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pertronix issues

Discussion in '308/328' started by mfennell70, Jun 28, 2019.

  1. mfennell70

    mfennell70 Formula Junior

    Nov 3, 2003
    557
    Middletown, NJ
    My friends and I are having trouble getting a pertronix conversion to produce so much as a single feeble spark in a '79 GTS. We're using the MR-183 kit with the recommended coils (flame-thrower II?).

    On the bench, we see voltages vary from 3 to 11.x (old motorcycle battery) as we spin the distributor. Apparently this is OK (I expected to see 0 on the low end). Installed in the car and we see nothing out of the coil. The voltage sags quite a bit when starting with an old battery so we even went as far as to hook up a battery directly to the hot side of a coil, thinking that might be an issue.

    I should admit that the installation has been a bit of a comedy of errors. The first go, the sensors were hooked up backwards. I've been told the smoke show was quite good. Now we have fresh sensors.

    I think the coils may have been hooked up backwards too but they're showing about 1 ohm across the leads and 10+ kohm from positive to center tap.

    We had someone over who has a lot of experience with installing them on various old racecars. Nothing amiss found.

    Any thoughts? We're vaguely suspicious of grounds but can't find anything amiss. Maybe we should test all the way from the battery to the distributor?
     
  2. derekw

    derekw Formula 3
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    Sep 7, 2010
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    Derek W
    Are you using shielded cables and suppressed plug wires. The Pertronix modules are known to be sensitive to EM noise. good luck!
     
  3. Fairview

    Fairview Formula 3
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    Mar 16, 2009
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    Jeff Ward
    This may be too basic, but that is my level of expertise and experience with the MR183, so I chime in hoping there is something of use to you. I did successfully install the MR183 in my 308. The only problem I had was I needed to slot the mounting holes on one sensor to adjust the timing on one bank that was a few degrees off from the other.

    It sounds like the problem is that the low tension circuit is not making a complete break as the distributor is rotated.

    Can you hook up a simple 12 volt test lamp to the low tension wire connection at the coil opposite the low tension connection that is always hot from the ignition switch and see if it winks fully on and off as you turn over the engine? I’ve always understood that the alternating (breaking) current from the low tension circuit is what makes the coil fire. If the test light doesn’t go completely out, the coil won’t fire.

    Back in the good old days of points and condenser, if the points were bad, the test light hooked up as above would tell the tale. If the test lamp winked on and off cleanly, all was well with that circuit. Sometimes the test light would glow bright then dim as the distributor rotated, showing the points were bad or installed/gapped incorrectly. That seems to be the condition you report with the voltage going from 11 to 3 volts, rather than all the way to zero.

    The MR183 simply takes the place of two sets of points to break the LT circuit. It should replicate how the points behave, and if it doesn’t completely break the circuit, that says to me the sensors aren’t working properly. Your particular unit seems snake bit to me.

    I hope there is some nugget in this that will help! I know it is awkward working in that corner of the engine bay, especially if the engine lid is still on the car.
     
  4. kcabpilot

    kcabpilot Formula Junior

    Apr 17, 2014
    780
    California SF area
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    Paul
    While I completely understand why you are doing this (I put a Pertronix in my Alfa) I still miss the old days of breaker points where they would just slowly get worse and worse until you finally changed them. Kind of like how you used to get a snowy picture on the TV but now in the digital world it's either a perfect picture or a blue screen. No warning in between. Same with the Pertronix, you can't get it to kinda work, either it does or it doesn't and there aren't even any symptoms to give you a clue. Best of luck I hope you get it figured out.
     
  5. Martin308GTB

    Martin308GTB F1 Rookie
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    Jan 22, 2003
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    Did you already seek for help from their customer support? I installed an Ignitor I on my Alfa and had a mechanical problem. Their support was great and fast and we got things sorted fast. Even between the US and Euro time zones.

    Best from Germany
    Martin
     
  6. mfennell70

    mfennell70 Formula Junior

    Nov 3, 2003
    557
    Middletown, NJ
    Sorry for the slow response. Thanks for all the thoughts. Someone did get in tough with customer support, who seem to think we may have damaged them by keeping power on for too long. I'm not so sure about that but we're going to try another set, this time an updated part number (which I can't recall off the top of my head).

    This is where I'm a little confused. We saw 3V on the low end. Supposedly pertronix customer support says that's OK but it must be enough to keep a 12v test light glowing
     
  7. Martin308GTB

    Martin308GTB F1 Rookie
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    Jan 22, 2003
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    The Ignitor I was sensitive regarding this actually. Though I once kept ignition on for half an hour and the Ignitor survived it and lives since 12 years.
    From Ignitor II onwards they implemented a safety automatic switch off function.

    Best from Germany
    Martin
     
  8. Rory J

    Rory J Formula Junior
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    May 30, 2006
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    WA
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    Rory
    I don't have anything to add except that I was warned about Pertronix reliability from two Alfa friends who switched to Crane systems.
     
  9. Martin308GTB

    Martin308GTB F1 Rookie
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    The Ignitor II had reliability issues actually. Ignitor I seems to be bullet-proof. I put one into my Alfa distributor in 2006 and never touched it again since. Except an oil drop for the shaft from time to time.

    Best from Germany
    Martin
     
  10. kcabpilot

    kcabpilot Formula Junior

    Apr 17, 2014
    780
    California SF area
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    Paul
    I switched to the Pertronix a number of years ago on my Alfa due to quality issues I was having with replacement ignition parts - namely the condensers. I had two of them fail in the same fashion (lead just popped right out of the canister) But I was somewhat wary about this new fangled system so I stowed a complete spare Marelli distributor with new breaker points in the trunk. It's still there but to this day I've never needed it (probably 7 or 8 years now)
     
  11. Martin308GTB

    Martin308GTB F1 Rookie
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    Jan 22, 2003
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    Haha. Exactly the same here. Except that it's a Bosch distributor and 13 years :)
    BTW; what Alfa do you have? Mine is a '72 2000 GTV.

    Best
    Martin
     
  12. kcabpilot

    kcabpilot Formula Junior

    Apr 17, 2014
    780
    California SF area
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    Paul
    Martin I have a ‘72 Spider that I’ve owned since 1980.
     
  13. Fairview

    Fairview Formula 3
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    Mar 16, 2009
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    #13 Fairview, Jul 3, 2019
    Last edited: Jul 3, 2019
    It’s been a few years, but I’m sure my tester light went completely out and back on as I rotated my engine with the newly installed Pertronix. I remember I was relieved as I wanted to statically time the engine to verify it was all set up correctly. Then I used the timing light and discovered one bank was firing about 5 degrees later than the other, which I fixed by slotting one of the sensors to make it adjustable.

    It sounds like yours is cooked and allowing voltage to leak through when it’s not supposed to. I can’t find anywhere that an automotive coil will fire with a varying voltage, rather than a total interruption of the low tension voltage. Maybe the 3 volt deal is correct, as I’m no expert, but it runs contrary to my experience. I’ve earned my experience though as I’ve had to walk back home a few times!
     
  14. mfennell70

    mfennell70 Formula Junior

    Nov 3, 2003
    557
    Middletown, NJ
    Just to follow up, 3rd time was a charm. The car is running great. I wasn't involved in the final solution so I don't have the exact details.
     
  15. derekw

    derekw Formula 3
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    Sep 7, 2010
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    It would be nice to hear the issue/solution to close the circle and help others who may have this problem :)
     
    Martin308GTB likes this.
  16. mfennell70

    mfennell70 Formula Junior

    Nov 3, 2003
    557
    Middletown, NJ
    Agree. I'll try to get more info the next time I see the car.
     

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