When comparing how the wires are plugged into the distributor vs what the AIM shows, the order seems to be off by 1.

For example....

Instead of cylinder 1 being at the bottom right position, it is 1 off at the bottom left.

Does it matter where the cylinders are plugged in as long as the firing order stays as its supposed to be?

 

Nope
As long as #1 fires at TDC (well you know) for cyl #1 all is well.

There was a document floating around (Paul74 had a pic) showing a GM service bulletin to re-clock the distributors to get the tach-drive cable in straighter, that meant the vac-can is pointed almost sideways in some cases.

HIH
Mooser

 

Mine ended up here when it was all said and done


Mooser

 

Let me clarify my question and let me know if you read it right the first time around. Looking at your picture..... without moving the distributor, if you were to unplug all the wires and move them all clockwise or counter clockwise by 1 spot.

This is what I meant....will everything still be good?

Thanks

 

Negative. Unless you move the distributor body, moving each wire 1 terminal in either direction will change the timing. And there may or may not be enough travel in the distributor body to compensate.

 

Simplified: Age old rule of thumb is the rotor and #1 plug wire terminal should point rougly at cyl #1 at TDC on the compression stroke. The proper fix is to re-index the dizzy if it doesn't.

 

Well then thats interesting. For a few years now the car has been running perfect with the wire terminals 1 off from what the AIM shows.

I only noticed because Im changing the wires. I guess Ill put them back in according to the AIM and see if there is any difference. If it doesnt feel right Ill put it back to how its been.

 

The location on the cap doesn't matter as long as the rotor is pointing at the #1 wire when the #1 piston needs to fire. Location around the cap is more or less irrelevant.

Here's a link to the service bulletin
Lars also has a writeup in his timing papers




Here's my setup before I moved it



The vac can is pointed forward (like a normal chev) and the tach drive was kinked pretty good.
The #1 is on the second tower from the hold-down bolt there,

In the new pic above, it's back one tower (3 over from the bolt) but by pulling the dist out and moving it over 2 teeth (well actually I flipped the gear over and it's 1 and 1/2 tooth but that's a different story) I got the vac-can around back and the tach cable goes almost straight in.

If you look at the #1 wire in relation to the motor, it really didn't move (much) since the rotor still needs to be pointing at the #1 wire when that piston is at TDC

Not sure if this helped

 

The wires can go anywhere as long as the rotor can point to the right place.
If you re-clock according to the aim, you'll need to turn the housing to put the new #1 tower to the place where the old #1 tower was (relative to the engine block)
If there is not enough travel, you'll need to index the distributor (pull it an move the shaft one tooth)
Mooser

 

OK I think I get it now. I guess Ill put them back in as they were.

Thanks

 

The routing order in the AIM is for advance can orientation and tach cable purposes.

 

That's correct. You can install a distributor to make the #1 tower any tower you want, and you can install the distributor in any clocking orientation and still make it work. If it times correctly, it's not going to run any differently than if you move things over "1 tooth" or 1 tower and then re-time it again.

Obviously, on the assembly line, all the distributors were installed the same way, so there is a "factory correct" clocking and sequence to the wires. The distributor body clocking was established to orient the vacuum advance control unit in a certain position so it would not hit the back runner on the manifold, clear the shielding, and still provide adequate rotational adjustment for timing. #1 tower position was used consistently so that plug wire lengths would be consistent.

On a standard points-type distributor, the vacuum advance control unit is oriented at a 45-degree angle forward as shown in the diagram posted above. The #1 tower is the forward passenger side tower. That's the "standard" Chevy clocking and routing used from the '50s through 1974. There is an "alternate" C3 Vette clocking where the distributor body is rotated 45 degrees clockwise (as shown in the above illustration).

For HEI, the body is clocked with the vacuum advance at the regular 45-degree angle, such that the square top-mounted coil is clocked "square" in the engine compartment. The #1 wire on the HEI was moved to the forward driver's side tower position.

Lars

 

Does anyone know why GM changed the #1 spark plug position on the cap for the HEI ignition? Lou.

 

It simply made the plug wire routing appear "neater" by not having the front 2 wires crossing each other.

 

I went back to the drawing I did before unplugging everything and in my case it looks like this

 

As noted, you can make it work any way you want to do it, but the way you show it isn't "right." The "right" way is shown in the illustrations posted above. I can also send you a complete paper with photos on correct installation. Just e-mail me for a copy.

Lars
V8FastCars@msn.com

 

I also changed the clocking on my distributor to ease the kink in the tach drive cable. The vacuum canister ended up looking pretty much straight right, parallel to the firewall.

 

Sounds familiar. I followed the GM bulletin to get the kink out of the tach cable as Mooser did. Beats using one of those 90* adapters.