IronFist

iTrader: (3)

I hear this talked about all the time. What does it mean? Retarding vs. advancing timing... timing of what?

Thanks,

IronFist

Nuts

iTrader: (1)

ignition timing.

Nuts

iTrader: (1)

Advancing the ignition timing is an inexpensive (free) modification that can make a noticeable difference in throttle response and through the entire powerband with the largest gains in the midrange, around 5500 rpm. Fuel economy is also improved if your driving habits remain the same with the additional power. Adjusting the timing can produce gains of up to 5 hp at the wheels. The amount of gain, you can expect depends on where the timing is currently set now. If it is too low you will feel a larger SOTP difference. Timing advance helps produce more power by igniting the sparks sooner, providing more time for the fuel/air mixture to burn completely, increasing cylinder pressure, thus providing more power.

hope that helps

Bartkat

Ignition timing relates to when the spark plug fires in relation to where the piston is at that poit in the cycle.

"The timing of the spark is important, and the timing can either be advanced or retarded depending on conditions.

The time that the fuel takes to burn is roughly constant. But the speed of the pistons increases as the engine speed increases. This means that the faster the engine goes, the earlier the spark has to occur. This is called spark advance: The faster the engine speed, the more advance is required. "



How Automobile Ignition Systems Work

IronFist

iTrader: (3)

Thanks...

If it's free, how does one do it?

And how do you know what the best setting for your car is?

IronFist

Nuts

iTrader: (1)

What is the Ignition System?

Your ignition system is the part of your vehicle/engine that fires, or ignites, the compressed fuel and air mixture within your engine. The system combines a primary voltage delivery to the ignition coil and electronic control units and secondary voltage released from the coil travels through the distributor, out through the plug wires, to the spark plugs where it jumps the gap and ignites the mixture.


Your ignition system consists of supply voltage (in most cases a 12-volt battery), an on/off switch (your ignition switch), a spinning distributor (or crank trigger) that houses a triggering device, an ignition coil to deliver 20,000-50,000 volts of secondary voltage, spark plugs, and spark plug wires to get the current to the plugs.



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How the Ignition System Works?

Your electrical system (typically a 12-Volt battery) gives supply voltage to your coil and ignition unit (if electronic). When the coil is told by the trigger in the distributor (contact points, electronic module, magnetic breakerless, Mallory Unilite®, Crank Trigger, or other type of trigger) to release voltage, the coil builds secondary voltage and releases it to travel through the coil output wire. It does this at a very high rate of recovery speed.

The spark then travels into the distributor cap into the spinning rotor and out the corresponding terminal in the distributor cap that the rotor is aimed at and then through the spark plug wire to the spark plug. It is now the gap in the spark plug that creates the actual spark in the combustion chamber when the secondary electrical voltage now must jump the spark plug gap to "ground". It is the "jump" that is the spark that ignites the compressed air/fuel mixture.

That's the easy part!

The trick to the ignition system is in when the spark actually occurs at the spark plug. This is the ignition TIMING. Timing is controlled by the relationship of the position of the piston to when the spark occurs. If the ignition spark occurs too soon it can actually push against a piston traveling up the cylinder as it is compressing the fuel/air mixture. This causes detonation, lost power, much higher combustion temperatures, backfires out the carburetor, and early internal engine part failures. If the spark occurs too late, the ignition of your fuel mixture occurs after the piston is traveling back down the cylinder. This is wasted energy, unburned fuel, high emissions, and lost power.

How do you control the timing you ask? Well, late model cars use computers that monitor engine load, piston position, incoming air quality and temperature, engine RPM, and more. The computer then tells the ignition system what the engine needs based upon those inputs from the sensors and a pre-determined MAP within the computers' programming. On older OEM engines, and most race cars with aftermarket distributors, the ignition system used a simple mechanical advance (or a combination of mechanical and vacuum advance) system built into the distributor. You would set "initial" idle timing with a timing light looking at the balancer mark and timing tab indicator. As RPM increases, the mechanical advance (weights and springs) moves due to the inertia occurring within the distributor, thereby changing the timing causing the point that the spark plug receives voltage to also change in relation to piston location. You can tune your timing curve (shown later on this page) for your engine's optimum performance curve by changing initial, mechanical as well as vacuum advance settings and parameters.

See Breakdown of Mechanical Advance Distributor

What this means is that if you have your initial timing setting at 10° advanced, your ignition is firing that cylinder at ten degrees "before" top dead center (BTDC). TDC is where the piston is at it's highest point in the cylinder. As engine RPM increases there is less time to be able to fire the cylinder. The parts are moving faster so you must get the spark in there sooner, but not too soon that it will cause detonation or engine damage.

Say for example that you have that 10° initial timing and then you have mechanical advance of 24°. This means you have a "Total" timing of 34°.

10 + 24 = 34


Now, that 34° does not happen all at once ... the "Timing Curve" is the staging of advances, or increases, in your timing. Remember, as the RPM increases it puts inertia against the weights and springs that move in the distributor causing this added timing. All of these values are adjustable by changing initial settings, the weights that control the MAX advance, as well as the spring pressures that control the RATE (or speed) of advance..

Now, when adding vacuum advance to the equation you would have the total (34 degrees) PLUS the additional vacuum advance. On a street application, adding 8-10 degrees is plenty. But, each individual application will vary slightly.



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What Tools Do I Need to be Able To Work On My Ignition System?

The tools you need to work on your ignition system are not too complicated. Read the listing and the descriptions below.

Basic Hand Tools: This includes screwdrivers, box end wrenches, socket set (usually 3/8" drive) and possibly in metric for newer applications, and in standard for older vehicles.

Timing Light: OK, before you freak out I'll tell you up front .. "This is the 21st Century, you need tools that are correct for the time and technology available". What this means is that you need an ADVANCE TIMING LIGHT. This is a timing light that is adjustable so that you do not have to shoot the high numbers on your timing tab (over zero) or fully degree your balancer to be accurate, as well as view, high RPM timing readings. You adjust the timing light to always read "Zero" on the balancer/timing tab. You will adjust the light to read zero at a given RPM and then read "the light" to give you the actual timing. If this is confusing, oh well, buy one and read the directions! Expect to ante up a BIG dent in the checking account for an accurate and reliable advance timing light ... the computerized Snap-On® advance timing light (at right) is the one I use and it costs nearly $400.00. You can also order a generic low-priced advance timing light from Harbor Freight Tools for about $40.00.

To you "older folk", this is like a hand-held replacement of a "no longer made" Sun Distributor Machine. You can do everything the distributor machine did, but with the engine in the car. A bit more strenuous, but less $$$ than the big machine and easier to carry around.

Digital Multi-Meter/Ohm Meter: Yes, this can be "expensive item #2" if you want the quality of a Fluke (brand name) Digital Multi-Meter (DMM). I will not bother to scare you with the pricing, only to say you will be up into 4-digits! If you work on late model vehicles, this tool is more useful and used more often than a screwdriver.

You use the DMM to measure voltages at all sources on a vehicle, measure resistance, electronic pulse widths, troubleshoot power spikes, and more. This tool is definitely a required friend if you want to take the time to learn and use it's features and time saving benefits it gives you.

Tests include: Plug wire resistance with the Ohm Meter, primary and secondary coil tests, voltage spikes, Battery voltage, charging voltage, amperage draw, dwell (if you use contact points ... hehehe, excuse me as I laugh at Model "A" technology), temperature readings, electrical shorts, battery drains, and even more tests if your vehicle is computer-controlled.

Vacuum Gauge: I will not describe it's benefits here, but it is a mandatory tool for anyone's tool box. More info on Vacuum Gauge Tuning is HERE. I will not describe it's benefits here, but it is a mandatory tool for anyone's tool box. More info on Vacuum Gauge Tuning is HERE. I will not describe it's benefits here, but it is a mandatory tool for anyone's tool box. More info on Vacuum Gauge Tuning is HERE. I will not describe it's benefits here, but it is a mandatory tool for anyone's tool box. More info on Vacuum Gauge Tuning is HERE.

Specialty Tools: Specialty tools are any tool that is optimized for working on a vehicle's ignition system. Specialty tools are any tool that is optimized for working on a vehicle's ignition system. Specialty tools are any tool that is optimized for working on a vehicle's ignition system. Specialty tools are any tool that is optimized for working on a vehicle's ignition system.

These include:

Specialty wrenches designed for distributor hold down bolt tightening and removal.
Plug wire "puller pliers" to prevent boot damage when removing the plug wires from the spark plugs.
Spark Plug "Starters" that are basically a piece of flexible rubber tubing the goes over top of plug to ease plug installation into the cylinder head.
Spark Plug Gapping Tool ... you get what you pay for and the feeler wire (or gauge) method is not the accurate or fast way.
Spark Plug Wire assembly tools (stripper, crimper, etc).
Other Possible Tool Requirements Include:

Tools for finding TDC (Top Dead Center), usually part of a camshaft degree kit.
4 or 5-Gas Analyzer. Yes, this is a smog machine ... most of you will not be able to get one or afford it, though this machine is a definite helper for finding optimum timing settings based upon exhaust gas emissions. I will not describe the procedure here, but it works! If you have a friend that has a shop and he or she offers you access to it, it can be an invaluable tuning device.
Shop manuals as well as ignition product documentation. This is good for stock as well as performance ignition product applications.
back to top


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What is Initial Timing and Total Timing?

Initial timing is that setting you make while your engine is idling with a timing light. This is typically between 4° ATDC (After Top Dead Center) to 16° BTDC (Before Top Dead Center). For performance applications "in most cases" you want as much initial timing as the starter can handle (the more timing the more cylinder pressure that the starter must overcome to crank the engine). Too much initial timing, besides the starter load, can also run the HC (Hydrocarbon) emission levels beyond legal or breathable levels <hint to the smog machine as a tuning tool above>.

Total timing is the calculation of the combined initial and mechanical advance timing settings (max). This "can" also include your vacuum advance though, I like to describe it as "total timing plus vacuum advance". Since vacuum advance is a nearly inconsistent value I like to use it after I have set up the correct mechanical values in the distributor. At times I must use the vacuum advance to generate the timing values I require, but I try to only use it as an "economy" tool to give a street driven vehicle more efficiency and throttle response by this addition.



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What is a Timing Curve?

The timing curve is the mechanical timing values plotted over an RPM curve. What this means is that at a given RPM based upon the weights and springs used in the distributor you will have a specified amount of timing advance. Remember, as your engine RPM increases, so does the inertia against the distributor weights within the distributor. The springs holding the weights is the opposite resistance force that controls the speed, or rate, that the weights move "out" causing the distributor advance plate to move which advances the timing. So, what happens is that at each RPM change there is a variance in the amount of timing advance up to a point in which the weights usually hit a "stop" that does not allow them to move out (advance the distributor) beyond that point.

Changing the springs to a lighter one (or both) will make the advance occur faster, and of course running a heavier (stronger) spring will slow the advance rate. You can also in most cases modify the weights (or stops) as to what the advance limit will be. Mixing springs to control the desired advance rate is how you modify your timing curve.


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How Do I Change the Mechanical and Vacuum Advance Settings?

Mechanical advance (also called centrifugal advance) as stated above, is adjusted by change the springs that control the weights and in many distributors you can also adjust or modify the advance "stop point". The stop point is where the mechanical advance no longer continues. On a Mallory distributor there is a wrench you use to adjust the stop point (in degrees). On other OEM and aftermarket distributors you need to change the weights by going to a different weight or modifying the weights to control the stop position.

This is a job that can be done by just about anyone, but it takes the correct tools and some trial and error. In most all cases, aftermarket distributors are good for your engine right out of the box, but when change needs to be made you will need assorted springs, a distributor machine, fully degreed balancer, or an advance style timing light.

You start the engine and write down each timing number at 100, or 500 RPM intervals. This means you write down the timing at idle, then raise the engine speed in 100 or 500 RPM increments (whatever you decide), and write down each one of the timing readings. To make the rate faster (more timing advance sooner), you install lighter combination of springs. To make the rate slower (less timing advance), you install a combination of stiffer springs. NOTE: Too much timing too soon can cause detonation problems, having the timing come on too slow can adversely affect performance and efficiency.

With adjusting the vacuum advance it is on the same principle, except you are now adjusting the pressure on the diaphragm in the vacuum advance can. NOTE: Only those vacuum cans with the octagon body near the nipple can be adjusted. If you are working with an OEM style distributor you must either change to an adjustable can or change cans to one with a different rating. (Most ALL aftermarket vacuum advance distributors are adjustable) On the adjustable vacuum advance cans you simply insert a 3/32" Allen Wrench in through the vacuum line nipple on the can. Turning the Allen Wrench one way or the other will add or subtract the preload pressure on the vacuum diaphragm. Lower pressure offers more vacuum advance, higher pressure lowers the amount of added vacuum.

It is our recommendation that when you are using vacuum advance distributors, that you connect the vacuum advance to "full manifold vacuum". There are two schools on where to connect the vacuum advance line. On older applications the connection point was to "ported" vacuum. Ported vacuum means the port is drawing vacuum "above" the throttle blades in the carburetor. This means that as RPM increases, vacuum increases and in turn, vacuum advance increases. This was fine on older applications with high lead fuel and other ancient engine designs. Using this set up today can cause detonation problems, overheating, and other grief.

With our suggestion of using the vacuum connection to full manifold vacuum, the port will be drawing vacuum below the throttle blades. A good running street engine will have a measured vacuum at idle between 14"-20" of manifold vacuum. Now, this will give you a ton of advance at idle, but as load increases (vacuum drops) you will take timing away. This is excellent for the faster burning fuels offered today as well as in the fact that when you put your foot into the throttle and get the RPM building, you DO NOT need or want additional timing. On a RV or tow vehicle, when you put your foot into the throttle and downshift to climb a grade, you DO NOT want added timing that will slow the vehicle and add heat. You want the added timing for subtle throttle response, and low load engine efficiency. So, when you are cruising at freeway speeds or in town traffic, you have the added timing to save fuel, add throttle response, and overall give you a better feel.



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What Modifications Can Be Done to Improve My Ignition System?

One of the common early modifications to increase the performance or your vehicle is to upgrade the ignition system.

Here's The Secrets That Most Ignition Manufacturers and Speed Shops DO NOT Tell You:

UNLESS your vehicle is also getting performance improvements that increase either the amount of fuel your engine will be using (camshafts, cylinder heads or porting, superchargers, turbochargers, nitrous, and other modifications along these lines) or the demand for higher RPM, You SHOULD NOT get a substantial performance or horsepower improvement from an aftermarket ignition. On a stock engine you should really not see an improvement.

NOTE: Of course, if you are using a prehistoric contact point (yes, dual points too) ignition system or have an engine tune-up that is not where it should be (too much fuel from poor jetting or a bad carburetor, too much plug gap, worn ignition components or just an engine that is getting tired), you will see an increase in performance because of basically a "Band-Aid" with the better ignition components to hide obvious other problems.

Now, if you do not fall into the categories above because some idiot behind a counter (or on the phone at the "sell a gazillion mail-order parts" outlets) tried to sell you something you did not need, let's get into really upgrading your ignition.

Of course, there are a few myths of what your ignition system can do. We all see the advertised "Power Output Levels" that many ignition manufacturers use to build interest in their products. Do you feel the fish hook locking through your lip with the words "sucker" on your forehead? Yes, it's true ... many ignition manufacturers will tell you whatever it takes for them to get you to believe that their ignition is the best. One of the good ones is advertised coil output and also aftermarket Ignition Unit output (usually an Inductive Electronic or CD "Capacitive Discharge" Unit). What people tell you is that you MUST have the highest output ignition unit because it's the best. Do you believe this? If so, read the Italic text above in this paragraph.

What really happens is that your engine (each cylinder) will ONLY use the amount of voltage it takes to jump the spark plug gap and fire the air/fuel mixture in that cylinder. Guess what I'm going to tell you now? If you guessed that I will tell you, "Your engine requires a lot less spark than what is advertised", then you are right. Yes, it's true ... even if you have a Gazillion Millijoules of advertised output, if your engine only needs 20,000 volts to jump the plug gap, that's all the unit will give. What they should tell you is that the unit "can" deliver up to that rating if the engine demands it. So, does your engine really demand that much voltage output ... probably not.

Want another misnomer? Well, this one is on multi-strike ignition systems. Well, you probably may not have guessed it, but the analog multi-strike has less time as engine RPM increases to get off as many sparks. Do these extra sparks help your engine? Not really, the major concern is the actual spark duration in "Crank Degrees" that you have for each spark on each cycle. Most aftermarket ignition manufacturers give you 20° of spark duration with each spark. Now, this spark will not carry full voltage over the entire 20° . As the spark duration continues it loses voltage output. The reason behind the longer spark is to make sure there is a complete and thorough burn of the air fuel mixture. With high dome pistons, tight valve shrouding and other issues, you can get portions of your mixture that do not get a decent ignition. By holding the spark up to 20° of crankshaft duration you virtually eliminate these problems (if your engine is in proper tune). Having a greater voltage hold over the entire 20° should be more of a concern to you than peak voltage output.

OK, now the parts:

Ignition Coils, Electronic or Magnetic Trigger Distributors, Performance Wire Sets, Inductive Electronic or Capacitive Discharge (CD) Ignition Units, Electronic Timing Controls and Retards are the most common ignition upgrades.

The ignition coil is the workhorse of the ignition system and must be the first upgrade you consider. OEM or coils not designed for your application can overheat, cause mis-fires, boil over (possibility of causing a vehicle fire) and otherwise just cause you grief. You must have a coil designed for electronic ignition if that is what you are using. Also, there are a few coils on the market that are for "Limited Use Racing" as in Drag Racing or short term use. These coils are designed to give Maximum Output, but cannot safely do it for extended periods. You should not use coils with this designation on the street or in circle track applications.

Electronic or Magnetic Trigger distributors are "only" your triggering device. A performance distributor gives you better control of timing curves and triggering accuracy. In some of the later model computer-controlled engines, a performance distributor is not available as well as not required. Technology has increased to a point that on many late model applications your distributor is perfect the way it is. If you have a computer-controlled distributor there is NO mechanical advance in it. These distributors will only work on computer-controlled applications.

Performance Wire Sets are still argued about and hopefully I can clear this mess up. One of the biggest arguments is on solid core wires Vs. spiral core (or suppression) wire sets. If you have anything that is electronic on your vehicle (computer, ignition unit, triggering module, radios, etc) You MUST Use spiral core wire sets. There is not much gain going to solid core wires unless you are using a Magneto, and many racers are still using a spiral core wire with their magnetos because of the computerized vehicle controls and monitors that are in use. With the low resistance of the spiral core wires it is ridiculous to take a chance using a solid core wire and damaging another component on your vehicle.
How do you damage electronic parts with just a set of plug wires you ask? I knew you would ask. Well, have you ever heard of EMI (Electro Magnetic Interference) or RFI (Radio Frequency Interference)? Either or both of these are generated by your ignition system and when running a solid core wire it is like leaving your front door of your house open with a neon sign saying "Rob and Rape Me, Come on In!" You are leaving your electronic parts on your car wide open for damage from EMI and RFI that is released from the wires at each spark cycle. More info is in the Spark Plug article.
Performance Ignition Units are a great upgrade if you are "really" upgrading your engine and vehicle combination or put your vehicle through driving styles that could use some ignition help (racing, towing, off-road, harsh climates ... "like you do not believe in tune-ups"). An electronic or capacitive discharge ignition will help your engine burn more fuel as well as give your engine the ability to safely reach higher RPMs (than it is designed to do so). The added output that the ignition unit tells the coil to give out will really help your engine survive longer, make more power, as well as lower emissions, and be consistent in winning races. You can gain in performance with an aftermarket ignition control in efficiency, faster starting, smoother performance, higher RPM, and lower emissions.

Electronic Timing Controls and Retards serve as an added feature to making sure that the timing curve is "exactly" what your engine demands to make maximum horsepower and torque and prevent engine damage when using high power engine upgrades such as nitrous, superchargers, etc. Electronic timing controls in many cases give you full computerized programming capabilities of your timing curve, eliminating the sometimes binding and inaccurate mechanical advance controls. The timing retards allow you to select degrees of retard based upon your engine demands. From a high speed retard (your engine needs a bit less timing in many instances in racing applications at high RPM or top gear), to retarding the timing based upon the amount of boost from superchargers to the use of selected retard settings upon activating a nitrous system. This retard also works well l as based upon exceeding normal engine loads or fuel quality in street use towing applications to eliminate engine damage from detonation and other occurrences.



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What Are Timing Retards and Controls?

Timing controls and retards are just what their name implies. A timing retard is an electronic device that retards the timing at a specific or controlled RPM, or event (such as a gear change, or nitrous activation). A timing control is typically an electronic device that controls the timing curve or rate of timing at a given RPM, but it can also be an ignition amplifier.

Some of these devices are controlled by resistors (chips), others are controlled by computer electronics, and some are manually controlled by the simple turn of a dial by the driver.

<font color=white style="background-color: 3E3E3E;">What is the Ignition System?</font ft>

Nuts

iTrader: (1)

and thats my ignition timing FAQ.[IMG]i/expressions/laugh2.gif[/IMG]

macH

iTrader: (5)

nice job...but i think you have too much time on your hands man

IronFist

iTrader: (3)

Whoa! That's the kind of reply I like! I'll read it all and then come back with questions tomorrow [IMG]i/expressions/face-icon-small-smile.gif[/IMG]

IronFist

Nuts

iTrader: (1)

yes i do
[IMG]i/expressions/laugh2.gif[/IMG]. i can't do anything for 3 days with my broken jaw and stuff so i just chill on the net making something for myself to do.

IronFist

iTrader: (3)

btw, I don't think you typed that, I think you cut and pasted it. Because in the Vacuum gauge part you forgot to include the hyperlink that should be there [IMG]i/expressions/face-icon-small-smile.gif[/IMG]

IronFist

Nuts

iTrader: (1)

yes it is copyed and pasted from some different sites. you think i'm gonna type that . hellllla no...[IMG]i/expressions/laugh2.gif[/IMG]

hell i'll shorten all that B.S, ---go get it DYNO tuned from a shop.

kjgracing

iTrader: (3)

Yeah...the information doesn't even really pertain to our civics.
We don't have distribitors, we don't even have spark plug wires.
That is why there is no DIS IGNITION from MSD or from Jacobs Electronics.

You have to use JET PERFOMANCE V-Force or Apexi S-VAC or greddy,
or have your ECU re-programmed with the mods.

JET PERFORMANCE advances the ignition timing 5 degrees. That is
a little grey area about running N2O on that. Better with the timing
at OEM specs or retarded up to 2 degrees.

Boosted2k2

iTrader: (3)

I saw that exact same thing on Centuryperformance.com mister Nuts. You're in BIG trouble![IMG]i/expressions/laugh2.gif[/IMG]