Correct me. Sorry for the tangeant.

Isn't the stock GM hei module limited to 5v to the coil primary and some of the aftermarket boosted to 7.5v to try to attain a hotter spark capability.

 

I think I just figured something out. If that diode wire is attached to the S terminal the diode would be needed I think because when the S terminal is not being fed 12 v from the ign switch it is going to ground through the solenoid-so in the run position the pos term of the coil would be grounded out by the S terminal.Does that sound right ?

 

Sorry, but neither voltage statement above makes any sense to me. Perhaps I'm just looking at things from a different angle than you.
But, in an attempt to offer some usable info in my reply, let me say this: The HEI module is designed to operate correctly in the 6-16 volt battery range. The coil will run just fine in this range also, as the module will increase or reduce the dwell time/angle to try to maintain a 5.8 amp primary current.
Most aftermarket systems are not designed with the robustness and sophistication of the HEI. That is why many aftermarket systems continue to require a ballast resistance (a key indicator of a crude design), or a cool, low vibration mounting surface (indicating fragile, possibly cheap internal components).

 

Sorry guys. The Powermaster starter I have (#9502) has only the Battery and S terminals. However..............according th the guys at Powermaster Tech help, there is a terminal on the backside of the starter (has a large guage wire coming from inside the starter) that this "R termianl diode wire" attaches to and connects to the small guage wire from the + side of the coil.

Hope this clarifies it somewhat. I'm still undecided what is best to do for my situation. Just don't want to have a system that is subject to fail due to too much voltage.

Thanks,
Rex

 

Good point, you probably hit the nail on the head. I perfer not to use a ballast resistor and do away with the need for any of it. Assuming you have chosen to go with electronic ignition here.

 

Well that shot down what I was thinking.
Now I'm getting confused though-do you have this R term diode wire connected ?

 

If you jumper 12 volts direct to the pos side of the coil (leaving the resistor wire in place) and start the engine and then remove the jumper will the engine continue to run ?

 

If this diode wire cant be connected to your starter and your engine wont fire on just the current supplied by the stock resistor wire then I dont see why you cant wire in a small 4 terminal relay"using all the stock wires at the coil as I was talking about in my #20 post".Then you wont have TOO much voltage because your still using the resistor wire.

 

See my response below highlighted in red italics

Thanks,
Rex

Originally Posted by Dr L-88
Posted this in the C2 section but got no response so I'll try it here......

Has anyone experienced this problem, and if so, how did you resolve it?

67 Corvette with std point type ignition, runs great.

Modifications:
1. smallblock engine changed to big block
2. point type distributor converted to breakerless electronic (http://www.lectriclimited.com/mainpage.htm Breakerless Ignition conversion)
3. 9502 Powermaster mini starter with #600 replacement R terminal diode kit (http://www.jegs.com/i/Powermaster/713/600/10002/-1)

Problem:
1. Engine will crank, but will not fire, unless the ballast resistor is bypassed.

2. With the #600 replacement R terminal diode wire installed, the ballast resistor still must be bypassed in order for the engine to fire.
Where do you have this wire connected to ? It is connected to the terminal on the engine side of the starter, per advice from Powermaster Tech. Maybe this is for use as the R terminal where necessary.

3.Engine will start and run fine as long as the ballast resistor is bypassed (regardless of whether the diode wire is used), which results in a continuous 12 volts to the coil and distributor (not true now that I have actually checked, actual voltage is 9.76 at coil)
Powermaster Tech Service says "it's probably OK to bypass the ballast resistor as long as the R terminal diode wire is used".
Why would you need the R terminal diode wire if the resistor wire was bypassed ? To project the coil from excess voltage???????

Lectric Limited Tech help says "the ballast resistor MUST BE USED in order to avoid damage to the coil and the electronic ignition".I would think if the R term diode wire was doing its job (getting the engine to fire while cranking)and the new module was designed to run using the resistor wire then you should be done. (Perhaps I am)

As I see it, my current options are:
1. Use the system as is with the ballast resistor bypassed and run the risk of damaging the coil and / or electronic ignition.

2. Convert back to a points type distributor and put the ballast resistor back in the circuit.

3. Hope someone here has experienced this same problem and they figured out how to get it to work.

As always, I'm open to any and all suggestions / advice and I appreciate everyone's input.

 

Dr L-88 how did you resolve this ?

 

If your talking about a shunt relay for starting as opposed to the starter shunt, then yes.

 

Why is that so hard to understand for most people?

 

Because in "my" case I'm just a mechanic not an EE like you guys. Since Mike explained it I understand it , that's not entirely true , because Mike took the time to explain it "I believe it" would be more accurate.

 

Seems like the puropse of the R terminal diode is so the ign circuit won't back feed into the starter solenoid and keep it engaged, am i missing something? Seems like if the diode is cutting the voltage to the coil down that much , it;s defeating it's purpose.

 

If it was attached to the purple wire that might happen but since its supposed to go to the second large lug on the solenoid I think it has more to do with grounding the yellow wire through the windings in the starter once the starter is disengaged.
I don't think the diode cuts down the voltage or current it just acts as a 1 way valve.

 

It would still supply power to the motor circuit of the starter, but not enough amperage to actually make it spin, so thereby drawing down the voltage that supplies the coil from the resistance wire. I thought read that he only had 9.?? volts coming to the coil when using the diode.