DC3

While chasing down some engine gremlins on my recently purchased '73, I bought a piston stop tool and verified the timing mark as correct.

Next I began to replace the bad vacuum advance with an adjustable one. It's an HEI distributor. Once I got the distributor cap off, I realized the distributor was in need of at least a thorough cleaning. Moving the rotor against the tension of the springs did not allow it to snap back cleanly. It moved very slowly back to normal position and the mechanism was obviously gummed up. This may explain why I was only getting 14 degrees of mechanical advance.

So I pulled the distributor, took it apart, removed all the gunk, cleaned it and lubed it and put it back together. So far so good. I knew when I pulled the distributor that it had originally been installed incorrectly (the #1 tower was pointing in the general direction of the #2 cylinder and the vacuum advanced was roughly pointing to the passenger side mirror and would hit the firewall when trying to retard the ignition).

I reinstalled the distributor by setting the timing mark at 12 degrees of advance and installing the distributor body so the #1 tower would point slightly toward the #1 cylinder. I then used Lars method to "walk" the rotor into position pointing at the #1 tower.

The engine fired right up with no issues. However, after letting it warm up and connecting my timing light, I was surprised that I could not even see the timing mark that I had previously verified as being correct. I finally "found" that timing mark on the passenger side of the balancer over 100 degrees away.

Coincidently, the previous owner had put a yellow dot on the balancer that now showed up at 12 degrees of advance. Using this spot as an index, I was able to determine that I'm getting at least 18 degrees of mechanical advance so my efforts to clean the distributor had paid off.

But, what's up with the timing mark moving? Can this be anything other than my balancer slipping?

DC

lars

Your distributor was not installed correctly when you started. Pull it out and start all over. You stated that the #1 tower pointed towards the #2 plug, and that the vacuum advance pointed towards the passenger side mirror. This is completely wrong. On an HEI, the #1 tower is the forward driver's side tower. The distributor should be installed so that the vacuum advance points towards the 7 o'clock position as seen from the front of the engine compartment, and in this position, the coil on top of the distributor should be "square" in the engine compatment with the wires coming squarely out the driver's side of the distributor. Bring the #1 piston up to TDC on compression and install the distributor over again in the correct position with the wires re-located to their correct cap position. You can then time the engine and see what you get.
Lars

DC3

Thanks Lars,

I'll pull and re-install. It now looks like the previous owner had shifted the wires and by assuming he had installed the wires correctly, I've used the wrong reference points in re-installing. Your description of the coil needing to be square will help me get it right this time.

But I'm fuzzy on the timing mark moving. Will it be correct when I reinstall according to your directions? Why was the timing mark correct with the distributor installed wrong by the previous owner and not when I re-installed it? I'm somewhat new to verifying timing marks and installing distributors and such and I can't get my head around the timing mark moving.

Thanks again.

DC

DRIVESHAFT

Are you absolutely positive that you had the timing light connected to the #1 spark plug wire?
If you have already verified that the balancer is correct, then that is about all that could cause that problem.

DC3

I am now absolutely positive that I had my timing light connected to #7! Damn. When I reinstalled the distributor in what I thought was the correct position, I had to reposition some of the plugs wires and so I took apart the wiring clamps. When I put it back together, I accidentally swapped the #1 and #7 in the upper clamp. I just clamped my timing light on the far right wire from memory. Guess I'll be a little more careful in the future. Oh well, that snafu helped Lars catch the fact that my distributor is still not installed correctly.

Good catch! I owe you and Lars both a beer.

DC