Firing order

[ahgrafx]

Doing a tuneup tonight new dist cap and rotor and guy across the street says my timing is off and we start to redo the firing order and all hell breaks lose and now the trick wont start and every firing order i look up online doesn't work. I would love some help.

[Jacksdad]

If it's a 390 you're talking about, it's 1-5-4-2-6-3-7-8

390_firing_order.jpg

[ahgrafx]

Is that front little piece on the distributor represent the vac advance? And should it be in that position? Mine right now is pointing straight forward i beleive the motor is all stock

[ahgrafx]

My apologies yes its the 390, pretty hard to find a chiltons for these.

[71Fe2O3]

You should be able to find plenty of information on this site and others. Think about what you want the engine to do; fire a spark in the cylinder when the piston is at or near the top of the compression stroke. If you remove all the spark plugs and crank the engine by hand and listen carefully, you will hear each cylinder, in turn according to the firing order, puffing out some air as the piston approaches the top of the compression stroke. If you put your finger over the spark plug hole you will feel a suction as it goes back down. You just cranked that piston through the compression stroke, the stroke when both valves are closed.

To get the firing order correct, crank the engine until the number 1 piston is at the top of the compression stroke. Then, (assuming you have stock points ignition) go to the distributor, cap removed. You want the breaker to be positioned at one of the vertices on the octagon so that contacts are slightly spread, which, if the engine was running, would cause a spark to fire, ignite the fuel-air mix, and force the piston downward. Put the distributor cap on and make sure that the wire from cylinder 1 is in the right place, and also that the other plugs are wired properly according to the diagram from the previous poster. If you look at the indicator on the front end of the crankshaft (you may have to clean it and rub some white chalk on it to see the timing marks) the timing mark for 0 TDC should line up with the indicator on the engine. Sorry, I don't have any pictures, but I know there are some on here if you look around, and, because these engines were used in many vehicles, on other sites as well.

If all other things are OK, your engine should be ready to run. Things that can prevent it from running properly: weak battery, bad starter solenoid, worn ignition components (cap, rotor, contact breaker, condenser, coil), and wiring issues. Once you get it running, fine tune it by adjusting point gap, dwell, and timing. These engines tend to run best with timing advanced, generally somewhere between 6 and 15 degrees. Good luck.

[ahgrafx]

Thank you very much that is what I started doing this morning we had the motor running great and then a well-meaning bystander wanted to address the firing order thinking it was out of whack and it wasn't now we're trying to put it back together and it doesn't seem to be exactly the same as everything I'm reading so we're trying to find one

[Mispeld]

What 71Fe203 said... remove #1 plug. Put your finger over the spark plug hole. Have someone tap the key until you feel the compression push your finger (not suck it in). Shine a flashlight in there and you'll see the piston. Get that at the top before it goes down by tapping the key. You can also look at the timing marks on the crank to confirm (0°). Pop off the distributor cap. Wherever the rotor is pointing is where #1 cyl is located. Put your cap on and where that rotor is pointing is where #1 wire goes. Then follow that diagram above.

#1 location on the distributor is rarely what it shows on diagrams.

[71Fe2O3]

Did you get it going yet?

The firing order for your engine, as jacksdad said, is 15426378, and is determined by the crankshaft. If you follow the directions I gave you for finding TDC on compression stroke for cylinder 1, and your ignition components and battery are in good shape, your engine should run. You can bump the key, as mispeld described, use a starter switch across the solenoid, or turn the engine with a socket and long-handle ratchet or breaker bar. It sounds as though your neighbor, well meaning though he may be, is not very knowledgeable about your engine.

There is a lot of knowledge here. If you don't get satisfactory responses in the forums, you can search the archives from the search function on each page, or by specifying fordification in a google search.

[71Fe2O3]

Sorry, I didn't pay enough attention to your last sentence. Cylinder 1 is up front, closest to the radiator, on the left as you look at the engine from the front of the truck, as indicated by the diagram jacksdad posted. The distributor turns counterclockwise as the diagram indicates. Wire your plugs up as shown, get it set on cylinder 1, and you are on your way. I don't think you damage the engine by doing this wrong, but it won't run right until you have it set up correctly. Mine survived my ignorance as I worked my way through this a few years ago, and has been running fine since then.