Any experience with Mallory HEI conversion...

[Bob Booth #33372]

Hello all,

I currently am running a Mallory dual point distributor in my '72 350 and wish to convert to the electronic module that supposedly installs in the existing body and replaces the troublesome points.

Has anyone tried this or known of anyone who has?

Thanks, Bob Booth

[Robert C.]

Re: Any experience with Mallory HEI conversion...

Bob, Three friends in my local club have converted with success. I believe the current Corvette Fever mag. has a step by step series on how to convert, this month! Bob # 23737

[William Brown]

Re: Any experience with Mallory HEI conversion...

Bob,

I ran this Mallory unit for years in a 78 Camaro dragster. The installation is a very simple drop-in install and the units themselves are very, very reliable. You will be amazed at how smooth the ignition will become, especially in the upper RPM range, after you have installed the unit.

Best of Luck. --Corey

[Michael W.]

It's not actually HEI,

at least the units I am familiar with. The Mallory and the Pertronic units merely replace the stock mechanical points and condenser with an electronic 'switch' to energise/de-energise the the primary winding of the stock coil. It will NOT give you the higher energy output to the plugs of a true HEI system.

I have always maintained that these units, while providing a certain 'convenience' factor of not having to adjust/replace the points and condensers of a stock system, cannot possibly provide massive performance improvements by fixing all the supposed evils of a system where the limiting factor is usually the stock coil.

It is true that these units can fire the plugs more consistantly and accurately, but if the basic problem is a weak spark, this is the wrong fix.

Mike


NCRS Quebec chapter

[Jeffrey S.]

Re: It's not actually HEI,

I installed a Pertronix unit in my 69 300 horse car. It was so easy and I didn't even have to remove the distributer from the car. I also put in a 40,000 volt coil to boost the spark. Only one extra wire exits the distributer and when the coil is painted gloss black it's very hard to tell that anything but stock is there. The unit performs beautifully and the engine runs smooth as silk with good response. We have installed 2 Mallory units, one in a 66 big block and one in another 69 small block. They were much more complicated to install and had more wires exiting the distributer. The distributers were removed for these installations.

Good luck! Jeff

[Jerry Clark]

Re: It's not actually HEI,

Mikes evaluation of the system in question is on the money. While the "pointless" ignition is superior to the pointed distributor in relation to point performance, damp start capability, it isn't within the system to provide a hotter spark, only more consistent.

jerry

[Doug Flaten]

Re: Question

Knowing that as speed increases, the amount of time that the points afford the coil to build up its field is decreased and results in a weaker spark. Would an electronic ignition increase this time slightly thereby allowing the coil to build up a greater field before the electronic ignition triggered the discharge? Granted, it would not be any huge gains, but would an electronic ignition allow slightly greater output vs point type ignition using the same coil?

[Michael W.]

Re: Question

In theory yes, it would allow more time to build a charge in the primary, but in practice you can only put 10 pounds of stuff in a 10 pound bag. I don't think the limiting factor of the system is dwell time, but the actual capacity of the coil.

Also, I do not believe that the electronic ignition module 'opens' the primary circuit for any lesser dwell angle than regular points do. This controlled by the shape of the cam that triggers the module.

Mike


Quebec NCRS Chapter

[Duke W.]

Partial answer

The Delco HEI has circuitry that increases the dwell angle with RPM, which helps to maintain per cycle ignition energy. I don't know about the aftermarket single point conversion units. Once the basic ignition ENERGY is sufficient to light the fire, additional energy does not improve engine output or efficiency, but all ignitions have "reserve energy" to maintain a reliable spark as system componets degrade. The single point system has less energy (41 millijoules) than the the TI and HEI (74 and 76 millijoules, respectively), so the TI and HEI have considerably more reserve, but the basic problem with the single point is inconsistent breaker arm action due to distributor shaft end play, worn and wobbly breaker plates and using the low tension (19-23 oz.) instead of the high breaker arm tension (28-32 oz.) points in a high RPM (>5000) engine.

High voltage coils are, dare I say, snake oil. The actual voltage developed by the system is whatever is required to bridge the plug gap, which is only about 10,000 volts on an engine in good tune. If you open the secondary circuit the high voltage will just breakdown some other component such as the plug wires or distributor cap that were not designed for these voltage levels. For anyone who's shopping for a "high voltage coil" ask them what the (per spark) coil energy output is? If they don't have a clue (a likely event), you might want to consider looking at another alternative. To save space and time I didn't specify the SAE paper sources of the above information, but if anyone wants the reference cites, I'll dig them out.

Duke

[Bob Booth #33372]

Re: It's not actually HEI, Thanks guys...

...for the info. Sorry I haven't been able to reply for the last few nights. Between not being able to access the board and a 16 month old boy and running a buiness and...

Thanks again,

Bob Booth