how do you loosen/tighten the distributor clamp?
 

I have the valve covers,intake manifold and coil removed from my 305E, which is still in the truck. I was going to remove the distributor, it was tough to get a wrench on the bolt holding the distributor clamp, finally got it loose. I then realized I don't think I could get at that bolt if the coil and intake manifold were in the way, so I tightened the bolt up and left the distributor in place. Is there a trick to getting to the bolt to adjust timing or am I just more lame than I realized? It is under the vacuum diaphragm, which is at 7 o'clock or so when standing in front of truck looking toward the windshield.

Re: how do you loosen/tighten the distributor clamp?
 

I just did this. They make special broke-neck distributor wrenches, but I couldn't get mine to get on the bolt. So I found out I was able to put a regular wrench behind the engine between the distributor and the firewall and twist it in small increments until it was loose enough to spin.

Counterclockwise is advancing too, which I found to be counter-intuitive lol.

And it only takes a little turning to move it alot of degrees.

Good luck!


P.S> Make sure it aint hot or you'll have a heck of a time putting your feet on the exhaust and your butt on the radiator to get at it!:ahhhh:

Re: how do you loosen/tighten the distributor clamp?
 

Hi Guys and Gals!

It's been so long since I've worked on a 305 (or any other GMC V-6 for that matter,) and if I remember correctly, I think there is a remote possibility that you might be able to access the distributor lock down bolt using a 10" long (or longer) 3/8 drive extension and a flex-socket. The only other option, as was mentioned, is a distributor wrench, which should be available from any auto parts supply store/outlet. As to the rotating the distributor counter clockwise to advance the ignition timing being counter-intuitive, the reason is, if you look at the distributor from the top, the rotor rotates in a clockwise direction, hence you have to turn the distributor body in the opposite direction to advance the ignition timing.