Upgraded Ignition System Startup

I am not sure of the pickup configuration of the duraspark/msd unit, but I static time hei all the time. The coil will fire when the reluctor tips just pass the pickup poles. at that point the rising voltage which has been charging the ign coil changes polarity and the magnetic field collapses causing the plug to fire. Armed with this knowledge, it is a simple visual alignment task to get it right the first time.

1. Rotate crankshaft to initial advance point, ~8-10° btdc, #1 cyl.
2. Remove dist. rotor so you can see the reluctor and pickup coil.
3. Turn distributor body so so that reluctor tips align with pickup tips exactly.
4. Reinstall rotor and note position of electrode. This must be the #1 tower no matter where it is pointing.
5. Install cap. If the tower does not align with the rotor electrode, do not turn the distributor to correct it. You need to remove distributor from the engine, turn the oil pump drive a little bit and try again.
6. Install plug wires 1-5-3-6-2-4 clockwise.

If it still doesn't work, then you have another problem, most likely mis-connected wiring.

Hope this helps.

 

The plug from the MSD module only connects one way to the adapter....and the adapter only connects one way into the distributor. I'm not sure what the procedure would be to reverse this.

 

You guys are a huge help....Im definitely going to give this a try. In item 5 you mention turning the oil pump drive. Is this the same as the gears of the distributor? ....a rotation and realignment of the distributor? Also, I'm not sure exactly what the "pick-up coil" is but I assume I'll figure it out one I remove the rotor.

 

OK I just looked at the duraspark guts on google images. Once you have the rotor removed from the shaft you should see another rotor lower on the shaft with 6 tips sticking out. (It's a 258 right?) this is the reluctor. It is a permanent magnet. As the distributor shaft turns, these tips pass by another part with 2 wires going into it. There is just a few thousandths of an inch clearance. This is the pickup coil, and it is actually mounted to the vacuum advancer. If you look carefully at the coil, you will see it's iron core at the center. The module triggers the ignition system to fire precisely when the reluctor tips pass this point. When you have everything lined up correctly, a random reluctor tip will be pointed directly at this iron core when the initial timing mark on the crankshaft is aligned with the index on the timing cover AND the distributor is aligned with any tower on the cap. This tower will fire #1 cylinder.
If you do all of this and find that the rotor does not align with the cap tower, the you must remove the distributor from the engine, and with a long flat blade screwdriver reach into the hole and turn the oil pump a little bit, say one tooth looking at the distributor gear. Drop the distributor back in and try again.
The oil pump is driven by the flat blade on the end of the distributor shaft.
Actually, as I am writing this it occurred to me that if your advancing mechanism in the distributor is worn, possibly the pickup clearance is increasing or something else is going on in there. It's easy to check these parts for wear and fitment issues. If you put in a used distributor there is no guarantee that it has no problems.
Alignment is everything.

 

Do yourself a favor and view this youtube video. It's very brief and gives an excellent overview of setting the distributor into the engine. It's very short and very clear.

I don't think that turning the oil gear has anything to do with where the rotor ultimately points, that's a function of the distributor drive gear mating with the camshaft gear, you only have to move the oil gear to get the distributor to seat properly.

It's helpful of course to have your engine at TDC when setting the distributor.

[video=youtube_share;YdIGZ-tVuZA]http://youtu.be/YdIGZ-tVuZA[/video]

 

You know, you're right about that. I was thinking of times in the past installing distributors in engines where other parts may limit rotation of the distributor body. Not an issue with a mid seventies 258. My bad.

 

SUCCESS! Guys the static timing advice was some handy information. I couldn't have done it without you. Another forum had said that the vacuum advance should be angled toward the engine and the rotor at about 5 o'clock. When I was finished with the static timing, the vacuum advance was pointed straight toward the front of the vehicle and the rotor just a hair past 6 o'clock. Based on the sticker under the hood, I dynamically set the timing at 4' BTDC (with the vacuum hose off). It's too icy outside to get out for a drive but it sounds considerably smoother idling than before.

 

Glad your getting it ironed out.

 

"It's too icy outside to get out for a drive"

??? That's what four wheel drive is for!
After ice storms here in NH I've come home with the whole tub filled with crushed ice, like a champagne bucket.

 

You may want to bump that timing up to between 6 and 9 btdc . Mine is running at 7 and no problems.

 

I finally got out for a drive and the timing at the factory recommended 4' BTDC didn't run well at all after it warmed up. Adjusted it to 9' (w/o vacuum) and it runs good. When folks talk about setting the timing, is it typically with the vacuum disconnected and at a warm idle?

 

That's how I set mine. After reading this thread, I went out and fooled with mine, set it at about 8 btdc. Looks to me it made no change. Glad yours is running better.

 

Yes.


Sent from my iPhone

 

You did reconnect the vac after setting the timing? If you replaced the dist with a aftermarket or one not specific to your year of jeep and engine, you will probably have to recurve the dist if it isn't running right after setting the initial or static timing.

 

The distributor is intended for a 258, so the curve should be ok. I would use the tune-up specs for the vehicle that the distributor came out of.

If you are a fan of Jeephammer, he has a series of posts about setting the distributor curve yourself - https://www.google.com/search?q=site:jeepforum.com jeephammer recurve distributor

 

Though it may or may not come to this, I would do everything I could to get it running right before I started recurving the dist. I recurved mine and it took a lot of trial and error, like weeks. I think it is easy to do, you just have to find the right combination. I would make a recurve my last option especially since the dist "IS" for a 258.

 

It's running great with this latest adjustment. I did reconnect the vacuum after setting the timing at 9' BTDC. The distributor is a rebuilt unit for a 78 model. Right now I don't sense a need to look into a recurve but I only ran it for 20 minutes. I'd be curious what the original spec is for a 78's timing. My 75 is a California model so I don't know if that had anything to do with such a small amount of advance.

Getting ready to start work on improving my electrical grounds and maybe light relays. Funny thing on my ignition upgrade - the fuel gauge didn't work before the project but is working now. I'm hoping a little ground work will solve a few minor problems with the dash lights and some flickers in the running lights.