Won't start, no spark, GM HEI ignition

[username]

Hey guys, been using this site for a while, but this is the first time I've not been able to find/figure out a solution...

My bike is kick-only (only because the starter doesn't work - I think this is a solenoid problem), and has been converted to a GM HEI ignition by a previous owner.
Borrowing 12v from a car battery, I get 12v at the red wire on the coil, but no spark. The coil reads .6 ohms, which other threads say is right.
I have a spare coil and a spare HEI unit, both of which I have swapped in with no effect. Also built and installed a Radioshack rectifier, and I have the Chrysler regulator on hand, but haven't installed it.
Another puzzler - the HEI unit did not appear to be grounded (it was mounted to the battery box) even while the bike ran well. Also can't figure out if there's supposed to be a condenser with it.

I put my meter between the coil and a plug, kicked it, and got nothing. Not sure if this is a resonable testing method, but I tried to just hold a gap for the spark and got nothing.
I'm not sure how the new HEI pickup works, or how to test it, and I can't find anything about how to test the HEI unit itself.

Wit's end is long gone, and and help will be much appreciated.

Thanks

[tomterrific]

The HEI module is really rugged but the coil you use, at .6 ohm, is a bit high current and will have the module running hot. This coil (a GM?) will work and give a massive spark but is tough on the module. A higher resistance coil is safer and still will give a hot spark. I feel the module should be on an aluminum heat sink of some sort. This could be a 1/8" plate attached to the battery box or anywhere else air and mass can remove the heat. The module comes with a heat sink paste that is spread on the back of the module. This paste facilitates the heat transfer from the hot module to the heat sink. Improperly or not using this paste is a reason these modules would fail in a GM car.

Ground the module with a separate wire to the securing screw.

You did jump the bike with the car battery and it still won't spark? It's unreal how many non starting XS650's are due to the battery being dead from a duff charging system.

Tom

[username]

Yeah, I tried to start it with a car battery hooked up - no dice.
I'll get some new HEI units and coils next time I'm at the boneyard.

Any idea what the resistance on primary and secondary coils should be?
And is there a way to check the HEI units? I want to be sure that this is the problem, and that the units are bad and not something else.

[tomterrific]

The only module test I know of is replacement. The problem is found if the new module works. New modules are about $25 at any auto parts store. The HEI module can handle extremely low ohm coils but there needs to be a way to get the heat away from the module. A coil with more resistance (higher ohms)won't heat the module so much and the heat sink is less critical. The HEI module is rugged enough for just about any coil if the heat sink can keep it cool. I don't have any recommendation for a specific coil but a general rule of thumb is, the lower ohm the coil primary the hotter the spark and the more heat and stress to the rest of the ignition.

[xsleo]

Scrap it all and put in a Pamco. Easy permanent fix.
Leo

[username]

If I had the money to do that I wouldn't be messing around with this stuff.

I've mounted up an HEI unit on a heatsink with a ground lead, and made sure all the bits are ohming out at what they should. Going to stick it all back together today and see what happens.

[tonyc2me]

Have you read Mr. Rigg's $19 ignition article on this forum. You should find you answer.

[kopcicle]

If you do your homework and it isn't something like a dead module or bad ground or open pickup or ...
Brett is very approachable . Leave a PM for him and you will get an answer . Links to his sight are here somewhere although he isn't much of a self promoter he is an enthusiast . With people like him that usually have a bunch on their plate Ive either lost direction , found an insurmountable obstacle , didn't read the fine print or I'm having a bad day before I call . Search Mriggs posts here and elsewhere just because ...

Now me , I'm a self trained idiot of inconsistent proportions that usually has to read it three times , get it wrong at least once and have to fix it twice before I get it .

~kop

[tomterrific]

"Scrap it all and put in a Pamco. Easy permanent fix.
Leo "
---------------------------------------------------------------
Leo, that is poor advise. The HEI ignition is better. Here's why:

The HEI module can handle much higher current. It is a monster for powerful coils!

The HEI ignition is more rugged, more reliable.

You can buy a replacement HEI module at any auto parts store if a repair is needed on the road.

A minor but significant reason is the Riggs HEI ignition is home made and the maker knows the ignition and can repair it himself. This is also the reason a Pamco is popular. A Pamco is easy.

The HEI is already on the bike and is a great ignition. The advise to switch ignitions is what I dispute.

Tom

[xsleo]

Yes, the Pamco is easy to install, Pretty much plug and play. It's also a very rugged ignition, I believe just as rugged as the HEI units are. As far as reliable how many years has Pete run one? I've had several years of no problems with mine.
How long have the parts Pete uses in his ignition been around? Just as long if not longer than the HEI units
And as far as coils I run 75K + volts. They are now selling one with an 85K+ volts. I think that's plenty hot.
I stand by my advice.
Leo

[mrriggs]

One big advantage of the HEI that has not been mentioned is the variable dwell. On my bike, the duty cycle at idle is only 8%. That means that the coil is charging 8% of the time and can cool off for the remaining 92% of the time. Even at 8% it is still overcharging the coil. The coil holds a finite charge, once that is reached any current run through the coil does nothing but add heat and waste power.

A lower duty cycle also means the average power draw of the ignition is much lower even when pulling higher peak amps. At idle the HEI is pulling about 3 watts where the Pamco pulls over 13 watts. The coils hold the same charge so the difference is all wasted power. This makes a big difference when running without a battery.

The original Pamco had a fixed 50% duty cycle but it could cook the coil so Pete changed it to a fixed 33% duty which is still way more than the coil needs at low speeds. It's also less than optimal at high speeds since it isn't long enough to fully charge the coil. However it is just about perfect at 4000 rpm so if you spend most of your time cruising down the open road then the fixed duty cycle is good enough.

You really should run a low resistance coil with the HEI, that is what it was designed for. It has a current limiter built in that keeps the peak current through the primary consistent. You can raise or lower the source voltage and the peak current (which determines power output) will always be the same. You can feed the HEI 6 volts and the power going to the plugs will be 100% of what it would be when fed 12 volts. When running a high resistance coil (points, Pamco) your current is limited by the resistance. If you cut the voltage in half then the peak current is also cut in half. More importantly, you will only have 25% of the power going to the spark plugs. Again, this is a big deal when running without a battery. I had a buddy who tried to run a points bike without a battery and had to kick it to death to get it to start even with all the lights disabled. I have the lights on my bike hard wired and it will start with a single lazy kick.

I'm not trying to dump on the Pamco. It is a good system if you are looking for something simple and innexpensive. But to keep it simple and innexpensive Pete had to leave off some things, like a current limiter, dynamic dwell, electronic advance, overload protection, and a potted enclosure. If you want all that then you can buy a Boyer. If you want all but the electronic advance then you can piece together an HEI. If you just want an innexpensive easy bolt-on then the Pamco shines. Each system has it's strengths and weaknesses. It's not about which one is "best" but which one is best for you.

[mrriggs]

Oct 3, 2012 15:12:44 GMT -5 xsleo said:

It's also a very rugged ignition, I believe just as rugged as the HEI units are. As far as reliable how many years has Pete run one? I've had several years of no problems with mine.
How long have the parts Pete uses in his ignition been around? Just as long if not longer than the HEI units
And as far as coils I run 75K + volts. They are now selling one with an 85K+ volts. I think that's plenty hot.
I stand by my advice.
Leo

I would disagree about the Pamco being just as rugged as the HEI. [The following is based on opinion, I have no empirical evidence to back it up.]

For starters, the HEI uses a thick film circuit board that is encased in a protective enclosure and is mounted away from engine heat and vibration. The Pamco is a bare board with through-hole components hanging way off it, mounted inside a hot-a$$ paint shaker. Heat and vibration are the enemy of electronics.

The dwell strategy and current limiter in the HEI puts less wasted power through the coil which limits heat. A cooler coil will last longer.

The HEI has built in overload protection. If you forget to turn the key off it will not fry the coil and module. If your voltage regulator glitches out and runs over voltage, you will not fry the coil and module. When experimenting with permanent magnet alternators my bike was running over 20 volts at one point. The headlight blew out but the ignition didn't miss a beat. If the coil shorts out it will not take the module with it. I intentionally shorted out the coil on my bike to test this. The motor died but one kick brought it back to life.

Obviously, nobody does these things on purpose and Pete is good about replacing damaged modules when they do happen.

The ignition components I used on my bike were all 20-30 years old when I put it together over 6 years ago. This bike has been my main source of transportation for most of that time and the ignition hasn't missed a beat.

Like I say, though, there is no evidence to suggest that the Pamco can't also last for 30 years. After all, it's only been around for 5 years.

The point here is not that the Pamco is junk, because it definitely is not. It is a brilliantly simple and effective ignition and Pete has many, many satisfied customers. Clearly it is rugged enough.

By the way... A "75k volt" coil just means that the insulation in the coil can handle that much, not that it will acctually fire at 75k volt. The spark plug determines what voltage the ignition puts out and it will never demand that much. Even if it did, the spark plug wires would be lucky to carry half that.

[ignitionsystem]

mrriggs,

Well, I don't often come out of retirement, but your very good take on the state of electronic ignitions is, well, very good, but my approach to electronic ignitions for the XS650 was a little more down to earth. I wanted a simple, reliable and inexpensive system for XS650 riders, and I think that I have achieved that. In regards to the PAMCO working with a battery less PMA capacitor type charging system, which is all the rage now, the PAMCO is very popular because it will work all the way down to 3 Volts. The coil is where the demand for some current comes from. Modern coil construction can result in a non HEI coil (IE 2.5 Ohms) producing upwards of 60K Volts with a battery voltage of 14.5 Volts, almost equaling the performance of an HEI coil. What that means is that same coil will produce a workable voltage all the way down to 5 or 6 Volts, which is the key to a batteryless PMA system kick start only having a one kick start. The PAMCO is very popular in those systems for that reason.

Here is a video of a PAMCO working off of a 6 Volt lantern battery:



I also have a PAMCO system for the Honda CB750, which works off of the crank, and that system will go all the way to red line, about 9500 RPM with no problem. So, 9500 RPM on the crank is equivalent to 19,000 RPM for the XS650 with the ignition mounted on the cam, but it does have a fixed 120 degree dwell, so without doing a lot of math, that would be equivalent to 19,000 / 2 = 9500 RPM for the XS650?

Like I said, my focus is on the practical. The reasons for the development of HEI ignitions was primarily for EPA mandated emissions requirements. I am somewhat skeptical of any benefit from an HEI system installed in our beloved 40 year old engines, and the PAMCO does work all the way up to 9,500 RPM on a 6 Volt lantern battery, so, what more do you need?

pamcopete

[preston]

Thanks Pete... and others for such good insight !
Welcome back Pete.
Like has been said above, plug and play, easy, simple, dependable, long lasting, no maintenance are words that seem to have a good ring in my ears.
Those of us who are not gifted in mechanical issues, but love to ride the 650, are blessed to have such a economical, system, as PAMCO.
Thanks for this thread, and thanks Pete for the development and sale of this product.
preston

[mrriggs]

Oct 4, 2012 19:16:29 GMT -5 ignitionsystem said:

I wanted a simple, reliable and inexpensive system for XS650 riders, and I think that I have achieved that.

No arguments here. Before the Pamco ignition, the only choices for the XS650 masses were to either live with the points, convert to TCI, or shell out the bucks for a Boyer. Your ignition filled a valuable market niche.