The Stovebolt Site Forums The Shop Area The HiPo Shop Plugs for HEI

I am wondering what you guys are using for spark plugs with your HEI systems? You can't really gap beyond .050 on stock plugs, so what are you using? Also, what do you gap your plugs to? Thanks! I am looking to get HEI plugs for a 1959 235 engine.

E3 makes a E3.52 that is supposedly the replacement for the stock plugs. But what I don't know is how far you can gap them for HEI. The guys on the TV show are using them with a Pertronix.

Here's a link to Tom Langdon's store, showing plugs for HEI.

http://www.langdonsstovebolt.com/store/online-catalog/#!/Spark-Plug-Large-Gap-for-HEI-For-216-235-261-and-Mopar/p/37315489/category=361515

I don't think you can change the gap on the E3 plugs, or at least it doesn't look like you can by the way they are made. Personally, I stay away from gimmick spark plugs.

Thanks for the responses. Yep, I knew there was someone here that knew where to go!

Why does an HEI system need a wide gap?
Jerry

HEI puts out a higher voltage spark. Able to jump a larger gap. Longer spark has to be part of the reason why HEI helps the fuel to ignite easier and burn better in the cylinder.

When car companies went to HEI they greatly increased the spark plug gap. Jeffrey

That's a pretty common misconception about the reason for having a wide gap. It doesn't apply to stovebolts.
Jerry

The instruction for the CRT Performance HEI for the 235 shows plugs gapped at 0.045.

Timing about 4deg BTDC

Tom Langdon recommends .060 using his high gap plugs for the 235/261.

Does anybody say why the wide gap is necessary, or desirable? The spark will have a longer duration across a normal .035" gap- - - -check it out on an oscilloscope sometime.
Jerry

maybe this might help

http://www.custom-car.us/ignition/spark-plug/gap.aspx


basically electrode gap affects engine performance, the spark magnitude may be insufficient to ensure complete combustion if gap is to small or for HEI large enough to use the higher voltage for greater kick in combustion.

It's a myth. The problem with poor combustion was limited to a few extremely lean-burning engines in the late 1970's/early 1980's that needed a gap of .060" or .080" to assure there might be some combustible gases between the electrodes when the plug fired. Cadillac was one of the worst about developing a miss with .045" gaps, and a .080" gap cured the problem.

I managed shops and taught hundreds of trade school and high school students the intricacies of the HEI system for over 30 years. Once catalytic converters got efficient enough to clean up slightly richer mixtures without violating EPA rules, the manufacturers went back to a .035-.045 gap without a problem. The lie about HEI needing a wide gap dies hard, like the old idea that a hot engine needs to be running when pouring water into it. That advice went out of date when they put a water pump on the 1928 Ford Model A.
Jerry

We are fixin' to find out. I will have fuel consumption tests completed in the next few weeks that will test this issue out completely. Stay tuned to the thread here for the test results:

https://www.stovebolt.com/ubbthread...in=163874&Number=1114854#Post1114854

I will leave it to you to tell Tom Langdon, CRT Performance, Bubba's Hot Rod Shop, etc, etc, etc, etc, etc, that they are all full of crap. Be sure to tell them that your vast knowledge and years of experience trumps anything they could possibly know or comprehend. Honestly though.. we ARE going to find out real soon. I really hope you are right Jerry. I would love to just leave the gap alone.

Yuma that is a great place to get information. They cover just about everything. Thanks for posting that!

Clean, properly-gapped plugs fire at less than 10KV. The other 40K available with a HEI system is for lazy owners who refuse to do preventive maintenance on a regular basis. The whole concept of HEI was to satisfy the government mandate that emission control related components had to last for 50K miles without maintenance. It's possible to cut the ground electrode completely off a plug and still fire it with enough voltage available.

People with something to sell have a habit of lying about what's necessary, and they have just the thing to solve the problem for people gullible enough to open up their pocketbooks.
Jerry

Would an O2 Sensor help in the testing of the different gaps? I am mainly testing for fuel mileage, but maybe it makes sense to test the exhaust gases to see if one gap causes a leaner or richer condition?

No

I guess it must really be all a waste of time putting in a 40KV system for a wider spark gap when a 10KV system and small gap burn the fuel just darn well as good. Progress is not progress.

Since I was around and working as a line mechanic/shop manager when the entire electronic ignition concept was developed, I believe I can offer a perspective view of what it is, and isn't. Electronic ignition is simply a way to avoid routine maintenance. Mechanical points cannot tolerate more coil primary current than about 5 amps without having extremely short point life due to arcing, no matter how effective a condenser is installed. The average service life of points was 10K miles, plus or minus a little. When the clean air act of 1968 mandated that emission-related components HAD to function service-free for a minimum of 50K miles, it was impossible for point-ignition systems to meet that standard, the points had to go. GM and the other manufacturers went for a massive overkill, designing a system that would not only meet the mandate, but was capable of firing terribly worn and/or burned plugs with lots of fouling and huge gaps. The coil primary current went up to 15 amps or more, which allowed the open-circuit voltage to exceed 50KV. Clean, properly-gapped plugs still fire at 10-12 KV, regardless of the capability of the coil. Once the gap is ionized it is IMPOSSIBLE for the voltage to rise above the ionization voltage. That 40-50 KV coil is operating at 10KV or less virtually all the time. Of course, the hucksters who want to sell us ridiculously expensive flamethrower coils really don't want that little tidbit of information publicized. It cuts into their profit margin.

When the plugs get worn out, with rounded center electrodes and eroded ground lugs, then it might take 20KV or more to get a spark started. That's still less than half the capability of a standard HEI coil.
Jerry

It seems to make sense that a wider gap/spark might affect the ignition of the fuel and the flame propagation. I'd want to see the cylinder pressure curves. Deve's fuel consumption tests will be interesting, and an O2 sensor in the exhaust would provide potentially valuable data.
For me, I enjoy NOT changing plugs, points, and condenser...or paying someone to do it...only plugs at around 50k ('97 GMC 4.3). All the platinum plugs, with wide gaps, I've changed out didn't look bad at all. Worth the few extra dollars, I'd say.

One of the really bad side effects of a wide plug gap is the tendency for that high firing voltage to find its way to ground somewhere other than across the plug gap. If the plug is gapped to need 25K to bridge the gap instead of 12K, what happens when a plug wire gets tired and goes open circuit, or a wire falls off the plug? How about hitting a puddle and getting a little water on the ignition system? That high voltage will jump all over the place instead of bridging the plug gap.

If somebody does something really stupid like converting a stock-appearing distributor to electronic ignition with a high voltage coil, the tendency for stray sparks to find their way somewhere they don't belong is just about a certainty. There's a definite reason the design engineers chose to use a large-diameter distributor cap and 7MM wires when they converted to HEI. That extra space between conductors and better wire insulation is an absolute necessity.
Jerry

There is a larger group everyday going to the small body HEI and it works flawlessly. The concerns back in the early 70's about internal crossfire were never realized back then and they have zero affect on the small body HEI's today. I think it was more of an added excuse to put the HEI module and coil on board the distributor. Problem is, it looks terrible.

What some people fail to realize is the 45Kv coil is producing a hotter spark and wider gaps allow for a much more violent combustion. The engine just runs better. (every article written about HEI since the 70's says it). The gap WILL matter, I think, but I will be much more sure when I run the tests here in a few days. It isn't true because I said it. EVERYONE in the industry says it. With no dissention whatsoever among the guru's who have spent their lives doing this.

There is way more to HEI than just extending the life of the ignition system or impune someones character by insisting they are too lazy to do routine maintenance. The computer controls the dwell based on RPM and takes those duties completely away from the distributor. Timing is much more precise and for much much longer. I do not want an HEI that just fires at 12Kv and gives me the same spark I get with a points distributor. Why would I do that when I can get a 25-30Kv spark and have much hotter and more fully burned fuel at leaner mixtures? The tests will include three gaps. Those three gaps will tell us if the HEI is happier with a small gap or a large gap.

Just like anything else, you don't push the limits of your system by gapping to .080 or some ridiculous number. This is why GM has specifications on how they want each of their systems plugs gapped. Its not in their best interests to have ruined systems due to signal grounding anymore than it is ours.

Tom Langdon uses a V6 distributor and recommends .060, probably mirroring what the car it came out of was spec'ed at. Jim Linder who has spent his entire life paying attention in class tested the one I use now and decided that .045 was his recommended number. These people do not set out to screw the public out of their hard earned money by selling wide gap spark plugs just to keep a myth alive.

I keep getting told over and over by MANY of you Bolters out there to stop paying certain people lip service. They don't know what they are talking about but for some unknown reason desperately want you to think they do. I don't get it! On my own, I do not profess to know anything. I have to actually make phone calls, leave messages, emails, interact with people and reliable web sites from all over the world before I open my mouth. Its baffling, but since I am the OP, thanks to all of you who actually have an HEI and actually know what your plug gaps are recommended to be.

An O2 sensor and bung are on order. I am excited to see what it can tell me as far as air/fuel burn using what few parameters we have to work with. For $30 bucks, I just want to know! Testing will end this discussion once and for all anyway. At least for those who can use their cognizant ability to make their own decisions based on real data.

So all of the actual HEI testing is complete and you can see the differences in fuel mileage depending on the gap. It clearly shows that gap DOES matter. I didnt stop there. I wanted some comparison data between HEI and Stock systems.

Turns out gapping your stock ignition system to .040 will get you a bit more power and better mileage. I also discovered something totally unexpected. Spark plugs really have an impact on fuel mileage! It turns out those (what I would have called gimmicky) E3 Spark Plugs (part number 52 for our purposes) give you another boost in fuel mileage. The E3 plugs are not gappable and are gapped to .040.

When I did the tests I did them all the same so there is no question about the results. I know you can do the same tests and get the same results.

Another thing I found out was that coils make a great deal of difference when dealing with HEI. An everyday stock coil will get you poor gas mileage with no other variable even with stock gaps! It runs just fine, but at a fuel mileage cost.

These tests were done at idle which is the very same idle that you get in your truck, so the numbers will track. The numbers at 30mph and 55mph were not done with a load, so they will not track, but are offered to give you an idea of the fuel percentage differences between idle and these speeds. As you can see, LOTS of difference in fuel consumption.

The O2 sensor was very important to the tests because I was able to adjust the engine at the start of the test process slightly on the lean side. This way the fuel consumption would be repeatable and similar throughout the process.

It was fun and if there is any way I can improve the data so it makes more sense, please let me know!

http://devestechnet.com/Home/HEIgnition

about halfway down the page.

"If there is any way I can improve the data so it makes more sense, please let me know!"

How about telling us how many miles you drove, the percentage of the grades you traveled, plus temperature, atmospheric pressure, humidity, etc.? It sounds like you're pulling figures out of thin air otherwise.
Jerry

this seems to be a big long Advertisement for E3 plugs.

No, in fact I had no intention of even testing them but decided to at the last minute. The proof is there. It's not very much difference, maybe 2-3 minutes an hour at speed, but it was interesting.

Idle tests are very telling for everyone to see since Idle is the same as if it were in the truck. The other tests are offered to show the minimum gallons per hour the 235 engine will use at 30 and 55 mph, as well as how much throttle is used.

But the real cool thing about this is, exactly like the O2 Sensor thread, I was able to prove that Mr Driveby doesn't have a clue about any of this because it was him (or her) that said, "That's a pretty common misconception about the reason for having a wide gap. It doesn't apply to stovebolts." and this one is a really good one if you are trying to be a jerk... "If somebody does something really stupid like converting a stock-appearing distributor to electronic ignition with a high voltage coil, the tendency for stray sparks to find their way somewhere they don't belong is just about a certainty." And gapping plugs to high gaps will have no good result, and.. you can't use a small body distributor for HEI." *sigh* In fact, Now we have another bolter Bill, who makes those distributors and runs them all the time with this TBI system. These are engineers that have designed these systems. WOW!

You just can't help yourself can you? I think everyone should read the O2 sensor thread so you don't have a question about who Jerry is anymore. Be sure to watch the video I included so you can really see what everyone is talking about.
Really Jerry? You REALLY want to keep this up?

How about getting back to us when you have some real road test info to share? Otherwise, playing with your stationary engine with no way to put a load on it is a huge waste of your time, and ours. Your so-called results are phony because they don't duplicate real-world operating conditions, and running an unloaded engine at highway RPM is an exercise in futility, no matter how much name-calling you engage in. Shoot the messenger if you must, but your numbers resemble what comes out of the north end of a southbound Holstein, and you refuse to admit it.
Jerry

Everyone other than you understand why those numbers were offered. Has nothing to do with driving. 235's are found in cars, trucks, generator applications, etc. They are not load tests! Why would I pigeonhole the data by running it on just one platform? Once again, offered to show minimum fuel usage at three common speeds. Also to show that the ignition is firing up and down the spectrum when I engage in changing each variable individually within the specific controls.

Everyone but you knows this. Its amazing! You just can't help yourself can you? You HATE the fact that I am contributing valuable information when its YOU that's supposedly the genius. Guess that one went out the window awhile back. How about getting off your butt and doing some tests to augment mine? You know, CONTRIBUTING as opposed to tearing everyone down? It will never happen folks.

I don't understand any of this .Deve,starts a thread asking for input on spark plug gapping,then turns it into it into a long commercial of self importance. Step back from the keyboard for a bit and take a few deep breaths.

Not everyone will understand. That's okay. You can't reliably do testing at speed on engines. The reason why is because what is your platform going to be for these extensive tests? 1/2 ton? 3/4 ton? You would have to weigh them first and create all kinds of controls that I just don't have time for. So I did what I am capable of doing in my limited shop and got the ball rolling by testing with Zero load. Now we have baseline data. Others can take it from there.

I dont HAVE to do this stuff, nor share it. I don't get paid for any of it. Yet I get emails and PM's thanking me for the effort so I know its the right thing to do. Then some clown comes along who has been proven to be wrong on almost every occasion and starts belittling the effort. No control over that, but how I respond every time I see it from now on, I sure do.

Then, couple that with.. "okay, lets use the dyno at $1000 an hour". But how does that tell you more on how it will run in your truck? It's just a little better than no load testing, but your gas mileage will swing from the dyno number dramatically depending on weight and gearing of your vehicle. (I am talking about the kind of dyno that is in a room engine only). Not sure if there is one big enough for the outside kind that you actually put your truck on depending on the wheelbase. Not sure how worth it it is to go to the trouble. Everyone here knows how to do MPG testing on their trucks.

I have no issues with self importance. Nobody has ever thought so. I am just on a mission to stop certain people from bullying everyone here and trying to diminish their contributions. I am sorry if you didn't catch that. You will have plenty of opportunity in the future the way it looks right now.

The last time I checked, public roads were free to travel. Map out a 100-mile loop, set up a particular ignition system, carb jetting, timing setting, etc., and take a drive. Do it again. And again- - - -and again. Minimum of 10 trips. Document the fuel consumption.

Make ONE change- - - - -maybe a different power valve spring- - -repeat the test. Document. Do something else, maybe a plug gap change. Test again. Change coils- - -test again.

These real-world results might mean something worth reporting on.

Taking the last refuge of the scoundrel, making personal attacks toward the people asking questions instead of giving answers- - - -that's beneath most of us.
Jerry

This coming from you? You dont ask questions. All you do is very hatefully ridicule everything everyone says. Making people feel small is not acceptable. But keep it up, I am here for you.

We would have to do what you describe with every model vehicle we support. The controls would be pretty daunting. Vehicle weight, gearing both trans and rear, environment data, then altitude ground elevations, changes to them, how long it was going up a certain grade, etc etc. If we had enough volunteers with the necessary vehicle specs, yes, we could do it.

I do not mind the thought of static tests as they are great for comparison.
I do not mind a load or driven test after the static test for showing usage values.
But a open live road test does not mean a thing as to many variables come into play, doing ten or a hundred loops dilutes those variables some but only so far.
If you want a road test then a closed track test removes a major portion of those variables. But a dyno test with variable loads can achieve the same thing.
But you need access to a track or a dyno for that effort.

Real world road testing is the ONLY thing that matters, unless the entire purpose of this silly charade is an endless conversation between a bunch of cyberspace computer jockeys whose entire world consists of a keyboard and a total lack of a real life.

I'll be in Kansas City in a month, driving a real truck. Anybody who's interested can look me up, and we can continue this conversation at handshake distance over an adult beverage or six. Somehow I have the feeling the whiny cyber-heroes will be no shows!
Jerry

I will be looking forward to meeting you Jerry. I was there last year and we had a great time. This year will be extra special!

There are many different reasons to test fuel consumption. In this case HEI was the entire purpose. I needed to make sure the system Jim Linder and looks now like many others, who created this in the first place were very helpful, but I needed to know myself that the adapter plate I engineered would work properly. His original one works flawlessly (I have both so I can compare) but it was important to me if I am going to make kits for my friends, that they be 100% vetted.

The most important was the Oscope triggers had to be the same, which they were. But since I didnt have fuel consumption tests and wanted to see if Jims suggestion to gap the plugs to .045 was spot on, I went about the extra testing.

All of the fuel consumption tests I did at idle are the EXACT same as if you had the engine in the truck, so those numbers are exactly what we can expect, be it in a car, a truck or anywhere else. Each gap was tested individually to see not just how much fuel was used, but how well the engine ran throughout the spectrum. To do this I needed an O2 sensor to set the fuel mixture at the onset of the tests. That worked out perfectly and the engines settings were not touched throughout. This way we can see the affects a different coil has, gaps, stock comparisons, everything.

There is no question that my adapter plate has no adverse bearing on the function of the very well engineered small body HEI system, which uses our stock distributor without making any modifications to it.

The reason static testing is just as effective is because you can track the results between tests. For example, Stock Ignition system gapped to .040 versus HEI Gapped at .040. If the data at 2568 RPM were off by a mile there would be reason to believe the HEI distributor is flawed in some way, (missing, arcing, something) since we KNOW the stock system that GM designed is reliable. Since they track each other (with HEI doing better mileage wise) we know BOTH systems are as capable of getting us from point A to point B. Also, in looking at the cap and rotor, both systems look as clean as the other. (used separate ones).

There was never a question about the quality of the HEI system. This has been tested by several engineers over the years. All I was ensuring was my adapter plate and the extra 12 gauge plate height made no difference.

There was never any reason for you to disrespect all these engineers and people working on it. You chose to do that, then tried to lie to everyone here about how an O2 sensor works. If you weren't lying about it, you didn't know that it's the ECM that causes what you were describing. Then why didn't you just say "Bravo Deve! You got me on that one! I guess I never tried it with the ECM disconnected" and move on. But no, you lied again and tried to cover your tracks by attacking every aspect of OUR tests, projects, anything having to do with it.

Its so sad to see someone that I used to look up to trying to cover their tracks rather than just admitting they do not know, nor should they be expected to know everything. I cant WAIT to see you in KC Jerry.. we have so much to talk about. I will bring my laptop and we can reminisce about all the lies you have told to cover your tracks and all the downright hateful things you think don't matter to anyone. I will be sure to have them all referenced and indexed and share the entire thing here before the event so everyone can join in on the conversation. I wouldn't miss it for the WORLD!

Brave words from behind a keyboard.
Jerry

That wont be a problem soon Jerry! We get to meet in a little more than a month!

When is the weigh-in? Will it be pay-for-view? Has Vegas posted the odds yet? Could either one last a round against Ronda Rousey?

I didn't even know there was an HEI plug. I thought you just used spark plugs. I have bought HEI Dizzy's at swap meets for $5 and put them in (v8's) and nothing changed except no points to worry about and simple wiring.

Here is what you get with large gap:
The potential to fire a leaner mixture.
The potential to fire with a higher compression engine.
If you don't need it, you really don't get anything.

Here's what you may get with large gap:
Hard starting
Burn up caps and rotors quicker.
If you cause the plug tip to get too hot, it may cause pre-ignition and blow up your motor.

The HEI bigger gap was to operate leaner mixtures in the beginning of the emissions era. Not Stovebolts, not pre 73 motors. I use them because they last forever, no other reason. I use the recommended plug and gap for the motor.

Deve does get a bit lost in details when details are not necessary. He studies the entire internet and then asks here, like he really wants to know. It's just Deve's method, he's a good guy.

Jerry gets sucked in once a year. When he says "why does an HEI need a wider gap" He is not asking you, He means: "Why the hell does it need a wider gap". I think he may have more experience and knowledge than those other names. A great resource for us.

I think this is the nicest post I've ever done!

OOps wait...Carl, women's cage fighting analogy? really?

FYI: There are known insulator material "strengths". There are known jump gaps and creep distances for voltage values. The HEI original caps were designed using the insulator material of the day and the design knowledge of the day. The original HEI caps were designed properly and tested, they were not mistakes. Crossfire was never realized because of the design. Placing the coil inside the cap means short circuit distances, no long wires, no exposure to the elements, a super idea that has lasted the test of time. The module has to be in there. The small body HEI are smaller because they don't have the coil inside and are different designs.
Also, Not sure what looks terrible? you mean not stock?
What exactly do you mean by small body HEI mentioned in your post? What unit is a larger group going to? Is there a small body, one integral unit available?
Nothing will ever be as flawless as a GM.