Moss Motors, Ltd

Sorry to rain on your ignition, guys, but actual dynomometer testing shows that MSD boxes and 40kw coils do zero, zip, nada, for power production.

A plug gap will fire as soon as the voltage in the system builds to a point where it is capable of doing so. You don't put actual extra "zap" into the system simply because of the extra available voltage. It's fundamental to the principals of the way an ignition system works. The only thing, in my opinion, that gets a better spark is the bank account of the high performance parts manufacturer. Unless you are running such high combustion pressures that you are having the spark blown out (we're talking 12.5:1 or higher compression ratios) you don't really need this stuff.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Ah Motorbill,  so much deceptive truth in your statement. It's true that all this mumbo-jumbo of high voltage coils and electronic ignitions don't add any horsepower on a dyno with a properly running and set up engine that has its electrical system and carb mixture all lovey-dovey but in the real world   spark is better than no spark and a couple swings at igniting a questionable mixture is better than just one and both of these things lead to better horsepower and dependability/driveability. Come on brother, you said yourself just a couple postings back that you throw a breakerless system in your customers' cars and they like it.

I really like your statement that "A plug will fire as soon as the voltage in the system builds to a point where it is capable of doing so." Absolutely correct. However, that "point" is constantly changing and it's good and prudent to build in as much reserve into the system with a higher performance system to give you a margin of safety to ensure that the spark occurs in the first place. No spark=no horsepower. If you put two brand new systems side by side with one stock and the other with  a hot coil, heavy duty wires, a breakerless ignition,and msd ignition and new plugs they might seem to run similarly initially but over time with wear of each system taking place the souped up one with a reserve is going to perform more consistently =better and give you better performance because of it. A stock system stops being "capable of doing so" under much less severe circumstance than a high performance one.

Now, if you are lucky enough to get a spark to occur it has to be hot enough to light the mixture as strongly as possible to ensure good flame propagation.

Also, under certain situations such as lean part throttle driving and start up the mixture quality can be on the edge of ignitability and the mixture that is in the proximity of the spark in the combustion chamber may be unigniteable. As the mixture swirls in the chamber the mixture near the spark changes. This is a bigger problem at lower rpms because the mixture swirls more slowly plus at higher rpms the swirling increases the consistency/igniteability of the mixture. The multiple sparks of a multiple spark discharge system give several more bites at the apple in igniting a poorer low rpm mixture.

I wonder, does that little red cigar shaped thingy with four wheels ya got posted have a high performance ignition? If so... Why?

LCJUTILA 

LCJ,

Once again we cross our light sabres!!, or is that rubber swords? Well, maybe cardboard paper towel tubes.....

Don't trust me, ask Ted Schumacher of TS Imported Automotive, who's been building Hi Po motors for a LOOONG TIME. He actually keeps a Multi Spark Discharge unit on his dyno to demonstrate the lack of improvement to disbelievers. And, he's not the only one.

I put electronic systems into my customers' cars for dependability and accuracy. The accuracy does contribute to performance, but does not add horsepower or torque. It simply brings consistency, and does not degrade in performance like a points and condenser system, over time.

Yep, you need a margin of performance with regard to spark reserve to fire those babies in various demand conditions. That is built into every decent ignition system made.

Don't you find it curious that new cars don't come with MSD systems? After all, they must ignite much leaner mixtures at much higher temperatures. Both of these factors increase the resistance across the plug gap. These cars come with "hotter" coils, true. That's because they need to fire in a higher resistance environment. But they don't seem to need multi electrode plugs or MSD boxes, or any of the other Gee Whizz industry stuff.  Touche, maybe...

That little cigar shaped "thingee" is a Lola T-340, from 1973. It had points and condenser, and was carburetter equipped. It ran like a banshee, under all conditions.  "Real race cars don't have fenders". 

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Motorbill-

I thought the only thing you believed in was the "Sacred Stopwatch" not no "die-know-mommy-tour". Your example of that engine builder's demo goes to the point I was making about tests under "Lovey- Dovey" laboratory dyno conditions where everything is properly adjusted and screwed together fresh by some guy who actually knows what he's doing under specific temperatures and atmospheric pressures. This is not the typical environment of the hobbiest British Sports Car motor. Those motors can only benefit from higher voltages and extra sparks. (If it doesn't cause them to catch fire.)

Speaking of questionable dyno results, did you know that a Stromberg carburetted Lotus Big Valve Twin Cam  makes 129 BHP on the Brake (That's Brit Speak for Dyno, but you knew that)  and the twin 40 DCOE Weber carburetted version in the same trim makes........129BHP also!  They sure don't drive the same though.

Question: Is that car of yours shown "Actual Size" in that photo? 

Final comment(Not Likely): I only cross die-grinders with people.

LCJUTILA 

LCJ,

Sir, Unto you I say only this: "Thou readest not my posts with great care" It is ended.

And yes, that car is shown full size if you have the standard 130 ft. (measured diagonally) monitor like us real men.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Motorbill-

Real men don't need monitor enhancement.

LCJUTILA

 

No, we don't.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Michael, I purchased a 1980 Spitfire in 1997, I was quite lucky because it came with a Crane electronic ignition and a Weber DVG. The combination make for a very reliable car and provides nice performance.  Some of the things I did to make it better are:  First I installed a set of Bosch Platinum plugs, (I used the recommended heat range from the book) installed a set of good low resistance wires (I used Accel generic wires so I could cut them to the length I wanted and had 4 extea wires for the next time) and an Accel coil.  I found the vacuum  advance had been disconnected  so I took the unit off the distributor and covered the  opening.  I discovered that the distributor plate was loose and caused the car to stutter during acceleration.  To remedy this I installed a set screw  through the distributor plate then set the timing at the highest advance setting recommended, I believe it was 10 degrees BTDC  (it has been a while since I did this so my memory is a little foggy on the exact setting).   Altogether  These changes produced a very nice accelerating car and has been very reliable, I could drive the Spit everyday from late March / April to November ( thats pretty good in New Hampshire) Never a problem starting or running at reasonable highway speeds. I have gotten up to 85 mph without an overdrive thats pretty decent.  Most of the parts are available at your local discount auto parts store.  By the way a PURE ONE oil filter is my recommendation it has an anti drain-back valve and one of the best filter elements, I believe the number is 1117. As you can probably tell I am not a purest when it comes to using only original parts.  Replacing the stock carb (which has a reputation for leaking) and replacing the Lucas (Prince of Darkness) ignition may be considered unconventional but the end result increased reliability and more driving fun far outweigh the alternative.

Enjoy your Spitfire!!  I know I enjoy driving mine!! ;-)

Dan 

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Dan Beliveau
Who Dares Wins