8n will start and idle fine but missfires at half throttle to full! PLEASE HELP

[the old grind]

It's extreme point gap variations that affect coil saturation significantly, thus spark strength, more than anything else, and within normal rpm operation. Re-time when you adjust it or don't expect useful results. If std setting doesn't work, I'd look elsewhere.

btw: Don't ever trust a visual inspection of a distributor cap. (Unfortunately, one can't just assume whether a miss is either fuel or ignition-caused.)

(Wish I was there to help ..)

 

[mbryant51375]

your statement does not make sense.

ground polarity is defined by which battery post is tied to the chassis.

What ignition coil you run also makes some difference.

on a round can ignition coil with 3 conenctions, you can orient the primary to the same polarity as the electricl system by swapping wires. on the front mount with the square coil.. that is harder to achieve as 2 connections on t he base are fixed so that the coil cannot be reoriented. thereare ways areound it.. but in a properly functioning system, the polarity mismatch, if it exists, is of negligible concern.

I was referring back to a question I was asked earlier. It is a front mount distributor and it has been converted to 12v. But thnx

 

[rsallen]

Have you checked the advance thru the rpm range?
I know it's hard with all kinds of ideas we have with what 'could' be wrong.
You've got to start at one place and work one step at a time till you find what the issue is.
Do you have a dwell meter and a timing light?

 

[sd455dan]

Have you checked the advance thru the rpm range?
I know it's hard with all kinds of ideas we have with what 'could' be wrong.
You've got to start at one place and work one step at a time till you find what the issue is.
Do you have a dwell meter and a timing light?

how is he going to check dwell on a front mount distributor of this vintage...?

 

[Midniteoyl]

My dwell meter uses the coil to check for dwell....?

 

[Soundguy]

My dwell meter uses the coil to check for dwell....?

and do you have to hook to the wire leaving the coil that connects to the points? hard to do on a front mount.

 

[rsallen]

Is the coil and distributor two separate units?
Is there room some place to run a bit o'wire?

Then maybe just maybe someone can figure out how to get it done.

As the distributor has been out and apart to replace bushings all is probably okay in there profiding the rebuilder knew what he was doing.
So dwell may not be worth anything but to be able say for sure all is okay. And knowing something for sure seems at this point is something worth doing.
That and a timing light.

 

[Soundguy]

it's obvious here that some of the advice givers are 100% unfamiliar with the ford front mount coil and distribuitor. the coil mounts atop the distribuitor bottom to top. the outgoing primary and secondary connections are completely warded and unavailable without creative work..

 

[bigdeano]

I would try a different condenser. Sometimes new ones are defective.

Do the points have a screw to hold the wires from the coil and condenser? If it just uses spring pressure it may not be making a reliable connection.

I've had vehicles run terrible or quit from both these problems.

 

[kydick]

my father purchased one new in 1950. it still has a 6 volt postive ground system with the orignal generator. still runs and use it for some light work. when yours was new it was a 6 volt postive ground with a generator and volatge regulator. now that it is a 12 volt system did they change it from a generator to a alternator?