Should You Ditch the Distributor?

Do you want to take the time and effort to convert to a distributorless ignition system (DIS)? Keep reading and find out if this is something you want to do. Yeah, it looks cool and high tech.
Do you want to take the time and effort to convert to a distributorless ignition system (DIS)? Keep reading and find out if  this is something you want to do. Yeah, it looks cool and high tech.
Do you want to take the time and effort to convert to a distributorless ignition system (DIS)? Keep reading and find out if this is something you want to do. Yeah, it looks cool and high tech.

Automotive ignition systems have gone through a number of evolutionary steps since the first cars started rolling around country dirt roads.  Electronic ignitions are all the rage these days as they give you much more granular control over your engine’s ignition system.  The newest ignition systems available, distributorless ignition systems (DIS) look worlds different from what we’re used to and add an extra layer of control when the right components are used.  If you’re looking to build up an engine from scratch for your strip burner, should you go with the newest tech and go DIS or stick with the tried and true high performance electronic ignition systems and distributors?  Let’s take a look.

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Sensors and Switches Everywhere!

I’m an old school gearhead.  One way I describe cars equipped with DIS ignitions is that we have to ask permission of several sensors first, and then we have to ask other sensors how much of this and that to use.  Once we have permission (to send spark and fuel to the combustion chamber) and we’ve checked air density, volume, and temperature, plus exhaust gas temperature and oxygen content, we cans tart motoring down the road.  No, I’m not really a fan of much of the newer tech we’re seeing in the auto industry.  Suck, bang, blow.  That’s all we needed to know “Back in the day.”

If any one of those sensors or switches stops working, or worse starts sending erroneous data to the computer, we’ve got problems. The car isn’t starting and you’ve determined that no spark is getting to the cylinders. Why? Start the diagnostic chart:

  1. Check the crank position sensor (CPS). Is it installed and gapped correctly?
  2. Is the crank sensor getting power?
  3. Is the CPS creating a signal as the engine turns?
  4. Is there a camshaft position sensor? Is it installed and gapped correctly?
  5. Is the cam position sensor getting power?
  6. Is a signal being generated as the engine turns over?
  7. Are you getting power to each of the coils in the coil packs(s)?
  8. Is internal resistance in each of the coil packs within spec?

 

These are just the first steps in troubleshooting and diagnosing a “no start condition” with a DIS engine. Sure, if you’ve got the money to spend on a scantool, great. You can skip most of the diagnostic steps and plug the scanner in. However, some of the trouble codes that might be present will have you doing exactly what I described above.

Circuit schematic for the average standard breaker-type ignition system.  Basic schematics for electronic ignition systems are pretty much just as easy to understand.
Circuit schematic for the average standard breaker-type ignition system. Basic schematics for electronic ignition systems are pretty much just as easy to understand.

Sensors and Switches Create Problems

With points/breaker-type ignition systems and even with electronic ignition systems, properly setting the ignition dwell (the amount of time the spark pulse lasts for) is quick and easy.  If the points or reluctor/pickup move (or wear) out of adjustment, readjusting them is easy and straightforward.  In a points-type system, cams on the distributor shaft cause the points to open and close.  A small screw allows us to adjust the points gap quickly.  With most electronic ignition systems, this adjustment is accomplished by loosening the pickup plate.

Here's what you'll need to diagnose problems with computerized DIS systems.
Here’s what you’ll need to diagnose problems with computerized DIS systems.

That can’t be said when you’re talking about distributorless ignitions.  If the signal telling the ignition system to begin the cycle isn’t received or is corrupted somehow, getting to the sensor in question can be a pain.  You may have to remove accessory drive belts and pulleys to get at the crank position sensor.  Getting at the cam position sensor can mean pulling the intake off and maybe even removing the valve covers.

This and a test light are all you need to diagnose most breaker-type and electronic ignitions.
This and a test light are all you need to diagnose most breaker-type and electronic ignitions.

DIS Limits Your Induction Options

The computer that controls the DIS system requires ultra-fine control over the engine’s fuel management system in order to function properly.  This means you’re stuck with fuel injection.  There’s just no way to tell a carburetor to limit fuel delivery to number one cylinder and increase it to number four.  Fuel injection systems also allow the computer to advance or delay the delivery of the fuel to the combustion chamber.  Again, that’s something that can’t be done with a carburetor.

This is an automotive computer diagnostic program that you can buy for computerized DIS systems.  They usually only run a few hundred bucks, at least.  This is one of the ones that you can run on a laptop and sometimes make mapping changes on the fly to improve performance.
This is an automotive computer diagnostic program that you can buy for computerized DIS systems. They usually only run a few hundred bucks, at least. This is one of the ones that you can run on a laptop and sometimes make mapping changes on the fly to improve performance.

DIS Lets You Make Changes on the Fly

I’m guessing most of you have seen at least one or two of the Fast & Furious movies.  You’ve seen the scenes where they’re racing and fiddling with a laptop computer during their race.  What they’re doing is mapping the engine parameters so as to improve the engine’s performance during the run.  This is pretty cool.  We can check the engine’s performance live and make changes to affect/improve that performance during the run, not after like we’ve had to before, even with electronic ignition systems we’ve had to wait to make changes between passes.

DIS Is Harder to Install

Installing electronic ignitions is easy.  Installing high performance ones like those from MSD and Accel is easy compared to even a stock DIS system.  Wires not long enough?  No problem, just grab some that fit.  Tap a wire here, mount a control box there, and you’re pretty much done.  Not so with DIS systems.  The wire going to the computer from the CPS isn’t long enough? You’ll need to make sure the wire you splice in fits certain parameters, otherwise it could throw off the computer.

DIS Looks More Star Trek High Tech

The first time I saw a car equipped with a DIS system, I reacted pretty close to how WWII pilots did when they saw jets flying for the first time – “Wait! Where is the distributor and where do the plug wires go?” Then I started thinking about it.  It does look pretty cool to not have a distributor and wires.  Some of the coil caps, especially the aftermarket performance ones, also look pretty cool.

Personally, I’m going to stick with electronic ignition.  I’m more familiar with it.  Keeping it running is easier and cheaper.  I still like the look of a billet distributor and nine millimeter plug wires.  I prefer the look, feel, and sound of a big carburetor feeding through a big manifold.  What about you?  Is a DIS system in your future after reading this?  Can you think of any pros and cons of each that I didn’t touch on?  Leave me a note in the comments section below.

This is a crankshaft position sensor.  Some are installed like this, in the engine block, while others are installed on the front of the engine where they can be damaged.
This is a crankshaft position sensor. Some are installed like this, in the engine block, while others are installed on the front of the engine where they can be damaged.

Timing Problem with DIS? Uh-Oh

With electronic and standard ignitions, if you’ve got a timing problem, fixing it is usually a matter of a few minutes with a timing light and a distributor wrench. With DIS?  Sorry, it’s going to be much more involved than that. A timing issue with DIS either means that the engine control module (ECM) is interpreting the data incorrectly, or one of the two or three sensors dealing with timing is malfunctioning. The only way to determine what is wrong is with a scanner. The only way to fix it is usually either by adjusting the proper sensor, replacing the malfunctioning sensor, or tracing the wiring fault.

With DIS, the computer controls everything. Unless you have access to some pretty expensive and technical equipment, you can do nothing. Don’t like the spark curve your system has? If you haven’t got the chip programmer, you’re out of luck. However, if you’ve got electronic or breaker-type, grab your distributor wrench and timing light and reset it how you want it in a few minutes. It’s as simple as that.

 My Conclusions

The long and the short of it is this: If you’re on a limited budget, DIS isn’t for you. If you want to get rid of the ancient breaker-type ignition, performance/competition electronic ignition systems can be had for a couple hundred bucks, while, unless you’re really lucky, if you want DIS, you’re going to have to buy a whole new engine.

If you’ve got two working hands and ten working fingers, you can install a new electronic ignition system. On the other hand, even with all my experience, I would be hesitant to perform a conversion on my own cars. Sure, it can be a pretty cool learning experience, but so can doing your research on the various performance and electronic systems on the market.

About Mike Aguilar 199 Articles
Mike's love of cars began in the early 1970's when his father started taking him to his Chevron service station. He's done pretty much everything in the automotive aftermarket from gas station island attendant, parts counter, mechanic, and new and used sales. Mike also has experience in the amateur ranks of many of racing's sanctioning bodies.
  • Keepin it real.

    Mike, as usual, you are correct. On a drag car with a carb and electronic dizzy, as long as jetting and timing are correct, your at no disadvantage at wide open throttle. However, on a street engine with DIS, some computers are making thousands of calculations per second and constantly making injection and timing changes to suit the conditions at hand. As most of us know, some even cut out cylinders as load conditions change, all to save us every precious drop of hydrocarbon. After market DIS systems are becoming more reliable and less expensive all the time as is there diagnostic equipment and it’s also becoming easier and quicker to use. Having been let down a few times over the years by electronic dizzy transducers (and electric fuel pumps), i don’t see them as the bullet proof way to go either. It all comes down to the time you want to spend setting up your engine correctly to better cope with all conditions. Is an electronic dizzy with decent leads, MSD, good fuel pump, new carb and a dynotune to initially set jetting parameters ect really that much cheaper? Remember, there’s no substitute for technology, or ALL the manufactures wouldn’t waste millions doing it..

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