Hot Rod Forum banner

41 - 60 of 75 Posts

·
Registered
Joined
·
1,048 Posts
Discussion Starter · #41 ·
Easy to rule out. Disconnect the Alternator and run on a good charged battery with no other electrical accessories running. Surely you can run it long enough to see. I am still suspect of voltage at the coil and polarity correct and then perhaps a faulty coil at temperature. I like Mallory stuff myself. They have been quality for the 40 plus years I've bought it and the older stuff is no different.
I haven't had a chance to work on it again yet, but yeah, I thought of disconnecting the alternator.
How would I check for polarity?
 

·
Registered
Joined
·
1,048 Posts
Discussion Starter · #42 ·
If it is a single wire, most I have seen are almost always closer to higher output operation than generally needed. Most tractor guys are points or diesel plus they run in a fairly harsh environment, i.e. rebuilt more often and battery(s) replaced in 2 years not 5 or 7. But the paramount issue being pointed out by all is, electronics need clean sine wave power for proper operation and longevity. The days before electronics didn't matter so much.
Looks like I better look into switching over to a 3 wire alternator. I don't suppose that you can convert a one wire to 3 wire? There is a 2 wire plug in type spade terminal next to the output terminal. I probably can't get that lucky?
 

·
Registered
Joined
·
1,822 Posts
Mallory is a wholly owned subsidiary of holley performance who is owned by sentinel group , an investment capital firm . The " bean counters" are in charge , profitability rules over quality !
 

·
Rod...from a Chrysler?
Joined
·
5,322 Posts
Best 12 bucks I spent. I plugged it into my lighter. My alternator was toast. The numbers were jumping up and down like a yo yo. This is now my permanent voltage gauge and thermometer and phone charger.

Voltage Gauge
 
  • Like
Reactions: jaw22w

·
Registered
Joined
·
28 Posts
I haven't had a chance to work on it again yet, but yeah, I thought of disconnecting the alternator.
How would I check for polarity?
Your points are the switching ground that allows the windings to build up then when the points open, the energy in the coil releases into the distributor and thru the wire the rotor is aimed at. SO, the negative side of the coil is towards the distributor no matter what the switching device is. The positive naturally receives the hot from the ignition switch. Again, an Oscilloscope will give you this info fairly quick if you know what a good pattern looks like. Reversed polarity and % of dwell that equals timing and how much it changes with RPM, coil output are a few things you can determine if you had it on one, but for now, let's get you running.
 

·
Registered
Joined
·
13 Posts
Plus of possibilities all the most is points run on 6 to 9 volts so somewhere in the run position wiring of the ignition switch is a resistor, it can be in line somewhere, a resistive wire from switch to coil, or a stand alone under hood resistor. These whatever the configuration need to go, electronic ignitions are really designed to operate on full B+ voltage of 12.5 volts. Some advertise as being able to operate on resistor voltage but they never do it well.

Another is ignition electrical noise, electronics need to be protected from the spark arcs in the cap and plugs, this means the use of resistor secondary wires and plugs, the wires can be spiral wound as an alternative, straight metallic plug wires are out.

Grounds, can’t have too many; it’s a good idea to wire the intake and heads and maybe even the distributor body to take them to a chassis or battery ground terminal connection to insure there are no transient voltages finding a ground potential through the electronics as this smokes them expensive little parts.

Bogie
 

·
Registered
Joined
·
13 Posts
Jaw22w, I would recommend isolating the alternator as per Betterdays suggestion. If I understand what I’ve read the engine runs ok on point ignition. I’ve seen several late model vehicles with excessive AC ripple cause communication problems between the various modules used on these vehicles.
The best way to confirm this is with a lab scope but without one simply disconnect the single energize and B+ wire and test run. A fully charged battery should allow plenty of run time.
One final thought is have you disconnected the tach wire to confirm it’s not causing problems on the trigger side of the ignition?
That’s the first I did when diagnosing ignition problems on vehicles with aftermarket tachs.
 

·
Registered
Joined
·
1,048 Posts
Discussion Starter · #49 ·
Just to be clear the car is running on the points setup.
I have checked the Alt output. It is 14.2 volts and steady. Seems pretty high. I am looking into changing to a 3 wire setup.
As far as polarity, I don't see how that could be messed up. If I had an oscilloscope I wouldn't know what to do with it.
 

·
Registered
Joined
·
13 Posts
Jaw22w, then put one of the electronic systems back in the engine, run it till it acts up, isolate the alternator from the cars electrical system, run again and see if the problem goes away. If it does, sounds as if it needs a quality alternator or have it tested by a rebuilder for excessive AC voltage and have it repaired. If isolating the alternator f do doesn’t change anything at least you can move on to something else
 

·
Registered
Joined
·
14,040 Posts
Your switching back and forth between electronic and point ignitions, we’ve probably been down this path already but there is the question of how your are managing the voltage differences between electronic’s preferring 12 volts and points 6 to 9?

Your marginal alternator output of 14.2 sounds in the OK range. While we talk about ripple in that without a scope there is no way to tell as a gauge in not sensitive enough to react to these wormy excursions.

It has been suggested that tach can be a trouble source this is true and you should test for this by disconnecting the tach connection at the distributor.

For wiring to the plugs electronic systems recommend resistive wiring. To some extent as with the coil to module this is an impedance function not just a situation of random RFI being generated, which is an issue, so don’t let me lead you astray. The impedance issue between module and coil (perhaps better thought of as the secondary circuit of coil to spark plugs) subjects the module to differing amounts of current flow. With solid state (transistor) systems as the load impedance goes down the current flow goes up. The higher the current flow the warmer to hotter the module becomes. At some point the module goes wonky if not just dies.

Combat story; on my shop stereo I hooked up some automotive 4 ohm speakers, being that’s what I had at the time, but the amp specified 8 ohm speakers. I didn’t need to twist the volume very much before you could smell the hot electronics. Now I happen to like Boston’s first album at about a 120 dB but until I get a set of 8 ohm speakers built I‘m stuck on low level cruise. I just got some heavy duty wire wound 4 Ohm resistors that I’ll connect in series to balance the load, but these from a listening stand point only turn music into heat not sound, but the amp will be happier. Why build speakers, we’ll you know it’s about the money I have champaign likes on a supermarket beer budget, but I have a pretty good shop so I can bridge my esoteric likes with my mediocre budget with some Ebay parts shopping and couple sheets of Home Depot birch faced 3/4 plywood.

Bogie
 

·
Registered
Joined
·
13 Posts
Your switching back and forth between electronic and point ignitions, we’ve probably been down this path already but there is the question of how your are managing the voltage differences between electronic’s preferring 12 volts and points 6 to 9?

Your marginal alternator output of 14.2 sounds in the OK range. While we talk about ripple in that without a scope there is no way to tell as a gauge in not sensitive enough to react to these wormy excursions.

It has been suggested that tach can be a trouble source this is true and you should test for this by disconnecting the tach connection at the distributor.

For wiring to the plugs electronic systems recommend resistive wiring. To some extent as with the coil to module this is an impedance function not just a situation of random RFI being generated, which is an issue, so don’t let me lead you astray. The impedance issue between module and coil (perhaps better thought of as the secondary circuit of coil to spark plugs) subjects the module to differing amounts of current flow. With solid state (transistor) systems as the load impedance goes down the current flow goes up. The higher the current flow the warmer to hotter the module becomes. At some point the module goes wonky if not just dies.

Combat story; on my shop stereo I hooked up some automotive 4 ohm speakers, being that’s what I had at the time, but the amp specified 8 ohm speakers. I didn’t need to twist the volume very much before you could smell the hot electronics. Now I happen to like Boston’s first album at about a 120 dB but until I get a set of 8 ohm speakers built I‘m stuck on low level cruise. I just got some heavy duty wire wound 4 Ohm resistors that I’ll connect in series to balance the load, but these from a listening stand point only turn music into heat not sound, but the amp will be happier. Why build speakers, we’ll you know it’s about the money I have champaign likes on a supermarket beer budget, but I have a pretty good shop so I can bridge my esoteric likes with my mediocre budget with some Ebay parts shopping and couple sheets of Home Depot birch faced 3/4 plywood.

Bogie
 

·
Registered
Joined
·
1,048 Posts
Discussion Starter · #54 ·
Your switching back and forth between electronic and point ignitions, we’ve probably been down this path already but there is the question of how your are managing the voltage differences between electronic’s preferring 12 volts and points 6 to 9?
With the points system, I have been running a ballast resistor. It reads 2.0 ohms with either a .9 ohm or a 1.5 ohm coil. Both work.
When using the electronic systems I wired 12+ straight to coil. In each instance I used a Speedmaster e-core coil with .4 ohm resistance. I talked with each manufacturer concerning the use of this coil. Each assured me it would work fine. It did work with the chinese RTR with the GM type module for several thousand miles.
As you suggested earlier I have 3/8" ring terminals ordered to make a nice job of grounding the heads, so I can use the 3/8" accessory holes in the back of the heads. My main ground, engine to frame, is at the bellhousing. I can connect right there and make a nice looking job of it. For manifold and distributor grounding I am thinking to run a ground wire to the distributor hold down bolt. That should ground both the distributor and the manifold.
I did try disconnecting the tach. It made no difference.
I still have the Fast XRi conversion unit. After the frustration level declines, I may try it again. As for now it is running on the points.
Thanks
 

·
Registered
Joined
·
14,040 Posts
Which Speedmaster coil? While reading static resistance is not exactly the same as impedance .4 ohm seems pretty low. Most HEI coils run around 1.5 give or take a few tenths. Going back to what I said about current flow which increases as resistance/impedance goes down which for switching transistors makes them run hot and they go from running wonky to just crapping out as they get above some design temperature. Points as a mechanical device while not immune are much more tolerant of what you can consider in this instance an ’overload’ so your points may well function with that coil where the switching transistors or some other nearly microscopic part in that module may not be finding happiness at the required current level the coil demands.

Manufacturer and retailer help lines are notoriously staffed by people who really aren't qualified. There are exceptions but in my experience they are far and few between.

Bogie
 

·
Registered
Joined
·
371 Posts
I’ve experienced the GM’s HEI module requires one of the low ohm age coils to function as designed. Unfortunately GM does not offer them with studs so they would mate with the ring terminal harnesses of 50’s & 60’s vintage cars. I shoved flattened 8-32 threads into the female plugin’s. They seem to bite in pretty good.
527312

I also think the ohm’s reading on these “E” core coils are very low, under 1 ohm. I have repeatedly measured a couple tenths ohm on both types pictured below.
Here is a photo I grabbed of the interweb of the type shown above without 8-32 studs.
527314


This GM type also works just as well. You can obtain either type on line for around $10 bucks if you look around. This type is a bit more difficult to add 8-32 studs since you need to drill a small hole up the center of the stud to press onto the small projections.
527313


But the reason I’m sharing this is the HEI module needs to be matched to a “E” core coil that matches design requirements or else the module will die. The only down side to the last photo is the coil high tension is not standard. I cut down the phenolic about 1/2” and added a male prong to accept normal HEI plug type wires.

I’ve been running copper plug wires and non resistor plugs without issue. Not to say it is necessary or not since GM in the 70’s used resistor wires and plugs. Is one any better than the other....don’t know.
 

·
Registered
Joined
·
1,048 Posts
Discussion Starter · #57 ·
I’ve experienced the GM’s HEI module requires one of the low ohm age coils to function as designed. Unfortunately GM does not offer them with studs so they would mate with the ring terminal harnesses of 50’s & 60’s vintage cars. I shoved flattened 8-32 threads into the female plugin’s. They seem to bite in pretty good.
View attachment 527312
I also think the ohm’s reading on these “E” core coils are very low, under 1 ohm. I have repeatedly measured a couple tenths ohm on both types pictured below.
Here is a photo I grabbed of the interweb of the type shown above without 8-32 studs.
View attachment 527314

This GM type also works just as well. You can obtain either type on line for around $10 bucks if you look around. This type is a bit more difficult to add 8-32 studs since you need to drill a small hole up the center of the stud to press onto the small projections.
View attachment 527313

But the reason I’m sharing this is the HEI module needs to be matched to a “E” core coil that matches design requirements or else the module will die. The only down side to the last photo is the coil high tension is not standard. I cut down the phenolic about 1/2” and added a male prong to accept normal HEI plug type wires.

I’ve been running copper plug wires and non resistor plugs without issue. Not to say it is necessary or not since GM in the 70’s used resistor wires and plugs. Is one any better than the other....don’t know.



The Speedmaster PC-91 coil I used was recommended by Bogie in a thread I started called "Small Cap HEI" it worked very well with the small cap HEI type distributor for several thousand miles before I changed out the whole system. I thought from the description when I bought it that it was .4 ohms. I just checked it. It is .2 ohms. So it should be within range for the HEI. I suspect the reason for the recent failure was the cheap module in the import distibutor. This is the same module I used with all the different electronic systems as blessed by their tech.
I never tried to use this e-core coil with the points, assuming it would burn up the points.

57Nomad. I really like the small cap HEI that you built. I think I would trust a good HEI module before I would trust anything else. Especially with the ease of roadside replacement. I just don't want to tackle the build myself. Tell me please. How far away from the distributor can the module be mounted? The reason I ask is that I noticed that Davis Unified Ignition has 2 small cap versions. One uses a GM type HEI module mounted to the base of the distributor. I don't have room to have it mounted in this position, but if the module could be moved to... say the firewall, I would have room. I might be interested in that if the module can be moved. I assume you would have to mount it with some type of heat sink?
 

·
Registered
Joined
·
3,757 Posts
Perhaps relevant---a friend build his own fuel injection and ignition system back in the early 1990's, he told me that the GM HEI modules have current limiting built in to protect them from failure.
 

·
Registered
Joined
·
371 Posts
I’ve mounted HEI module to the bottom of the distributor with a 1/4” thick heat sink. I’ve also remote mounted the module also on a thick heat sink under the dash in a spot that is easy to get to in the event I need to.

I just did another car with HEI module on a heat sink mounted to firewall. Again access is good. All my HEI’s are small cap.

Something to consider mounted under the distributor with thick heat sink between module and distributor should sink heat better since heat rises.
527326

527327


Access to the module screws is a bit tight with the distributor installed on the engine. I elected to use button head hex socket screws so an Allen wrench fits in there easier. One has to be able to do roadside repair/replacement should the case ever arise.

Honestly I feel the under dash location (passenger side) or firewall is more accessible than under distributor. JMHO
 

·
Registered
Joined
·
1,048 Posts
Discussion Starter · #60 ·
I’ve mounted HEI module to the bottom of the distributor with a 1/4” thick heat sink. I’ve also remote mounted the module also on a thick heat sink under the dash in a spot that is easy to get to in the event I need to.

I just did another car with HEI module on a heat sink mounted to firewall. Again access is good. All my HEI’s are small cap.

Something to consider mounted under the distributor with thick heat sink between module and distributor should sink heat better since heat rises.
View attachment 527326
View attachment 527327

Access to the module screws is a bit tight with the distributor installed on the engine. I elected to use button head hex socket screws so an Allen wrench fits in there easier. One has to be able to do roadside repair/replacement should the case ever arise.

Honestly I feel the under dash location (passenger side) or firewall is more accessible than under distributor. JMHO
Yeah, I really like the idea of the under dash installation. Couldn't possibly be any easier road side service. I'll have to give Davis a call. Thanks
 
41 - 60 of 75 Posts
Top