Technical Can't figure out stumbling with MSD coil on GM Points Dizzy. Please Help

Needing help diagnosing the cause of stumbling in my GM points ignition.

Hi guys, my names Rob and I have not posted much on the HAMB, as I can usually figure out my problems by the resources on this board (the all mighty search bar) and other areas such as suggested phone numbers, websites, other boards etc. I also haven't posted much in other regards as I'm not yet an expert with expert advise to give.

What I've got going right now, is something I have spent countless hours reading and searching, as well as many hours trying to correct and spending a few dollars on as well, all to no avail. Maybe it's sickeningly obvious and right in front of me, or its stored away in the brain of the most experienced hotrodder, either way I hope I can have some help looking in the right direction.

PROBLEM : I cannot get my 1963 GM Points distributor, with MSD coil to rev up, under load past 2000rpm, while my stock coil with exact same set up will rev to 6000.

Specs/backstory : I'm building a 1964 Chevelle that I want to resemble a 60s street racer, owned by a mid 20s budget minded hotrodder. I acquired a 1963 GM points distributor a few years ago, and ran it in the car for about 2 years. I never had a tach in the car until last summer, at which time I noticed I was only getting about 4700 rpms out of the car before point bounce would occur. As I also drag race the car, I swapped in an HEI for the last race of the year just to get her in the upper rpms and compare ETS. I get a lot of "why?" At the track for staying old school, but I told my 5.0 mustang buddies I would build something pretty traditional and still beat them, needless to say I can't back down now, and haven't had to. No losses to street class 5.0litres yet in heads up racing or bracket.

Anyways...

Over the winter I had my points distributor rebuilt and curved by a very reputable fellow in my home town (Victoria BC). Once installing the distributor in the car (2 months ago) I noticed the car came totally alive right up to 6000rpm. It was great. The only thing I didn't like, was the orange (with occasional blue) spark at the spark plugs. I was told to purchase a GOOD quality coil (at the time of picking up my distributor) and I should be good to go. I have left a message to the builder, as I know he will be the guy to ask, but I know he's away on vacation for the next little while and racing starts soon.

The car idled fine with the newly purchased and installed MSD Blaster 2 Coil and Ballast Resistor (part number 8203) so I took it out for a drive, and was presented almost instantly with stumbling and sputtering right around the 2000rpm mark. I was not and am not able to push the engine past 2000rpm unless I am in park or neutral. The engine idles fine in park and neutral, but stumbles slightly around the 3500-4000rpm zone In said gears. The spark is also orange with the occasional burst of blue.

The 1964 Chevelle came with a resistance wire from the factory, mine was also a 194 6 cylinder up until about 8-9 years ago. My resistance wire had burnt up on me years ago, and was replaced with just regular wire. I purchased the MSD Blaster 2 coil with Ballast resistor. My stock coil, as mentioned, works right up to 6000, with the ballast resistor and everything that came with the MSD kit. I switch only the coil, and that's when I get the break up/ stumbling issue. I made a call right away to MSD and was told to return the coil as it was most likely faulty. I received a brand new kit and immediately ran into the exact same issue, the old coil worked right up to 6000 and the MSD wouldn't go past 2000. I was instructed again by MSD to return for a third coil. In the meantime, I had been feverishly reading everything I could and searching everything I could. I found a few similar posts, that had a few different circumstances so I tried there responses and recommendations. I also had sent an email off to MSD for some online support.

I tried removing the tach, I added a wire from the starter (mini starter) to the + side of the coil for 12 volts on cranking with a diode to prevent back feeding, I've tried a new cap, new rotor, I've tried running with and without the ballast resistor, I've cleaned the plugs, gapped the plugs, and tried another set of plugs (AC Declo r45s both times). I've cleaned the points contact to remove any film or residue and lastly today, tried a new condenser as recommended by MSD. I may be missing one or two other trials but I think I've pretty much written it all down. Also I've done everything independently. Not all at once, in order to try and isolate the single problem. Not one thing or group of things has changed the stumbling in any regard.

My emailing attempt with MSD wasn't successful either. The response was to check resistance on both coils and report back (something I did after reading a forum suggestion as well). After doing so, the technician suggested I run a ballast resistor...if he/she would have read my first email thoroughly they would have noticed THATS WHAT I HAVE BEEN DOING. I politely told them this and have yet to hear back.

Today's technician at MSD seemed to be much more knowledgable. He explained that the MSD could be putting out to much power for my components to handle. He suggested I replace the condenser. I replaced to condenser and still no luck. I called back again, in hopes of picking another techs brain, and was met by the same tech from earlier. He flat out told me to buy a MSD Billet unit or a 6AL. I told him that it wasn't an option on this car, and even though that is the modern product that seems to be the way everyone is going, that it was a pretty bad excuse. I told him "I can't accept that as an answer because the parts you sell, that I have bought are for a points ignition, and therefore should work for me, I shouldn't have to buy a modern unit." The tech was totally understanding, though perplexed to why someone wouldn't want to upgrade. He said he couldn't offer me any more advice and wished me good luck.

Everyone seems to say that points belong in the trash, but they did work for millions of cars for many many years. My car isn't anything wild and crazy. It's a 11:1 compression 327 with a nostalgia + L79 comp cam, with headers and a 1963 corvette 340hp intake manifold. I run small chamber heads, ported with 1.94 intake and 1.6 exhaust. Pretty much everything on my car worked with points at one time in its life, and I'm sure there are many cars more performance oriented then mine still running points most likely with one of these MSD coils. I've read that grumpy Jenkins still ran points in 1974 up to 9000rpm with a 1962 GM dizzy in pro stock, heavily modified obviously for the application.

I apologize for the length of this, but if there's one thing I see asked more and more to the Original Poster of the topic it's "we need more info".

I really appreciate anyone's time who can offer any type of insight to my issue. I'm not totally screwed, if I have to run my stock coil for the time being I can still make it down the drag strip, I would just like to get my $100 MSD coil working and providing me with the better spark it should be capable of.

Thank you,
Rob

 

I don't think your points and handel the spark from your msd coil go back to your old coil

 

I was hoping to help out but my ADD took over after a few paragraphs. New coil primary resistance is correct for points?

 

I'm getting .7 ohms and MSD said that was fine. I appreciate your help. And sorry blowby about the ADD lol...my OCD kept me re writing and re reading it.

 

First off, I gotta say I like your methodical approach to fixing your problem. And the fact that you're unwilling to just throw money at it till the problem goes away.

I would say first off to check the operating voltage at the coil with both the stock and MSD coils. Maybe check it at idle and at 2000 RPM. I'm guessing it should be maybe 9 to 10 volts, but mainly check to see if there's a noticeable difference.

Does the MSD coil run noticeably hotter than the stock coil after running a while?

Is the MSD coil mounted upright, on its side, or upside down? Does MSD make a recommendation on the mounting position?

Double, no triple check all wiring and terminal connections. Especially the little harmless looking harness that goes into the distributor. It has to flex a little bit every time the advance plate moves. Is the insulation brittle or cracked? Flex test it with a continuity tester.

You gotta start somewhere. It might as well be the cheap and easy stuff...

 

No fear..."Squirrel" will come along soon. Jim will probably have an answer.

 

Maximum voltage: 44,000 Volts (Tested with 6AL Ignition)
Peak current: 220 mA
Spark duration: 300 uS

You are putting a 44,000 volt long duration lightning bolt into a distributor cap designed for half that voltage. Might be you have too much fire in there. There are caps with ribs that provide longer arc paths to prevent spark jumping.

 

What is the resistance of the primary winding in your old coil? Close to .7?

Is there any backfiring, which might indicate crossfiring in the distributor cap, which might be likely with a small diameter distributor cap and a real high voltage coil.

 

Thanks for all the quick replys guys.

ClayMart I wasn't able to get a good reading on running voltages with either coil or between two meters. My electrician neighbour came over and helped me. I was getting anywhere from 8-18 v on the stock coil and 3-14 on the MSD. I hope I'm not doing something wrong? Just putting the leads on the primary side of the coil + and - as far as heat, I idled the car, with both coils for 5 minutes. The stock coil ran up to 89* and the MSD up to 85. The coil is mounted upright, vertical. I believe you can mount them either way but may need a differ not coil to mount horizontally to avoid fluid leakage. The wire going from the distributor to the coil - is nice and flexible and free of any cracking. I checked it for resistance, as my neighbour said that's what continuity is. I wasn't getting a reading.

OldBuzzard I appreciate the reply. I get more and more comments about this MSD coil making to much juice for my set up to handle. So I've gotta ask, how do I get a nice blue spark, with a points set up?

Ebbs speed
The old coil primary resistance is 1.6 compared to the MSD at .7. I don't get any backfiring through the exhaust, just a real nasty stumble and what has been described as coil break up. It sounds like a rats nets of electrical sputtering if that helps any.

Now, I don't know why my meter isn't giving me a good reading on either coil, and my neighbours fluke meter is only letting him read in AC. I guess his meter will automatically go to dc or ac. And for what ever reason gives the MSD coil a reading of 6volts AC at 2000rpm.

 

The 6 volt reading at the coil is because there is a voltage drop across the ballast resistor. I'm not sure that a .7 ohm coil is a good match for a set of points. That's pretty low, meaning the coil will draw a lot more current through the points, and they simply may not be able to handle it. Do you know what the resistance of the ballast resistor is?
Send a PM to GMCBubba, he could likely read the info here and tell you immediately what the issue is. He's a bit of an ignition wizard here on the HAMB.

 

Ebbsspeed I really appreciate the information and the lead! I will get right on that. The resistance of the resistor is .80 ohms.

 

Have you tried not using the ballast resistor?

 

Beemon thanks for the reply. Yes I have. It was one of the first things I tri d before hitting the boards and tech lines

 

You cannot increase voltage without a transformer, which is essentially what your coil is. However, how much it increases the voltage is based upon your initial voltage and the windings in the coil. Your resistor will decrease voltage across the system. Your MSD coil is rated at 45000V, your primary resistance is the .7 ohms ballast resistor and the secondary resistance in the coil of 4.70k ohms, or 470000 ohms. So in order to deliver the 45000V, the coil acts as a transformer. Your ballast resistor drops voltage across it. You can work backwards in this case, where V1I1=V2I2, where V2 is the 45kV and I2 is the 4.70kA. V1 would be the voltage from the resistor and I1 would be the amperage across the resistor. Both of these in your current setup are unknown and will need to be found in order to fix the system. There are two windings in your OEM coil, the outer and inner. To find the resistance values, you need a multimeter. Your primary resistance will be across your positive and negative leads, and your secondary resistance will be across the negative lead and the coil terminal. You can then model the system with the 1.6 ohm ballast resistor from the OEM application and compare it to the MSD application to find the correct ballast resistor as obviously you're not getting the correct amount of resistance. The reason why the tech told you to get a 6A box is because it deletes the ballast resistor and instead meters resistance internally to your specific car application. Not every car used the same ballast resistor so throwing in a universal coil won't always work the way it's supposed to.

Personally, if you're against the 6A, I would get a pertronix kit, which also eliminates the ballast resistor and is hidden under the cap. Or, just use the OEM coil. Before anything can be done, you'd need to get the specs of your OEM coil and then compare them to a new OEM coil to see if your old coil is still working properly. What size spark plug wires are you using anyways? With 45kV, there could also be a lot of interference between sparking if the wires are next to each other and aren't thick enough to contain the spark.

 

I've gotta ask, how do I get a nice blue spark, with a points set up?

All the points do is provide an intermittent power feed to the coil primary in order to pulse it to create a spark with the secondary winding.

You don't say whether your orange spark is right out of the coil or at the plug or somewhere in between. If it is right out of the coil you have low voltage to the coil. If you have good spark out of the coil and orange at the plug the energy is being lost along the line somewhere, probably being sprayed around inside the cap.

 

The condensor isn't up to the task of keeping "clean" function at the points with the higher coil output. I know that's a really simplified asnwer and it's too friggen early to get into the science of condensors, for me anyways. I had the same problem what feels like a milleium ago with a Boss 302. I had a dual point in her and lost about 2000 RPM, top end. I felt really dumb when I changed a $1.49 part (back then). Your issue sounds very similar, although only with the extra "work" your system has to do in order to "manage" that coil. I know you want to stay early and traditional with your car, I think that's bitchin too, but there were a few forms of ignition amplifiers back then, MSD not the least of which. I may be wrong, I don't want to sound like you need to "throw a new part" at the problem, but i though MSD was making their igniton box in vintage form for guys like you (and a bunch of us). Check it out. Maybe they'll hook you up for sticking with it...?

A quick edit: Even if you were to add an MSD box into the system it doesn't have to be in plain sight, in fact I've always found it better to keep it inside and away from engine heat. Just sayin, good luck...

 

This may help you out with your troubleshooting... And it's from a very traditional source.

http://www.jalopyjournal.com/forum/threads/hot-rod-technical-library-basic-ignition-systems.983424/

 

Guys this thread is coming up way too often and i understand the trouble the poster is having with his car!
There are many very incorrect assumptions and wifes tales used in this thread that i dont have the time to answer. I will in the very near future get a page up on our new web site to try and cover the entire thread. ( as time allows)

Now to the problem and the cure .
1-You run good with the old coil and terrible with the MSD coil. Thats easy get rid of the .7 ohm MSD its way to low on the resistance to run with this car.
2-Get a set of CS786 contacts and a RR175 NAPA points and condensor. They are the best made today and will run the 6-7000 rpm you need. While you are there get a NAPA IC12SB ignition coil and a ICR13 resistor.
3-This will give the system all the correct primary resistance and run great!!!! (with good plugs and wires)

Spark color can no longer be used as a diagnostic tool with resistance plug wires !!!!
A 45,000 volt coil doesnt put out any where near 45,000 volts . Often will idle at 5-8000 volts and only increase levels with load etc.
Let us know how she runs.......

 

I dunno on this. I am using a 40,000 volt coil on an old stock farm-all tractor distributor cap with no issues.

 

Listen to Bubba - .7Ω coil with a ballast resistor that is probably around 1.2 to 1.5Ω is just to much juice for a points system. You want to be closer to a total of 3.0Ω. So you can either run a 1.5Ω coil and a 1.5Ω ballast resistor or a 3Ω internal resisted coil. I would go with the 1.5 combo as you will have higher cranking energy if you are wired correctly. As for the comments about 45kv being too much, that is silly. Coils that are rated at 45,000 ~ 50,000 ~ 60,000 volts will never really create that much energy. The coil will only out out how ever much voltage is required to jump the gap and create a spark. And that is determined by many things in the engine, including fuel mixture, compression, cam overlap, and load on the motor. A mild motor cruising down the highway at 65mph will only require somewhere around 5,000 volts and that same motor with your foot smashed to the floor will still only need about 20-25,000 volts.
Your problem is too many amps for the points and condenser.
If you want to run a "Performance" coil you can run this one http://www.summitracing.com/parts/pnx-40011/overview/ WITH a ballast resistor and your points.

 

I dunno either. All I am doing is making a guess like everybody else (except BUBBA) based on too little information about the condition of his equipment and suggesting something that has some possibility/probability of being related to his problem. Carbon paths in a cap are not an unheard of problem.

Since BUBBA has checked in & has seen more of this kind of stuff than probably all of us put together, I would suggest that the OP pay close attention to it.

 

It isn't the theoretical output of the coil that is the problem, it is the internal resistance combined with any ballast. There are plenty of 40,000v coils with a 3Ω rating. I also doubt that your Farm-All sees 6,000 RPM! I work at PerTronix and have a little understanding of all this

 

Does it seem odd that MSD would replace the coil twice? It seems that they might be having a problem if they assume it's bad. Most companies are farming out their manufacturing and might encounter problems.

 

definitely not an rpm screamer. It also has a pertronix module in it, I bought as a set. I love em and buy em for everything I own.

 

Thanks for all the replys, links and help guys, please know that I read them all and appreciate everyone of them. I will get on this right away and really appreciate your advice GMCbubba and will be sure to post what my end result is.

-Rob

 

I couldn't find the Napa product info online, so I made a call to the store. First off, those are the points and condenser I do have, so that's a bonus.

Now the coil you mentioned GMC bubba, is a stock replacement coil. I'm guessing (as long as my working coil is in good working condition) that I would be seeing the same performance from both products? I saw the coil linked by Hotrodron (pertronix flame thrower) and wanted to get your thoughts on that.

I really appreciate your input, and making sense of why the MSD coil is the wrong coil for me. I also very much appreciate and understand that all the parts you have mentioned will make my car run great, but would that also just be how my car is running now, with my original coil? I'm glad you pointed out that you cannot go by the spark colour anymore and now I understand why. The orange spark (at the plugs) is the reason that I went to the MSD coil and was actually the only reason, as my stock coil was getting me up to 6200rpms. So what I'm asking, and mean no disrespect or want to show any lack of appreciation for your help, but if I purchase the Napa coil and resistor, would I be just back to were I started at with my stock coil?

Once again I appreciate all the help and by no means want to sound contradictory or that I'm not listening to well educated answers, I just dont want to fork out the cash to duplicate the same performance I get now, with my stock coil.

Thank you,
-Rob

 

If your stock coil isn't breaking down at high RPM, changing it will probably make no difference what so ever. If it is over saturating, or breaking down and mis firing, then you would want to replace it.

 

NAPA is usually just stock OEM parts, but if you search online using their interchange, they have parts numbers dating back to the 50s - I just sourced all my differential bearings through their parts interchange. I think you should still check the amperage across the primary and secondary windings of both coils, just to see if your stock coil is performing as it should and if the MSD coil is really bad or not.

 

Not a problem i thought you needed a coil.......clean up the old coil with some baking soda, measure the resistance from pos to neg and secondary terminal to primary. should be 1.5 or so on primary ( actual GM spec is 1.37 ) use a approx 1.5 ohm ballast. Spray coil down with wd40 after cleaning blow dry and run it. I guess then my question would be do you really have a problem with the ignition?????? The low resistance might have damaged the points as well but you can handle that.
Then if a problem really is present we can go from there ...
Friends dont let friends drive MSD off shore stuff!!!! rbg :>)

 

Does this work the same for a dual point distributor, with the MSD coil being to powerful ?