i need tdc/distributor/firing order help

OonDeanisS

Founding Member
Jun 16, 2002
902
1
19
Danbury, CT
I have a 351w that i recently took apart and now that its going back together, i need some help. Problem is, i didnt mark which plug the rotor was facing.

You know how the cap has the #1 on it? well, if i start there and wire them 13726548 (do i go clockwise or ccw?).

THen i need to find TDC for piston #1(front pass. side) and turn the rotor so that its on the #1 plug when dropped into the engine. Is this correct?

Thanks

Oh, and how do i find TDC? I heard you can replace the spark plug with tissue and turn the crank until it pops out, can anyone confirm this?
 
To get top dead center remove all the sparkplugs, rotate the motor while sealing the #1 sparkplug hole with your finger when the air pressure blows your finger off the plug hole you are on the compression stroke. insert a screwdriver carefully into the plug hole and rotate engine slowly (dont let the screwdriver bind) until the top of the piston is all the way up this would be top dead center now wire it up as in the diagram below..


2055.webp
 
thanks. Now when i get to TDC, am i correct that this is when the rotor should be pointing at the #1 plug wire?

Yeah that is right. Um as far as taking all the plugs out you dont have to do that. Take out the number one and have someone bump the motor over seal the number 1 plug hole with the tip of your thumb and when it blows it out then you are at TDC then put the rotor on number 1 then crank it.
 
I know I'm bringing a very old post to the top and I apologize. With that said, I have to thank the above poster for his comment. I've been struggling with my '74 351W in my '58 F100 for two summers now. I could get it to idle great but anything above idle acted like the timing was off. I've gone from an MSD box running a Duraspark II distributor, to a complete Duraspark II system, to a Mallory one-wire, GM style distributor all with the same result. I had it timed at 13726548 and never even thought to try 15426378 until I saw that post. I just swapped those four wires and it runs awesome and just chirped the first brody since 2010. I was this close to selling the thing. So thank you OonDeanisS, if you're even in Rockford, IL I owe you a beer or 2. To answer your question, yes, it is possible. Out