"Back-grading" from Pertronix to to Points.
 

Having some ignition issues, and here's what my tech had to say:

Ignition system:
Checked ignition system and found the following:

- MSD 6AL ignition unit has been installed.
- Power and ground wire connections are too small (insufficient current)
- Should have red B+ hooked up to the starter B+ terminal. B- needs to go to a chassis ground using consistent gauge wire.
- Distributer is a small diameter 2.4/2.7L unit with points conversion (Pertronics)
- This conversion is not timed correctly and is firing the ignition between ignition cap posts causing a cross fire.
- This could be caused by the Pertronics or the non stock distributer drive gear.
- The distributer should go back to points to see if the timing issue is resolved. If this corrects the problem, the distributer should be converted to a Crane ignition XR700-0292 system.
- Also – the coil primary wires and the distributer signal wires are zip tied together in the same bunch. This can cause signal interference and should be corrected.

I have a spare points set that he gave me to test, but I just need to make sure I install it correctly. I've never installed points before, as I've always had pertronix. Any thoughts/suggestions/tips?

Post a picture of the distributor wires and the primary wires your mechanic referenced.
Also some pics of how the MSD is wired up.
'79 3.0 engine with a 2.7 distributor.
Get the right electronic distributor and do it right!

you need a set of points and the little screws that come with them. Leave the adjustment side a little loose, pick a lobe that is at the highest point (points open the most) and adjust to .3mm with a feeler gauge, tighten it down and your done. Dwell angle if you have one of them fancy meters is 38+- 3˚ and thats it

Points are used as a trigger in place of the pretronics. but thy do have to be set correctly. good part is the points don't get burnt and should last a long time.

Good advice. I don't have a Dwell meter, but I can track down a feeler gauge.

With an MSD in place you don't need a dwell meter...just set the proper gap.

- MSD 6AL ignition unit has been installed.

Ok.

- Power and ground wire connections are too small (insufficient current)
Do the wires out of the MSD connect to different wires in the harness? In that case they may actually be too small

- Should have red B+ hooked up to the starter B+ terminal.
You certainly can do this, but there are other places to tap into +12v unswitched in the engine compartment

B- needs to go to a chassis ground using consistent gauge wire.
This is true, it needs to go to the chassis. Remove the paint, drill a small hole and use a short self-tapping screw to hold the wire to the frame. When you want to win the Manhattan Trophy you can weld up the hole.

- Distributer is a small diameter 2.4/2.7L unit with points conversion (Pertronics)
- This conversion is not timed correctly and is firing the ignition between ignition cap posts causing a cross fire.
What is your technician saying-- that the timing is set incorrectly, or that the magnet wheel that attaches to the distributor shaft is improperly set, or that the magnets have shifted? An explanation of HOW this conclusion was reached would be helpful.

- This could be caused by the Pertronics or the non stock distributer drive gear.
Ok, there are only two diameters of distributor shaft, 2,0-2,2 and everything that came later. If he is suggesting that there is backlash on the drive gear, that is unrelated to the ignition trigger. Did he pull the distributor to examine the gear?

- The distributer should go back to points to see if the timing issue is resolved.
Before converting back why not answer the above? And why not borrow a 2,7 distributor to check with so you don't have to tear your presumed working setup apart for diagnosis purposes?

If this corrects the problem, the distributer should be converted to a Crane ignition XR700-0292 system.
Now he's suggesting you use an optical trigger instead of a hall-effect, which is not without its disadvantages, not the least of which is the occlusion of the IR window in the trigger. And the whole system is not required, just the optical trigger portion, as you already have MSD.

- Also – the coil primary wires and the distributer signal wires are zip tied together in the same bunch. This can cause signal interference and should be corrected.
OK, fair enough.

I have a spare points set that he gave me to test, but I just need to make sure I install it correctly. I've never installed points before, as I've always had pertronix. Any thoughts/suggestions/tips?
Remove Pertronix unit, using the same screw that held it to the base plate, install the points following the guidance in the manual. Install rubber insulator block that passes through distributor body-- the Pertronix install would have removed that. Set gap with feeler gauge, don't forget to clean and lube distributor while you are in there. Check dwell with dwell meter, even though points trigger on the rising edge you can still screw up if the dwell periods overlap.

swap the wires going to the dist. IE, connect the violet to ground/shield and the green to hot/center conductor.

Out of Phase Rotor Pics
 

Here's the rotor out of phase at TDC
http://forums.pelicanparts.com/uploa...1371058088.jpg

http://forums.pelicanparts.com/uploa...1371058097.jpg

I don't understand this...what will this do?

Michael, why wouldn't you turn the crankshaft to Z1 on compression TDC, turn the distributor body until the rotor points at the radial notch in the distributor body, tighten the clamp a bit, start the engine and set your idle timing by further rotating the housing, then tighten the clamp down?

Am I missing something here? Did the poster above nail it, do you have a counterclockwise distributor gear installed, and you are trying to use a clockwise distributor? You must change the distributor gear if you want to use the earlier distributor. It's easy enough to check, remove the cap and turn the engine over carefully by hand and see which way it turns. If it turns CCW then you need to source an SC distributor.

the MSD is looking for a neg to pos signal. yours may be pos to neg and if so, the front edge is not very "clean" and that makes it fire between cap posts. if you look at your timing at idle, it is probably VERY advanced, like 30-50 degrees.

look me up and find the thread i started about MSD and timing, but here is how i figured it out:
i was/am having a miss issue on my 930. so i looked at the dist output to the CD unit. (CCW rotation). the signal was clean from pos to neg but on the front side ramp up to the pos peak, the rise time was not very steep and and some oscilations on it. i put in an MSD to eliminate my speed relay but the car ran like crap. in short, i found the timing VERY advanced even though i touched nothing else. i started to rotate my dist to fix it then i said no, something is not right. so i researched and found MSD wants a neg to pos signal. i swapped the violet and green and it fired right up.
i dont know what the pertronix signal looks like or your rotation, but i would swap the 2 wires.

with that said. i prefer the reliabilty of the points.

i think this is only a real issue with CCW porsche distributors. as for yours, not sure.

That seems pretty easy to test. If it's NOT that, can this do any damage?

i was going to do that on my 930 but you cant.

this is very confusing to explain.
imagine a line drawn at about an 80 degree angle, from left to right, top to bottom. the left side is the front/begining and it is positive(POS). the top right is negative(NEG). the center is 0volts or ground.
then the signal goes back up to the POS side of the next pulsse to fire the next plug. BUT, in between the signal is not a straight line and can look kinda "funky", like maybe an "S".
the bosch CD uses the staight line where it crosses from POS to NEG, or about.
the MSD is looking for the point where the signal crosses 0volts in a NEG to POS direction. unfortunatley this point is the "funky" "S" part of the signal. this part can also be very inconsistant and make the timing jump around.
so simply swapping the 2 wires now makes the signal "appear" to go NEG to POS.
its like connecting a multimeter up to a battery backwords. its still 12.6 volts, now it just reads -12.6v

i hope i did not make it worse. its hard for me to explain typing.

here is something from some info i have on MSD.
notice what i have in bold. it says it will fire early, which = advanced timing. it will also advance even more as the RPM's go up.

The magnetic pickup inputs are the violet and green wires. The green wire is grounded internally to the unit. My unit fired when the voltage on the violet wire reached about +0.3 V, and it triggered on the rising edge of the signal. This is important information, as it will affect the timing depending on the polarity of the signal from the magnetic pickup. In the correct case: as the rotor in the distributor approaches the

magnetic pickup, the voltage will go negative to some max value, then swing positive. It will pass through 0V as the rotor is exactly lined up with the pickup (this is where you want the ignition to fire); the voltage will continue to go positive to some max value, and then return to 0V as the rotor rotates away from the pickup. It is the negative to positive transition that you want as the trigger reference. If the wires are reversed so that the signal goes positive first, the unit will trigger early (as the rotor approaches the pickup). This will cause early timing. Even worse, the trigger point will change depending on RPM, as higher RPM will create higher voltages. This is illustrated in Figure 1.

Here's my wiring diagram...which ones should I swap?

http://forums.pelicanparts.com/uploa...1371060899.jpg


Also, my guy had this to say about swapping the wires: "That doesn’t apply to your car.
That applies to a late distributer with magnetic pick up. Just replace the points and tell me if rotor position improves."

I'm way out of my area of expertise here, so I'm fumbling a bit.

You don't use the magnetic pickup wires with MSD and Pertronix, you use the white points wire.

Click this link for diagram: http://www.pertronix.com/support/tips/pdf/msd6series.pdf

If you still have points, you only have one wire.

i was trying to help with your pertronix setup.

if you have the points back on and i take it the timing is very advanced at idle, then that is a mechanical issue with the distributor. either the points are mounted wrong, the plate is wrong or the advance springs are not connected and it is at full advance at idle.

No...I currently have a brand new Pertronix II ignition installed. It's wired exactly like the diagram I posted above, with the MSD Tach adapter.

i will have to look into the pertronix hookup some more, i thought it used the magnetic hookup, not the points hookup.

what is your timing at idle?
it may come down to what 304065 said, rotate the dist shaft so you can adjust the timing. thats the problem i had. it was so far advanced, i could not retard it enough to come close to the proper timing, and like yours, mine was sitting between to posts

i would stay with points, but thats me. i like reliability.