Timing screwed.....

[2eighTZ4me]

78 280. Carbed setup. OEM distributor, MSD 6AL and Jacobs coil.

 

Leaving the gas station one day, the car died as I pulled away from the pump. Not a fuel death - an ignition death. No sputter then die - just dead right there.

 

Tested MSD box - found it to be bad. Bypassed it and ran the original wiring to the coil.

 

Starting the car is now a royal pain. It needs excessive amounts of timing just to start and run. Like 22 degrees initial. Anything less, the car dies.

 

I have set everything to TDC and verified my timing mark on the crank pulley AND on the cam gear are on the mark. They are. Nothing has slipped or moved.

I even went so far as to pull the dist. drive shaft (while at TDC) and verified it is indeed pointing at the 11:25 position.

 

The only thing that has changed is that the MSD box is out of the loop.

 

Mechanical advance on the distributor is working fine. With vacuum unhooked, goes from 22deg. (idle) to 44deg. at 3000rpm. With vacuum hooked up, it goes to nearly 51 degrees at 3K RPM.

 

I am pulling vacuum PRE-throttle plate.

 

I am totally baffled as to why the car (now) needs so much timing to run. I'm pinging like a sombich when I get on it. (I did that one time only). There is way too much timing. It used to run fine on 10deg. initial and 38deg. at 3K.

 

When I try to start the car when warm, it chugs and chugs (starter) but doesn't catch the first time. Turn off the key and try again, and it will catch.

 

This is the strangest problem I think I've run into to date. ANY suggestions what else to look for? This is beyond me......

[randy 77zt]

cam timing or a vacuem leak?

[Tony D]

How wide is that rotor again... 50 degrees advance on a cap with terminal spacing of 60 degrees seems to me like you are firing back one too far. I had that on my MS till I fixed rotor phasing.

 

Is there vacuum before the throttle plate? Or do you mean ported vacuum (shut off by the plate at idle)? Or do you mean POST throttle plate?

 

What is the condition of your fuel filter? Fuel Pressure? I have had a pingfest after ONE fillup of bad gas in Arizona where a BRAND NEW fuel filter plugged almost SOLID with red clay from dust in the tank.

 

I would almost say firing order of the plug wires, don't know how you got the dizzy out, so don't know what happened with the wires.

 

LAST THOUGHT: You were runnning a CDI to a hot coil meant for a CDI.

 

You now are running 'stock wires' from the chassis (?) to the new coil. Are you running BALLASTED voltage to a coil that is supposed to have a full 12VDC to it? Is your OEM transistor ignition box up to snuff and are you getting nice fat, hot, blue-white spark after this little change?

Edited September 2, 2010 by Tony D

[2eighTZ4me]

Hey Tony and Randy - thanks for the replies.

 

The stroker motor came out of my racecar that was running Electromotive crank fire ignition. I didn't pay attention to ANY of the distributor accouterments because I wasn't going to be using one. Now the motor is in my 280. I did find my dizzy shaft was indeed off one tooth (pointing at about the 10:30 position) - I dropped the pump, pulled the shaft (while at "known TDC") and got it on the right tooth. I also found that I have/had a 240Z distributor base plate. It doesn't bolt up near the way the 280 one does. I got the correct baseplate and set everything back up after testing the dizzy.

 

The vacuum is ported vacuum - that's the term I was looking for. I'm pulling it from the vac port on the middle carb. It is prior to the throttle plate.

 

FUEL = Just installed a brand new filter, as well as put in a new pump (thought it was that at first), and also put in a Fram G3 filter b/t the tank and the pump. Still clear as a bell. My inline gauge says 3.5psi when I kick the car over.

 

You may be on to something. I am NOT running a ballast. Blue wire to negative of the coil and Black w/white stripe wire going to the positive of the coil. That's how it was on the other 78 that I just bought as well. The spark is orange, and I was a little concerned. I will have to recheck again tonight. I put a screwdriver in the coil wire and laid it near the strut tower. It was arcing from the screwdriver to the strut bolt - but it was clearly orange in color. Not the blue that I'm used to seeing.

 

So......are you thinking my Transistor Ignition box is faulty? I thought they were "all or none" - they either worked or they didn't.........hmmmmmm. I will test more this evening.

[Tony D]

big thing is to know what the coil requires. If it's not a high voltage coil when getting zapped with 275V, it may be the issue. The stock transistor unit will blast nearly that much into a coil to get a spark! I've measured it with my fluke and I can tell you it will fry the input circuit on a MS if you hook it up wrong!

 

Lots of times when people swap coils and ignitions around, some stuff gets misapplied. If you have an internal-ballasted coil running off a BALLASTED supply (which depended on getting zapped with 275V to a NON-BALLASTED coil) then I may indeed be on to something!

 

I long for the days when ballasts were external, sex was safe, everybody wore rubbers in the rain...

[2eighTZ4me]

The coil I have is the Jacobs Ultra.

 

http://www.amazon.com/Jacobs-380876-Ultra-Coil-Universal/dp/B000BWE1PC

 

Looks like either they bought Accel - or Accel bought them, b/c apparently they don't make the Jacobs coil anymore - it's been re-branded as an Accel Ultra. I can't determine if it is a high voltage coil or not, but based on the description, it can do both (???). I do recall, however, that the last time my MSD box took a dump, I ran the car just fine on the coil alone for 3 weeks while the MSD was out getting repaired.

 

I'm at the point now where I may just yank the Electromotive out of the racecar with the crank pulley, put it on the 280, and be done with all of it.

[Tony D]

"I'm at the point now where I may just yank the Electromotive out of the racecar with the crank pulley, put it on the 280, and be done with all of it. "

 

YES!

[Powerglide]

Every Z car I see has the de riguer red, high voltage MSD coil in place of the stocker. Which begs the question: Is the MSD coil one sees on most Zs a mismatch/misapplication when it's used with the stock ballast and stock ignition on a 75-78 EFI Z?

Edited September 4, 2010 by Powerglide

[2eighTZ4me]

There is no ballast on a 78 Z - I know this to be a fact, as I own 2 of them. I also just referenced the FSM - no ballast in the circuit.

 

So - got the MSD box back and put it back in. Car runs perfect at 10 degrees initial, 38 degrees at 3K RPM. I have no explanation for the necessity of excess timing advance when running just the coil from the transistor box. NONE.

 

What I DO know is that the last time the MSD box died, I ran the car just fine for several weeks on just the coil - this makes absolutely NO sense whatsoever.....

 

Oh well - at least I'm back up and running until I get the time to swap the Electromotive setup in......