The Stovebolt Site Forums The Shop Area Engine Shop Testing Stage! HEI for the Stock Distributor

Well, it was a pretty decent day of testing. Things always go wrong for me it seems, and I hooked up a stock distributor with no permanent modifications with the reluctor and reluctor pickup for the first time, hooked it up per the diagram, made sure the distributor was dropped in right, and guess what?

Started right up and runs every bit as well as the points distributor I pulled out minutes before! Even when gunning the test engine, the vac advance turned the distributor even further than the mechanical advance as its supposed to, and there was no hesitation, no choking, just ran all the way up and all the way down the same as the points distributor. THE FIRST TIME! Guys, that NEVER happens to me. I should go out and buy a lottery ticket.

What makes this so significant in our quest to find less problematic ignition systems with hotter spark, etc, it that it does not require a lathe and damage to the lobes on the
shaft. There is also no reason to remove the top inside plate unless you just want to inspect the mechanical advance.

This is still under development, but in the near future I will need a volunteer to install it and tell me what it does under load. I designed a plate that is on the computer and sent to the waterjet for precise cutting that mounts the reluctor pickup to make it adjustable on both planes.

I will be providing O'Scope pictures of how it all works once I figure out how to download the scopes pictures to the computer. You can hook the Oscope up to the completed distributor and spin it and watch the spikes the reluctor produces so you can get a good idea of its performance before you do the modifications.

LOTS has already been done and you can read all about it here:

http://forums.devestechnet.com/foru...i-for-your-216-235-261-stock-distributor

As with everything else I do, the detailed instructions on how to do it yourself are included. Comments always appreciated no matter what.

Did a little testing today again. I have two distributors set up for HEI. This way I can compare the two waveforms to make sure I can duplicate the success of the first one.

It's at the bottom of the article here:

http://devestechnet.com/Home/HEIgnition

Next phase is installing that second distributor and testing it at all RPM ranges like the first one.

Finished testing the system and did everything exactly like my Ignition Specialist told me. The Oscope measurements went surprisingly well. This system is proven and worked long before I made my modifications to it. All I really did was make it removable so you can put your points back in if you don't like it.

This answers the question once and for all.. "Can we use a stock distributor and get the very same results as those big ugly looking ones." YES WE CAN!

In the coming months I will be putting together kits for the 216/235/261 engines to make it easier for those who do not have metal fab facilities. I will announce it on my Home page.

I was able to reproduce the success of the first one with ease, so I know this system is solid and repeatable. Now I can get on to other things! Thanks to alot of people right here for your contributions! You can read all about how to make your own, how it works, how it looks, here:

http://devestechnet.com/Home/HEIgnition

To answer some skeptics next question I include an excerpt...

"NOTE: According to Jim Linder, the Electronic Ignition Specialist that I have been collaborating with throughout this entire process, we are DONE here! He says if the test engine runs smoothly through all RPM ranges even through the advance mechanisms, it will run just as smoothly under load in an actual car or truck. The reason for this is because the GM HEI Module computer controls the dwell and adjusts using the RPM as part of its process. So there is no logical reason for it not to work perfectly if it passes the test engine tests. Gap your Spark Plugs to .045 and use an HEI approved set of Plug Wires along with the aforementioned 45,000 volt coil and you are good to go!"

Great Stuff thanks to others. I just do the compiling.

I'll be your guinea pig:)

Well done Devey boy! I said a long time ago when you were beating yourself up over the details (ohms etc), that you just need to "build it, they will come."
Nicely done.
Carl

Just think how many times you hear you can't re-invent the wheel. Glad you got it done Deve.

Sounds good.

I may be trying this mod once I get some other things straightened out. Good info and documentation.

I can't figure out why everyone wants to trash can the points and condenser system.

Not everyone.

I have had a few bad condensers, but the only "bad" points I have seen are the sets that come with two "springs" (one is a lead and the other is for tension/spring, I guess?). Some people do not use the tension spring (and, I guess, the other thinner "spring"/lead fails, eventually). Of course, points have to be cleaned/adjusted somewhat regularly, and they wear out.

My experience only includes 6v and 12v 216, 235, and 261 engines (I have also used 6v and 12v Pertronix systems with no failures).

Of course, I have no problem/criticism with do-dads being used on anyone's engine/truck.

You don't trash can the points and condenser. If you would read Deve's write up, you would understand that he designed his HEI to be easily swapped out so that you could replace it with the points if needed. Put them in the glove box.
HEI ignitions are far superior in performance than ever-degrading points. The HEI has no mechanical parts that wear out, nor points contacts to corrode.
Carl

Ed it isn't about trashing a system that has stood the test of time for about 100 years, it's about finding a more efficient upgrade while still honoring the era, keeping the engine, and getting the most out of it. We know the points system works famously. I never rebuild an engine and start with HEI, I use a points distributor to set the timing, valves, carb, etc. then I go to HEI.

In fact, I was so adamant about making this upgrade 100% reversible without doing any damage to vintage parts, I caught all kinds of flack. I want to be able to remove the HEI plate, install points and condenser, remove a jumper and drive the truck home on points if I want to. Its all about choice.

When you see the difference for yourself, you will understand the transition better. The engine runs much stronger, more deliberate and more efficiently, burning leaner mixtures more completely. The GM HEI module is a mini computer that controls the dwell at all RPMs, making the timing absolutely perfect and not subject to mechanical parts that wear over time.

Nothing wrong with points at all. Keep them and enjoy your ride and the feeling that you rightfully should have knowing you didn't modify a vintage vehicle.

That attitude is not for everyone however. Some of us just want performance tweaks that are mild. VERY mild. NO V-8s, etc... in an AD. Just a little improvement to upgrade things to today's driving conditions. I do every engine I rebuild, every modification with the idea in mind that I am creating these things for a daily driver. If you get your vehicle out for an occasional parade or local car show, alot of them are not for you. No trash can here.. I will have on board my vehicles a brandy new set of points/condenser to get me home if my newfangled (1973) system fails me!

Oh,I read it, and I understand it perfectly. HEI ignitions were designed for emission purposes, leaner fuel mixtures, catalytic convertors,etc. HEI works well with higher rpm's, however these stovebolts will never see these revs. You won't see a lick of performance gain in these engines from installing an HEI. If you spend the money to change out the points, then feel the need to carry an extra set of points in the glove box, then you might as well leave the points in the distributor and save the money. I have had the same set of points in mine for four years and 8 thousand miles. Adjusted them twice, keep em lubed. In my opinion, getting to tinker and adjust is part of the antique vehicle experience

Keeping a spare set of points in the glove box does not express a lack of faith in the HEI unit any more than keeping an old spare tire in your truck expresses a lack of faith in your tires.

Agreed - that is why a carry a completed, spare, replacement distributor (with tested parts) in all my trucks. I have never had to use that spare distributor.

In other vehicles (VWs in 60s/70s), I have had bad condensers and caps - that is why I carry tested-spares of all distributor parts.

Deve, will you be able to do a dyno comparison?

Have you been able to do an emissions comparison test?

Let us know what your real world MPG comparison test results are?
Jeffrey

Someday. Not likely to happen for a few years. That's why I am hoping someone will test it out. But it will have the exact same results as any HEI unit out there. It has to do with the way the triggering works. The GM module doesn't care where it gets its signal as long as the signal meets its requirements. It not just meets its requirements, but far exceeds them the same as the other HEI units out there. This isn't about inventing a NEW HEI SYSTEM, its about using what has been out there forever without destroying the vintage distributor. Jason McElroy runs it, Jim Linder has done many of them for his customers. The only difference between theirs and mine is its interchangeable.

I am not an auto mechanic, I just use common sense to solve problems and enjoy the challenge. I just know from the tests my specialist in this field recommended how much better the engine reacts to changes in RPM and how nice it is to not have to deal with dwell issues within the distributor since the module takes care of all that.

Its like the shifter, the PCV, the list goes on and on and on of things I devise, you can always purchase someone else's units. I do not do this for the money. Its about the challenge and helping others. If YOU take on the testing, please share the data with the rest of us.

You see, this is the beauty of the way The Think Tank works. I am not the only participant. If I were, I wouldn't give myself the time of day! Experts in the field are a MUST for this sort of thing to happen. Good news is, I found a whole bunch of them. Some of them right here. Collaboration with others can yield amazing and unheard of results.

I did the hard part Jeffrey, now its YOUR turn.

Now that those pesky Volts, Ohms, and Current, issues have made some sense to you. You had to add "Dwell" to the conversation. Keep tinkering Deve. The only way to learn something is with both hands and minds. I have no doubt that HEI is an improvement over "Points, Coil". I am reminded however on the efforts to make Flat Heads run better. Lots of work for little gains(opinion, I know). The use of "High Performance" items on an engine with limited breathing and RPM range, in a Truck is about as Exotic as it gets. Keeping the Stock parts unmolested is a very good thing. We won't see more in the future. Enjoy and have some fun. Nice project with a good outcome.

I have six points distributors, and if you chuck them up in a drill (oil pump end) you can check for wobble. I was very surprised at how worn all six of mine were. Wobble is apparent in every one. Then, some are looser between the shaft and the housing than others.

What that does is cause dwell problems and very erratic timing varying sometimes as much as 5 degrees. The wobble creates point gap issues and the looseness creates timing issues. BOTH of these problems are irrelevant when you stick the HEI system in. Those two problems are completely cleared up providing the wobble or looseness isn't just crazy. The older these distributors get the more this problem is emphasized. After all the testing I am doing, going through all of these distributors, I am learning alot. The neatest thing is the Timing Light I got for these tests. It allows me to change the advance to measure. Very sweet! Everyone needs one of these:

http://www.amazon.com/INNOVA-5568-P...999926467&perid=03MPFQQJBBJF1YVH2317

I am not an auto mechanic, but this tool is really helpful when testing ignition systems. Between that and the Oscope, I am very confident the system works flawlessly. Thanks!

The hard part?

That would be you giving me a distributor to the testing.

I wished I lived close enough to watch you do this stuff.

I remember around the late 80's people were putting early HEI distributors in full size rear wheel drive cars such as Chevrolet's, Buick's, Old's, and claiming 20 MPG. Jeffrey

I guess I can see improved gas mileage since it burns hotter and more cleanly, but I do not know.

I have this same problem for pretty much everything I create. Limited funds such that I can't just send parts to the willing to test them. Its why I include a parts list and complete instructions on how to do it yourself with everything I do. If I can be of any help otherwise I am always available.

To do a MPG comparison between points versus HEI in a Stovebolt, you would have to do it over a long period of time. I would guess that there would be no appreciable difference when the points are brand new. The problem with points is, they are only brand new and fresh for one revolution of the camshaft. After that, wear, and corrosion begins and continues until degradation of the spark intensity requires attention (clean and re-gap).
HEI spark intensity does not degrade over time.
Carl

send me he kit and ill try it for you.

The people that said better MPG went straight to plugs with gaps that were about double of the original gap.

So to claim how much was due to the HEI or plugs has never been found out.

Controls needed: Stock ign with stock SP gap.

Stock ign with increased SP gap.

HEI with stock SP gap.

HEI with same increased gap.


I hear you when you say limited funds. If I did not have my son's truck to work on I would not be involved in the antique car hobby. That's why I said I wish I lived close enough to of worked on this with you. Cause not only to get to play at being an inventor you are able to do so while allowing things to easily get changed back to original.

Since its a test engine sitting on a stand, I suppose I could put a calibrated amount of gas like in a quart jar with all things being equal. Then run the 4 conditions you mention. I would then run the sequence backwards to make sure I could repeat the results. Hmmmm. Any of you want to comment on how you would set this up in detail?

I don't think that you could achieve any usable MPG data from running on a stand. An engine on a stand isn't doing any work.
Carl

My dad worked for Wright Aeronautical during the big one. He met my mom there. Mom made the cylinders for the B 17 engines.

Dad was put on engine testing and break in. He would run the engines and compile data in a book that went with the plane that each engine was installed in.

I do not remember all he the data he did record. Though I know dad would chart oil consumption, SFC, specific fuel consumption, at various RPMS at other settings.

That data would be given to the navigators. They then would be able to determine the point of no return for there own plane. And let the pilot know what RPM to run his engines at to get the maximum distance.

I did a SPC test on a small 1 cylinder engine in a college auto mechanics course to bring practical experience to the theory of SFC. Outside of remembering doing it I do not remember any details.

First I would do all the tests with the same weather conditions. Because you will of have removed any variables.

Also have the engine warmed up before you do any test to removed engine temp as a variable.

Use fuel from the same batch and unless you can think of something else we have removed all the variables.

Record the weather at the time of the test. Barometer, temperature, humidity. Because those three conditions will effect how the engine runs.

Then you should have valid results.

Now SFC tests have been done at a wide range of RPM's.
And you will see graphs of SFC from idle to max RPM.

There is no need for you to test your engine at high RPM's.

Though I would suggest a SFC test at 500 RPM idle.

A second test at what the engine's RPM would be doing 30 MPH.

Then a last test at what the engine's RPM would be doing 55 MPH.




Then if you ever felt the need to do more testing you can wait for weather conditions change to see how air temp, and humidity effects SFC.

Carl it doesn't matter at all if it's not doing anything. That's one of the controls. It's not doing anything for all four of the conditions. So it would tell you a lot. If the HEI uses less gas, and it's quantifiable, you can calculate the differences and be able to prove the issue once and for all.

If it WERE doing something and had a load on it, it would have to have the exact same load in all four conditions. So driving a truck wouldn't work for that since you can't drive EXACTLY the same each time.

So the best I could do in the above scenario is tell you the difference between the two in consumption rate. It will not tell you how much more/less gas for YOUR driving conditions, but it would still be very telling.

Jeffrey my Dad died awhile back and took with him all sorts of very valuable information, and the right person to do this is always the person that isn't here! Your Dad would be a real valuable asset in a test like this.

Deve, all good reasons you gave Carl.

Deve how long do you think the engine would run on 1 quart of fuel? I think enough fuel for 4 to 5 minutes would be enough.

Maybe 8 ounces.

So just thinking about this all the time, I am coming up with the following. Tell me where I need to alter the idea...

1) There are only two valid conditions (not 4) because the stock points distributor gap number should be what's in the shop manual for optimum performance. .035

Then there is only one HEI number that matters and that is the HEI plug gap which in my research is .045. You would never gap an HEI system to .035 and you would never gap a points distributor to .045.

However, I want to do 4 tests anyway because a lot of old codgers out there mention your points system runs better if you gap to .040.

I want to also include a HEI gap of .050 just because.

So,

Test one: Points Distributor (.016 points gap) with stock coil using ballast resistor with plugs gapped to .035.

Test two: Points Distributor (.016 points gap) with stock coil using ballast resistor with plugs gapped to .040.

Test three: HEI Distributor (.007 reluctor gap) with HEI coil (45,000 volt) no ballast with plugs gapped to .045.

Test four: HEI Distributor (.007 reluctor gap) with HEI coil (45,000 volt) no ballast with plugs gapped to .050.

I will use a 28 ounce bottle attached to the top of my gas tank on the Start Kart. It's a little larger than 28 oz, so when it hits the 28 oz. mark, I will hit the stop watch. When it gets down to 4 oz. I will stop the stop watch.

Doing it this way, the engine is running and warm before it ever hits the 28 oz line so the results will be more exact.

I can then take the time it takes for 24 ounces to run through the engine and compare the differences. Of course, I will then do this same test over again in reverse order to see how repeatable the test is. By then calculating how long the engine runs on 1 ounce of gas, we can correlate just how much the difference really is.

My thinking just because we are dealing with mechanical fuel pumps and carbs, to go about 10 minutes or so, so the time it takes to run 24 ounces will be interesting.

Also, the RPM will be just under the RPM when the mechanical advance kicks in or about 1000 RPM. All of this is of course negotiable, so please if you want me to do this different, say so. I won't be able to get to this for about another week, but it seems to me like a worthwhile project.

Should I take vacuum readings or at least record the vac readings while I am at it? What else?

Like Sam Kinison liked to say.. SAY IT!!! SAAAAY IT!!

The weather is not an issue because my shop is at a constant 74 degrees and I will be doing it in the shop. I will record the humidity and temp anyway while I am at it.

Check your manual. My 1946 Factory manual says set points to .018. Though read a bit farther the manual says that when putting in new points set it to .022 because the points wear down.

My Motors manual says .022 with no reference to the points age.

So for me the ideal setting would be .022. The larger the gap allows for better coil field saturation and a stronger spark. Now I do not know what year engine you have though I can look up your engine in my Motors manual.

I have seen HEI spark plug gaps up to .060 to .080. I do not see why you would limit your test to .045.

Also you have to use a spark plug that will fit yet is designed to have a wide gap for the ground electrode end has to be above the center electrode as when using a regular plug and gap.

Though you have to find out is there enough clearance between a large gap plug an the top of the piston.



As to the old codgers 1940 to 1948 SP gap was .040. points were .022.

1949 to 1953 SP gap was .035. points were .016, except corvette was .015

This points out that there was more to just a difference in point gaps and may yield questionable results.


Test one: Points Distributor (.016 points gap) with stock coil using ballast resistor with plugs gapped to .035.

Test two: Points Distributor (.016 points gap) with stock coil using ballast resistor with plugs gapped to .040.


I agree on the first two tests.


Test three: HEI Distributor (.007 reluctor gap) with HEI coil (45,000 volt) no ballast with plugs gapped to .045.


To me test three would be more valid with using stock plug and gap of .035 because you will be testing apples to apples. You will have one variable. The HEI ignition. By having everything else constant you can show exactly how much HEI compares to points.


Test four: HEI Distributor (.007 reluctor gap) with HEI coil (45,000 volt) no ballast with plugs gapped to .050.


Test four to me is tying one of HEI's hands behind its back and then tell it to get into the ring and show me what you've got. As said 1981 Buick 231 V6 had a SP gap of .080. Now if there are clearance limitations then maybe you will have to run a SP gap of .060.


Test should be done at idle RPM, for no advance, minimum throttle opening.

Then at RPM to do 30 MPH in 3rd/direct drive, for partial throttle, light load condition simulation.

Then at RPM to do 55 MPH in 3rd/DD, for wider throttle opening, increased load condition.

The reason for different RPM's is to show if there is any changes at idle. Where low RPM and low engine load may show the stronger spark of HEI may not be a benefit if there is no change or very slight change.

Now the 30 MPH and 55 MPH tests are important for as engine RPM increases the dwell from point gap does not change though the time the points get to saturate the ignition coil decreases and the voltage available for the spark will be reduced.

Now when doing the 30 MPH and 50 MPH test the second time with the HEI you will get very valuable numbers to compare not only is HEI better but at which operating ranges.

You are testing how much which way uses the least amount of fuel. Though nothing wrong with taking vacuum readings and RPM readings. For they can provide supporting data for your tests conclusions.

Though say HEI allows your engine to pick up RPM's without touching anything. That is ok. However do not readjust anything on the engine because you are adding unknown variables and may not be able to see how you are then providing advantages that will skew the test results.


As to your shop being climate control you still need to record climate conditions.

One you are running an engine indoors so there must be an exhaust system. So your shop will not be air tight. Then even if your humidity and temp is constant in the shop weather outside changes and that means barometer change. Like a valve opening an closing pressure differential moves air through an engine. Every time your shop door opens even into just your house nature will try to balance out the pressure differential between the inside and outside.

Though recording the Baro reading or not for the day of you test will not effect the reliability of your test results.

Though it will take away your ability to do further testing if your were bored on a cold rainy late fall day to test how air temp, humidity, a baro effect air density and it's relationship to engine performance. Jeffrey

I did check my manual and it says .016. There is no way I have the time to do all the different gaps over the years. The new style 1959 235 is the engine under test, so I have to go with the shop manual. (.016/.035)

To me test three would NOT be gapped to a gap designed for a points distributor, high ohm stock coil with ballast resistor and much lower voltage, so no.. HEI is a totally different animal and needs to be gapped to HEI standards. This is because the coil is much hotter, there is no high ohm values or point gaps/dwell issues. The HEI system is NOT just the distributor. It includes the 45kv coil and the HEI modules controls.

You are correct however that the HEI gap has not been totally determined. Not sure which TWO gaps make the most sense. I am NOT going to go to different spark plugs. That adds unnecessary expense to the hobbyist trying to switch to HEI. Your stock plugs will have to do. I have a set gapped to .045 and the electrode is already bent higher than level, so that's why I was thinking .045 and .050, however that is for sure negotiable.

There IS a scientific reason not to gap much further. This is a small body distributor and cap. You cannot gap too far lest you get the fire going the opposite direction instead of jumping the gap. You can also get crossfire and quicker burned out parts. I know from experience the system works flawlessly at .045 and I know from the ignition specialist that longevity of parts is not an issue when using .045. This is the nuance of using the stock dizzy.

If you can tell me the RPM it takes to go 30mph with no load and no transmission or rear end, let me know what that number is. Same for 55. Please let me know cause that makes sense. (although now we are talking about TWELVE tests). I feel idle is just slightly too slow for the test because of the erratic behavior of a points distributor at very low rpm. That's why I suggested bumping it up, but not enough to trigger the mechanical or vac advance. I wish you could be here to see what I am talking about when using a high tech timing light.

The shop is a commercial building with exhaust venting and total climate control. I will be sure to write down the humidity and temp anyway.

Remember that none of those issues matter Jeffrey. The reason is the same I stated for Carl's concerns. Controls placed on ALL tests will give exacting, repeatable results. Sure a rainy day will change the results, but across ALL tests. I will also make sure I use gasoline of the same grade for all tests and make no changes to the engine during the tests. Remember that most people don't drive their vehicles around in a temperature controlled 74 degree environment from point A to point B. So the test is more for the relationship between the tests. If it's repeatable, and I will make sure it is, we will have good data.

Please continue the conversation (and stand your ground on what you would like to see), I am wanting to make this a meaningful test. The results will look really nice in my HEI How-To article.

To me, the test isn't going to prove anything. All you are doing is an off idle test, and if the fuel will light off with a .030" gap, going wider isn't going to matter. With a no load engine, the throttle is barely cracked open, so cylinder pressures and heat don't come in to play like real world driving. Even the most basic system will run a "no load" engine.

I found this in an online text book,

"Coils operates according to Faraday's Law of electro-magnetic induction.

As the high tension voltage in the secondary winding builds up, a particular voltage level is reached when the spark plug gap suddenly becomes conductive, allowing the spark to occur. This is known as the “plug firing voltage”.
The level of plug firing voltage depends on many factors, such as:

The mixture density
Turbulence
The pressure in the cylinder
The spark plug gap
The condition of the spark plug electrodes
The resistance of the secondary circuit
When the spark reaches the point where a high intensity current is flowing in the secondary circuit, the voltage drops to a much lower spark voltage level, sufficient to sustain the spark. This gives the mixture the opportunity to ignite during the duration of the spark. "



I had a Ford Flathead engine I played with for a while, it had a four speed transmission on it with a park brake on the tail shaft. I could really load that thing down with the park brake and fourth gear. We had a water hose running over the drum to cool it. The Ford really made noise at full power and pulling on the brake lever!

Joe

So help me understand Joe. If I test this under no load, but do all the tests exactly the same, and lets say that the HEI gets better mileage, how does this change when its under load? The HEI does not all of the sudden get weaker. Nor does the points distributor. A weak spark may ignite the fuel, but not as quickly, nor as cleanly as a hotter spark. No? Then, the hotter spark will combust much more violently. Sort of like black powder vs modern gunpowder. No? I am not as versed as you, so please explain. I am being sincere here!

Lets take this one at a time.

Mixture density.. same for all tests.
Turbulence.. same for all tests.
pressure in the cylinder, same for each system
spark plug gap.. same for each system being tested
condition of the electrodes, same
resistance of the secondary.. same for each system being tested
same plugs, same plug wires, same distributor, same rotor.

My feeling without testing is the results will be very close to the same. But people want to know! I personally have nothing in the game other than curiosity. This HEI is the very same as any other so without having experience with HEI, I do not know if mileage is an issue at all. What is your experience with mileage vs ignition systems?

BTW, if you have any ideas on how to properly load my test engine without causing me great financial pain, please share!

Those who seek to be first on race day, without running out of gas an the last lap, do not test engines on a stand with no load.
I certainly am no expert. I am just trying use logic to try to understand. There is a lot going on when an engine is under various loads while going down the road.
If we just consider what's going on with the distributor, such as centrifugal advance curve, vacuum advance, while under various loads, you won't learn how these impact the real world MPG. It has been mentioned that the HEI automatically self-adjusts the dwell. What if the Stovebolt engine does not function optimally with these preset (I assume) parameters while under load?
Your no-load stand test may be a good starting point, but will not provide a definitive conclusion.
Carl

The spark plug gap never suddenly becomes conductive. The distance across the air gap never changes so the resistance does not change. Electricity only jumps the gap when there is enough energy for it to jump the gap.

Yes there are factors that effect how hard it will be for the electricity to jump the SP gap.

That is why sometimes when holding a spark plug wire close to the engine and seeing a spark but the engine will not start because the coil output is to weak to fire under load in the engine.

Any way Deve's engine has no variables but points or HEI. To talk about variables has no place here. For people that put in HEI distributors did so for better gas mileage based on a better spark. All they did was change their ignition system and spark plugs. Deve is seeking to confirm that variable.

A dynamometer is not needed for Deve to put on a load. By Deve running a test at idle, then a RPM that would be used to do 30 MPH and then a test at 55 MPH will provide a load on the ignition system for at higher RPM on a stand will have more air and fuel entering the cylinders making it harder for the electricity to jump the SP gap.

Deve is working low budget trying to have fun and do an experiment. He is not doing a research paper to be presented to the SAE.

Deve will either see that there is a change in SFC or not. And if there is him not having a dynamometer will not be needed to make his findings any more valid.

A dynamometer will allow true engine load to be placed to match actual road conditions though Deve does not have to show actual SFC but only if there is a change.

1959 6 cylinder will do 46.7 RPM for each 1 MPH.

30 x 46.7 = 1,401 RPM

55 x 46.7 = 2,568.5 RPM

I get this a lot about needing load to prove things, but when you talk to the specialist about it, he says "Phooey, it will work exactly the same". He goes on to say "My HEI Distributor machine that I test with does not have a load, yet all my customers still seem to have a smile on their face."

This is because of the design of the GM Module, not because some genius said so. If the reluctor stays gapped correctly and the wiring connections remain in place it will work exactly the same. I thought we moved on from that...

Carl could be right however, in that, if you are driving a truck up a hill, gas consumption could be more or less depending on which ignition system and there could be a bending curve where the HEI system takes less at load and the stock one takes more as the hill gets steeper.

That is all fine and all, but not what I am testing. If the HEI system consumes less gas on the test stand, it will consume less gas in your truck. A wider, hotter spark will not change due to where its mounted or whats behind it.

I didn't miss your concern about HEI modules not being made for these particular engines, but lots of them are out there and working fine. Ask anyone with Tom Langdon's, a regular GM distributor machined to fit, etc, etc. This HEI Mod uses the same computer. Can't lose. It's all very exciting!

Yes load changes can effect SFC. This is why I have been pushing for you to do the tests at three different RPM settings.

Then you will see whether HEI produces an constant decrease in SFC across the RPM ranges or the percentage of change is greatly improved as the RPM increases. Jeffrey