saiguanas

I have a mallory ultra...something or other ignition in my 72 (350). I have printed out a couple of diagrams that show where each spark plug wire should go on the distributor cap but none of them come even close to the way mine is.

The reason that I am doing this is because I have had this backfire issue ever since I changed plugs, air cleaner, pcv valve, valve cover gaskets, and spraying the crap out of the inside and outside of the carb with cleaner (I didn't know any better). I'm pretty sure each plug wire went back where it was supposed to but I want to double check.

Can I do that finger in the number one hole trick and go from there just like any other ignition? I just think it's strange that my wires are nowhere near any of the diagrams. It ran great before this.

Gordonm

18436572 is the firing order of a Gen 1 SB Chevy. The dist does not matter. Where the number 1 plug wire does. You should bring it up to TDC and find where the rotor is pointing. That should be pointing at the #1 post on the dist. Then run your plug wires around from there. If your wires are crossed it will never run right.

dmayhew

I am no expert but the firing order listed on the manifold to me is the ordr that the plugs need to fire in. The dist will send spark out each wire as the rotor turns. The dist does not know where the wire is going.

The key is to get # 1 cylinder at TDC on compression stroke and then drop dist in with the #1 port at proper location. about 7 o clock looking straight down from above. Then run your wires from that starting point.

Once you find # 1 it all falls in line behind that.



Now , Others will help me know if I should find another hobby or not.


Good Luck

David

aussiejohn

G'day,
Nothing to worry about, mate, it sounds like you've got it one place out. The first thing to do is to get the engine to TDC on #1 cylinder on the firing stroke - there are only two possibilities, one wrong and one right. Then pull the distributor cap and see where the rotor button is pointing. Make a mark on the manifold or air cleaner or wherever that the rotor points to. Then put the cap back on and put #1 plug lead into the hole that lines up closest to the mark.

Then put the rest in in order (1)8436572 and it should start. There are several threads here on how to set your timing once the engine is running (reasonably) smoothly. If you have a timing light, set static at about 10 degrees with the vacuum advance line from the canister removed and the line plugged. If your engine is basically stock, this will get you into the ball park.

Keep us posted.

Regards from Down Under

aussiejohn
8 months to go

SteveG75

The small block firing order is 1-8-4-3-6-5-7-2. This is determined by the cam not the ignition. Cylinders are odd numbers on drivers side, even on passenger's side, front to back.

1----2
3----4
5----6
7----8

Best way to do this is get your engine on the #1 cylinder firing stroke. Do this as follows.
- Pull distributor cap.
- Put a breaker bar on the harmonic balancer nut and turn engine till timing marks are lined up with timing tab. You are looking to get the timing mark on the balancer lined up with timing mark on the tab.
-If the distributor rotor is pointing to firewall, you are on the #6 firing stroke. Rotate the engine 360 degrees (distributor will rotate 180 degrees).
- Rotor should now be pointing towards the front of the engine. Make mark on distributor body and reinstall cap. There should be a tower on the cap right by the mark. That is your #1 cyl.
- The rest of the plug wires go around the cap in firing order in a CW direction (looking down at the cap).

Hope this helps.

saiguanas

Now here's another problem and I'm assuming that it has something to do with this aftermarket ignition but...

My timing tab (if you are facing the car) is at about the 2 o'clock position. The car runs best when the timing mark is at 12 noon. This is several inches away from the tab. If I try to put it right on the tab it will probably stall and at least it definitely won't run right.

SteveG75

You have the plug wires one position off. Follow the directions above (we said basically the same thing) and you should be able to time your car.

Mike Ward

Are you sure that your timing light is attached to the wire going to the #1 plug?

saiguanas

Had 6 and 8 swapped....doh! Headscratchers are always something simple.

V77Vette

yepp been there done that

7T1vette

Just info: There is a camshaft design for small block Chevys that swaps two of the cylinders...not sure which ones...4 & 7 maybe. This minor change apparently provides a bit more power than the standard timing pattern. I'm only mentioning this because the timing is established by the camshaft...not the distributor. The order of the distributor wiring has to match the timing of the camshaft. These cams are strictly special order, but if a PO put one in and didn't tell the buyer, you'd never know it otherwise.