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New Pertronix coils don't work in 28 Studebaker President- why?

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(posted in general AACA forum before noticing a Stude sub-chapter)


after testing the coils for my 1928 Studebaker President (straight eight, twin 6V coils), my new friend Edinmass found them "shot", couldn't believe the car would start and run with them (92yr old originals!).

I got a set of Pertronix "Flame-throwers", and with the choice of 1.5ohm or 3.0ohm resistance, some "Q&A" made me think 3.0ohm was better, "if it even mattered".

(strangely, they don't say whether 12V or 6V, though I was searching for 6V. Does it matter?).


PROBLEM: replaced the coils yesterday, excited to see if it solved my "drive for a mile and it dies" problem.   WOULD NOT START! ;-(    Pulled plug to check for spark, IT STARTED.  Put plug back in, no start.   Took a 2nd plug out (check other coil), and IT STARTED.   Put it back, no start.   Pulled all eight plugs just to check that all were sparking, and they were.  Put them back in, no start.  DID NOTICE that very weak spart with our 'typical check" of shorting screwdriver from plug to the head.    Removed one plug again (crazy, but only time it would start), this time no start.   
Finally, wondering if 'bad coil(s)', took my Model-A Ford's coil and substituted for ONE of the Pertronix;  she started up at the first touch of starter (albeit rough, only one 'good' coil).  AND, the tried-and-true screwdriver method gave MUCH brighter spark to the cylinder head.


What the heck is wrong with my new Pertronix coils?   They don't even offer a choice of voltage, and 1.5ohm vs 3.0ohm doesn't seem like an issue for a non-electronic ignition system like an old Stude.

Only reason I didn't simply buy a set of 6V coils at NAPA was all they had were too large a diameter to fit the mounting bezels I found for the firewall.   What do I order instead?  (and anyone need some scratched up but brand new Pertronix #40511 coils? 😞  Doubt they will accept returns; $35/each.....)


I have to be missing something simple (or the statistically improbable chance Pertronix sent two bad coils; I doubt it).



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Thanks: re: NAPA, the one they had was too large a diameter.  (same at Advanced Auto).  WIth the firewall-mounted coils, I had to get a similar mount that is reproduced for '35 Dodge truck (lucky to find it!  original coils and bezels are one-piece).    But 2.15" (or something like that) max diameter to fit.


Re: needing a 1.5ohm for 8cylinder engine; this is a twin-coil straight eight, so one coil for four cylinders (right? assume every other one or some such splitting?  Don't understand WHY there are two coils to be honest).    I'll call Pertronix, but can you explain that, and what is the resistance for a "standard NAPA coil" or any other 6V coil on Amazon or something?   I've only bought coils for my Model-A Ford and Dad's Ford 8N, and they are from restoration catalogs, so "only one choice".    A coil is a coil to me (or, so I thought).  Thanks guys!


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It isn't that simple but.....


Assuming a car with a distributor.....


In general a higher resistance coil draws less electrical current and charges the magnetic field in the coil slower. A lower resistance coil draws more current and charges the magnetic field faster.


In general, a coil's design is a dance between charging the magnetic field fast enough so there is a spark for the next cylinder at maximum RPM, yet not drawing so much electrical current that the points burn right away.


Most (probably over 90 percent) of 6 volt coils have about 1.5 ohms resistance or less, and no ballast resistor. The few oddballs that use a ballast resistor probably have a resistance even lower.


12 volt coils are typically about 1.5 ohms if there is a ballast resistor connected in series, and about 3.0 ohms if there is not.


The ballast resistor, if used, limits current and the 1.5 ohm coil runs at about 7 or 8 volts, pretty close to what would happen if it was used on a 6 volt car.


Some electronic ignitions (GM HEI for instance) have some form of current limiting designed into the ignition module, and use 1.5 ohm or less coils with no ballast resistor.


When a points ignition (or electronic for that matter) cannot keep up, it is usually because there is not enough time between firings to charge the coil for the next spark. There could also be mechanical considerations due to points floating or bouncing or something.


To charge the magnetic field faster, you would use a lower resistance coil.


With that in mind, an ignition that starts failing at 5000 RPM on a 1960s American V-8 engine would be good for almost 10000 RPM on a 4 cylinder engine, because the cylinders fire half as often, and there is twice the time to charge magnetic field in the coil.


Assuming you have 2 coils, 2 sets of points, and the cylinders fire alternately......


An old prewar slow-turning 8 cylinder with 2 coils as you describe is extremely low demand on the coils. How fast can you spin it? 2000RPM? 2500? The coils will see HALF of that because the coils fire alternately, doubling the charge time.


It is the easiest job imaginable for the coils. It seems to me that literally any coil should work on that car, although I'll bet the originals were something closer to 1.5 ohm.


I can't explain the behavior you were seeing, starting with the one plug wire removed.


Be sure your distributor is grounded well, and that each coil is getting pulled down to 0 volts on the points terminal when that coil's set of points is closed.


If there are pertronix ignition modules being used as well as the coils, the distributor ground still matters.




Edited by Bloo (see edit history)
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2 hours ago, maok said:

For an 8 cylinder engine, you need the 1.5ohm coil with the Pertronix

Oops, sorry, I miss the fact that it is a twin coil setup. If each coil is power 4 cylinders then most likely 3 ohm coils are the way to go. My understanding is that the Pertronix I module/s cant handle much more than 4 amps applied to them continuously, hence the requirement for the correct resistance coils for 6/12volts and the number of cylinder application.


I would love to see a pic of the distributor setup. Is there 2 Pertronix modules in the distributor?

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I should have also mentioned, car is 100% (well, got repainted at some point and someone put a heater in about 70+ years ago) original and stock.   So maybe the pertronix coils simply are not compatible?  I looked on their site for the number to call tomorrow and ask about this, and noticed a Q&A that mentioned "do NOT use solid core spark plug wires".   Have no idea what the 92 yr old wires are, likely braided, but just in general sounds like a specialized coil that for some reason does NOT like 1928 ignition design? 😞    $70 wasted, just because NAPAs coils a  1/16" too large a diameter.   Will have to get some Model-A Ford coils or Ford 8N, at least I know they WORK and fit.



Studebaker 1928 FB President.jpg


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Would be nice, but I had them quote it; $525.   If I were restoring it for real (vs trying to get it running to drive on rare occasions... it's up at my dad's farm 3 hours away) I would consider it.   I'm spending too much money on my '57 Stude Golden Hawk project as it is.  The President will have to wait for "someday" 😉


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Thanks guys.  I did call Pertronix, and the rep (who has a vintage 1918 auto himself so thought he would be helpful) was pretty clueless, DID point out the 0.5ohm would be 'better' but with a twin coil  system (only 4 cylinders per coil) had no idea why these 3ohm coils wouldn't work as well. After endless discussion of what I must have done wrong in wiring them (ignored the fact IT FIRED, and then RAN with an old Model-A Ford coil wired in exactly the same way), he rudely said "everything I'm trying to help you with, you have an answer for, so I guess our coils are just not going to work for you".  And (didn't expect them to but HOPED), would not take them back since I'd used them and DID scratch them. SO I'm stuck with $70 worth of Pertronix coils; anyone need them? 🙂    Would they work for my 1957 Studebaker Golden Hawk with 289 supercharged V8?   


Regardless, I DID have NAPA order in a couple of 6V coils for a Ford 8N tractor (figured close to my Model-A Ford, which works), and they will fit; going up to the farm tomorrow and hopefullY DRIVE THE CAR for the first time in 3 years! 🙂 .     

Really strange the Pertronix rep said NOTHING about it not being for a points system, just endless quizzing of how I had it wired and assumptions I had it backwards for a positive ground system (and then he reversed himself, agreed I was correct; thanks to a diagram one of you posted here years ago! 🙂 

Thanks for everyone's help!    What a hassle for such a SIMPLE problem; if only NAPA's stocked coils had fit my firewall bezels, I'd have been done and $70 ahead.   Or ordered a set from a Model-A Ford supply house as originally planned, but would have taken too long (2 weeks ago; ha!!)

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On 9/20/2020 at 10:33 PM, maok said:

If you are not using the Pertronix modules in the distributor, your current spark plug wires are fine with the flamethrower coils.


I dare say you have a couple 12v coils not 6v.

Interesting in regard to this:  the Pertronix coils (nor the website, I realize in hindsight) do not specify 6v or 12v.   (I SEARCHED for 6V coils and these came up; NEVER RUSH is the lesson learned again.     Taking to the Pertronix rep about this, according to him it "doesn't matter" and they don't specify a voltage for their coils, but do recommend different ohms (thought 3.0ohm was right for 8 cylinder then when I explained again TWIN POINT/TWIN COIL system, though 0.5ohm, BUT still argued either one should work with this slow-cranking sytem and I must have wired it wrong.  Anyway, you can bet I'm done dealing with Pertronix, though I know people like their ignitions for my other Stude, '57 Golden Hawk (in progress). Maybe I'll keep these to try in THAT when I get it completed.


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UPDATE:  popped a set of NAPA 6V coils (yes, theirs SAY 6V on them unlike the Pertronix 'voltage doesn't matter') in the '28 President yesterday, and it popped right off and ran smooth as silk.  Well, it also RAN smooth on the original coils; until a mile or two down the road when it sputtered and died on me all the time.   Yesterday, drove it a good 5 miles, not a hiccup.  Think the problem is fixed.  No clue why the Pertronix coils didn't work but that's all I did was swap them out for a "Ford 8N" equivalent 6V NAPA set.

(the NAPA resistance IS 0.5ohm, vs the 3.0 ohm on the pertronix I bought.  Whether that makes any difference,.... the pertronix rep didn't think so but also couldn't keep from saying I must have it wired wrong as his best explanation).


OK, here's a weird question that i can't think of ANY relationship to coils; but...    For years (ever since we've had it? 40 years?) the President has had a tendency to overflow the radiator, even when not overheated (per working temp gauge).  Typically when de-celeratirng and coasting or coming down the driveway from a short run around the country road.  Erupts around the radiator cap and flows down the hood.   Used to think it was incorrect cap, but found a correct (fluted to match headlights!) cap several years ago, and still did it.  Dad always ran water in it and it didn't seem to bother as much. Again, car is NOT overheating.   I took the head off a few years ago and put a new head-gasket on (head appeared flat, did not plane it).  Didn't change, still threw frothy coolant out if not plain water.   Thought maybe air leak in pump or something...  Only reason I mention it as YESTERDAY'S drive had NO overflow at all.  And taking cap off, coolant was up at top of the neck (hot).  "Normal" drive all the way around,  for first time with coolant in it.  (and I DO have Prestone in it year round; never could get those rear drain plugs out of the beast so fear water in Minnesota!)


I can't think of any possible relationship to the coils or how the engine is running since it was not overheating previously, but....  how to explain new coils, "good spark" at last, and now no more throwing coolant around the radiator cap?     Strange.....

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Are you SURE you aren't overfilling it? Old cars typically only want the tubes in the radiator covered, and not much more. They spit out what they don't want. I imagine you know that, but I have to throw it out there.


You could have radiator foaming, or your water pump packing could be leaking excessively, or some combination of the two.


Slight head gasket leak? Have you retorqued the head recently? Many oldies need it when they get a major tune up. I hesitate to suggest it because I don't know if it is a dangerous thing to do on the President. You might see what Studebaker recommended, and also what other President owners say today before trying it.


If it's not overfull, my money is on the water pump packing needing tightening.. or a little more packing.


Nice car!



Edited by Bloo (see edit history)
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I thought the same thing after talking with Jon Meyers (Stude guru for post-war cars, Avantis etc).   He figured it was just overflowing, and sold me an Avanti overflow kit which I have yet to have time to hook up.   But yesterday, coolant was right up to neck simmering like it should after I got home, and it had  not spit a drop.  Strangest thing.   Yes, I was thinking air from pump or somewhere due to the foaming (and water was ok).   Might have been dumb luck yesterday, and will start spitting again next time. 🙂     Can't believe that has anything to do with coils or "spitting engine"!   I torqued the head when I put the new gasket on of course. and no change.   I'll dare bet the waterpump has not been touched in OVER 40 years since we got it; I know I've never touched it.  Dad just drove it (along with his other five old cars) in parades and such around the farm, so no serious miles on it in all that time, nor any real 'work' except what I've done (rebuild fuel pump as I first suspected lack of fuel at the cause of dying on the road, since it always required priming to start also).    Just happy it runs again, Only drive it a few miles once or twice a summer, as the farm is 3 hours away.    As long as Dad hangs in there anyway! 94 and going strong; yet.


Edited by 53BuickSuperConv (see edit history)
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  • 2 weeks later...

I have owned a 1930 President Eight FE Roadster for over 60 years and driven it as a daily runner running up over 350 000 miles during that time. 

I have experienced all the issues you speak of re water overflowing upon slowing down to  fitting a pertronics distributor. 

For the electronics setup to work successfully one must have a near new cap. After the engine gets up to temperature, with the high spark voltage required , any sign of carbon tracking or a breakdown of the insulation inside the cap resulted in the Pertronics unit failing to preform. 

However if you are running the original Delco twin points ignition system, it is absolutely important that the correct Delco points be used. Each set is different in their heights. But once installed, with one set sitting on the adjustable sliding plate, the contact points must be absolutely in a straight line with one and other. Failure to achieve this by using “Jo blogs” El Cheepo points, will result in you never being able to achieve the correct “Dwell Angle”” Resulting in one half of the engine out of sync with the other. Half the engine will run hotter and often results in the hotter water surging from the back of the motor when braking towards the front with the result of hot water surging out of the top of the radiator. If you doubt this, simple check out your temperatures down the length of the block using a didital laser temp gauge. The rear cylinder should only be a few degrees hotter than number one. 

The final thing I did to resolve the overflow of hot water problem was to get the engine professionally tuned with the emphasis on reducing the “hydrocarbons”  achieved by a sensor pipe up the exhaust pipe. The end result was no more water surging out of the radiator. Finally FYI an egg cup full of “Soluable Cutting Fluid”  added to the water totally eliminates all sign of rusty water. Hope this helps. David Lane New Zealand. 




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decostude is 100 percent correct on the correct points........everyone today puts in stuff that "looks the same" and people "say" are correct. Well, I can assure you, that more than half the cars pre war going down the road have the incorrect points in them. I also have run cutting oil as a rust inhibitor and water pump lube for forty years........especially when sorting new cars......since I lived in a cold climate, I always had antifreeze in the cars long term.........but with newly rebuilt engines and water pumps, or any car with a overheating issue, cutting oil is a cheap and easy solution until all problems are worked out. Also, it rinses off with a hose if it gets on your paint....super easy to clean up, and won't bother animals. David....great car....and impressive milage total. You have my respect sir.........fantastic accomplishment. I tell many people, talk to the guys who actually drive them. I have somewhere around 150,000 miles on pre war cars. 

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Further to my comments regarding water and points problems  with my 1930 President Eight, I also want to share one other issue that has plagued me for a number of years which resulted in an engine failure resulting in a rebuild. 

It is now becoming evident that many of our old engine blocks are becoming porous as they age. 

I have experienced a problem of tiny water droplets, (very visible to the naked eye) very slow in appearing, in the valve chamber area. These tiny droplets eventually gain weight and drop down into the sump. Because water is heavier than oil, it finally gathers at the lowest point, the sump plug. After the car has been stopped for say two weeks, I would crack open the sump plug very carefully holding a glass underneath and bingo, out came just an egg cup size of water. 

Obviously it was a very small amount but eventually left unchecked the engine oil was seriously compromised and in my case, eventually damaged the engine. 

The solution:

Engine block had to be removed and stripped. The entire valve chamber was micro blasted and a product called BELZONA was applied as a coating. This product is a two pot application which can expand and contract as the engine heats and cools. 

The engine had to be rebuilt once again. 

The results were outstanding. Today (after 20 years) I still check the sump plug out of habit after the car has been stationary for a while. No more water. 

It appears that this problem is not just confined to Studebaker engines. I know of other cases in the 20’s through to the 40’s era where this problem has been discovered in different brands and subsequent resolved very successfully using  BELZONA. 


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1 hour ago, nvonada said:

Was porosity the purpose for the red lead paint that all the car companies seemed to use? 


Your mention of read lead reminded me of my Studebaker engine which tossed a rod in 1995, although it was not taken out of the car until nearly 20 years later.  The red colour of the interior of the block is what I recall from when I first went inside it in 1990. As far as I knew the engine had not been rebuilt at anytime but someone had been inside it before because the wire ties on the bolts of one of the roads had been disturbed.


I was astounded at the amount of damage the rod did. The cam was in three pieces in the tray in the side of the engine bay. The rod knocked the carb off the manifold and also broke the starter mount casting. The piston remained in the cylinder.


I still have the block somewhere. My son built another engine using bits from three others but the crank from this one. It lasted for a few years but the rest of the car needs work. Some day we will get back on to that project but in the meantime there are other things to do.




IMG_0153 (2).JPG

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