Long-ish read:

Swapped a rebuilt 351m into our 78 F-150. Dropped the dist and rotor in with #1 cyl at TDC, rotor pointed toward that cylinder. Made a timing mark on the balancer - a white line where the timing indicator tab was lined up.

When we finally went to fire it, ended up shooting flames out the carb and couldn't advance the timing (or retard it) enough, so figured I was 180 out. Flipped the rotor and ended up firing flames out the exhaust - advanced all the way and didn't have enough movement, so ended up moving the plug wires over 1 post at a time - did that 3 or 4 times and now the engine will start and purr - runs really really good.

Put the timing light on it and cannot see the mark near the timing indicator tab. Crawled under the truck and with it running perfectly (by my ear) the timing mark is visible on the bottom of the harmonic balancer.

Can y'all help me interpret what that means?

joe

 

you can run it as is, or put the plug wires back in the "factory" positions on the cap and pull the distributor and re-stab in the correct position. you can pull the #1 plug and run it on TDC and see where the rotor bug is currently pointing to determine how far you need to rotate the distributor when you re-stab it....

 

I guess the question is, "How did this happen?" Did I point the rotor at the incorrect cylinder? Where did I go wrong with that install?

 

my guess is yes, the distributor was stabbed in the wrong spot. you do know which cylinder is number 1? did you pull the plug to make sure cylinder 1 was coming up on compression stroke?

 

Yes, passenger front is #1, and yes - it was coming up. That said, I'm not certain what the intake valve was doing when it was coming up since I had the valve cover on at that point.

 

Well "coming up" is not the same as "at" top-dead center. But maybe you can get close enough in some scenarios.
Why make new marks at all though? Where are the original timing marks when the piston is at the top. Since they're keyed on the damper, they should fall at the same spot near the pointer every time the piston gets to the top of the stroke, either on compression (the one you want) or exhaust (180 out).
When you don't have the option of finding the original marks on the timing gears, you can put your finger over the #1 spark plug hole and while rotating the engine (clockwise of course) and feel for the pressure trying to push your finger off. If this happens when the marks are coming up to the pointer, you're good on the TDC of the compression stroke part. If it's just a relatively weak pressure, it's probably the other stroke.
Then continue to get the piston all the way at the top. At least you can visually check for approximate height. There are piston stop tools you can use to get a precise TDC spot, but it's not a requirement as long as the marks are in the area.

Did you leave the plug wires on the distributor cap all the time? Or did you remove them and put them where you pointed the rotor?
Reason i ask is that I've seen this written far too many times in such a vague way as to be very confusing. You don't point the rotor at the number one cylinder. You point it to where the number one plug wire is on the cap.
Which on Fords is "usually" (but not always) at approx 1-2 o'clock when looking down at the distributor cap. Sometimes you're lucky and there is even a "1" molded into the cap as a reference point.
But as said, you can run it the way you have it now that it's running well. it's just not how the factory did it. Instead of moving the wires (which is definitely a legit experiment to find out what's going on) you re-stab the distributor with the rotor pointed at the plug wire that goes to cylinder #1.

Maybe that's what you did and the damper ring has moved on the hub. This is not uncommon and really messes with people trying to get an engine running and tune it. is this an original damper, or a new one you put on the rebuilt engine?
Some have a double-notch with one half on the ring and the other on the center hub, so that when the elastomeric isolation gunk in between the two loses it's grip you can see when the two notches are separating. When that happens it's time to replace the damper completely.

Whichever way you go, there is a wonderful product called "timing tape" that a few companies make. Including Mr Gasket. Summit sells a bunch too, probably under their own label.
Once you get your setup close, or even if you decide to leave everything where it is, you can line up the degree marks on the timing tape installed on the damper ring to line up with the pointer. From there on out you will be able to see your new marks very clearly.

Personally I'd make sure everything is good, then put the wires back where they were from the factory and put the distributor in so it's working that way. It's not required, but it makes diagnosing other issues later down the road much easier when more than one person is trying to figure out the tune.
Maybe someone's got a picture of where theirs are, or where the factory book says to put the #1 wire. Or maybe someone has a cap that still has the #1 mark on it. That'd be great!

Good luck.

paul

 

Paul,

I had come to the same conclusions as far as what to do but I am very grateful for your confirmation of my next steps.

joe

 

This is why I love this forum. Guys are always willing to help. I wish had a small portion of the knowledge some of the guys here.