View Full Version : firing order ford 302
alv69
12-16-2017, 12:52 PM
I have an early ford 302 in my roadster. I am putting in a sniper fuel injection and was checking the firing order and instead of 15426378 it is 13726548, I found that this was used in later 302's, it runs fine was just wondering if it matters which firing order is used? maybe some of the ford gurus know this.
If memory serves the firing order is based on the camshaft your running. If you use the wrong firing order the engine will definitely not "run fine" as you stated yours does.
frankb
12-16-2017, 02:08 PM
Naz is correct...firing order is determined by the camshaft. If your current firing order is 137...you will need to keep it that way with the new injection system. Cam grinders offer the "switched firing order" to distribute the hits to the crankshaft (at least that is how my machine shop described it!).
edwardb
12-16-2017, 02:46 PM
X3 or whatever. Firing order is determined by the cam. 15426378 was used for a number of years. Then they started using 13726548 for the 302 HO and 351. Most aftermarket cams are the 13726548 HO order. Be sure to check though. They don't run very well when the cam and the distributor don't match. Ask me how I know...
Big Blocker
12-16-2017, 05:55 PM
As stated above, later model 5.0's and all early 351's use 13726548. Early 289 and 302's use 15426378. It is DEFINITELY controlled by the cam shaft lobe positions. Since the cam controls the valve timing of opening and closing, we don't want the plugs firing when either intake or exhaust valves are open. That is why the plug firing follows the cam profile/timing.
Doc
alv69
12-16-2017, 08:41 PM
thanks the engine builder must have used that cam, just used to the old style firing order and have not had a ford for awhile.
TexasAviator
12-16-2017, 09:37 PM
as others have said the cam dictates the firing but that doesnt really help you... What you can do is trace the cap and rotor wires to the cylinders. Verify the order because the cylinders are always 1 thru 4 passenger side front to back and 5 to 8 driver side front to back. Trace the wires coming of your rotor to what cylinder they go to. If the car is running right this will tell you the order.
See this for more info and what numbers you are looking for.
77856
http://www.gtsparkplugs.com/images/ford-302HO-351W-firing-order.jpg