CHEVY 250 IGNITION TIMING/ FIRING ORDER

[bob77]

The firing order on my 250 checks out ok, but I am suspicious that perhaps sometime in the past (previous owner) someone may have put the wires on the distributor incorrectly. Although the sequence (clockwise 1,4,2,6,3,5) may be correct, is it possible that the number 1 was put on the the wrong place and thus putting everything in the wrong place? Looking at a schematic on the Autozone website, my Number 1 would be pointing toward the front of the truck, however, my number 1 is closest to the engine (pointing toward the drivers side). Is there a way to check for certain if I am wired up correctly? Would this even make a difference if all wires were still in the proper clockwise order? If this were possible, would the truck still run but not quite run in time? I just want to make sure that I have it wired up correctly. I was a little concerned when I saw the diagram and my #1 was 90 degress from where it is shown in the schematic. My truck seems to be running just a bit off and using way too much fuel for a 250 (barely 11 mpg).

Thanks a bunch.

[bob77]

I meant 1,4,2,6,3,5 counterclockwise, not clockwise.

[Lt.Del]

It doesn't matter.  You can twist the distributor housing in any direction, so long as the plug wires fire in order and the timing is set...in fact, to time it, you will be turning the distributor housing anyway.  You can have #1 fire at the 3:00 position, 6:00 position, 12:00 position....it doesnt matter as long as #1 fires when#1 piston is TDC.

I just pulled my distributor out of my suburban two days ago to get at the oil sender.  When putting the distributor back, I could'nt exactly line it up to where it was (i didnt bother with the long screwdriver thing to line up the oil pump) so I just put the distributor in where it went all the way down.  I then started my plug wires, ensuring the plug wire matched about where the rotor now points.  If the rotor pointed at #3 wire before removal, I started with #3 (lining it up w/ the rotor) after installation.  I then timed it and it was pretty darn close.

If you dont like how your distributor sits due to vacuum adv. hose too short or diaphram hitting something, whatever, just pop the cap, see where the rotor points (which plug wire) then remove distributor and turn it where ever. Push distributor in. Your rotor will point in a different direction, just start with that plug wire (which ever it was pointing to initially) and put the rest on.

You really don't need to remove distibutor if you don't want, you can pop the cap off (note which plug wire rotor points to), then you can just loosen the hold down bolt and turn distr. wherever, remove plug wires because they will be offset some now, put wires back on according to where rotor points now.