[Sun Tuned]

Yes, Bart is right….”good oil”.

Used to be fairly common occurrence around here years back to see HEI distributors triggering MSD boxes. Don’t hardly see it anymore at all these days.

I think a lot of folks were mistakenly under the illusion that MSD was firing multiple sparks throughout the ENTIRE rom range and that is simply not correct. They only do the multiple spark thing up to 3000 rpm then it reverts back to a single long duration spark.

Works just like a regular msd distributor… except instead of the black with purple tracer and black with orange tracer for the msd mag pickup….. you just use an HEI and the green and white mag pickup leads.

I think another reason you don’t see as many HEI’s is some people can’t spare the room for it…. Multiple carbs etc.

Fixed properly with good solid parts the damn things are near indestructible. Now I know lots of folks have had issues, but I believe there were other underlying things going on to cause them.

Just like a points distributor … fixed properly with the right parts…. Their also near indestructible , at least for about 15,000 miles or so before one needs to check the dwell.

Endplay on all these distributors is a real “sky is falling subject”. Personally I think folks place way too much emphasis on this. For sure more than is needed.
I’ll say this. On a cast iron unit you can within reason so pretty much whatever you want. You can shim them tighter than the aluminum units simply because the aluminum expands at a greater rate than the iron.

With that said, there is no need to do this. That shimming thing was originally designed as a sort of workaround to counter a looser than ideal reluctor assy . And that idea was an opinion at best to begin with.

I see too many shimmed too tightly on a regular basis.
That will cause far more harm than good.

[Sun Tuned]

Dragncar,
I do endplay differently than I used to 30 years ago, and certainly different than most people. Most will break out feeler gauges and try and shoot for some specific number they’ve heard or read about.

It’s fine to do that, as one needs to know when they’re getting down close to too close. Folks getting all caught up in those numbers. At GM they set the distributors up with a go/no go gauge. I was told by the fella that was in charge of the plant that built them that originally they had 2 gauges on a key ring attached to a small chain. These had a dime and a nickel on each workstation. They were told to “nickel and dime it” meaning nothing wider than a nickel and nothing tighter than a dime. That’s where the factory clearance came from. I’m also told some idiot raised hell about “defacing money” in the plant so these got turned into “formal” plug gauges…

Sure the factory setup looks to have heaps of clearance in there, but they work fine even with it there. Due to the helix on the gear teeth all but the Oldsmobile distributors run or are thrust “UP” into the bottom of the housing against the thrust washer. The olds is naturally thrust “DOWN” onto the iron boss in the block. In each case once running the excess clearance is dealt with accordingly. As long as the engine is running there is none.


As far as numbers go I’d not shim an aluminum housing tighter than .025, and although you can shim the iron tighter due to less elongation of housing due to heat expansion I’d not go much tighter there either.

Those days and for at least the last 20 years I just shim them a bit more snug than stock to make people feel better and leave it be. It’s not the big issue most make it out to be. Originally racers did it to compensate for loose reluctor bores, to try and cheat what they felt was a non issue to begin with in my opinion.

[65 Lamnas]

Out of all 42 responses here, only one mention of Progression ignition. To choose an advance curve and load it from my phone seems like a pretty attractive deal to me. www.progressionignition.com

I'll let you know if/when it fails.

[Skippy597]

I've looked into progressive but all that fancy whiz bang technology terrifies me.

Lol, not really but I do like the simplicity of points and carbs and mechanical fans and pumps.

[Sprocket]

One of the best ignition systems that I have ever used was a factory points distributor with Crane XR700 ignition box. Essentially, the Crane unit replaced the points with a hall effect trigger system. Totally flawless and maintenance free for 25 years. Would still be using it except I "upgraded" for fuel injection purposes.

[Formulajones]

Originally Posted by Skippy597

I've looked into progressive but all that fancy whiz bang technology terrifies me.

Lol, not really but I do like the simplicity of points and carbs and mechanical fans and pumps.

I am of the same thought process. Not interested at all in putting anything car related on my phone. Prefer the simplicity of points, mechanical fans etc..... all our daily are that way and rock solid dependable.

[ta man]

Originally Posted by 65 Lamnas

Out of all 42 responses here, only one mention of Progression ignition. To choose an advance curve and load it from my phone seems like a pretty attractive deal to me. www.progressionignition.com

I'll let you know if/when it fails.

I like mine.

[firechicken]

Love my progression ignition.

[dataway]

I've always been torn ... I really love the simplicity and reliability of some of my old analog gas and diesel engines, aboslutely bullet proof most of them. But, I'd also love to own an old Pontiac engine with the latest greatest FI system, roller cam, coil on plug, programmable ECU ... as much modern systems as you could stuff on one .. just to see how efficient you could make it run. Problem is you'd have to use aftermarket stuff in most cases rather than heavily tested and researched factory parts that have billion dollar R&D departments behind them.

[Formulajones]

Don't get me wrong, I like some of the wiz bang stuff on the market and I do use it on other cars, but those are cars that are weekend toys. EFI, hydraulic rollers, MSD billet distributors and digital boxes with all the gadgets etc..... and I do drive the wheels off those cars without issue and we do go some long distances of 3-400 miles with them at a time, I just don't use that stuff on my daily drivers. They are all flat tappet cams with points distributors, mechanical fuel pumps and carbs. Not because I don't fully trust the other stuff, but the dailys happen to be cars you don't really want to go changing all those things around, like a 70 RAIII Formula and a 69 Z/28 all with numbers matching stuff. They have a little bit of value, not really something I want to monkey with so they stay stock. They also work perfectly fine as dailys that way too, with respectable mileage, dependability etc.... Not the fastest thing on the road but that's not what they are about.

So I'm kind of on both sides of the fence with this stuff, it just depends on the car we are talking about. There are however a lot better choices for ignition systems than pertronix stuff. MSD distributors, MSD boxes, points distributors, and things like that, I don't have a problem using and don't question it. HEI's I tend to shy away from, Nevermind if there is a reliability issue with modules these days, I shy away from them only because they are big and bulky and take away from a stockish appearance.

[Sun Tuned]

Man, big fat factory GM distributors need love too, every now and then….

lol

[Formulajones]

......

[locomotivebreath]

Does a “ hotter” spark coil even matter on stock distributor systems or is just a bunch of hype/marketing ?

[Tim Corcoran]

Originally Posted by firechicken

Love my progression ignition.

I might consider using one but can't justify the high price tag.

[Dragncar]

Originally Posted by locomotivebreath

Does a “ hotter” spark coil even matter on stock distributor systems or is just a bunch of hype/marketing ?

A coil will only give enough volts to jump the plug gap. Its a law of physics.
Some engines, boost, high CR require more voltage to jump the gap so the coil will put it out to do the job.
But a stock engine is never going to see the full 40,000 volts of a 40,000 volt coil.

[george kujanski]

^^
A large plug gap will demand higher output voltage to create the spark. Going to a whiz bang hi- V coil will do nothing by itself. When triggered, the output voltage rises quickly up to a voltage that breaks down the gap. A 60kV capable coil will most likely not be providing 60kV with normal plug gaps.

[Cliff R]

"Does a “ hotter” spark coil even matter on stock distributor systems or is just a bunch of hype/marketing ?"

NOTHING waiting for you there over a stock coil except point life suffers with most of them. Bug Zapping ignition systems absolutely and for sure and the least returns for the dollar spent in this hobby. I learned this decades ago with several of the cars I drove and raced. Never saw the slightest improvement anyplace messing with aftermarket ignition systems and components, except they have a much higher failure rate than the factory parts. My first big lesson in switching from points to an MSD was with my friends race car. Powered by a "budget" 400SBC we threw together for less than $3000, stock crank, stock 5.56" rods, light weight forged pistons, Sportsman heads, hefty flat tappet solid cam, Victor JR and 850 Holley DP it ran 6.50's at 105mph at our local track in his late 70's Monza. My buddy got a nice bonus from his job one year and bought an MSD billet distributor. We'd been triggering the 6AL with a stock set of GM points with the advance plate brazed down and mechanical advanced locked. Installing the MSD distributor knocked about .03-.04 seconds right out of it and a little MPH as well. We were stunned since we locked the timing at the exact same place. We were at the track frantically trying to figure out why the car slowed down some and an "old timer" walked over and asked us what we were doing? We told him, and he responded by telling us, "well that's simple, you lost the natural timing retard at high RPM from the points".

An early lesson is how good aftermarket parts aren't. We went back to the points triggering the MSD and although I've lost contact with my friend a few years back I'll bet that same points and distributor are still in that engine.........

The factory attempted wide gap plugs once HEI's were out, and it failed miserably. A stock HEI makes so much voltage and will "throw" a spark nearly an 1", therfore it's going to find the path of least resistance. Start opening up plug gaps, resistor wires/plugs and raising resistance and first thing that happens as the plug wires break down is that they cross fire o r even worse burn a hole right thru the center of the rotor. About all you will notice with bug zappers, MSD's and such is that in really cold weather the engine roars to life about 1 millisecond quicker than a stock points distributor set-up does. Once the engine is running and warmed up, street, dyno and track testing shows no measurable improvements over the stock stuff you just replaced, if it was in good working order.......FWIW......

[Formulajones]

It's been shown even back in the smoky yunick days that opening plug gaps doesn't do anything except make the ignition system work harder.

All the talk about more flame front and all that jazz I've found does nothing on any engine I've ever tested.

[Sun Tuned]

The biggest sham ever put on the motoring public is still going on to this day. I was digging through some stuff I’ve had stashed in the garage about 6-7 years ago. Just running out of places to put stuff these days. Older friends are passing away and before they’ve passed they sometimes given stuff out to those left behind who they know will use it, instead of the kids tossing it at the front of the street for trash because they dont know what any of it is what it’s for….

Anyhow, I was going through this stuff and found some old Delco rotors. This stuff is heavy, built to survive the worst of nuclear disasters you’d think just looking at it.

Long ago somewhere around 1972 or so rotors started showing up with the firing tip shortened about 1/8”. This was done as a booster gap. The thought being the volts pile up at the end of the firing tip and then jump to the terminal . At the time this was thought to be a good idea.
The aftermarket folks followed suit and would put an “E” stamped on the brass tip of these rotors.

Somewhere along the way, someone has made the decision to make them all this way. You nearly cannot buy a rotor with the correct length firing tip anywhere local anymore. The end of these firing tips are near level with the outer body of the rotor. They will require more firing voltage to jump the gap as witnessed on a scope.


Never really thought just a whole lot about it until that day I found these and then had one of those moments….
Hmmmm……
Put one on my dually truck. Next morning came out… there was one hell of a noticeable difference in startup for sure. Now to be clear, the old rotors I found had an 1/8 LONGER firing tip than the currently available ones you buy anywhere in the last 15 years as they are SHORTER.

Later that weekend I got some out and did a little testing. That shorter tip rotor adds a good 6,000 volts to the firing voltage compared to the old longer tip rotors. So the longer tip gives reduced required firing voltage, a tick faster starts, and just fits like they used to. Don’t know when , where, or why someone went to the shorter tips and could frankly care less. But I do know we got gipped because of it.

The easier you make life for the coil and the cooler you can make it run the better off you’re going to be. Wider gaps will show a slight benefit, BUT, there are rules.
There is a diminishing returns deal on that and honestly much more than .010 bigger than stock setting is about all you’re gonna get there worthwhile. And for sure the gain you do get is going to be so small you won’t notice it , and almost impossible to feel it. As was said earlier all you’re really gonna do is work the coil harder.

This rotor gap deal is most definitely a thing. They use to specify a test just for it back in the scope days in the 70’s. That’s how they could tell you had a worn rotor without taking the cap off. How we managed to get away from that concept I’m not sure.

The smaller that gap between that rotor tip and those cap terminals … the better off we all will be.

[Sun Tuned]

That .010 bigger gap I was talking about was meant to be only about spark plug gap. Wider, especially much wider as some will promote is not a better deal as formulajones alluded to. Sorry for the confusion.