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1941 Plymouth P12 TDC - completely lost


Quest Master

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Restoring my 1941 P12, I decided to remove and clean the distributor and replace the plugs. It has never run again.

Here are the facts: I have a 1941 Plymouth P12 with a P20 engine. Here is where I am with TDC:

- On the crank pulley, I have the pointer exactly on top of the DC (dead center) letters, with IIII10 on either side.

- I have the inspection bolt on the head over #6 cylinder, with a rod in it - it is all the way up. At TDC: #1 and #6, both pistons are up, one compression and one exhaust. By removing the spark plugs you can partially see the valve tops. #1 is closed #6 is open - so I am on TDC for #1 compression. I set my distibutor to fire on #1, with the order being 1, 5, 3, 6, 2, 4 clockwise rotation. No start.

- The new plugs are Champion J12YC, set to .035 gap. Positive battery ground. When I ground a plug to the positive on the battery - I get spark during rotation.

 

So, what am I doing wrong? Wrong plugs,? Gap? I am using gas in the carb. Ignition key is turned....so what is the problem? 

Edited by Quest Master
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Remove distributor and turn it 180 degrees. 
usually i will crank with my finger over #1spark plug hole,and bump starter. As soon as i feel compression im good to drop in distributor. About 6 degrees advance,can get it close just while cranking. 
you have spark, so all that is left is fuel. 

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Did the engine run before you pulled the distributor?  Did you install a new distributor cap? When your all set at TDC for #1 cylinder (top of compression stroke), where is the distributor rotor "pointing"?   If all is set up correctly the rotor should be pointing to approximately the 7 o'clock position with respect to the distributor body.  Then the #1 plug wire should come off the cap tower above the rotor and up to the #1 plug.  Then clockwise rotation to other plugs in 153624 order as you stated.  If however the oil pump was removed and then not properly indexed when reinstalled  the  rotor position could be somewhere else other than the 7 o'clock position.  This is no real big deal as long as #1 plug wire comes off the tower above the rotor.

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Make sure you have the correct cap and tuneup parts for your distributor number. Caps are different depending on which one you have . Order parts using distributor number from a reputable seller.  If the cap is too tall a weak or no spark condition can occur.  

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J 12 Y have extended tips and were used in Chevrolet sixes.  A J12 would be the plug used by Plymouth.

Your intake valves hammered all the gaps closed the first time you cranked the engine .   no gap   no spark  no start,

Edited by dpollo
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Any time I have to retime a engine (such as over haul , or pulling dist for any work ) I time it manually by hand to get it started. Forget all the marks etc. to get running at 1st. With dist out , all plugs out , turn engine by hand with finger in  no 1 plug hole when you feel pressure pushing on finger stop turning engine. Either look in cylinder and watch for piston to get as close to top as possible, or look at TDC mark as you continue turn engine by hand on balancer/ pulley ..Look in dist hole on block and see where oil pump drive is clocked . Try insert your dist  with rotor pointing close to where you want no 1 plug wire to be. Might have to pull dist out and back off a few degrees on pointer since gears are helical cut and dist shaft will rotate as you drop in. Run all your plug wires in firing order leave dist loose fire it up. might have to turn dist few degrees either way to get to fire. If engine binds as you crank with starter you are too far advanced ,turn dist few degrees other way till it starts. I can listen to rpms as engine runs and move dist back and forth and usually get within 5 to 8 degrees without time light. BTW doesn't matter on dist cap which tower is number 1 plug as long as rotor is approaching that tower with no 1 cyl at tdc and you put rest of wires on in firing order.( might limit because of length of plug wires, primary wire from coil or room around ign advance can though)  I know I will catch heat but im old never could afford timing light till I was 25 yr old.! P S on Chevy  you can use a long screw driver to turn oil pump drive It slotted to where you want it to help line up with dist shaft  I once passed a maintenance mechanic test at St Louis main post office the tester took the distributor out of a postal jeep turned engine over with starter,  handed me the dist said put it back in and make it run, had it going in 5 min, they offered me the job but I turned down, went into trucking Hind site is 20/20 right Macthefinger?!!!!!!

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on all Chrysler built  flathead sixes the distributor drive  fits into a slot. It can go in only 2 ways. The drive gear is on the oil pump.

If assembled correctly, #1 wire will be at 7 0'clock on the cap.   No matter what brand of plug you get, do not use extended tips.

Edited by dpollo
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10 hours ago, dodgeguy said:

 had it going in 5 min, they offered me the job but I turned down, went into trucking Hind site is 20/20 right Macthefinger?!!!!!!

 

Too many possibilities to troubleshoot this problem online. Hindsight, what's that?   ?

 

"I'm the one that's going to die when it's time for me to die so let me live my life.....the way I want to." 

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  • 1 month later...

OK...took some time. Read other threads. Worked on other projects and decided to work on the 41 Plymouth P13 again. It has a P20 engine. 

Here is where I am with trouble-shooting (it ran before I started any of this).

TDC: Main pully pointed/centered over DC mark. Put rod in #6 cylinder hole, rotated by hand to verify TDC (it is). Put pencil in #1 spark plug hole (spark plug out, ignition off, board pressing clutch in) pushed down on starter, electrically rotated engine - felt #1 intake valve open and close (hand on a pencil sitting on top of the valve), then hand moved pully to TDC (which is actually BDC for #1 cylinder, with intake valve just closing). Rotated by hand another full rotation to bring #1 cylinder to TDC (compression stroke), set distributor to fire on #1 (about 7 o'clock position), oil pump index shouldn't matter (didn't replace it anyway). New (same plugs) gapped at .035....gave it a squirt of gas, closed choke, turned ignition key, engaged starter....nothing. Will not run. 

 

Spark plugs are firing when they are out and grounded to the battery (just as a check - and no they are not smushed from being too long - an earlier comment above). 

 

I've got spark, fuel and air. Is my distributor still off somehow? 

 

All I replaced were the spark plugs. Everything else is the same when it was previously running before I pulled the distibutor.

Edited by Quest Master
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I'm also going to add, because it took me a bunch of threads to find this, the pully nut (to hand turn) requires a 1 13/16" socket (3/4 drive) reduced to 1/2" drive - because a 3/4" extension bar will NOT fit through the grill and under the radiator, only 1/2" will.

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I had the same problem finding the socket size, too.

 

Many years ago I was helping a buddy on his 89 Ram.  No matter what he did it would not run, not even try to.  Now he had gotten more in depth into the ignition system than you did, so we double checked and triple checked the plugs, the plug wire routing, the rotor position, etc.  We had spark, fuel and air as well.

 

He had pulled the distributor and swore up and down it was in right, I finally convinced him to rotate the rotor 180 degrees, the 318 has the same drive tang setup as our flat heads so it can be in right or 180 out.  Now my buddy is one of those overly meticulous guys that polishes the ******* till it shines, but we all make mistakes.

 

Boom it fired up.

 

It might be 180 out for you too.

 

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Put timing light on #1 at tdc.   Loosen dizzy bolt.  

Turn on key but do not start.

Wiggle dizzy.  If light flashes you are in right.   If not you are 180 degrees out. 

 

If it's still not starting check the short wire inside the dizzy, it often breaks, killing the motor.   

 

Check fuel delivery as wel l.  

Edited by Sharps40
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I have flipped the distributor 180 now several times at TDC, just as a sanity check. My next step is to remove the manifold to see if somehow there is something caught in there (critter, I don't know).

 

I also re-gapped the plugs to .038 (just in case, I saw that larger gap somewhere else)

 

Open to any other suggestions.

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 Rotated by hand another full rotation to bring #1 cylinder to TDC (compression stroke), 

Correct me if I'm wrong, but as the intake valve closes, that is the compression stroke and the timing marks should appear soon after, not a full rotation later.

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