Points vs HEI vs WHAT?

[mistaake]

So, this might seem like a dumb question, but please bear with me

I don't understand what is Points vs HEI? I've searched in online, but it's just a different type of distributor?

What are the pros and cons of each technology, what is the difference, what needs to be changed to convert one to the other, are there any other types besides these two, and if I'm in CA and need to smog it can I even change it?

Thanks in advance for answering this question that problem seems totally goofy but would really help me make sense of it all!

PS: Oh, and if I get a cheap tach off eBay or Amazon where do I hook up the wire?

 

[firebane]

HEI > Points

But if your points system is working fine then I would just leave it. If you convert to HEI there is a lot of wiring you need to change and redo.

 

[mistaake]

Okay, so they are two different types of ignition systems? How do both systems work, and what components do they consist of?

 

[GTME94]

Here is a quick explanation.

Points are an actual physical electrical switch inside the distributor. There is a cam on the distributor shaft that pushes open the switch (points) for every time the spark plug needs to fire. The points have to be adjusted to open at the proper time and open the switch the proper distance. The electrical contact wears over time and must be re-adjusted or replaced.

HEI uses an electromagnetic signal from a star shaped wheel to send the signal to fire the plug. It doesn't need adjustment but does require a electronic module inside to make it work. That module can go bad and the distributor doesn't function at all.

Points were used for 70-80 (?) years. They can always be adjusted for filed down to function properly. If something goes bad and you are in the middle of nowhere they could be made to work good enough to get you to civilization but may not always work perfectly. HEI works perfectly until the module goes bad and then doesn't work at all.

Sort of like carburetor vs fuel injection. A carb is simple and can be adjusted with a screw driver but seldom works perfectly under all conditions. Fuel injection works great for all conditions but when electronics fail can make the engine not run.

 

[mistaake]

Thanks man, that really helps. Appreciate you taking the time to provide that kind of answer So, then a 1983 doesn't have points - what does it have?

 

[CSFJ]

HEI ignition.

 

[mistaake]

HEI ignition.

I think I like that Thank you very much!

 

[HotRodPC]

Points ignition was usually 73 and earlier. 74 and later was HEI where the Electronic Ignition Module replaced the need for points. Then HEI ESC (Electronic Spark Control)came about. The ignition modules and wiring are different, though both are still considered HEI. Standard HEI is about as bullet proof ignition system you can get but it's true, the Ignition Modules can go out without warning at all. Usually they last many years but sometimes they can last months too. Always a good idea to carry a KNOWN good spare module in your glove box with a screwdriver and a 1/4 in nutdriver. They can be changed on the side of the road if need be. (74 was transisition year, so some vehicles still may have points, but by 75 all were HEI)


One other note, some say when and if we have the nuke or electrical power spike blah blah blah, that Electronic Ignition modules will burn up then you're dead in the water. So keeping a points type distributor around for your post apocolypse transportation may be a good idea. I'll be having one in my Zombie Recon vehicle. The spare dizzy that is. I'll run HEI for certain.

Other things to note if converting, Points type runs on 6V, this is why the starter has S and R and why firebane mentioned wiring changes. Really it's not that hard though. So on a points system, you're on the S side of starter solenoid to have 12 volts to the points while the motor is cranking so it starts. Once it starts, now the R side of the solenoid takes over and cuts the voltage down to 6V. This is why on HEI vehicles, the R side of the starter solenoid is not used. Now, the HEI system takes 12 volts all the time, both cranking and running, so 12 volts direct from the igntion switch works fine. Easy way to remember this is, S for Starting/Cranking, R for Run which is 6V. That is NOT what the S and R stand for, but you can use it as such to remember the S is 12V and R is 6V.

 

[chengny]

PS: Oh, and if I get a cheap tach off eBay or Amazon where do I hook up the wire?


There are two external connections to a basic (i.e. non-ESC) HEI distributor: One is the power supply to the coil (pink). The other is a pulsed signal that is used to drive a tachometer or supply an engine speed signal for other reasons:

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

If you want to run a tachometer, it will be necessary to tap into that white wire. A tach usually has 4 leads:

1. An ignition switched power supply
2. A variable voltage feed from the dash illumination circuit
3. A ground wire
4. The pulsed signal from the distributor

Rather than trying to locate the end of the lead that would go to a factory tach, it is often easier to just cut the white wire (near the distributor) and splice a new wire on to it.

 

[HotRodPC]

And if running a tach on the Points style distributor with the external coil, (HEI has internal coil in the dizzy cap) you'll run your tach wire to the negative side of the coil that goes to the distributor. The positive side of the coil is where your 12V/6V ignition switch wire goes.

 

[firebane]

Also if you don't have the OEM connectors they are available to allow a proper connection to the distributor.

And regarding the wiring for the distributor if the truck is stock the power wire for the distributor will be a resistance wire which you also don't want to use as it will only provide a minimal amount of power to the distributor.

You can either pull the wire from the bulkhead connector and make a new one in its place or run a seperate wire for 12v to the distributor. I bought new connectors and ran a 12g wire from the bulkhead to the distributor.

 

[HotRodPC]

Yep, there was 2 ways to cut the voltage down, resistor wire as mentioned was common on GM's. Other method was to use a Ballast Resistor.

 

[mistaake]

Wealth of info as usual Thanks guys!

What's a compatible tach? I would love this one but it's too expensive:
http://www.gmsports.com/content/new-tachometer-1973-1988-chevy-and-gmc-trucks

So what about something like this on eBay? Would this be compatible? I'm assuming there is some way to adjust whether you have a 4,6, or 8 cylinders? And I sure hope I can turn off the backlight!

http://www.ebay.com/itm/2-52MM-RPM-...-US-/111347361481?hash=item19ecd1e6c9&vxp=mtr

I know it looks ugly and cheap but if it works, it works. I can always buy the nice expensive one later when i can afford it

 

[HotRodPC]

For $13, you can't go wrong. It's worth the risk being it's only $13 shipping included. I do see a switch on the back of it.

 

[mistaake]

Ordered