What could effect ignition timing while running? Strange problem.

[240260280z]

That's the other weird thing, my plugs almost always read about the same. Might be due to the hot coil and MSD box....

What is you plug heat range?

Hot plugs and projected plugs will burn off more colour/deposits. Alcohol in gas also makes plugs look leaner.

[BadDog]

I guess the answer to that would be "normal": I use the same NGK BP6ES plugs that I've always used i.e. the "recommended Z car plug" :-)

What is you plug heat range?

Hot plugs and projected plugs will burn off more colour/deposits. Alcohol in gas also makes plugs look leaner.

[240260280z]

If they are all the same then you are balanced... aim for mocha brown colour

[BadDog]

I'll check the plugs again (they're new) after running this way for a couple hundred miles. I need to get some new float bowl gaskets and sight glass setup from ZT so that I can the float levels set correctly. I still have an inconsistent idle.

[BadDog]

Update: I never did get a chance to get the sight glass setup, and I've been chasing this problem on and off for the last year. I put back in my SM needles last week thinking I could enrichen things at higher RPM...  set my mixture, set the timing, seemed to be better. Odd thing was that I couldn't set the timing below 20 degrees advance or so. Drove the car for two days like this.

The Saturday, it's running like crap. Barely idling (400 -500 RPM) and smoking at rest, but running sorta-OK once past 1500 RPM or so. Not great, but not rough. "Hmm" I think...  "it's almost like my timing is retarded, and the mechanical and/or vacuum advance at higher RPMs is probably getting it into the normal range". Sure enough, I get home, hook up my timing light and it's at like 0 or just below. Crank the distributor as far as it will go, and sure enough it smooths out but maxes out at like 10 degrees advanced. "WTF? 2 days ago I couldn't get it this low, and now this?" So I go to move the wiring that leads to the dizzy/pertronix a little bit so that I can see the little A/R plate better, and suddenly the idle speeds up about 200 RPM. I check the timing again and it's off the scale! Bump it again and it drops. "Agh! wiring issue!" So I unwrap everything connecting the MSD etc. to the dizzy/pertronix and sure enough, the pertonix's black/ground wire connection to the MSD is looking kinda crappy. I used slider-style connectors instead of soldering the pertronix connections when I first installed the MSD in case I didn't want to keep it (I bought it to try and facilitate easier start-up). So I re-did that connector and now I can't affect my timing/idle by jiggling the wires.

If this fix holds up for a couple of weeks without regressing, I think I've finally cracked it. What a pain! 

Now if only my plugs would stop going bad... it seems like once a month, I get a skip and sure enough, one of the plugs' terminals has come loose/unscrewed and I need to replace it. I think I got a couple bad boxes on NGKs last year. Never head a problem like this with them, ever.... **edit** nope, just did some research and found out that screw-cap terminal plugs and solid terminal plugs are different parts numbers. I need the solid-terminal plugs due to vibration...

Edited July 22, 2015 by BadDog

[BadDog]

Update: I didn't get a chance to post this in a timely fashion, but about two weeks after I cleaned up the ground connection for that MSD box and it was running like a champ, the MSD box suddenly died on me. Luckily it was at home in my own garage. It was weird though, I drove it about 100 miles one day, parked it in my garage, and the very next morning it wouldn't start. No spark at all. Swapped the coil, checked the plugs and wires, used a spark tester, nothing. Ripped out the MSD box and "reset" my wiring to where it was before I put the MSD box in, and it started right up...