#61  
Old 01-27-2022, 07:40 PM
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MarkS57 MarkS57 is offline
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Quote:
Originally Posted by george kujanski View Post
Or anything with a Lucas electrical system

george
Lucas electrics?!11 AIAAAIIIYYYYYEEEEE!!!!! One of my forays into something other than GM was a 72 Triumph GT6. Loved that little car but Lucas is something I prefer to forget. Could make a good book.
Maybe 4 fuses; several at 35A as I remember- a lot of damage can occur before a 35A fuse blows.

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  #62  
Old 01-27-2022, 08:40 PM
dmac dmac is offline
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Originally Posted by Formulajones View Post
I agree with that. I've had some HEI's that run without problems, and others that seem to go through modules for what ever reason.
It's a sick feeling when you're in a busy intersection and that module just dies with no warning, and really puts that classic in a dangerous spot. I've never had points do that to me.

And I absolutely avoid those pertronix. I've told my story with those things on here a few times and the frustration I went through with them. Pertronix was a good company at the time and warrantied everything, but the hassle and frustration of breaking down on multiple occasions had me pull those things out and go right back to points many years ago. Never tried them since.
Electronic stuff is great right until it fails. Mechanical stuff that electronics has replaced almost always gives you some notice it is going bad, when used as intended.

  #63  
Old 01-27-2022, 09:00 PM
tjs72lemans tjs72lemans is offline
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Well not sure about Alfa Romeo, but my 80 Fiat spider has electronic ignition!
I bought my 75 Camaro in 78 with stock HEI and have 155,000 flawless miles on the ignition. I hated some of the points cars I had out in the rain and would act up and miss from the moisture. That's one reason I decided on HEI from points in my Lemans.

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  #64  
Old 01-30-2022, 09:03 PM
Dragncar Dragncar is offline
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I picked up this cast iron GTO distributor from a member for 115 $. Ready to go, perfect shape.(thanks Paul C)
I would take it over a MSD any day.
Plan to use a shaft I have with welded advance weights and a MSD crank trigger.
Like i have said before, if you do not spin your engine past 8K what does any electronic distributor get you ?
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  #65  
Old 01-31-2022, 02:27 AM
Schurkey Schurkey is offline
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Originally Posted by Dragncar View Post
if you do not spin your engine past 8K what does any electronic distributor get you ?
According to GM literature, an HEI would get you more coil saturation (more potential ignition power) starting at idle and lasting to 8K rpm; and zero potential for point bounce.

Kinda guessing faster rise-time as well, but less sure about that. CD ignitions seem to be the king of rise-time.

  #66  
Old 01-31-2022, 05:14 AM
Dragncar Dragncar is offline
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Originally Posted by Schurkey View Post
According to GM literature, an HEI would get you more coil saturation (more potential ignition power) starting at idle and lasting to 8K rpm; and zero potential for point bounce.

Kinda guessing faster rise-time as well, but less sure about that. CD ignitions seem to be the king of rise-time.
I run a 7-AL2 so I am sure the rise time is all good.
I am sure a HEI has more juice starting and all that. But that is only without the CD.
There is zero point bounce with a good set of Accel points.
I have the same distributor in my old 455. My pal has a old Sun distributor machine in perfect working order.
When we double checked the advance curve Whitmore set up he spun that think all the way to 8,000RPM. Never missed a beat, not one miss fire.
And it was kinda scary standing next to it at 8K.
I have had 2 sets of points in 30 years. Only changed to first 'just because".
Everyone at the track has had a ignition issue from time to time.
Not me, ever.
Best ignition there is. Simple, reliable and effective.

  #67  
Old 01-31-2022, 04:12 PM
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Tom Vaught Tom Vaught is offline
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1) If I remember correctly, ....LOL.......... the Timing gears on the crankshaft/camshaft are: small gear for the crankshaft and large gear for the camshaft.

This means that the camshaft turns at 1/2 the speed of the crankshaft.
Since the camshaft drives the distributor gear this means that the crankshaft goes around twice for the camshaft to have one full rotation.

2) Since the points work (open and close) 8 times because there are the same number of lobes on the points cam as the number of cylinders that need spark (with a V-8 engine), for each full rotation of the distributor driveshaft gear.

3) Since the normal distributor machine spins the distributor at the same speeds as a engine camshaft would drive the distributor, I would say that your distributor was actually spinning at 4,000 distributor rpm (without point bounce) but would be the same as your 8,000 engine rpm assumption you posted.

With a decent set of points you really do not need a HEI type coil signal vs a points signal to the coil.

JMO Not disagreeing with you Dragncar, just getting the theory to match what you posted.

Tom V.

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  #68  
Old 02-01-2022, 05:11 AM
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Kenth Kenth is offline
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Spinning the distributor 8000 rpms in a Sun distributor machine would mean 16000 rpms at the engine crankshaft! Unreal.....

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  #69  
Old 02-02-2022, 02:07 AM
Dragncar Dragncar is offline
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Maybe 8K on that machine is 4K at the distributor. It was over 20 years ago last time we had it on there. Standing next to it was kinda uncomfortable. Had a whine to it for sure.
Next time I am out at my pals place I will check out the machine, ask him about it.

  #70  
Old 02-02-2022, 08:15 AM
Sun Tuned Sun Tuned is offline
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Well, Sun never made a distributor machine that had a tachometer that went higher than 4000 distributor rpm, until 1976…. That was the 506. Even the last of the ones they made, the EDT-5001 was a 6,000 rpm unit.

The 506 would spin a distributor 6000 distributor rpm. And yes that speed will stand the hair up on your head if you got stuff rattling around. That is equivalent to 12,000 engine rpm.

All of the 504’s, 404’s, had a 4000 distributor rpm tach. The earlier 400’s, 500’s, 600, and 680 machines had a 3,000 rpm tach with the last few years of that series having an optional 4,000 rom tach available.

The MDT’s and such generally only went to 2500 rom but you have to remember those were the testers made in the 50’s. They didn’t need the higher rom because those engines generally weren’t able to go much higher anyhow.

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Old 02-02-2022, 08:55 AM
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Cliff R Cliff R is offline
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Maybe someone smarter than me can break that down into how many times per second the distributor would be firing on a V-8 engine when it is spinning 6000 RPMS? It would be a BUNCH!......

As far as MSD, and the 6AL and other boxes, there is not a single HP waiting for you anyplace over a stone stock Factory HEI with a 990 module in it. I back to backed them on the dyno and actually there was a very slight advantage to the HEI over the MSD. I would imagine that happens because of how accurate the reluctor is machined with it's "knife point" edges in comparison to the much wider unit in the MSD.

Even with that said I've used plenty of MSD distributors, billet and ready to run and they work as intended without a lot of monkeying around with them before installation. I also like some of the features that you can add with those systems, like a rev-limiter........Cliff

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  #72  
Old 02-02-2022, 12:00 PM
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I am not "smarter than you", but I'll take a stab at that anyway.

6000 crankshaft RPM = 3000 distributor RPM.

3000 X 8 cylinders = 24,000 sparks per minute

24,000 / 60 seconds in a minute = 400 sparks per second.

If this is a points-style ignition with 30 degrees of dwell, it's got 1.7 milliseconds to charge the coil between firings. An HEI has dwell-stretching circuitry, so there's a bit more time--and more voltage--to charge a coil that has less internal resistance = more coil current/improved saturation = better potential spark.

Adding a CD spark-box to the points-style ignition should improve theoretical performance.


Last edited by Schurkey; 02-02-2022 at 12:18 PM.
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