Electrified

• IGNITION CURVES

Almost all hi-performance distributors have mechanical advance system.  The centrifugal advance system is designed to advance the firing of the spark, typically using springs and weights inside the distributor body.  As engine speed increases, the spark for each cylinder must be triggered slightly sooner to allow some time for the full ignition of the air and fuel mixture prior to the piston reaching top dead centre.  In operation, the distributor shaft speed of rotation builds up and the shaft speed increases. The mechanical weights tend to fly outward, stretching the springs more as the engines rev’s increase.  Pins on the weights act against a plate fitted to the base of the dizzy cam.
The further the weights fly out, (hence the name “centrifugal” which is the description of the action), the further the cam position moves which results in advanced timing the firing of any engine fitted with one of these distributors.

In order to check out the mechanical advance system, remove the distributor cap. Hold the rotor by hand and see if you can turn it in the same direction that the distributor shaft normally rotates.  There should be some pressure of the advance springs holding back the movement.  Release the rotor and it should snap back to its original position. “Total timing” is the amount of ignition timing, (in crankshaft degrees), that the engine “sees”.

Now, if you think about a typical vacuum advance-equipped street distributor, you can easily see that the total amount of timing can approach huge levels if not held in check and adjusted accordingly. Look at the variables: Initial advance, centrifugal advance and vacuum advance.  Too much of each, (and it isn’t difficult), can result in 50 or more degrees of total timing, (this would be considered way too much). Initial advance and total mechanical timing can vary from engine to engine, (even those that are seemingly identical), and only your own engine can “tell” you the exact numbers required by trial and error.

Generally spreading, a hi-performance combination can utilize total timing figures ranging from 36-46 degrees. This includes initial and mechanical advance.  Auto transmission equipped vehicles can use more initial advance than their manual stick shift counterparts.  However, the total timing should still be the same.  What is meant by all of this is the mechanical advance will have to be shortened with an automatic transmission in many cases.

While this may sound frightening, in reality, it is quite simple, (depending upon the distributor type that you have selected at the time of the engine modification).  You might be able to shorten the advance curve by increasing the size of the weight stop thus slowing the action down slightly. Other examples may require minor welding of an advance slot, while some aftermarket distributors have provisions to change the duration of the overall mechanical advance curve. It’s just a matter of examining your specific distributor and determining how the mechanical advance weights are limited.  Generally speaking, the mechanical advance should be between 2000-2400rpm for automatic-equipped cars and in the range of 2400-2800 revs per minute for manual gearbox examples. You must go through the motions and identify the best possible variant.

• INDEXED DIZZY PERFORMANCE

There’s no question about it that the distributor cap and the rotor must be positioned precisely in order to properly and efficiently distribute the spark at the correct time.  There are two areas where cap to rotor fit are critical.  The first is the rotor to distributor cap clearance.  It must be close enough to allow the ignition spark to cross the gap easily, (not too short and not too long). In the second case, the rotor end or point of discharge must line up exactly with the distributor cap terminal precisely when ignition spark fires.  If the distributor cap to rotor blade clearance is too great, the given spark can easily ‘jump’ to the next cap post terminal in the firming order. The same thing can occur if the cap to rotor alignment is off, even if it is only off by only by a small amount.  Not only will this “jumping spark” result in a poor running combo, it can also destroy the engine if operated for any duration under these conditions.  To make it simple, the effect can be the same as far too much initial spark.

Its no secret that it is physically impossible to “move or adjust” a conventional rotor.  But that isn’t the case with the distributor cap.  If you look closely at the cap, you’ll notice that there is a margin of “free play” on the cap mounts.  Most rotor caps can be twisted slightly clockwise or anti-clockwise, even when the mount clips are lined up (but not completely fastened).  In order to check and properly phase the system, use the following process to find the exact rotor to dizzy cap post:

Prepare a “test cap” by cutting a large “viewing window” in the body.  The window should be positioned under the cap posts, but high enough so that you can see the body of the rotor.  It doesn’t matter where (in relation to the firing order) this window is cut.  Simply position the window in a spot that is easy to view on your engine while it is running.

Distributor Cap

• Mark the distributor cap with a series of index marks that correspond with the exact center of each post in the “window”.  Position the marks at the bottom and top of the window and be sure that the marks are lined up straight.  To make the marks visible on a brown colored distributor cap, use a fine black marker.  If your dizzy cap is black, lightly cut the marks with a fine file and fill the marks up with white Tippex correction fluid or find some white paint for the task.

o Mark the rotor with an index mark (a light cut with a small file works well).  This index mark must coincide with the center of the rotor blade tip.  In order to make the tip easy to view, fill the index mark with Tippex.
o Install a timing light to one of the distributor cap posts in your window.  Set the engine speed so that the rotor appears to be steady. Use the timing light to view the position of the rotor versus the distributor cap post.  As expected the timing light will “slow” the rotor speed so that you can spot the location of the rotor tip in relation to the distributor cap terminal.

Indexed Rotor  

• If you engine does not have vacuum advance, phase the rotor so that the tip lines up precisely with the distributor cap terminal.  To accomplish this with a conventional dizzy cap, you will have to note the test cap (mark it with Tippex or a felt-tip pen). Replace the test cap with a conventional cap, but make certain that you have placed it in the same position as the test cap.  (Be sure to use the same brand of cap as the “test cap.” (This will ensure that you get exactly the same timing marks). Once you have determined the location and marked the distributor body, you wont have to check the rotor phase again.)  As indicated earlier, there’s a slight amount of play available when installing a distributor cap. In most cases, this play should prove sufficient to phase or index the rotor or distributor cap position.

If the car has vacuum advance, you must take into consideration the advance will change the phasing of the rotor according to manifold vacuum.  A distributor with clockwise rotation (vacuum advance disconnected and plugged) should have the rotor just to the left of the  “target” distributor cap post.  When the vacuum advance is working, the rotor will appear just to the right of the target post. Similarly, a dizzy with an anti- clockwise rotation will be exactly opposite to the above.If there isn’t enough play in the cap to compensate for any misalignment,
there are ways to increase the amount of adjustment.  Many point breaker plates or magnetic pickup plates found inside the distributor can be repositioned slightly. Coupled with the available movement of the cap, you
should be able to properly index the cap and rotor combination.

• POWERED SPARK

It’s always a good idea to index the spark plugs, but what is it and what good does it do? Every engine responds differently in many ways to indexed spark plugs. Combustion chamber shapes, piston dome configurations, ignition systems and a host of other combinations influence the spark plug “location” in the cylinder head combustion chambers. In some examples with a large piston dome coupled with a tight fitting combustion chamber, indexed spark plugs are mandatory, only because the close internal clearances “tighten” the spark plug gap every time the piston comes to top dead centre.

In terms of performance, some engine combinations simply respond better to indexed spark plugs than others. The idea of the exercise is to position the spark plugs so that the gap is facing the center of the cylinder or central point of combustion chamber firing area, angled slightly toward the position of exhaust valve.  (That’s the most common arrangement. Some combustion chambers tend to “like” other spark plug gap locations).  Why is this so important?  As the piston approaches top dead centre the ‘charge’ or air/fuel mixture is being compressed. The “mixture” is forced toward the area of the spark plug (and usually this would be towards the exhaust valve area). The true speed of this force inside the combustion chamber is extremely fast. Some experts feel that it surpasses supersonic speeds.  Because of this the spark from the spark plug, the plug should be in a ‘position” to create the best possible flame front. Bear in mind that the spark plug will always burn outwards and away from the electrode stem. Twin spark electrodes plugs are available for certain configurations although if indexed correctly conventional plugs may be the better option.

If you look at a typical side gap spark plug, you’ll note that the electrode can actually block the flame process. On the other hand, if the electrode gap faces the on-rushing air/fuel charge, it stands a much better chance of igniting a flame front thus creating or igniting an explosion from a more central point. In order to index the spark plug correctly, mark the plug insulator body with a black felt marker pen on the side where the ground electrode attaches to the spark plug body.
Instead of rummaging through boxes and boxes of spark plugs in an effort to locate the elusive combination of perfect spark plug threads that match the respective cylinder head threads, use aftermarket indexing copper or ally washers.  These soft malleable washers are available from Moroso and B & B Performance. Moroso kits are supplied with .060-inch, 080-inch and .100-inch thickness washers, while B & B kits feature .010-inch, .021-inch and .031-inch gaskets for tapered seat spark plugs and .064-inch gaskets for flat seat spark plugs.

Due to the soft nature of the copper or ally, along with varied washer thicknesses, it now becomes a simple matter to thread the spark plug into the respective cylinder and tighten it to the point that the index mark is situated in the correct position relative to the combustion chamber as described above.  Just be certain that you do not double up on the washers. They aren’t meant to be used in tandem and using more than one recesses the spark plug lessening it’s reach to the central point where it should be in order to give the best chance for ignition and burn an optimum flame.

• JOINT FLAME

Spark plug gaps should always be set with either a Champion plug gapping tool or a high quality feeler guage set.  Although it has been discontinued, one of the best plug gapping tools ever released to the public was the Accel plug gapping tool. If you ever have the opportunity to purchase one of these tools, do so without giving it a second thought; you may not get the chance again!  All spark plug gaps should be set according to the ignition manufacturer’s recommendations and specifications.  (For example, a MSD multiple spark ignition will easily fire a spark plug with a gap of .045 inches. With good quality wires and added spark plug wire insulation, gaps of .065 inch and greater can be fired.)  Naturally, there are some things you can do to your combination that will ‘pick it up’ or intensify it, (from a spark plug perspective). One such trick is a “clipped gap.”

If you are struggling with your “combination” and can’t quite turn the elimination times you thought were possible, consider cutting back the ground electrode on your spark plugs. But in this case, it doesn’t mean a mere file job, it means clipping the spark plug with a pair of wire cutters so that the ground electrode is flush with the side of the center electrode or shorter than the center electrode.  What this does is to increase and create a huge spark plug gap (something in the order of a couple hundred thousandths of an inch).

This technical tip only applies to engines fitted with high powered ignition control systems.  A normal point triggered affair would have trouble starting, let alone running with severely clipped spark plugs. Be “gentle” on the vehicle combination once you’ve clipped the spark plug. By this we mean that you should not drive the car to and through the drag strip staging lanes if possible. Once you fire it up, do your normal burnout stage and make your pass without ‘wasting’ the new set of clipped spark plugs. (They don’t last very long, so depending on your engines degree of performance, add on’s and the fuels you are using all come into account, etc, etc).

In some cases, the “clipped” electrode will pick up your combination as much as a tenth (but like indexed spark plugs, other examples show little improvement). Just be sure that the spark plug wires and the balance of the ignition system are in perfect operating condition. Why? The answer is very simple. The huge spark plug gap creates a mini-flame-thrower inside the combustion chamber. The spark plug wires will eventually self-destruct when this much gap is used, but remember, this is just a one-shot deal to make your elimination time, work out for you. If it doesn’t quite work out on your run, return to your pit lane and replace the plugs with a more conventional spark plug gap arrangement.  But if a one-shot performance is what you are looking for, this trick is one that just might help to turn up the magical elimination times to the number always hoped for. This can only be determined through trial and error, so don’t throw in the towel after a one hit run, it will need all the right combinations to suffice.

• HOT TO COLD TRANSFERS

Spark plug heat ranges and the terms ‘hotter’ and ‘colder’ are often confused on the part of an engine tuner or a general mechanic that isn’t really affay with building horsepower in the big numbers. The terms are actually used to determine the thermal characteristics (heat rating) of a given spark plug. This is the ability of a spark plug to transfer heat from the firing end to the cylinder head, which in turn transfers the heat into the engines water jacket and then into the radiator / cooling system.

Cold spark plugs transfer the generated heat very rapidly. This type of spark plug normally used in engines with a relatively high combustion chamber and cylinder head temperature (such as racing cars or highly modified street engines). Hot spark plugs transfer heat to the water jackets at a much slower rate keeping the heat in the combustion chamber so that deposits are properly burned away, preventing fouling. In a nutshell, hot plugs are used where combustion chamber temperatures are cool and visa versa.

• IGNITOR WIRES

It’s no secret that ignition wires which feature ‘spiral’ inner circles are the hot ticket to success. These ‘street wires’ not only do a brilliant job of suppressing radio noise interference, but they also have found a stable home in pro racing circles. There’s no question that boom-boom-box sound systems are low down on the priority list when it comes to drag racing and street rod applications, but one thing these all out street rods and race cars do have nowadays is sophisticated on-board electronic computerized systems. Systems like high ticket data gathering equipment (read: on board computer systems), intricate high performance ignition systems, ‘two-step’ rev limit modules and other up-market electronic hardware and software has now become mandatory in modified street cars and all out racing applications in today’s muscle cars.

Almost all of this electronic wizardry can be affected by the same radio frequency (RF) noise that drives the stereo system crazy in a streetcar. When one spark plug wire fires, it induces a voltage into the parallel wire. Using a typical Chevy V8 as an example, the firing order is 1-8-4-3-6-5-7-2. Cylinder 7 fires directly after cylinder 5 and both are situated side by side in the bank numbering system. This is very significant because as number 5 fires, number 7 is just starting the compression stroke. If number 5 and 7 are running parallel, or if they are routed together when number 5 fires, it will induce a certain amount of voltage into the number 7 wire. With the fuel charge already in number 7 (along with a sufficient amount of compression), it fires easily. Chevrolet’s aren’t the only engines plagued with this side-by-side arrangement. As you can easily see, this very advanced and equally unplanned timing can quickly result in misfiring causing serious problems-not the least of which is outright cylinder wall failure. There are solutions to the problems faced and always ways to get around this.

• WIRED OVER SLEEVES

You’ve probably heard about ignition wire sleeves, but how do they work? As spark plug gaps increase and ignition power becomes stronger, the chance of spark leakage through the wire increases. High powered ignition control boxes have become the norm rather than the exception and because of this, almost all wires are susceptible and exposed to high voltage leakage and of course the problem of cross fire. Moroso, MSD and other companies offer ‘spark plug wire sleeve’ packages that can curb the problems that arise. Similar in concept, the sleeves generally consist of closely woven fiberglass ‘tube’, or a sleeve, which is sometimes, covered with a high voltage resistant silicon material. What’s the added wire protection worth? According to the guys at Moroso the sleeve adds 850 volts of extra insulation, almost double that figure in cross wire ‘insurance’, and a profound resistance to heat created by those hot close-up all out race headers that usually get tucked into the most impossible places imaginable. The guys that design and manufacture these tightly fitted spaghetti pipes are to be admired for the work they do. Some of these applications are made to clear obstacles unimaginable, and they do it day in and day out.

Virtually all sleeves slide over the ignition wire. As expected, one end of the wire has to be sans terminal and boot, which are then installed after the sleeve and associated shrink sleeves are slipped over the wire. Existing wire sets can be protected via the sleeve material, but you’ll have to remove and install the wire terminals and associated boots. The various wire sleeves don’t fit tightly over the wire-especially at the boot. Given this fact, a system of sealing the sleeve to the boot is usually incorporated. Moroso and MSD offer a special ‘shrink sleeve’ to totally seal the wire sleeve to the respective dizzy and plug boots. The shrink material fits part way over the boot and extends part way over the sleeve, sealing the actual wire sleeve to the boot. In order to make the seal, the material is physically ‘shrunk’ via a heat gun or naked flame. (Care should be exercised when using one of those open flame throwers for obvious reasons, so try and find a heat gun somewhere for the task at hand).

• THE ROMAN CANDLE

If you are looking to running low times at any ¼ mile run or just out on a Saturday night you need to ignite the cables with the best possible distribution of current. There are a number of different rotors on the market place. We highly recommend a MSD alkyd rotor or an Accel equivalent. These rotors (with alkyd construction) have a higher resistance to carbon tracking than the OEM part or jobber components. Also, the MSD and Accel rotors have much larger arc ribs surrounding the rotor blade and adjacent to the rotor screw holes. Other features include riveted brass blades, which are longer than some emission-style replacements, stainless steel spring construction and large, riveted contact buttons. In addition, we advocate the installation of nylon rotor screws in Delco-type distributors.

These rotor set up’s prevent sparks from arcing across the rotor creating simple insurance that the distributor’s spark will be correctly routed while spinning around delivering spark at the precise moment. Accel and MSD offer superior quality, performance-oriented dizzy caps. Constructed of an alkyd material, the caps are very resistant to carbon tracking and offer improved performance over a conventional assembly.  Further to this, MSD manufactures a special set of components called “Power Towers” that snap into the cap assembly.  These parts convert the cap to a spark plug style of wire retention.  This enables you to use large diameter 8mm plug leads in a cap that is normally jam-packed with smaller 7mm plug leads.  To add to this, the Power Towers provide for a more secure method of retaining the plug leads. In a nutshell, they will not fall out at will.  Another relatively new cap concept is the MSD “Cap-A-Dapt” system.  What it provides is positive wire retention (again with spark plug-type clips), extra wide post spacing and three-piece construction, which facilitate rotor phasing. Always check out what’s new and then ‘see’ if it’s going to work for your particular application.

• AC/DC

High powered ignition systems add loads on the battery as well as the charging system.  When you increase the demand upon the battery, it should be capable of handling the load. Batteries are rated by capacity. This is the amount of electrical current or amps a battery can supply for a specific amount of time.  The “generally accepted” rating system is the “Cold Cranking Amps” (CCA) method.

The CCA determines the battery’s capability of delivering current (amps) under cold conditions. This rating will generally range from 250 to 800 amps, but keep in mind that many (if not all) CCA ratings are rather optimistic. To combat the factory rating game, compare the “Reserve Capacity” (RC) ratings of the batteries in question.
This rating determines how long the ignition and other electrical components can be operated by the battery alone (without the generator functioning).  The RC rating is defined as the length of time (minutes) that a fully charged battery can deliver 25 amps of power at 80°F (maintaining 10.5 volts).

In other words, the higher the RC, the better the battery.  Thanks to the guys at MSD, there is a formula, which can be used to easily convert the RC rating into the “old” (you can read that as “useful”) battery AH rating number.  The AH figured determines the number of amps a battery can deliver for one hour.  The following is the MSD equation:

25 amps x reserve capacity (minutes) = AH
60

Using the above formula, if the battery reserve capacity is 30 minutes, the AH capacity is as follows:

25 amps x 30 = 12.5 AH
60

Translated, this simply means that the battery can supply 12.5 amps of power for one hour.  MSD states that ignition operating time decreases as engine rpm increases.  The smallest dedicated battery for use on a MSD 6- or 7- series ignition system is a 12 AH unit.  There’s no question that today’s crop of performance cars are becoming evermore sophisticated.  Large capacity electric fuel pumps, electric water pumps, electric fans, high powered sound systems, and even small things like gauge lamps and other hardware sap power and AH from the battery.

You have to consider and first determine how many amps (AH) each of the electrical “accessory” components continuously draws from the battery.  As an example, you might be surprised to find that one of the large “professional-style” billet fuel pumps can draw 8 AH or more.  Next, add up the total AH draw.  Using the following chart from MSD, you can then determine the total AH draw of a typical high powered ignition system at a specific engine rpm.

IGNITION AMP USE
RPM (V8 engine)                       MSD 6 & 7 Series
3000…………………………………………………………………3
4000…………………………………………………………………4
5000…………………………………………………………………5
6000…………………………………………………………………6
7000…………………………………………………………………7
8000…………………………………………………………………8

Imagine that you have one of the big 8-amp electrical fuel pumps in your car.  In addition, you have an electric water pump drive that draws five amps on a continuous basis.  Your other accessories draw a total of five more amps.  Finally, you engine sees a maximum rpm ceiling of 8000.  The addition is rather easy:

- Electric fuel pump: 8 amps
- Electric water pump drive: 5 amps
- Other accessories: 5 amps
Ignition requirements: 8 amps
Total: 26 amps

Next, multiply the total electrical requirements by the duration of time it must operate without the alternator functioning (i.e.: sitting at the local burger joint listening to the stereo).  Multiply the amp requirements by the time:

26 amps x half-hour = 13 amps

Now, the final step in the equation starting the car.  If your car has an on-board starter (and virtually all street cards do), multiply the final amp requirement figure by a factor of three:

13 amps x 3 = 39 amps
The final 39-amp number is the size of the battery required for the application.  Using the very first equation, which showed how to convert RC to AH, you can then go shopping for a battery (or a pair of batteries).