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Discussion Starter #1
Quick question about rotor position in a "healthy" engine.
Timing set at 12 degrees BTDC on compression stroke. Rotor pointing to plug #1.
Crank turns twice for every one turn of the cam.
So after one turn of crank, stopping at 12 degrees BTDC, the rotor would be pointing at the #6 plug.
Is this correct or am I mistaken?
 

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Quick question about rotor position in a "healthy" engine.
Timing set at 12 degrees BTDC on compression stroke. Rotor pointing to plug #1.
Crank turns twice for every one turn of the cam.
So after one turn of crank, stopping at 12 degrees BTDC, the rotor would be pointing at the #6 plug.
Is this correct or am I mistaken?
This is correct if your firing order is

1 5 4 2 6 3 7 8

It should be mentioned , That is not the only possible firing order

Clock

Ford 302HO / 5.0L and 351W Firing Order


1 3 7 2 6 5 4 8

(Plug 6 is the same position)

http://www.gtsparkplugs.com/firing-order-ford-260-289-302.html

http://www.gtsparkplugs.com/firing-order-ford-302-351.html

Z
 

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This is correct if your firing order is

1 5 4 2 6 3 7 8

That is not the only possible firing order

Z
Look at any V8 firing order you wish- AMC, Chevy, Ford or whatever. There is a 90% probability that #6 is the 5th cylinder in the firing order. If you find an engine that doesn't have 1 and 6 as the first and fifth cylinders please post it here.
 
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Quick question about rotor position in a "healthy" engine.
Timing set at 12 degrees BTDC on compression stroke. Rotor pointing to plug #1.
Crank turns twice for every one turn of the cam.
So after one turn of crank, stopping at 12 degrees BTDC, the rotor would be pointing at the #6 plug.
Is this correct or am I mistaken?
That is correct. It will be point to it's "piston pair".

1-6
5-3
4-7
2-8
 

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That is correct. It will be point to it's "piston pair".

1-6
5-3
4-7
2-8
Pete's right you can change "when" you fire them but NOT when they are both at TDC. The cam lobes must be changed in orientation as well. Three different firing orders have been used on production V8s over the years. 15426378 is the most popular. Chevrolet uses the same sequence though their cylinders are numbered differently and the dist turns clockwise.
 

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Discussion Starter #7
Thank you to all that replied. My motor is a 1967 390 s code, so yes, #6 is 180 across from #1. Just double and triple checking everything before I break in this rebuild.(my first time)hope all goes well.
 
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Well, it seems like GM were the black sheep with the Buick Nailhead's whacky firing order. 1-2-7-8-4-5-6-3
GM numbers their cylinders differently . . so you can' compare that to Ford. It may not be as wacky as you think.
 

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just as you say Pete, not that wacky, the nailhead Buick #4 corresponds to the Ford #6



I am surprised no comment on my posted Ford firing order of 1-5-4-8-3-7-2-6. I guess everyone's already in the know.

Z
 

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I'm hoping my next Mustang will have this firing order: 1-5-4-8-3-7-2-6


Hint: (think Voodoo)


Z
Yup , only with a flat crank.
 
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