Can't get spark!

Terry NJ

Terry NJ

Well-known member
So my Town Sedan is at the point where I want to start it. I wired everything by the diagrams I have (At least I think I did) and I have fire to the points and the cap on the dist. cap fires a nice blue spark when I hold it over a head bolt and crank the engine. But I can't get a spark down to the plugs. I've checked everything with the ohmmeter and it all seems fine, but still no spark. Any suggestions? Electricity is not my forte, anyway.
Terry
 
is your rotor actually touching the cap?
if youve got spark at the cap then theres only the brass strips, body, and rotor left...

how do you KNOW your not getting park to the plugs?

it could be sparking but timing could be way off thus not doing anything...(sparking on intake stroke or exhaust etc) aka distributor cam 180* off or something so its sparking the wrong cyl at the wrong time.

at TDC on cyl #1 the timing pin should just pop in int timing gear, the rotor should be pointing at the contact (if your standing on the pass side of engine) at the 4:30 position. turn the rotor counter clockwise to take the slack out of everything when checking. The trailing edge of the rotor contact should be just lined up with the contact.
 
Try a different plastic distributor body (with the four electrodes). Repo bodies made 20 years ago were often bad, cracking inside and grounding themselves = no spark to the plugs. This is especially noticeable in rainy, damp or high humidity weather. Even if your distributor cap is not a repo, but an original, internal cracking may still be the problem. I have a box of original distributor bodies, half of which have some kind of internal crack.
To check your present distributor body, lay the spark plugs on top of the cylinder head, still connected to the distributor body via brass connectors. Turn the ignition key on and slowly hand-crank the engine so that each spark plug fires at that cylinder's TDC. If you see no spark at the plugs' electrodes or a very weak spark, the cap is bad. Check all four cylinders this way, not just one or two.
Marshall
ADDED NOTE: I have been corrected on my previous continual buzzing thought that I had added here. 'Hard to get Model T's out of your mind when switching over to Model A's! They may both be antique Fords, but ya' gotta' have the right mindset for each. Thanks for catching my error, Tom Wesenberg!
 
Last edited:
One more thing - As you hand-crank the engine to check out the plastic distributor body, remember that the engine's firing order is 1-2-4-3. Why is that important here? After #1 and #2 fire at the spark plugs' electrodes, the next one will be #4, not #3. I mention this so that you don't think #3 did not fire after the first two did. It's not supposed to fire yet! :)
1-2-4-3.
Marshall
 
Try changing the rotor. I had more than one that the spark would jump through the rotor to the shaft.
 
"Try changing the rotor. I had more than one that the spark would jump through the rotor to the shaft."

At an antique car meet in Arizona years ago, some Model A club members played a mean trick on a fellow member, who had left his Model A unattended while he walked around looking at other cars on display. The guys switched his rotor with one that had been drilled down the center of the plastic so that the spark would travel straight downward and short out against the distributor cam's locking bolt. When the guy got into his car at the end of the day to leave, the engine wouldn't start. He frantically went through the usual visual inspection in the hot Arizona sun and of course couldn't see the drilled hole from above. The club members let him suffer through numerous repair attempts before they finally let him in on the joke and showed him the drilled plastic rotor. REAL funny! 'Dunno if the guy got p*ssed, but he couldn't have laughed as hard as his "friends" did. What a dirty trick! Who'd have ever suspected a "trick" rotor?
Marshall
 
"ADDED NOTE: The spark at the plug's electrode will stay constant as a continuous buzz as long as the rotor's brass tang is directly opposite the distributor body's electrode. So, you don't have to worry while cranking about missing a quick arcing spark. Even doing the hand-cranking yourself, you will be able to hear the plug buzzing. "

Marshall, I'm not sure, but this part of your reply sounds like a Model T buzzing.
 
If the wire will spark to a head bolt and not to a spark plug are you positive the spark plugs are grounded? Check with a ohm meter, I've seen it happen. Goop on the threads kept them from grounding.
 
Tom -
I go both ways = Model A and Model T. I think you are right. There may just be a single spark at the spark plug electrode with a Model A coil. The Model T will buzz all day long on that cylinder, though. I better remove my afterthought above and switch gears faster when thinking Model A to Model T and back again. Good catch!
Marshall
 
Thanks Everyone! I Timed the engine after trying everything else. Timing pin, TDC, feel around inside the cylinder to verify TDC, I can't think of anything I missed on that. To check the spark, I tried removing the connector from #1 and placing it about a 1/16" away from the pin in the cap. Nothing! Now any self respecting coil and connector should be able to jump 1/16, Heck it should be able to jump 3/4"if it was going to jump. Clearly, there is nothing there. I like the bad rotor suggestion. Somehow I think I bought the Dist Body new a couple of years ago.
Terry
 
Terry said:
Thanks Everyone! I Timed the engine after trying everything else. Timing pin, TDC, feel around inside the cylinder to verify TDC, I can't think of anything I missed on that. To check the spark, I tried removing the connector from #1 and placing it about a 1/16" away from the pin in the cap. Nothing! Now any self respecting coil and connector should be able to jump 1/16, Heck it should be able to jump 3/4"if it was going to jump. Clearly, there is nothing there. I like the bad rotor suggestion. Somehow I think I bought the Dist Body new a couple of years ago.
Terry
Click to expand...

Did you check the valves to make sure you were on compression stroke
and not exhaust.

Bob
 
Bob C said:
Did you check the valves to make sure you were on compression stroke
and not exhaust.

Bob
Click to expand...
Just to eliminate confusion that is not possible on an A motor. The timing dimple is on the cam gear and requires two crank revolutions to get it to the timing pin hole. If the pin was on the crank it would be a different story.
 
you can remove the distributor cap and hold the coil wire on the rotor flex terminal while someone cranks the motor with the key ON. If you don't see the rotor send a spark at the tip, then you know it's going to the shaft. Yep.......you've been shafted.:D
 
An Update! Still playing with this *&%$#ed engine! I discovered I have spark at Two Cyls, #2 and #4. #1 and number #3 are inactive. Does this condition jog anyone's memory banks? Also, she's way advanced. I'm getting tired! Which way to retard the spark CW or CCW! How do I know it's advanced? The starter stops for a second and I see the spark, sorta makes a "Uhh" sound. The dist. body is new! The rotor is not shorted. Any help is certainly appreciated!
Terry
 
I have had problems with some repo distributor bodies. When you put them on and clamp them with the top plate. It pushes down on the bottom plate advance, retard arm which them causes the point open to the point they will not close. If this is the case you will need to deepen the slot on the distributor body.
 
You must log in or register to reply here.
Back
Top