Distributor/ Spark plug layout

[AZbronco77]

Hi Guys,
Its been awhile since I've been on here, but I'm starting to move on my bronco build. My problem is: I labeled the old distributor and the exhaust manifold for the spark plug cable layout. However, I installed new headers and tossed my labeled manifolds. Now, I'm trying to install a new MSD distributor and have no clue on the layout of the cables. How do I figure out the layout now?

Thanks,
john

 

[Viperwolf1]

If it's just a carb'd 302 you can select any post on the distributor cap as #1. Then just wire the plugs in order of the firing sequence. The rotor spins CCW and needs to fire in this order 15426378. Don't forget to sync the crank/cam position (#1 at TDC, valves closed) to the rotor position (pointing at #1 wire).

 

[AZbronco77]

If it's just a carb'd 302 you can select any post on the distributor cap as #1. Then just wire the plugs in order of the firing sequence. The rotor spins CCW and needs to fire in this order 15426378. Don't forget to sync the crank/cam position (#1 at TDC, valves closed) to the rotor position (pointing at #1 wire).

Thanks Viperwolf! thats great info! However, you are dealing with a novice here. How do I "sync the crank/cam position (#1 at TDC, valves closed) to the rotor position (pointing at #1 wire)."

 

[Viperwolf1]

TDC is when the #1 piston is all the way up in it's bore. Pull the spark plug in that cylinder and put your thumb over the hole. Now rotate the crankshaft until the pressure tries to force your thumb off. If you look down at the timing marks now your'll see that it's close to zero degrees. Set it at zero. This will ensure the cam and crank are in the correct position.

Now you can set the distributor in place. If you turn the rotor before putting the distributor in you can see how to position the rotor where you want it. If you're real good and have a test light light you can actually time it at this point too.

 

[Broncobowsher]

Passenger side of the engine, front. That is #1 cylinder.
Same side of the engine moving back goes 2,3 and 4.
Jump to the drivers side, front of the engine again. That is #5
Work your way back toward the drivers feet of #6,7 and 8

To find #1 TDC firing, pull at least that spark plug. Put your thumb over the hole and bump the engine over. The starter solenoid is right in that corner to make it easy. Once you feel pressure pushing your thumb off the hole look at the timing marks on the balancer. Get it up to the TDC mark (actually about 10° before is a better starting point but anywhere close will be good enough to start).
Now where the rotot is pointing is where to start with #1 on the plug wires.
Follow the order counterclockwise on the cap.

Does that help any?

 

[AZbronco77]

Thank You Viperwolf! I think I got it! I was afraid it was going to be a big deal figuring this out. But its not!

Thanks!!
john

 

[AZbronco77]

Passenger side of the engine, front. That is #1 cylinder.
Same side of the engine moving back goes 2,3 and 4.
Jump to the drivers side, front of the engine again. That is #5
Work your way back toward the drivers feet of #6,7 and 8

To find #1 TDC firing, pull at least that spark plug. Put your thumb over the hole and bump the engine over. The starter solenoid is right in that corner to make it easy. Once you feel pressure pushing your thumb off the hole look at the timing marks on the balancer. Get it up to the TDC mark (actually about 10° before is a better starting point but anywhere close will be good enough to start).
Now where the rotot is pointing is where to start with #1 on the plug wires.
Follow the order counterclockwise on the cap.

Does that help any?

Yes it does! I think I can do it now. Thank You so much. I will let you know if I have any questions.

 

[Steve83]

How do I figure out the layout now?

It would help to tell us what ENGINE you have %), but like the others, I'll assume it's a pre-'93 302/5.0. ;D

FRONT IS DOWN

 

[Quick & Dirty]

A vintage 302 would be 1-5-4-2-6-3-7-8.
351W or 5.0 HO is 1-3-7-2-6-5-4-8, as in the Mustang chart posted above.

Conveniently, most dist caps have the #1 position marked as such. The firing order is cast into the intake manifold(assuming it's a vintage, unmodified engine).