"Spark plug gaps were increased in the 1970's to better fire the leaner fuel mixtures. The wider gaps also meant higher powered spark and that's why you got HEI."

Both of these statements are true if "higher powered spark" means "hotter and larger" spark kernel. Not only will a hotter and larger spark ignite a harder to ignite lean mixture, but it will also ignite an exhaust gas diluted mixture, an overly rich mixture, and an oil contaminated mixture. More consistent firing (no "misfiring") not only makes the engine idle smoother, run smoother, get better fuel economy, and produce more power, but it also keeps the spark plugs cleaner.

"When the point gap closes, it give the coil more time to built a hotter spark so it seems one would/could cancel the other and you'l get no misfire."

This is partially true. A non HEI coil as used on Chevys from the 1960s is capable of producing about 18 kV, although only about 12 kV of that is needed to cause a spark to jump a .035" gap in an atmosphere which is not exceptionally dense...........the residual capability of the coil is used to overcome losses in the secondary wiring due to breaks/high resistance. If a cylinder is running a denser mixture, that plug is gapped wide due to wear and the wire feeding that plug has high resistance, then the coil will supply enough voltage over the nominal 12 kV to create a spark.............up to its design limit of about 18 kV. "Hotter" 40-50 kV coils will produce whatever voltage is necessary to cause a spark to jump a wider gap with residual voltage to overcome bad wires with breaks/high resistance wide gapped plugs as well as major variations in mixture density and leanness/richness..........................up to the design voltage of 40-50 kV.

 

Exactly right!

 

I think this is why many who put in a "hotter" ignition setup claim better idling/running motors. The engine had some issues to start with.

In a perfect situation the spark is gonna jump the gap when it builds the potential energy to do so; as you state about 12K volts....in most cases.

I run Pertronix III with MSD Blaster II coils with plugs set at .040". No particular issues with points, I just like the rev limiter feature for the most part. These conversions do NOT mean you can forget about distributor maintenance. I just took my '61 dizzy apart after many 10s of thousands of Pertronix miles and, although the car was running fine, there was a coppery residue over everything; cap, rotor, advance weights. Took some serious cleanup and new cap and rotor.

 

That is not necessarily true. Old cars were built with just enough to make them run. There was little to no over-design built into them in the effort to keep them cheap. Another area we see this ad-nauseum is the cooling system, particularly the radiator. There was absolutely NO margin for excess cooling, so if the timing was a bit "off", it was a tad hotter than typical, you were stuck in traffic, or the mixture was too lean, the thing would overtemp and eventually boil over.

With the ignition system, the same situation existed, and given the fact that the fuel metering and spark timing was, shall we say, rudimentary compared to today's computer controlled systems, then it doesn't take much to dirty plugs and have misfiring. Add to this bad valve seals, poor gasketing due to engines being rebuilt numerous times over the years, and worn rings, and "just enough" spark is just not enough in many cases. All that aside, old tech ignition systems did not have sufficient power to prevent misfiring at very high RPM's. There has been a huge market for better ignition systems since the mid fifties when 12 volt systems were first introduced..............and before with 6 volt systems as well.

I can tell you first hand (and as you know, I race my car as well as drive it on the street) that plug fouling and misfiring is no longer an issue.

Back in the day, engines would routinely misfire, or not fully burn the intake charge. The driver wouldn't notice, but the engine would never be running at peak efficiency. This was routine because the spark was always "marginal". Emission testing was not an issue and gas was cheap, so nobody noticed, and nobody cared.............except the hard core racers who always wanted to squeeze every bit of power out of their engine. Additionally, emissions components are designed and built much more robustly so they pass emissions testing for the lifetime of the typical car.

That coppery stuff is very likely oxidized particles from the advance flyweights. If it bothers you, drill 2 - 1/2" holes at 180 degrees on the sides of the cap to let some of the ionized air escape and let fresh air enter. I simply wipe the inside of the cap with a clean rag every year or so, or whenever it comes to mind. Causes no issues with me.

 

I won't necessarily agree with all of the above. I'm 64 years old and worked at car lots in the 60s for several years and drove everything old imaginable. I was the guy that rode out to the customer's house or wherever he/she was broke down and got their car running enough to limp back to the shop. I saw it all and I'm still amazed at how much abuse could be dished out to those old motors and they would come back for more. Running optimally all the time ? Hell no....but run they did.

Cooling for example, by comparison today those old motors ran oceans of water through beefy radiators (some still going strong 50 years later)....now, today (talk about being "on the margin") let the temp get a little out of whack, or those thin-walled radiators get a little clogged, and the computer goes snake-poop.

I wish I could tell you how many times some Navy wife whose husband was deployed rolled onto the car lot and said her oil pressure light was on and I couldn't get a reading on the dipstick. Filled 'er up and away they drove. I'd say that engineering was more than, "...just enough to make them run."

The number one issue I saw repeatedly back then was little-to-no maintenance which lead to mechanical failures and performance issues; not the initial design.

I respect your obvious knowledge but you may be a little tougher on the old-school engineering than I am.

 

So, you remember the old days in summer traffic jams where half the cars on the road would be pulled over, steam gushing from under the hood. Explain to me why you don't see that today? It ain't the computer.

The second paragraph is not an argument about engineering. It's an observation of a dopey woman driver with no clue. There are a LOT more drivers like that today. You've probably seen those women with the cellphone glued to their ear who wouldn't know a rod knock from a dust ruffle. The entire statement does not support or refute an argument that today or yesterday's engineering is/was superior.

Paragraph three: you've got to be kidding! Maintenance schedules back then were MUCH more rigorous than today. Complete opposite of your statement. Cars of the sixties were much better maintained than cars today. Not only did the maintainance schedules mandate it, but trouble would soon follow if the owner didn't abide by them. Most people don't maintain their cars today mostly because service intervals are so few and far between that people no longer THINK about them, and ofter FORGET certain things. I'm guilty of not checking the oil level of my modern cars any more, because they never USE any between 12,000 mile oil change intervals! How about you? Secondly, cars today have become appliances, like stoves and refrigerators. There's no more TLC being lavished on them like days of old. Hell, nobody knows how to do simple things like change oil and change brake pads any more.

Thanks for your respect of my knowledge. I'm not bragging, but I CAN say, for sure, that I have enough knowledge beyond yours, that you cannot detect whether I'm knowledgeable or all smoke and mirrors. Remember: If you can't dazzle them with knowledge, then baffle them with bullshlt. I'm sorry to say that you wouldn't make a good VetteHead, like the Two Mikes (Laurel and Hardy) which occasionally pop-up and run a tag-team match around here.

Tougher on old school engineering? Not really. There were a lot of great mechanical designs back then. Of course, as far as styling goes, the Golden Age ended with 5 MPH bumpers and drag coefficients put the final nail in it so that today, all sedans (if you still want to call them "sedans") and SUV's have morphed into an unsightly abomination that should be cleaned with Easy-Off. One thing's absolutely certain though: yesterday's cars were built like shlt compared to today's "appliances".

 

This thread took a detour from what was a very informative lesson to a argument akin to incessant tire spinning.

I've been around here a while and I know both of you are smart guys with valuable information. What you are now tangling over is a matter of historical perspective and hard facts. I fancy myself as an automotive historian and am interested in these kinds of discussions though they have strayed far from the vagaries of spark plug gappage.

I often hear my fellow 50+ year olds belly ache about the days of yore when big block Chevys and Mopars prowled the boulevards, as if todays cars are no better performing than the leaned out, smothered and emasculated cars of the 70's and early 80's. Yet todays cars represent a renaissance of automotive engineering that parallels the electronics revolution in scope and improvement of the human condition. Ok, with apologies to my college philosophy professors maybe not the human condition, but certainly for the average guy's daily life.

I'm with Frank that our beloved old cars were tough and easier to diagnose and repair. With maintenance they would last a long time or until they rusted out, which ever occurred first, usually the latter.

And that is the point. Todays cars need virtually no maintenance beyond oil changes whose intervals have been extended three times or more from the old 3,000 mile standard via the use of synthetic oils, higher operating temperatures, hair-fine control of fuel/air ratios and better design and manufacturing.

It was common to see three year old cars in the 60's beginning to rust. Today, you must look hard to find a rusted out car, even one 10 years old. And in the 60's any engine could use a valve job or rings after 100,000 miles. Today my daughter drives a 15 year old sedan with 200,000 miles that uses one quart every 11,000 miles. Nothing in the 60's was capable of that.

On the other hand, and to Franks point, cars of the 60's could swallow abuse that todays cars cannot. You could overheat a 283 until it nearly glowed. try that with an exotic aluminum headed quad cammed vanos equipped nightmare (although its computer may not allow it) Cross your jumper cables at night on your 68 Impala and make some sparks, maybe use some tape on a burned wire. Try that on your 2015 Cherokee and replace 6 black boxes and a harness.

I wouldn't trade my Toyota Sequoia for a 70 suburban or IH Travelall as a daily driver, but the latter were sturdy bastards that needed...maintenance!

Remember, our opinions are steeped in historical perspective and experience.


Dan

 

No, I don't remember much of that at all, and when it occurred, it was from people continually refilling a leaky radiator with mineral laden tap water.

I worked at a just off the interstate gas station for several summers in the early 1970s, and every car i saw with mech problems, was due to gross neglect or bubba engineering or maintenance.

Steam from radiator? After pulling the cap, the calcium build up was so thick it was measured in fractions of inches, or a head was cracked or bad head gasket as evidenced by gas bubbles from liquid after a refill during idle. I never saw any hint of undersized cooling, as similar cars would be pulling travel trailers with no issues.

I checked the oil on numerous cars that needed 4 quarts (with a 5 qt capacity), and usually the owners would demand to check the oil them selves, thinking I was short sticking them, then they would get pissed becuase i was right, and then they wouldn't even buy oil from out station, they would go looking for a K-Mart where they could get oil 20 cents/Qt cheaper.

Doug

 

You must have been asleep most of the time.

That's because the cars built with that cutting edge 50s-60s technology and high quality industrial processes used more oil than my grandpa's old fashioned oil burner on his boiler.

Looks like you haven't changed much from your gas station days.

H A N D

Joe

 

My recollection of how things were back then were the same as yours, Dplotkin and FTF.

Biggest difference between me and you is they couldn't go to KMart and get oil $0.20/quart cheaper as straight 20 or 30W cost $0.20/quart and the multigrade was $0.30-$0.35/quart.

The old cars had very robust designs and were tough as nails. Maybe the reason was they were engineered in a way that produced wide variations in manufacturing that made for a cheap manufacturing cost at the same time, allowing for a big margin of error in the design. Lot's of things were designed that way. If I'm not mistaken, that same thought process helped us gear up very quickly for WW II and you know what happened there.

Today, the engineering is different, not necessarily better. But it is different to meet different product needs for the market. The engineers today design to some standards of expectation, just like they did 50-60 years ago.

You could drive a new Chevy car off the lot back then for $1600 and be done with it. Today, that won't even cover half the taxes in many places, let alone buy the car. Might buy one of these super duper radios or some other useless gadget.

 

You must be older than I....

The Conoco shop i worked at sold 10-40 for around a buck a qt,and you could buy it for 75-80 cents at K-Mart, heck maybe it was 65 cents at K mart, all I know it is is $3-4/qt now, maybe more, i try not to look at the price when i buy it at WalMart. My cars don't leak a qt every couple hundred miles anymore, so i am not as oil price conscious.

The Conoco shop owner bought the oil for the station at KMart because it was few cents cheaper than the Conoco distributor sold it for.

Doug

 

Neither do I actually. I'm seriously stating what I recall after working in the car biz in the '60s. Well-maintained cars did just fine; even poorly maintained cars somehow limped along -- the outright 'abused' cars did often go belly-up.

My 5'4" 105 lb Mom would load us 4 kids up and head from Norfolk to Pittsburgh in a single shot in our old Pontiac Silver Streak. She was so little she looked THROUGH the steering wheel to drive...she simply didn't think twice about breaking down - the car just kept on going...

 

I use the Old MSD 6AL with the Blaster coil on the 502...They recommend .50 Th..

 

One of the posters in this thread will likely die from constipation. It may be a first for the medical profession to document.

 

Mikey...Your the Best...

 

PM your phone number. I need to know how to hook up my surround sound I've had in the box for twenty years. I don't want to blow anything up!

 

PM Waiting to go ..but your PM Mail Box is Full...Will not send till you Clean It out

 

Go to VH's or regular email. I leave this one plugged up. Too much riff raff messages here.

 

Your VH box is full too.....................

 

My debates have all been on the race track, with the "Walts Puffers"...National Champions record holding drag cars.....All gapped at .035...

Emission engines with converters, air pumps, wide gaps, high tempertures. ect. ect {up to .080} were the product of the governments attempts at controlling so called dirty cars...One big reason the 1970 Vetters never got the LS-7 engines and as a result HP started to drop all across the board no matter what brand of autos.....Hell, Vettes even were sold with 305 engines and no 4 speeds....

But if you have one of those no power Vettes gap them wherever you like...I guess it don't matter....But the HP years of the late 50`s and 60`s all used .035 didn`t they........