I have a Joe Hunt Mag/dist in my 40 coupe. Had it for years now. I'm perplexed about one problem. They recommend a NAPA ICR 5500 ballast resistor to bring the voltage to between 7 and 8 volts to the distributor. Alls well until I adjust the idle below say 800 rpm's. AT that point, the voltage gets below 7 volts and the engine starts to sputter or it actually shuts down. HAppened several times over the years before I put an voltage tester on the balllast resistor and adjusted the idle accordingly. I'd like to get the idle down a couple 100'd rpms. Has anyone experienced this problem? What could the cause possibly be. I have a fresh battery and a Master Power alternator. I do have a battery kill switch for years and wondering if tis could be causing a weak ground inturn causing voltage variations. I'm getting 12 volts to the input to the ballast resistor and variable output depending on rpm. Thanks.
Did Hunt recommend that ballast resistor? I broke the one that came w mine and replaced it w a Chevy ballast. I'll bet that's my problem! Cutting out at higher rpms
Usually an alternator charges at about 13.6 volts. Maybe when the engine slows, the charging voltage drops causing a drop in the input voltage on the resistor resulting in the output drop.
<TABLE border=0 cellSpacing=0 cellPadding=0 width=750><TBODY><TR><TD></TD><TD>[FONT=Arial, Helvetica, sans-serif]Joe Hunt Magnetos Contact Information[/FONT]</TD><TD> </TD></TR><TR><TD width=247> </TD><TD width=280>Address: 11333 Sunco Drive #100 Rancho Cordova, CA 95742</TD><TD width=223> </TD></TR><TR><TD height=28> </TD><TD>Telephone: 916-635-5387 </TD><TD> </TD></TR><TR><TD> </TD><TD>Fax: 916-635-4058</TD><TD> </TD></TR></TBODY></TABLE> E-Mail: huntmagnetos@huntmagnetos.com BTW They are there on Saturdays
I go to "joehuntmagneto.com and they are on line. I have one that is 26 years old and they still help me to keep it going. They even rebuilt an old Spaulding Flamethrower for me. Normbc9
Unless you are running without a battery the voltage to your distributer should not be dependent on engine RPM. Your battery should make enough voltage to idle until you pick your RPMs back up. On a vehicle properly wired when the system is not charging everything runs off the battery.
Thanks to all on this problem.I'll run it by Joe Hunt as well as Master Power. I'll post any resolution other than high rpm fix.
Sounds like a charging issue and not a mag issue. First check you ballast resister with a good ohm meter, if the resister isn't marked in the porcelin, it could have been switched in the boxes before you got it. Now have someone with auto electrical knowledge check the alternator out put. Put the battery of trickle charge the day before hand, and he should check that first. Have the battery load tested to eliminate any possible issues there. I believe this to be a charging issue or a ground issue. Does the engine have a good solid ground to the frame? If your engine is painted, make sure you have a ground wire from the Alternator case to the cylinder head, especially if it is a High Output model. Clean all mounting points from alternator to the engine. It's easy enough to drive with a temporary volt meter hooked up, keep the idle above the 800 RPM threshold, if you eliminated the driveability issue, I believe you found your problem.
Don't mean to Hi Jack your thread, but I have exactly the same problem. I've just taken one out of my 331. It ran OK until I switch on the thermo fan,then the engine shuts down if the engine is idling. Runs perfect until extra load comes in. I bi p***ed the ballast resister and the trouble disappears. I tried a new Chrysler ballast resistor and same problem. Seems like the voltage drop is enough to cut the spark out. It is OK when the revs are above idle. Any one else had the problem and fixed it??? I have also ran an earth wire from the distributor to the block.
6.5-7 volts is about the threshold where the module in those will start to lose spark. If you aren't getting that amount of voltage, raise the idle speed.
Pretty sure his is talking about the distributor that looks like a Mag but is in reality an electronic distributor (No HEI parts are used in these)
As described in their advertising: Joe Hunt Ford Flathead Vertex HEI Distributor 1 of 2 (Enlarge) Looks exactly like a Hunt Vertex Magneto. Uses conventional HEI pickup and is simple to install. Works with EFI fuel injections or carburetors. Super high intensity spark. The Joe Hunt Distributor is a completely self contained unit. It looks identical to the standard internal coil Joe Hunt Magneto. The design incorporates a specially built high output coil, electronic pickup, and customizable advance mechanism. The Joe Hunt high energy distributor is designed for street, strip, show or track applications.
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