting it on the top side of the steering wheel
    Thanks for you guys input to my question
     
    #1
    willy200, Jul 8, 2014
  2. Mike Canter

    Mike Canter Top Dragster
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    The MSD relay kill switch works just find and is very reliable. Not sure putting it on the steering wheel is a good idea. Ours is located on the switch box on the overhead bar. I have also seen them on the transmission mounted stalk.
     
    #2
    Mike Canter, Jul 8, 2014
  3. Beal TAD519

    Beal TAD519 Member

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    We mount the solenoid near the coil/box. We've gone through (3) of them over the last year (Promod BAE dragboat application). We even had issues with the air kill type hanging up. We have since gone to a good quality Ford starter solenoid. It's already lasted longer than our (3) previous MSD solenoids (and at less than half the price). It works opposite the MSD solenoid (requires power to kill) so we just turned our toggle switch over on the steering wheel.


    Thanks,

    Shannon
    BealMotorsports.com
    SplitDecision2.com
     
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    Last edited: Jul 8, 2014
    Beal TAD519, Jul 8, 2014
  4. sune

    sune Member

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    I maybe doing it wrong, but it works.

    I just went and bought the biggest badest industrial emergency stop button i could find, and kill the 44 thru that. No soleoid.

    It has now worked for 4 years straight not a single mis or burned switch. I have enough problems with everything else to have to worry about one more thing so i am happy with it.
     
    #4
    sune, Jul 8, 2014
  5. willy200

    willy200 Member

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    Hi Mike what would the part number be for the MSD relay kill switch,
    Jr of rbs has suggested i use this http://www.rbssuperchargers.com/products.cfm?pn=2305-0027F&pld=7485
    Is this what you were suggested, and Do you then just use a switch to activate it.
    Thanks Greg
     
    #5
    willy200, Jul 8, 2014
  6. Beal TAD519

    Beal TAD519 Member

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    We used the button in our TAFC with great results. We just don't have room for it now.


    The MSD relay is this unit: CLICK HERE

    One thing you have really watch is the little white nylon or plastic isolation washers. If they are not installed, it will be a direct short (positive to ground). We were thrashing to change one and we had a crew member not notice they were in a bag in the box and not installed.
     
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    Last edited: Jul 8, 2014
    Beal TAD519, Jul 8, 2014
  7. Scotttrod

    Scotttrod Member

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    I am pretty new to the 44 mag setup as well. JR suggested, and I bought the part you have listed above, it has worked flawlessly. You can also toggle between crank trigger or mag for your signal. Helps me with troubleshooting.
     
    #7
    Scotttrod, Jul 8, 2014
  8. Mike Canter

    Mike Canter Top Dragster
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    Greg that switch that RBS is recommending would be really great if you used a crank trigger. It would still work if you just ran off the mag also. If you are using a 8973 or a 7730 Grid then just shutting off 12v power to thoses boxes will also shut the motor down.
     
    #8
    Mike Canter, Jul 8, 2014
  9. blownapex

    blownapex Member

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    msd kill solenoid

    ive had 4 of these go bad 2 step wo throttle vibration bounces the contacts
    I now just kill the 12v to the 8973/or powergrid
     
    #9
    blownapex, Jul 8, 2014
  10. Mike Canter

    Mike Canter Top Dragster
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    Blown apex I have been having cross over switch failure both on the Leahy and MSD units. I suspect it was because the switch was hard mounted to the front plate and getting max vibration and making the switches contacts bounce through the run. How was yours mounted?
     
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    Last edited: Jul 9, 2014
    Mike Canter, Jul 9, 2014
  11. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    kill switch fail

    The Johnny West style air kill switch is the most reliable, but you need to use a small pin of some sort before every run to make sure it has reset. It gets hung up sometimes.

    I have used the Mallory style kill switch for many years on several cars and never had one problem. I have heard people say the contacts shorted out and had problems. I just haven't seen it.

    I have never heard of anyone having problems with the MSD style relay until this thread. I'm curious to know what symptoms you found when it failed. Did it just kill the car completely, not start or did it cause misfire, cutting out, etc.

    It does make sense to rubber mount it for vibration.
     
    #11
    Will Hanna, Jul 9, 2014
  12. Beal TAD519

    Beal TAD519 Member

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    For us the relay just quit. It was between rounds and we caught it in the warm-up. Moisture could be one issue we face (our application is a promod drag boat). I didn't realize there was a way to reset the air kill. We got rid of ours since it hung up quite often.
     
    #12
    Beal TAD519, Jul 9, 2014
  13. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    pinhole

    Yes there is a little pin hole you can stick a safety pin or paper clip in to see if the plunger is reset. We kept a safety pin on the chassis by the kill switch for this purpose. In the staging lanes we would stick the pin in the hole to make sure it was clear. If not we toggled the switch a few times to get it to reset. This usually worked.

    I worked on another team where we had a quick connect between the kill switch and negative side of the coil. If the car wouldn't fire, we would disconnect it to make sure it wasn't a kill switch failure.
     
    #13
    Will Hanna, Jul 9, 2014
  14. Nitro Madness

    Nitro Madness Super Comp

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    I got a manual cylinder type kill switch from Ken Wright in West Liberty, Iowa....I think it might be designed for the tractor pullers or boat guys, but works great for our application...about 1.25" diameter x 4" long cylinder with "blades" or "plunger" inside....it has been very reliable but we only use it for emergency shut off.....we always start the car with mag pull wire and shut off with the fuel....ya might talk to Ken about what's inside just to ease your mind on the possibility of making contact or grounding during the run but I'm pretty sure the contacts are far apart when the switch is in the "open" position.....it has detents and "clicks" in open and closed positions with a fairly long stroke....Ken Wright 319-627-2688
     
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    Nitro Madness, Jul 9, 2014
  15. afueldigger

    afueldigger tire wiper

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    What I have been doing for several years is very simple and has never failed on my cars as well as many customers cars......
    simply use a quality honeywell toggle switch to interupt the signal wire (purple) going to the points box sure you have to splice into that wire but what I do is just install a two pin Deutsch plug on the points box and my spare points boxes then it is a very simple plug and play deal and you are not trying to switch high amperage
     
    #15
    afueldigger, Jul 9, 2014
  16. kosky racing

    kosky racing Comp Eliminator

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    west switch

    The reason the west switch hangs up is because they over tightened on the mounting screws . Use a nylock nut and only tighten enough to hold it in place.
     
    #16
    kosky racing, Jul 9, 2014
  17. tad1011

    tad1011 Member

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    When I used the msd relay the first sign that it was going bad was the car would intermittently miss, it appears the spring gets weak from shake and use and does not hold the relay closed.


    The command module is the way to go in my opinion.
     
    #17
    tad1011, Jul 9, 2014

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