Electronic ignition - Revisited after I gave up!

[Arne]

Test #3

Changes from Baseline:

• All changes from Test #2
  
• Replaced original resistor with the new one that shipped with the Crane PS20 coil
  

Results and notes:

• Car runs cleanly throughout rev range again. No change from the results of Test #2.
  

[Zed Head]

Have you checked the condenser/capacitor for proper function? Maybe it is wearing out, has turned in to a resistor and is hindering your coil charging. As I understand things they usually die completely but if the dielectric material started to break down it might leak current slowly. Many multimeters have a capacitance measurement function, but at the least the condenser should show infinite resistance.

FWIW, I have a condenser on my negative post but only for noise reduction to the tachomoter. I installed a Z31 coil and my tachometer stopped reading correctly, until I added the capacitor. I put it on the negative side because that's the side the tachometer sees. But that's another story, my point is that I have a condenser on my coil (-) post and everything works fine. This is a 280Z with the stock ECU , GM HEI module and a Z31 coil.

[Arne]

Test #4

Changes from Baseline:

• All changes from Test #3
  
• Re-installed Pertronix Ignitor.
  
• Timing set to 5° BTDC as before.
  
• Pertronix dwell angle checked at 35°, non-adjustable.
  

Results and notes:

• Car runs cleanly throughout rev range again. No change from the results of Tests #2 & 3.
  

Note that the only difference between this latest test and the test run w/Pertronix immediately after the arrival of the Crane coil (where the car ran bad enough that I actually pulled over and bypassed the resistor just to get home) is that the condenser at the coil is disconnected. I hear no radio interference, the motor runs great, and all seems good.

Now we'll have to see if it holds up this time. But I'm optimistic about this for the first time in a long while.

Edited June 17, 2011 by Arne

[240dkw]

Arne: this does look promising, are you going to try the positive side of the coil or leave it alone if it works well.

Dan

[Arne]

For now, I've completely removed it. I'll do some research eventually to figure out where it should/would have been connected from the factory. Still want to try one more test - wide-gap plugs. Will do that in a few days.

[sparrow6190]

any update? every time I ever had an ignition problem it was a "doh!" moment , its actually quite simple on every year except they made every year a little different...! ugh

oh, and as for running a zx dizzy and having problems like you said earlier (the autos have a 9* t-bar, and i think lighter springs, manuals have the 8.5 and a bit stiffer springs i think, but ive seen all different kinds...), the closest zx dizzy to an actual 240Z dizzy you could get would be an automatic with no vacuum advance hooked up, but you still would have very minimal mech advance so it would not be any sort of upgrade from the original points , not if they are working fine.

[Arne]

No change since test #4. Still working fine. I now suspect that the pair of condensers (one bad, and one possibly mis-connected to compensate for the bad one) was the cause all along. I still want to try a set of wide gap plugs (preferably BP6ES-11, as other than the gap those are identical to what is working now), but I haven't gotten around to picking a set up yet.

[240zdave]

The one thing I didn't see you mention is jumping the ballast resistor. It should run with the ballast in place but you'll get a lot hotter spark with it bridged. Having used both quite a bit (first Z had points) I wouldn't run a point distributor unless it was absolutely necessary.

Jon, when you say bridge the ballast resistor, do you mean get rid of it entirely? I race a 240Z in ITS, and I'm running a Pertronix, MSD 6AL, an MSD Blaster coil, and the distributor vacuum advance is disabled, with no ballast resistor at all. I took my 240Z street car down to John Williams in Atlanta to get the same setup, and we had a hard time getting the thing to run. The final setup includes the ballast resistor, but basically using it (I think) as terminal posts for termination/connection of some of the wires. I wanted to try taking out the ballast resistor to match the setup in the race car, but it was getting dark, and I had to get back to Nashville, so I have not tried that yet. The car runs great, but I don't know if I giving up some performance with the ballast resistor still there.

[SteveJ]

If you want to run without a ballast resistor, you need to get a 3 ohm coil. The resistance has to come in somewhere.

[Arne]

Test #5 (Final)

Changes from Baseline:

• All changes from Test #4
  
• Installed new NGK BP6ES-11 spark plugs, pre-gapped at .044" (1.1mm)
  

Results and notes:

• Car still runs cleanly throughout rev range. Can come off choke much sooner.
  

This was the last piece to implement. The wider-gap plugs give better spark, which is definitely noticeable in the need for less choke when cold.

It seems quite apparent now that my issues from the beginning were related to the condensers. The condenser at the coil is still not connected.

Edited July 22, 2011 by Arne

[jmortensen]

Jon, when you say bridge the ballast resistor, do you mean get rid of it entirely? I race a 240Z in ITS, and I'm running a Pertronix, MSD 6AL, an MSD Blaster coil, and the distributor vacuum advance is disabled, with no ballast resistor at all. I took my 240Z street car down to John Williams in Atlanta to get the same setup, and we had a hard time getting the thing to run. The final setup includes the ballast resistor, but basically using it (I think) as terminal posts for termination/connection of some of the wires. I wanted to try taking out the ballast resistor to match the setup in the race car, but it was getting dark, and I had to get back to Nashville, so I have not tried that yet. The car runs great, but I don't know if I giving up some performance with the ballast resistor still there.

Sorry, missed this. You will increase the voltage to the coil without the ballast. The resistor is there to lower voltage so that the points last longer. You don't have to remove it, just run a jumper wire from one side to the other.

Edited July 21, 2011 by jmortensen

[dhoneycutt]

When I installed the Crane ignition (XR3000 with PS91 Coil) in my 72, I was instructed to jumper the ballast resistor. I have not had any issues since I installed it a few years ago. I hope you get it all figured out Arne.

Edited July 21, 2011 by dhoneycutt