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Cleaning and Setting points on 55 H

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  • Cleaning and Setting points on 55 H

    How do you set the points on a 55 H? I presume the mag or a section of it drops down. Which section?
    Thanks again.

  • #2
    Below is excerpt from a email info I received from Jerry Wienandt on: carbs, mags, points settings, etc for the 40 and 44 ci powerheads on 55h towers and quicki gear cases. Jerry is a master on building and setting these engines up.

    Basically start with a 0.008 feeler in clean points on cam high point. Then you need a degree plate and buzz box (or Merctronic) for 48 degrees dwell if you want top performance and a good mag with good bearings, etc.Hope this helps as a starter.

    If you want to contact Jerry I am sure he will be happy to assist, he provided me with many emails of info on my engine work. He goes by tridant racing on this site


    Email from Jerry to me:

    Jerry Wienandt <> wrote:

    First, I really like KA19A carbs, used them on lots of D Mods. Also like
    KA21A... Didn't work much with the 'flower pot' versions.

    The point setting is just a starting setting to get it make spark, not
    nearly close enough for serious running... What you may measure as .008 covers a
    lot of dwell range. Do set the dwell with a buzz box and dwell plate, per the
    instructions. On an H tower a basic 44 is fine at .350 to .325 timing. Just don't go way high...

    Critical things from an old mag guy...

    4D3, 4D4 and 4D5 are superior to 4D1 or 4D2...

    Make super sure the magnetic armature has a very nice cam for the points and NO tiny cracks in the smooth round segment between the two rows of lobes...

    New bearings .

    Test the coil on the Merctronic, Some leak, some take much voltage to

    Use lowest voltage firing nicest no leaks one. Test or replace condenser.

    Really tighten coil in the housing, LocTite set screws. Ground very well.
    Make sure to copper finger springs tightly into the cap and the plastic
    'nut' has a star washer and its tight. Spray some LPS 2 on the steel housing segments,
    the coil segments on/in that nut, and on the magnetic rotor segments. Wipe most off.

    Set points with feeler, but then fine set with dwell as feeler is not
    close enough. Lube points cam. Dwell angle you want? Its 48 degrees on my plate. Set all mags exactly
    same dwell on dwell plate with Merctronic or buzz box, so you can change in a hurry without messing up the timing.
    Every degree 'off' in dwell is 2 degrees off in timing! Always bolt down, pulling any slop in locating to clockwise to be

    Take the retainer clip out of rotor... secure with small pea size spot of silicone sealer. Can remove it by removing vent red plastic fitting and
    insert a small screwdriver in through the vent hole and pry gently, slowly. Reinstall vent fitting aimed straight down aimed between the 2nd and 3rd plug
    wire. Make sure rotor doesn't stand too high and hit inside cap.

    Use Packard 440 plug wire or other 7mm SOLID core wire. No suppressor wire. Use O-rings in caps. Use the long plug boots.
    Drill 3 tiny 1/16" holes in distributor cap, aimed straight down... you'll see where, countersinking a bit, inside. Those are drains with funnels for any
    moisture. Lesson learned the hard way.

    Tighten cap screws very carefully, evenly. Loctite blue 242. Mags are Not trouble free, but CAN be serviced in the field.

    Some mags, BTW are just weak, usually because Magnetic rotor is weak from age.

    Any rotor with the dreaded cracks is weak, as now it has twice as many north and south poles on twice as many weak magnets. When you break a magnet, you have two magnets... but weaker.
    "Keep Move'n" life is catching up!
    No man's life, liberty or property are safe while the legislature is in session.


    • LarryR
      LarryR commented
      Editing a comment
      Good info. Pretty much what I've always done with service engines. One extra tip is that after you clean/file/sand points (by whatever method you like), give the open points a quick spray with contact cleaner.

  • #3
    Does this youtube video have any relevance? I don't know much about the 55H but found this on a bing search...


    • #4
      The youtube video isn't bad but I will say this, I bet more points are set with a feeler gauge than by a dwell plate. So don't think you need all this stuff to make your motor to run and yes I did use a dwell plate when setting up a mag. I also spun the mag with a die grinder and with a pressure box for the plugs to check the spark on a 7 to 8 thousand RPM. The best thing we ever did was go to a CDI ignition. But I will say this Vanover still uses a mag and he is the fastest 44 I have ever seen !


      • #5
        Zul, Shane, "Jerry," Great comments. Thanks very much.


        • #6
          Sometimes I test the mag when I'm done. With no cap I use alligator clips and hook a piece of plug wire to that coil tab and a ground wire about 3-4 inches down the plug wire. Then I use a pneumatic Dremel with a short piece of hose as a coupler to spin the mag. A good one will jump the gap at low speed and when spun up the spark will slice down the plug wire, catch the wire on fire and win races.


          • #7
            If you spin a mag with a die grinder or anything that will make it spin fast you need to have the the spark plug wires hooked up to plugs or something to ground the charge. I have spun the mag without doing this and the coil was toast.


            • #8
              We always carried a couple spare mags. Switched over to Electromotive electronic ignition, best thing we ever did. At one point we had 8 complete mags plus a pile of parts. Sold it all.


              • #9
                Important is the spring tension of points ???


                • #10
                  I think the tension is something to be concerned about. I never had a Merc tool to check the tension but I used a fish scale with a line around the point spring and pulled at a 90 degree angle to the arm to check tension. At one time I though I was getting points bounce and double up on the spring. I know this would make the rubbing block wear faster but I didn't care. I wasn't going 500 miles just 3 laps lol.


                  • #11
                    When I was racing I built a mag tester. I found a lot of mags would run well to about 5000 rpm then would come in and out. I would run them up to 7400 rpm it would jump about 3/8 in. Spinning them by hand will tell you that you have spark but not on the big end. When your motor drops rpm always check the mag first. Leigh,


                    • #12
                      I found out just what you have described. Most mags will work good up to 500 rpm but after that you better have everything in tip top shape. I also think it is very hard to tell if a mag miss fires when listening to a motor run. I have took mags off of motors that sound like they were running clean and test the mag in a pressure box and you could see a lot of miss fires.


                      • #13
                        Left off a zero, should have been 5000 rpm.


                        • #14
                          The reason a mag skips at high RPM is the point spring tension.


                          • #15
                            When servicing points I have found they have a thick layer of oxidized metal, I assume from the electricity. Sanding will not remove enough material so I remove the points and file them smooth and flat, cutting off all that bad metal, if you don't they won't work very long .
                            The other thing I do is replace the condenser. The old Harleys that had a Mag use a different part number than the other points bikes and I can get those cheap.
                            Yes I adjust the spring tension and like I said I test my work. It must work by hand so the engine will start, die grinder for high rpm and once again...
                            I connect a plug wire where that tab goes on the coil, a ground wire with a alligator clip I clip to the plug wire a couple inches down from the end so I can see the spark. Then for fun I wind is up and watch the spark torch the plug wire.
                            I use the Accel 7mm solid core wires, they are inexpensive and come two sets for the price of one (8cyl).
                            Last edited by PRO-MOTIONRACING; 05-10-2020, 12:22 PM.