Datsun Roadster Forum-311s.org

Dim the lights. If outside wait till dark.

Did you check if #1 TDC happens when the reluctor and rotor line up?? That's the starting point. That will tell you if you're drive gear is on the right tooth.

The distributor is firing when the vanes are lined up. And the stator line up and the rotor is lined up to #1 cylinder at TDC. Also with it at idle timing light flashing marks are lined up to 16 degrees when I give it gas it advance to only about TDC

"at idle timing light flashing marks are lined up to 16 degrees when I give it gas it advance to only about TDC"
That's not advancing, that's retarding the timing....something hooked up backwards?

Sounds like the mechanical advance is backwards, and I'm not entirely sure that's even possible.

Here's a quote from Dave Brisco on a fairly recent thread about EI dizzy issues:
"There is something with this type of ignition, mostly on GM cars or MSD systems but the principles are the same, where reversing the wires from the pickup coil to the module cause the ignition to either advance or retard, and funny enough the numbers are either 11 or 22 degrees. The rubber grommet the wires pass through to get to the module is usually stamped "red / green" to show which goes where,so it can be visually verified and Tom could confirm."

A pic of the EI lining up with the module wires correctly installed Linda

The red is going to one marked red and green to green, the pic looks just like mine

What I found on mine is the thing fired when the vanes in the center bit were about half way between the outside vanes. The red and green wires were correct. When I swapped the wires if fired correctly. To statically time, set the crank position to 16 BTDC with #1 cylinder at the end of the compression stroke. The distributor rotor should be pointing at #1 plug wire. Adjust the timing so that the vanes are lined up. When you fire up the engine your timing light should show that you are firing about 16 BTDC. If it runs very badly and the liming light shows the timing to be way off then swap the red and green wires. I am not sure why some are reverse polarity but it seems to be so. It is an easy fix once you determine the problem. I acquired a number of extra grey hairs figuring it out.

I am at my wits end on this one, I also think that this is the same symptom I had seen when the cam timing was off by a tooth - but that would not explain the fact that it runs OK with the Points dizzie. I think Keith's thought on reversing the wires is worth a try - though I sent him two different distributors, both of which checked out before they left my place!

What I am able to do is mount the distributor in my lathe and spin it up on the bench. The other thing I found was that the big spring on the mechanical advance had too much play. This caused the mechanical advance to go fully advanced as soon as the distributor started to spin. A little tweek and I think I have it sorted. We will find out next weekend. We have the old point unit in the car. I will be bringing two electronic and one refurbished point distributor. We will get this sorted out. Thinking about building a distributor test box to run them at various RPM and map out the advance and such. An old school distributor machine would be nice but I can't imagine that I could afford it even if I could find one.

Just read the updates, retarding timing as the engine accelerates. I made these before Tom took over, I had the same EXACT issue with only one customer(in Norway, just to add to the fun) who swore up and down the distributor was retarding the timing instead of advancing as it accelerated, in his words, "spinning backwards". We diagnosed to death via email, and finally we had agreed that if his old one tested good, I'd take it back, shipping both ways on him, if it tested bad and the exchange one worked, shipping on me. I exchanged the distributor, tested the old one thoroughly, VERY thoroughly, on a distributor machine and tried it in my car, and eventually re-rebuilt it and sold it to another customer, who had no issues. Man in Norway still had the same issue with the second one, sent the second one back too, which was again tested and sold with no issue. I assume he put the old unit back in the car. Never did figure it out.

Tom, I never saw his old points distributor and cant think of any way to even make one retard as it spun faster, I even tried to mis-assemble the parts, but it would need to be mirror image parts. Can't think of any way the oilpump/distributor drive could be spinning the wrong way, cam drives the gear, only one version of the engine, so just can't happen, but just for the hell of it, verify the direction it's rotating.

I built quite a few of these. Not to disparage the OP or guy from Norway, but this sounds really odd, especially with two distributors in a row both times. Making the distributors, whether it's 3 or 20 at a time is an assembly line,very routine, step follows step, I was careful and pretty organized and I know Tom is more organized and more meticulous than I was, so there should be very little variation between units, and even if there was a mistake, the same mistake twice to the same customer is unlikely.

But if the timing light says it' at 16 BTDC and advancing "x" degrees, then I would have to assume it is firing at that point. Only other thing would be if the rotor timing was very far off and it was crossfiring to the next cylinder, but that should jump timing forward, as the rotor would move that way. Very unlikely, but worth looking. Using Keith's test method, mark the outer diameter of the housing to show the location of the spark plug wire terminals on the cap, spin the engine with the starter and see if the timing light "freezes" the rotor over those points.

Keith's advice makes sense, reversed polarity will do strange things. MSD ignition even recommends reversing the polarity of the magnetic pickup if there are odd advance and timing issues when installing their boxes. It can move the timing 15-20 degrees, as Keith described. Look at the picture. Very good explanation here http://www.megamanual.com/ms2/pickups.htm The leads are marked red/green on the rubber boot where they plug into the module, but two in a row doesn't make sense. Might be inside the module too. Either way, a switch won't hurt anything. it would change the housing position and need to reset the timing. Be sure the trigger wheel had the same orientation, gentle slope and sharp dropoff.

If you look at the graph, it shows what Keith said, almost halfway between the trigger point


Tom has my number, happy to consult, but I'm stumped too. My best advice is drop the distributor in another roadster and see, removes all the variables.

Just had a thought...does the timing advance any differently with the vacuum advance disconnected and is the vacuum on the carburetor port or on full manifold vacuum?

If the vacuum advance is connected to manifold vacuum it certainly could retard on acceleration.

At least one of these distributors has a magnet/coil pair that produces reverse polarity that causes it to fire at the incorrect time. (the one I got) I did not swap the coil or magnet so I do not know the one causing the problem. If there is one then there are likely to be more. However, it is easy to test for with a timing light and easy to fix by swapping the red and green wires.

Not sure what this could do if incorrect, but in this pic, to the right at 3 o'clock you can see an "A" which is next to a notch, which is supposed to be lined up with a metal tab on the housing. You may be able to see it without the disassembly shown here. I'm sure Tom assembled correctly, especially twice, but worth checking anyway?? I also had this piece cracked: And a broken spring: Car ran but acted up.
Tom helped it get fixed
Linda