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 Post subject: High Energy Ignition Systems Jacobs MSD Mallory
PostPosted: Sat Nov 29, 2008 10:47 pm 
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When talking about high energy systems there are a few basic concepts that need to be understood so it all makes sense.

First, the voltage required to jump the spark plug gap is primarily determined by the number of molecules of fuel mixture between the spark plug electrodes. If you widen the spark plug gap there will be more molecules of fuel mixture between the electrodes and it will require a higher voltage to jump the spark plug gap.

If you increase the fuel mixture density there will be more molecules of fuel mixture between the electrode and it will require a high voltage to jump the spark plug gap. Increasing the compression ratio, turbocharging, or otherwise increasing the volumetric efficiency will increase the fuel mixture density and increase the voltage required to jump the spark plug gap.

Using less restrictive air cleaners, larger carbs, head porting, larger valves, and a freer flowing exhaust system will all increase the volumetric efficiency and increase the fuel mixture density, which will raise the voltage required to jump the spark plug gap.

Retarding the spark timing closer to TDC increases the cylinder pressure and fuel mixture density and requires a higher voltage to jump the spark plug gap. Using a hotter heat range spark plug increases temperature inside the spark plug gap and lowers the density of the fuel mixture inside the spark plug gap and lowers the voltage required to jump the spark plug gap.

Sharp electrode edges reduce the voltage required to jump the spark plug gap. When spark plug electrodes become worn and rounded, it requires more voltage to jump the spark plug gap, which is why your engine may begin to miss when the spark plug electrodes become worn and rounded.

Within a limited range, richer fuel mixtures are easier to ignite. However the richer fuel mixtures are not optimum for combustion. With a weak ignition system, some people richen their fuel mixtures to reduce missing, when in fact they should have either reduced the size of the spark plug gap, or better still improved the ignition system. Once the mixture becomes too rich, it becomes more difficult to ignite.

The conclusion is that nearly anything that you to to improve the performance of your engine will increase the voltage required to jump the spark plug gap, which either requires an improved ignition system capable of delivering higher voltage, or you must REDUCE your spark plug gap.

Wider spark plug gaps with a high energy ignition system will improve the performance and gas mileage of ANY engine. Improving your ignition system is the one modification that you can do that doesn't have any serious tradeoffs like most other performance improvements have.

Spark timing and ignition timing are not the same. There is a lag time between when the spark is applied and when the fuel has been ignited to the point that the ignition system no longer has any control over the burn. The amount of lag time varies with different engine conditions and CANNOT be compensated for. The result is that under some engine conditions your ignition timing will be ideal, but under all other engine conditions your timing will be retarded from optimum and your performance and fuel mileage will suffer as a result.

However, you can BYPASS much of this ignition lag time by using a high energy ignition system with wider spark plug gaps. The result is that your ignition timing will be closer to ideal under all engine conditions, and your horsepower and gas mileage will improve at all throttle positions.

Using a weak stock ignition system is like using a single match in the wind to try to light kindling on fire. You can't predict how long it will take, or even if you will be able to get the kindling lit.

Using a wider spark plug gap is like using 3 matches at once. You expose more of the kindling to the flame at one time and are more likely to light the kindling and light it faster.

Using a high energy ignition system is like using 3 propane torches to light the kindling. Not only are you assured to ignite the fuel mixture, but you will ignite it much faster.

There is no downside to using a higher energy ignition system. It gives you both improved perfomance and fuel mileage. By reducing or eliminating missing, there is no raw fuel to wash down the cylinder walls and contaminate your oil. Your piston rings will last longer. Your engine will run more smoothly which will also reduce bearing wear.

Of course there are real world limitations on ignition systems. The spark plug will have a maximum voltage limitation. There will be a limitation on the largest spark plug gap that you can have before the spark jumps to the spark plug body instead of the outer electrode.

The ignition wires will have a voltage limitation. However thicker insulation may be used to withstand a higher voltage. Good quality ignition wire is not the weakest link.

The spacings between the distributor cap terminals and between the distributor cap terminals and the distributor body will determine the maximum voltage that you can use. The voltage at the spark plugs can be affected by many factors as previously outlined. The practical method of limiting the voltage inside the distributor to a safe level is by adjusting the size of the spark plug gap so that the spark plug fires before the voltage arcs to the wrong terminal inside the distributor cap or to the distributor body.

The ultimate ignition system would consist of a distributorless ignition system with a separate ignition coil for each spark plug and and a high energy ignition system capable of driving the ignition coils. But that's another discussion.

There are two basic types of high energy ignition systems that we are concerned with. First there is the inductive switcher. It operates in similar manner to the conventional Kettering ignition system. A transistor inside the ignition system conducts current to the ignition coil just like ignition points do. However, it has the capability of adjusting the dwell time of the ignition coil to maintain the output voltage as the RPM increases. The stock Kettering ignition system will continue to lose output voltage as the RPM increases.

The second type of high energy ignition system is a capacitive discharge ignition system. This ignition system boosts the +12 VDC to over 400 VDC and stores the charge in a capacitor. Then at the appropriate time the capacitor is switched to the ignition coil and the energy stored inside the capacitor is transferred to the ignition coil which produces the high voltage for the spark plug.

Inductive switchers have longer duration sparks which work very well at lower RPM and are claimed to help the engine run more smoothly at lower RPM.

Capacitive discharge ignition systems have shorter duration but higher current sparks. They are claimed to run better at higher RPM but not as smoothly at lower RPM. The higher current spark is better able to fire spark plugs during fouling conditions such as flooding and over rich conditions. Capacitive discharge ignition systems often make up for the shorter duration sparks by using multiple sparks.

Also extremely important is the ignition coil design. For maximum performance you should use an ignition coil with an air gapped core without any extra ballast resistance.

The air gapped core will vary the spark energy as the spark plug needs it, and will deliver more current during fouling conditions to keep the spark plugs running clean.

I measured a voltage loss of 16% when I added a ballast resistor to a Jacobs ignition coil to equal the 3.0 ohms that a Bosch Blue coil has, when used with a capacitive discharge ignition system. Most high energy ignition systems internally limit the ignition coil current to a safe level so a ballast resistor is usually not required.

The terminal spacing inside the distributor caps, of most distributors available for air cooled VWs, is the weakest link in the ignition system. Most high energy inductive switching and capacitive discharge ignition systems are capable of outputting more voltage than the distributor caps can handle.

A small Bosch distributor cap can only handle a maximum of about 28,000 volts before crossfiring or arcing to the distributor body occurs. The small cap Mallory distributor can handle about 32,500 volts before crossfiring occurs, which is about 16% more voltage than the Bosch distributor caps. The Pertronix and MSD distributor caps appear to be similar to the Mallory in size and are not likely to handle much more voltage.

Left: Bosch small cap . . . . . . . . . . . Middle Mallory Comp 9000 . . . . . . . . . . . . Right: Mallory small cap
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Mallory Comp 9000 modified for VW
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They only distributor that can handle the voltage that most of the high energy ignition systems are capable of outputting is the Mallory Comp 9000, which must be modified to fit a VW engine. It will not fit a Type 3 or stock Type 4 engine, or engine with the 911 style fan shroud. It may fit an upright type 4 conversion. The Comp 9000 will fit with the stock mechanical fuel pump. With the Comp 9000 distributor and a high energy ignition system, there is not likely to be a significant improvement in spark quality using the available distributorless ignition systems.

As the rest of the world phases in distributorless ignition systems, people are selling their high energy ignition systems rather cheaply and great deals can be had. With the exception of a person that wants to maintain a period correct VW, there really isn't a good reason not to use a high energy ignition system.

A high energy ignition system draws so little current through the distributor points that pitting of the points no longer occurs. The rubbing block will probably wear out before the contacts do. Only periodic adjustment will be required to compensate for rubbing block wear. The gap in the points may also be reduced to increase the higher RPM capability.

Also required is a non-resistor rotor as a high energy ignition system will burn it out.

Non-resistor spark copper core plugs should be used for best performance. Fine wire platinum and iridium only improve weak ignition systems, as they will fire at a lower voltage. However, there will also be less power in the spark than with a copper core spark plug.

Low loss spiral wound magnetic suppression ignition wires should be used. The OEM ignition wires and resistor rotor will cause the voltage inside the distributor cap to be higher and force you to use a smaller spark plug gap. Between the OEM stock ignition wires with the resistor ends and the resistor rotor, there is enough voltage loss, that by switching to low loss ignition wire and a non-resistor rotor that the voltage losses will be reduced enough that you can open your spark plug gaps by around 0.005".

In general, I recommend an inductive switching ignition system for most street driven air cooled VWs. However, a turbocharged, or race driven, or off road driven VW can benefit from the increased fouling resistance of a capacitive discharge ignition system. But you can also use a capacitive discharge ignition system on a street driven VW with excellent results.

Scott Novak


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 Post subject:
PostPosted: Sat Nov 29, 2008 11:39 pm 
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Jacobs Omni-Series ignition systems.

The Jacobs Omni series ignition system contains the ignition computer and ignition coil in the same case to save space. The Omni series are inductive switchers. There are 3 versons of the Omni series. The Omni-Pak, Omni-Torquer and Omni-Magnum. A "Bug-Pak" is a Jacobs ignition computer and ignition coil packaged together with Jacobs ignition wires to fit a Type 1, Type 2, or Type 3 engine. There is no actual Bug-Pak ignition computer. Some of the Bug-Pak ignition system packages had 3 and 4 wire Omni-series ignition system that you DON'T want for your air cooled VW, even though it says Bug-Pak

Any of the Omni series ignition systems can deliver more voltage that your Bosch or Mallory distributor cap can handle if you open your spark plug gaps wide enough.

The 3 wire version and the 4 wire version require a negative trigger pulse. To obtain a negative trigger pulse you either need to use the stock ignition coil and connect the OEM high voltage coil wire to the secondary trigger, or you can connect the green trigger to the OEM negative primary ignition coil terminal and connect a load resistor from the high voltage terminal of the OEM ignition coil to ground, or you can wire up an inductive tach adapter that will also generate a negative trigger pulse.

But you obviously don't want to leave the stock ignition coil in place as it takes up room, and it can still fail and cause reliability problems. So you DON'T want a 3-Wire or 4-Wire Omni-Series, or any EZ trigger version Jacobs ignition computer for your Air Cooled VW. These EZ-Trigger versions were designed to fool OEM fuel injection computers into thinking that they were still firing the spark plugs, when in fact the Jacobs ignition computer is firing the spark plugs.

This is the 3-Wire Omni-series that you do NOT want for an air cooled VW.
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This is the 4-Wire Omni-series that you do NOT want for an air cooled VW.
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Please note the mold seam on the high voltage terminal. This should be scraped smooth. Sometimes the flashing at this seam is high enough that it spaces the ignition wire boot away from the terminal which can allow the current to slip out and arc to the case of the ignition coil. It only takes about 5 minute to scrap this off with the edge of a 6" long 1/2' wide machinists scale. This can help prevent arc tracking on the high voltage terminal.

The Direct Connection versions can be connected directly to your distributor points, or point eliminator module, Mallory Unilite or Mallory MBI modules. Below is a 6-Wire Jacobs Direct Connection Omni-Series, the one that you DO want for an air cooled VW. Note the accessory 2 wire secondary trigger with the ignition wire coming out of it, at the bottom of the photo, that will NOT be used for air cooled VW applications.
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Even though the Omni-Pak was the least expensive Jacobs ignition system, don't sell an Omni-Pak short. It will operate with full output to 11,000 RPM on a 4 cylinder engine. It's a lot more than just an ignition system for a daily driver.

All of the Omni series ignition coils have an air gapped core that gives you much greater resistance to spark plug fouling. An Omni series ignition will put out more than 50% more voltage with a new spark plug, compared to a Bosch Blue ignition coil, or the OEM VW Bosch ignition coil. An Omni-Series ignition will put out over 2-1/2 times more voltage into a fouling spark plug than a Bosch ignition coil. I have verified this myself with my own testing. It's not sales hype. This is why a Jacobs ignition system will keep your spark plugs clean while the Bosch ignition coil would let the spark plugs foul and leave you stranded.

The Omni Series came with a number of different versions of Ultra coils and Ultra Torquer ignition coils inside. An Omni-Pak with a 1:60 turns ratio ignition coil is one of the best ignition combinations that you can use with a Bosch distributor or a Mallory small cap distributor.

The 1:60 turns ratio Omni-Pak is in the center. It can be identified by the threaded brass stud that the aluminum terminal is screwed onto.
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The Omni-Torquer also puts out a very high energy spark with a longer duration spark. However, it is RPM limited to 8.800 RPM.

It's a tradeoff. If you want higher RPM capability, the spark energy per spark must be reduced. If you want a higher energy spark, you must reduce the RPM range.

The Omni-Pak does not multi-spark. However the Omni-Torquer and Omni-Magnum do multi-spark. Both the Omni-Pak and the Omni-Torquer put out a higher energy spark than the Omni-Magnum. But the Omni-Magnum will operate to over 20,000 RPM on a 4 cylinder engine. But who has a VW engine that can operate at 20,000 RPM?

I don't recommend the Omni-Torquer and Omni-Magnum because they seem to have a higher failure rate. When they are working they work great. The Omni-Pak seems to be very reliable.

Scott Novak


Last edited by Scott Novak on Wed Dec 03, 2008 2:24 pm, edited 2 times in total.

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PostPosted: Sun Nov 30, 2008 6:59 pm 
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Jacobs ignition computers.

This is one of the earliest Jacobs ignition systems called the CompuSensor. There were various versions including the Torkmaster, and Pro Racer. I believe that it is an inductive switcher. I do not know if it multi-sparks. I have never used one of these. There are unsubstantiated claims that it can run on a 6 Volt system.
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This has the same case as the CompuSensor and is called an Energy Pak. I do not know if it multi-sparks. Jacobs began calling all of their ignition computers "Energy Paks".
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Next is a Black Direct Connection version of a Jacobs Energy Pak just before they changed the name to Mileage Master. It has a built in anti-theft circuit. All Jacobs ignition computers from this model and newer multi-spark. I have used these with excellent results.
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The photo below shows three different vintages of Direct Connection Jacobs ignition computers. The Blue Brick shaped Mileage Master in the upper right corner came after the black brick shaped Energy Pak in the previous photo. Next came the oil pan shaped ignition computers in the lower left corner. The newest are the oval shaped ignition computers in the upper left corner. Note that each one of them has the orange and purple wires coming out of the ignition computer.
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The Brick shaped and oil pan shaped Jacobs ignition systems came with a built in anti-theft circuit. If the disarm button isn't pushed after the engine is started, about a minute later your engine starts running like crap as if it were running out of gas and then stops, leaving the would be thief stranded in traffic and a sitting duck for the cops.
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Some Pro Streets and Mileage Masters had the larger cooling fins like the one on the left.
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Direct Connection Perform Master. I believe this is a capacitive discharge ignition system which was later renamed the Pro Street. It does NOT have a built in RPM limiter. It has a anti-theft circuit built in. Again note the Orange and Purple wires that can be used with a magnetic distributor pickup coil.
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The Direct Connection versions can be connected directly to your distributor points, or point eliminator module, Mallory Unilite or Mallory MBI modules. Jacobs ignition computers with the Orange and Purple wires can also trigger directly from a magnetic distributor pickup such as those used in MSD distributors.

Below is a Direct Connection version of a Jacobs Pro Street ignition computer that you DO want for an air cooled VW. Note the Orange and Purple wires twisted together coming out of the ignition computer. It has a built in soft RPM limiter and an anti-theft circuit built in. The ignition coil is an Ultra Torquer coil.
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The EZ Trigger version requires a negative trigger pulse. To obtain a negative trigger pulse you either need to use the stock ignition coil and connect the OEM high voltage coil wire to the secondary trigger, or you can connect the green trigger to the OEM negative primary ignition coil terminal and connect a load resistor from the high voltage terminal of the OEM ignition coil to ground, or you can wire up an inductive tach adapter that will also generate a negative trigger pulse.

But you obviously don't want to leave the stock ignition coil in place as it takes up room, and it can still fail and cause reliability problems. So you DON'T want any EZ trigger version Jacobs ignition computer for your Air Cooled VW. These EZ-Trigger versions were designed to fool OEM fuel injection computers into thinking that they were still firing the spark plugs, when in fact the Jacobs ignition computer is firing the spark plugs.

The photo below is an EZ-Trigger version of the Jacobs Off Road ignition computer that you do NOT want for an air cooled VW. Note the single wire secondary trigger, with the high voltage terminal, that can only be used with EZ-Trigger versions of Jacobs ignition computers. Note that it does NOT have the orange and purple wires. It has a built in soft RPM limiter and an anti-theft circuit built in
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The Mileage Master is an inductive switching multi-sparking Jacobs Energy Pak that basically the same as an Omni series ignition except with a few more bells and whistles. Energy Pak was a name that Jacobs gave as a generic term for their ignition computers. But because the ignition computer is separate from the ignition coil, you can choose the best ignition coil for your particular needs. A Mileage Master and an Ultra coil can operate to over 14,000 RPM and it is also multi-sparking. The Mileage Master came in the black brick shape, the blue brick shape, the oil pan shape, and now in the newest oval shape. Mileage Masters do not have built in RPM limiters.

This is a Mileage Master with the CMD Ultra Coil bolted on top. Most of these are unfortunately the EZ Trigger models that you DO NOT want. The ignition coil also has the push on Male spade terminals which require a special connector. It has an anti-theft circuit built in
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The newest oval shaped Mileage Master appears to be a capacitive discharge ignition system. I haven't tried one of these yet.
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Jacobs Direct Connection RV Capacitive Discharge Ignition with a built in soft RPM limiter and anti-theft circuit.
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The Pro Street, Off Road and RV edition are all capacitive discharge ignition systems. I believe that the main difference between them is the size of the main storage capacitor inside. Jacobs idea of off roading was driving through the boonies and rock climbing etc. Someone off road racing should consider a Pro Street, as it was designed for racing. However, most people won't notice that much difference between these capacitive discharge ignition systems on the street. They will all work quite well and can handle the RPM that any air cooled VW can manage. The Oil pan shaped Pro Street, Off Road and RV edition ignition system have a built in RPM limiter that you set by reving your engine to the desired RPM limit and then grounding a terminal on a terminal strip underneath the ignition computer.

I believe that this Direct Connection Energy Pak model was a forerunner to the FC 1000 and FC 2000. It does not have a spark as strong as other Jacobs ignition systems. But it's still not a bad ignition system if you get it for a good price. It does not have an anti-theft circuit.
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None of the newer oval shaped Jacobs ignition computers have the built in anti-theft circuit.

The Fire Control ignition system series and the oval shaped Pro Street, Off Road, RV, and Mileage Master are ALL direct connection models. They are not available in an EZ Trigger version.

The FC 1000 and FC 2000 were designed to get by racing rules that prohibited digital ignition systems. The FC 1000 is presently the bottom of the line Jacobs ignition system. While the colors are difficult to see in this photo, it does have the Orange and Purple wires for the magnetic distributor pickup input. The FC 100 does not have an RPM limiter
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The FC 2000 has an RPM limiter which is set by plug in chips.
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I believe that the main difference between an oval shaped Jacobs Pro Street, and FC-3000 is color. Jacobs was trying to market their ignition systems directly as well as selling through a distributor network. To keep the retailers happy they came out with the Fire Control series. The Oval shaped FC 3000, Pro Street, Off Road, and RV edition all have a built in soft RPM limiter that is adjustable by setting two rotary switches.
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The FC 5.0 was specially designed for the Ford Mustang 5.0. It is basically the same as the FC 3000. However it works very well on a VW. But it does NOT have a built in RPM limiter.
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The Pro 10, FC 4000, and I.C.E. Pak are the highest current output ignition systems that Jacobs makes. FC 4000 is basically the updated version of the Pro 10 and they were both intended only for racing. The FC 4000 has a built in soft RPM limiter that is adjustable by setting two rotary switches. The Pro 10 a built in RPM limiter that you set by reving your engine to the desired RPM limit and then grounding a terminal on a terminal strip underneath the ignition computer.
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The FC 4000 has soft RPM limiters that are set by setting rotary switches.
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The I.C.E. Pak also has an extremely high output current, but was optimized for 4 cylinder street engines. It does not multi-spark for as many degrees of crankshaft rotation as the regular Jacobs ignition systems. The I.C.E. Pak does NOT have a built in RPM limiter. However I DO NOT recommend them because they seem to have a high failure rate. When they are working they work extremely well.
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Brick versus oil pan
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To sum it up, with the exception of the Omni Series and the DIS ignition systems, you do NOT want any Jacobs ignition computer without the Orange and Purple wires. Any of the the brick shaped or oil pan shaped Mileage Masters will work great for most street vehicles. The Jacob Pro Street, Off Road, RV, Perform Master, FC 3000, and FC 5.0 will all work great for the street or racing. The Pro 10 or FC 4000 should both work well for racing, with nearly double the energy output of the regular Jacob capacitive disharge ignition ssytem. However, I have never used either.

This is a Jacobs DIS ignition system for an 8 cylinder engine using 4 series connected ignition coils in a wasted spark configuration. However, it can also be configured to drive 4 regular ignition coils on a 4-cylinder engine. It's seriously worth looking into for someone that wants a high performance DIS ignition system. They aren't listed in the Jacobs catalog and I'm not sure if they are made anymore, but there is apparently NOS still available
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Scott Novak


Last edited by Scott Novak on Wed Dec 03, 2008 4:42 pm, edited 2 times in total.

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PostPosted: Sun Nov 30, 2008 9:50 pm 
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Scott, you say any Jacob's products with the orange and purple wires with the 6 wire setup would be the best for our air-cooled VW's. I get that.

Is there a range of serial numbers or part numbers that we could also be looking for when trying to find internet deals on these items? Sometimes, I've noticed, that ebay sellers often list the part number or serial number instead of having detailed pictures, or an explanation that's un-satisfactory to your inquiries about the Jacob's item they're trying to sell.

I've read all of your posts here and OTOS's about Jacob's and electronic ignition. All of the information , as a whole, can be a bit overwhelming and long-winded to some folks. I myself felt this way a few times, but I found myself going back and rereading until I felt I understood it all, at least to the point that I think you're just trying to keep us educated and informed of excellent electronic ignition alternatives that can be had "on the cheap".

Thanks for keeping us informed.


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PostPosted: Sun Nov 30, 2008 10:58 pm 
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Kelley wrote:
Is there a range of serial numbers or part numbers that we could also be looking for when trying to find internet deals on these items? Sometimes, I've noticed, that ebay sellers often list the part number or serial number instead of having detailed pictures,.

Unfortunately, I haven't found any Jacobs catalogs that give the necessary part number information to do any good.

Pictures are the best ways to identify the various Jacobs ignition systems.

Serial numbers may be more useful for some of the Jacobs ignition coils which I will be writing about next.

As an example, there are at least 7 different versions of the older cube shaped Ultra coils and they have different electrical characteristics. Some are better than others. However, even the worst Jacobs ignition coil is better than most of the other ignition coils on the market.

One word of caution is to try to get any seller to at least give you a No DOA warranty. I've had sellers knowingly sell me defective ignition systems. I was able to prove it in some cases by enlarging their ad photos, or catching them in lies during correspondence.

The Jacobs ignition system are fairly idiot proof. However, when someone connects a Jacobs ignition coil directly between +12v and a points eliminator module without a ballast resistor, it's gonna fry.

Scott Novak


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PostPosted: Sun Nov 30, 2008 11:52 pm 
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Great info.

I must say though I am QUITE happy with the performance of the 4 wire "ez-trigger" Omni-pak my son picked up at a swap meet for $5.

I don't even mind carrying around a "spare" coil.

I run it on the Pile, and contrary to Jacobs literature, it works GREAT with Bosch or NGK tri-electrode plugs of the W7DTC/NGK 1263 type.

The non-resistor Copper tri-electrodes probably weren't what Jacobs had in mind when he warned against using it w/multi electrode plugs, he probably meant the Bosch Platinum +4s and such, TOTALLY different plug design concept.

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PostPosted: Mon Dec 01, 2008 1:58 am 
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Piledriver wrote:
I must say though I am QUITE happy with the performance of the 4 wire "ez-trigger" Omni-pak my son picked up at a swap meet for $5. I don't even mind carrying around a "spare" coil.

Performance wise there is no difference between the EZ trigger and the Non EZ trigger models if you are triggering from points in good condition or a points eliminator ignition module. However, when you use an EZ trigger model ignition, your points will wear and pit as normal. With a NON EZ trigger model, your points won't pit as there is barely any current running through them.

My first Jacobs ignition system was a 3 wire Omni-Torquer. But when the Bosch Blue coil that I was using to trigger the Omni-Torquer with failed, I said screw that. I didn't want to use an additional ignition coil that could fail. The fact is that a Bosch ignition coil will fail from vibration long before a Jacobs ignition coil will and the Bosch ignition coil the weak link in the system.

Personally I'd sell the 4 wire Omni-Pak and buy a 6 wire Omni-Pak or other Non-EZ trigger ignition system. You might even be cash ahead if you advertise it right.

Piledriver wrote:
and contrary to Jacobs literature, it works GREAT with Bosch or NGK tri-electrode plugs of the W7DTC/NGK 1263 type.
The non-resistor Copper tri-electrodes probably weren't what Jacobs had in mind when he warned against using it w/multi electrode plugs, he probably meant the Bosch Platinum +4s and such, TOTALLY different plug design concept.

Do you bend the triple electrodes to adjust the gap with those spark plugs or do you just run them as is out of the box?

I would think you would get the same effect if you just side gapped a regular NGK spark plug.

During Jacobs initial testing they were recommending only standard spark plugs. Jacobs discovered that platinum spark plugs would still perform fairly well if the spark plug gaps were opened very wide. But he was never able to achieve quite as much power with Platinum plugs as with standard style spark plugs. Fine wire electrode spark plugs lower the voltage required to jump the spark plug gap. But you also have less power in the spark.

Scott Novak


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PostPosted: Mon Dec 01, 2008 2:42 am 
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The w7dtc (copper) is essentially a fixed gap, but is not remotely a fine wire type, ask to see a NGK 1263 or w7dtc at the parts store sometime and study closely... it's not a "normal" plug.

The projected center electrode (~5mm exposed, ~2.5mm dia) is nickel-copper, and at least the W7DTC side electrodes are some yttrium-nickel alloy. They wear gracefully...

They were originally developed for "tough" ignition conditions, particularly for the UrQuattro.

Stick one an a spare Jacobs sometime on the bench and compare the light show to a std plug.

I have the setup on a Vanagon hall effect ignition, the late Golf coil was no slouch.

I will be keeping an eye out, particularly for that 4 coil job you had, looks like it would work great with a pair of HD twincam coils I have... Do you have a part number or a source?

(The HD coils are nice because the common ion sense line is easy to work with ;-) )



I never managed to find any documentation on Jacobs website about the old Omni-paks, so I had to guess on connecting it... The website is remarkably information free these days.

I didn't use a ballast... have I been lucky for the last 10K miles?

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Piledrivers extensions of Newtons first law:
A vehicle on jackstands tends to remain that way.
Further:
The longer it stays on jackstands the more money will be needed to get it back off.


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PostPosted: Mon Dec 01, 2008 9:44 am 
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Pile, aren't the Bosch W7DTC 3/4" reach plugs? Are you using them in your bug?











Sorry, I forgot, Type IV powered.


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PostPosted: Mon Dec 01, 2008 3:39 pm 
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Kelley wrote:
Pile, aren't the Bosch W7DTC 3/4" reach plugs? Are you using them in your bug?

Sorry, I forgot, Type IV powered.


A lot of aftermarket T1 heads (even many stock replacements) are 19mm reach...
I'm not sure I'd consider anything else.

And these plugs are available hotter and colder.

The original NGK part# was BP6ET, if that helps finding crosses.

_________________
Piledrivers extensions of Newtons first law:
A vehicle on jackstands tends to remain that way.
Further:
The longer it stays on jackstands the more money will be needed to get it back off.


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PostPosted: Mon Dec 01, 2008 5:15 pm 
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Piledriver wrote:
And these plugs are available hotter and colder. The original NGK part# was BP6ET, if that helps finding crosses.


Try finding a BP7ET in stock someplace. It's in the NGK catalogue but I haven't found a place that sells one yet.

Could you measure the gap on that plug?

It could be that some careful grinding back of the electrodes to open the gaps might be beneficial.

Scott Novak


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PostPosted: Mon Dec 01, 2008 5:54 pm 
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Scott Novak wrote:
Piledriver wrote:
And these plugs are available hotter and colder. The original NGK part# was BP6ET, if that helps finding crosses.


Try finding a BP7ET in stock someplace. It's in the NGK catalogue but I haven't found a place that sells one yet.

Could you measure the gap on that plug?

It could be that some careful grinding back of the electrodes to open the gaps might be beneficial.

Scott Novak


I have found them at random auto parts stores in the middle of bloody nowhere Texas, in stock.

Try NGK#1263, looking for the old part numbers in folks stock causes issues. It's the same plug.

I only included the original# so one could cross ref other plugs, for heat range etc, as the new# is useless for that.

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Piledrivers extensions of Newtons first law:
A vehicle on jackstands tends to remain that way.
Further:
The longer it stays on jackstands the more money will be needed to get it back off.


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PostPosted: Mon Dec 01, 2008 6:00 pm 
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Piledriver wrote:
Scott Novak wrote:
Piledriver wrote:
And these plugs are available hotter and colder. The original NGK part# was BP6ET, if that helps finding crosses.


Try finding a BP7ET in stock someplace. It's in the NGK catalogue but I haven't found a place that sells one yet.

Could you measure the gap on that plug?

It could be that some careful grinding back of the electrodes to open the gaps might be beneficial.

Scott Novak


I have found them at random auto parts stores in the middle of bloody nowhere Texas, in stock.

Try NGK#1263, looking for the old part numbers in folks stock causes issues. It's the same plug.

I only included the original# so one could cross ref other plugs, for heat range etc, as the new# is useless for that.

Yeah the computer age is here if it aint in the computer. All ya here is well I just don't know. Sad it has come down to this in a way. The books had info the guys that computerized the system forgot. And thats a fact jack.

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Hot, humid air is less dense than cooler, drier air. This can allow a golf ball to fly through the air with greater ease, as there won't be as much resistance on the ball.


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PostPosted: Wed Dec 03, 2008 3:20 am 
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Jacobs Ignition Coils

What separates Jacobs igniton coils, from many other ignition coils, is the air gapped core which allows the ignition coil to put out more current under spark plug fouling conditions. Jacobs calls this a Variable Magnetic/Variable Permeabilty Ignition Coil and claims that it is patented. I've searched and could not find a Jacobs patent. However, air gapped coils and transformers have been used since the early days of radio when it was called a "Swinging Choke". I'm sure someone patented the design many years ago. I have no idea why air gapped core ignition coils weren't in common usage before Jacobs. It's a no brainer to use one.

For those wanting to keep a more stock looking ignition coil there is the Jacobs Energy coil. It's not as good as the C4 coil, Ultra Coil, or Ultra Torquer coil, but it's better than a stock Bosch or Bosch Blue coil. It can be used with an inductive switcher or a capacitive discharge ignition system.
Image
Unfortunately it seems that when Mr. Gasket bought Jacobs they had the turns ratio changed to 1:100 and I don't have any information on how to tell them apart without actually measuring the turns rato.

Left: Bosch Blue Coil . . . . . Middle: Ultra Torquer Coil. . . . . Right: Coil Ultra Coil
Image
The early Ultra Torquer coil puts out a very high energy spark. However, it's RPM is limited to 8,800 RPM on a 4-cylinder engine. This is my first choice for Jacobs ignition coils. However it is also not anywhere near as common as the Ultra Coil and does not come up for sale very often. The stock mounting bracket assembly is not the greatest and I would recommend fabricating a better bracket.

Coil performance a design tradeoff. If you want higher RPM capability, the energy per spark must be reduced. If you want a higher energy spark, you must reduce the RPM range.

The new version of the Ultra Torquer coil has a nominal turns ratio of 1:85. It was changed electrically and it's spark energy appears to have been lowered in order to operate at a higher RPM of up to 11,000 RPM. The flat mounting flange makes installation much easier.

Ultra Torquer Coil 1:85 Turns Ratio, New Style
Image
The backside of this coil has the core exposed and I recommend painting or epoxy coating the exposed core.

After Mr. Gasket bought Jacobs, they changed the turns ratio to 1:100. With no spark plug connected it puts out a higher voltage than the 1:85 turns ratio Ultra Torquer coil. However, when you connect the coil to a new spark plug, it's output voltage drops and it is no higher than a 1:85 turns ratio ignition coil. When fouling conditions are encountered the 1:85 turns ratio coil puts out more voltage than the 1:100 turns ratio coil. The 1:85 turns ratio coil puts out more current, than the 1:100 turns ratio coil, under normal engine conditions as well.

In short, the lower turns ratio 1:85 turns ratio coil is more desirable than the 1:100 turns ratio coil.

I don't have a 100% confirmation on this, but it appears that when Mr. Gasket had the Ultra Torquer coil turns ratio changed to 1:100, they also changed to the male spade terminals with the plug in connector block like Ford uses.

Ultra Torquer Coil 1:100 Turns Ratio New Style
Image
The backside of this coil has the core exposed and I recommend painting or epoxy coating the exposed core.

Below is the earliest cube shaped Jacobs Ultra Coil version that I am aware of. It does NOT have ground wire and it also has an undesirable 1:100 Turns ratio. The mounting flanges are thinner than the Ultra coil versions that came after it. Dr. Jacobs reduced the turns ratio to about 1:85 on later Ultra Coil versions. He stated in his writings that 1:85 ratio was about the highest practical turns ratio to use. The 1:100 turns ratio Ultra Coil is the worst performer of all of the Ultra Coils. However, even at it's worst it is still better than most other ignition coils. An Ultra coil can operate to over 14,000 RPM with any Jacobs ignition computer with a 4 cylinder engine.

Ultra Coil 1:100 Turns Ratio Early Model No Ground Wire
Image

There are at least 7 different versions of the early cube shaped Ultra coils that I am aware of with different electrical characteristics. One of the best versions, for the limited distributor cap size of the small Bosch cap and small cap Mallory distributors, is the 1:60 Turns ratio Ultra coil. It can be identified by the threaded brass stud that the aluminum tip is screwed onto. Its not an easy version to find, but you occasionally find NOS and used out there at surprisingly reasonable prices. This is my second choice of Jacobs ignition coils.

Middle: Ultra Coil 1:60 Turns Ratio. Note the high voltage terminal with the threaded brass rod with aluminum tip screwed over it.
Image

Ultra Coil 1:85 Turns Ratio, New Style
Image
The backside of this coil has the core exposed and I recommend painting or epoxy coating the exposed core.

Ultra Coil 1:100 Turns Ratio, New Style
Image
The backside of this coil has the core exposed and I recommend painting or epoxy coating the exposed core.

The early C4 coil shown below has a nominal turns ratio of 1:85 and it produces almost as much current under fouling conditions as the 1:60 turns ratio Ultra Coil. It can be identified by the brass 10-32 threaded stud terminals.

C-4 Coil 1:85 Turns Ratio
Image
The frontside and backside of this coil has the core exposed and I recommend painting or epoxy coating the exposed core.

C-4 Coil 1:100 Turns Ratio
Image
The frontside and backside of this coil has the core exposed and I recommend painting or epoxy coating the exposed core.

CMD Ultra Coil (Compressed Magnetic Density) 1:85 Turns ratio.
Image
Jacobs claimed that this coil used a different core material that allowed the core to be smaller allowing for a more compact size. It's a bunch of BS. When I opened up a CMD Ultra Coil what I discovered was that it was the identical size as the other Ultra Coils. The only difference was that it was not potted in silicone inside a larger aluminum case. Because it's not potted in silicone it only has a vibrational G-Force rating of about 20 Gs, where as the regular Ultra coils were rated at 82 Gs. Electrically it performs the same as the other Ultra Coils. It uses the push on Male terminals with a special connector block. It was designed to be small enough to mount on top an oil pan shaped Jacobs ignition computer.

Jacobs also makes ignition coils for DIS wasted spark ignition systems.

Below is a Mallory air gapped core ignition coil. However, it's performance is not quite as good as the Jacobs 1:100 turns ratio ignition coils, and definitely not as good as the 1:85 turns ratio Jacobs ignition coils. The coil is not bonded to the core, so the coil can flop around on the core. Jacobs has potting compound between the core and the coil which helps it to better transfer heat out of the inside of the coil. Also, because Jacobs igniton coils are potted, they run more quietly than Mallory coils and the potting dramatically improves the vibration resistance of Jacob ignition coils.

This Mallory coil is incredibly noise and I would NOT want to run it inside the passenger compartment and have to listen to it squeal. I should also mention that I got this Mallory 30440 ignition coil and a Mallory HyFire VI-AL CDI with a Mallory distributor that wanted, as a package deal. It had a miss during full throttle acceleration that I did NOT have with any Jacobs igniton system that I have used.

Mallory 30440 1:100 Turns Ratio.
Image

Some of the early Jacobs Coils have excess flashing on the mold seams of the high voltage terminal.
Image
This flashing can sometimes space the ignition wire boot away from the terminal and let the spark slip out underneath the boot. This causes arc tracking and eventually errodes the insulation on the high voltage terminal.

A simple cure to prevent this problem is to scrape the flashing on the mold seams smooth. This only takes about 5 mintues to do and it's well worth it, as most of these early Ultra coils have the desirable 1:60 turns ratio, or are the early Ultra Torquer coils. I use a 6" long 1/2" wide machinists scale as it just fits inside the hole around the terminal and can easily scrape the epoxy terminal smooth.

This is an example of the terminal errosion that can happen with a bad spark plug boot or contamination under the boot. A Jacobs ignition system has a HUGE amount of energy. Always may sure the insides of your ignition wire boots are clean and use fresh dielectric grade silicone grease on the inside of your ignition wire boots.
Image

Summary

The early 1:85 turns ratio Ultra Torquer coil is probably the best Jacobs igniton coil up to 8,800 RPM.

The new style 1:85 turns ratio Ultra Torquer coil is probably the best Jacobs igniton coil up to 11,000 RPM.

The early 1:60 turns ratio Ultra Coil is probably the best of the Ultra Coils up to 17,000 RPM

The early 1:85 turns ratio C4 coil follows a close second to the 1:60 turns ratio Ultra Coil, up to 24,000 RPM

The new style 1:85 turns ratio Ultra Coil follows third, up to 20,000 RPM

Avoid any of the 1:100 turns ratio Jacobs igniton coils in favor of a lower turns ratio coil.

Even the 1:100 turns ratio Jacobs igniton coils work better than other brands of non air gapped core ignition coils.

Only use the conventional round style Jacobs Energy Coil if you are trying for a more stock look.

Scott Novak


Last edited by Scott Novak on Fri Mar 06, 2009 10:49 am, edited 1 time in total.

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PostPosted: Thu Dec 04, 2008 10:56 am 
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Scott Novak wrote:
Kelley wrote:
Is there a range of serial numbers or part numbers that we could also be looking for when trying to find internet deals on these items? Sometimes, I've noticed, that ebay sellers often list the part number or serial number instead of having detailed pictures,.

Unfortunately, I haven't found any Jacobs catalogs that give the necessary part number information to do any good.

Pictures are the best ways to identify the various Jacobs ignition systems.

Serial numbers may be more useful for some of the Jacobs ignition coils which I will be writing about next.

As an example, there are at least 7 different versions of the older cube shaped Ultra coils and they have different electrical characteristics. Some are better than others. However, even the worst Jacobs ignition coil is better than most of the other ignition coils on the market.

One word of caution is to try to get any seller to at least give you a No DOA warranty. I've had sellers knowingly sell me defective ignition systems. I was able to prove it in some cases by enlarging their ad photos, or catching them in lies during correspondence.

The Jacobs ignition system are fairly idiot proof. However, when someone connects a Jacobs ignition coil directly between +12v and a points eliminator module without a ballast resistor, it's gonna fry.

Scott Novak


There's an ad in my local craigslist concerning a Jacob's ignition system, and I've established a dialog with the seller, here are some pics,,,,

Image
Image
Image

From those pictures, can you tell me anything to look out for, or possibly questions I should be asking. Like "is the potting stable, or is it leaking?", "As the seller, do you see any carbon tracks around the coil terminal?", stuff like that. Should I ask for better pictures from all angles?
I see an orange wire, but my eyes aren't what they used to be. Can you see a purple wire?

Essentially, it looks like the one you posted earlier, pre-mileage master black brick casing.
Image


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