dizzy woes

Pritchard · 12-13-2002, 07:04 PM

NEED HELP PLEASE!!
This is for a '74 2.0L with FI.

I hope that you guys can help me out. I am battling with an erratic spark condition that has progressively gotten worse over the past few months. Using my timing light, I know that spark plug wires 1 & 3 spark flawlessly. Wire number four sparks about half the time. And wire number two almost never sparks. I turned the dizzy to advance the timing and the symptoms improved slightly. With the dizzy turned almost all the way toward the rear of the car, number two wire sparks almost every time. I didn't let it stay that way very long. I turned the dizzy back to where it belongs and disconnected the retard tube on the dashpot. The symptoms were still bad but better than they were at the start.

Here are the things that I have tried so far: new rotor, cap, wires, plugs, coil, switched everything back to the old hardware, put points back in, tried the old coil, tried three different caps and rotors, switched the plug wires around. All this and no change.

I haven't looked below the points plate in a few months, but everything (springs and weights) was intact then. I was really confused about what was wrong, but after turning the timing up and seeing some improvement, I am even more confused.

Do I need a new dizzy or mine rebuilt? I read on another post about how after cleaning his dizzy a couple of times and putting it all back together another poster had similar symptoms go away.

Anyone have any ideas that might help me out? All thoughts would be appreciated.

Thanks
David Pritchard

BTW, I managed to fix my Type 3 MPS which would not hold a vacuum. It was leaking around where the electrical plug is built into the housing. A little silicon caulking and all is well with the MPS for now.

pbanders · pbanders's Garage

Seems like a LOT of 914 spark problems are related to the dizzy being out of position. Remove and replace, making sure it fully seats and that the shaft is engaged. Set the points initially with a feeler gauge and timing statically, then use your dwell meter and light after you get it going. Beyond that, it's a matter of signal tracing: power to coil, spark on HT lead from the coil (means coil is OK), new cap, new rotor, new points, new condenser, new wires, new plugs - it pretty much has to work. Even if your mechanical advance and vacuum cells are dead, you'll still get a spark distributed.

Perhaps a coil problem? Too weak, only see spark intermittantly?

pbanders · pbanders's Garage

One more idea - did you look at your dizzy points cam lobe? Does it look OK? No big chunk of goop on it that would prevent one cylinder from firing properly? Heavy wear?

Bruce Allert · 12-13-2002, 08:57 PM

David, I was having the same trouble. After cleaning the dizzy twice I finally got it started and it idled nice until the AAR closed and the idle went down as it is supposed to. I reset the points after it warmed up and then went on to the timing. I now have a very erratic timing mark. Couldn't time it at all. Took out the dizzy again only to find that the bottom of the dizzy (the thing at the bottom that rotates) was quite loose from side to side. Past posts indicate this would cause jumpy timing. In the morning I will go to my FLAPS & check prices on a rebuilt dizzy or the Crane ignition. It is supposed to smooth out the jumpiness and make it run better.... hope so.
bruce

Pritchard · 12-14-2002, 10:36 PM

Bruce, are you refering to the very bottom of the dizzy with the offset tongue that mates to the groove in the drive gear? Mine is loose from sided to side as well. I've never heard that it wasn't supposed to be. Keep me posted on your successes.

David Pritchard

Brad,the cam lobes don't appear to be overly worn. They look to all have about the same lift.

Bruce Allert · 12-14-2002, 11:50 PM

David,
Yes that's the part I'm refering to. If I remember right it wasn't as loose as it is now. Maybe my constant grinding on the starter while trying to start the darn thang loosened it up and... maybe it wasn't seated properly I dunno!

I went out & got a Pertronics Ignitor this afternoon and will put it on in the morning. I told the parts guy about the movement of the dizzy. He said if there's too much wobble it tends to take out the Ignitor. Wished I knew what is too much! $70 bucks is a bit much to wobble away!
I'll let y'all know what happens.
bruce

pbanders · pbanders's Garage

I'd pass that one about the dog gear on the dizzy past John Larson on Rennlist. I've never heard of the dog gear being a problem. It's supposed to be fairly loose in order to fit the slot in the distributor drive. What often happens is that the plain bearing in the base of the dizzy wears, and you get slop in the shaft. That slop is what can affect dwell, and apparently, can cause problems for the Pertronix. John Larson can rebuild a dizzy to factory specs for a reasonable price (much, much less than a new dizzy).