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1941 Plymouth P12 TDC - completely lost


Quest Master

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10 hours ago, Quest Master said:

Open to any other suggestions.

Just be sure you are not following pictures in a book, where #1 plug wire is on the distributor cap.

Put #1 where the rotor is pointing.

 

If for some reason the oil pump was removed or replaced and the mechanic did not properly set the timing, follow procedure installing the oil pump, Your TDC on #1 will be in a different location then factory.

 

I fought this issue myself, I pulled all my wires and threw them in the trash, pulled the distributor and did my magic with it ... put it all back together by the book with #1 at 7:00 o'clock and nothing. ....

Finally I put it on TDC compression stroke on #6 because am lazy, then installed #6 wire where the rotor was pointing and installed rest of the wires from there ... I was now one step counter clockwise from what is factory, #1 is at 6 O'clock instead of 7 ... and it fired right up.

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22 hours ago, Quest Master said:

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.

 

You can also try a  hand crank starter from a farmall A. This is was works for at least on the 3 engines i've tried. It inserts into the nut and catches on the two elevated points if that makes sense. Not sure if that will work though if you have to go clear down to 1/2" now that I've reread that

Edited by maddmaxx1949
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Thank you for the feedback! So for my 1941 P12 with a P20 engine, the #1 cylinder - the valve directly under the spark plug hole is the intake valve. I put a pencil on it, rotate the engine - when the valve closes, I look at the pully and rotate it the remaining way to DC - which is now the compression stroke (#1 cylinder is all the way up at TDC), #1 spark plug (7 o'clock position on distributor) is ready to fire. Distributor rotor is set directly at that position.

Key turned, clutch in, gas in carb, choke closed, rotate starter - nothing. I got a couple of minor coughs. Rotated distributor a little each way - nothing changed. Pulled a plug and grounded to battery (again) to verify spark - rotated engine, it is present.

 

I am felling really frustrated. It previously ran.

How much fuel should be at the be at the bottom of the intake manifold - barely wet with gas or a visible puddle. Should the rotor be exactly under the point of the distributor cap or slightly before?

Now I'm taking wild guesses what could be wrong because everything seems correct.

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Oh....and I want to add another point about the oil pump (in 70'ish years it had to be replaced), and this is for other readers - because I've now read a lot of similar threads...even if it was indexed wrong, it rides on the cam, and is keyed to only fit the distributor two ways (180 degrees each way). So let's say it was pointed/keyed at 5 and 10 o'clock - those are still your TDC for #1 and #6 and as long as you use the TDC for the distributor at those points/areas, you're still good (not paying attention to the 7 o'clock in the manual). Correct?

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Assuming you have the correct distributor parts and installed correctly: 

First turn it over to where you think it is on TDC for #1 (the front most cylinder)

Pull the front valve cover off and visually verify both valves are closed. Then turn it a bit more and verify the exhaust valve starts to open. If correct, back it up to TDC, if not go one rotation, verify and then set up to TDC.

Very important, verify all your plug wires are fully seated in the distributor, coil and plugs.

If everything is at "factory spec" your distributor should be pointing to around 7:00. (If not report back)

Verify the plunger in the distributor cap is fully extended and not stuck in the cap. Then reinstall and use the locking clips on the distributor.

Loosen the distributor lockdown nut so you can rotate the full 10-15 degrees in both directions. Set mid position to start.

Next you need a tester to verify the plug is firing. I use a cheap Neon AC tester (buck or two at Home Depot). Pull the plug wire off, insert one lead of the tester in the plug wire connector, the other lead to a solid ground (Just use an alligator clip jumper wire to ground).

Now the test:

Turn on the ignition, don't touch the starter. Did your ammeter slightly deflect to the left?

Now turn the distributor body back and forth the full rotation allowed by the distributor lock bolt you should see a flash on the tester when the points open.  If it flashes your ignition is fine. 

If it doesn't, start working backwards. Next try the tester at the cap where the plug wire goes in.  Still no go? Try the coil wire at the cap, then at the coil. 

Then report back what you found and we can figure out the next correct step.

 

 

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If a small back fire occurs from the carb and exhaust then your are 180* out.

Edited by maok
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Another thing. Wad up a piece of paper towel, wedge it in #1 spark plug hole. Set plug On head with wire attatched. Crank engine with key on. Paper will pop out milliseconds before spark occurs. 
 

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16 hours ago, P15-D24 said:

I use a cheap Neon AC tester (buck or two at Home Depot).

 

 

What tester are you referring to? Looking at the Home Depot website, everything starts at $8 and I do not see anything for 6v. Now, I understand that coming out of the coil the voltage is much higher, but it also says AC and not DC. I will go to Home Depot right now and buy whatever I need to, just tell me. Thank you everyone for your help.

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Something like this: https://www.grainger.com/product/40JZ70?gclid=Cj0KCQjw6PD3BRDPARIsAN8pHuGHmLfQxXMeLZzP-Z0GNyRXkz1zQT1bGmk0fWgdxOjDeenH-vF1NXIaAlEIEALw_wcB&cm_mmc=PPC:+Google+PLA&ef_id=Cj0KCQjw6PD3BRDPARIsAN8pHuGHmLfQxXMeLZzP-Z0GNyRXkz1zQT1bGmk0fWgdxOjDeenH-vF1NXIaAlEIEALw_wcB:G:s&s_kwcid=AL!2966!3!264955916558!!!g!439964433995!

 

You want something that is not incandescent or LED, but with a neon indicator. The voltage at the plug wire will be around 20,000 volts but very low amps. (It will bite you if you are holding it but it won't kill you ?)

When you turn the distributor you will see a brief flash as the coil discharges. Also a cheap neon timing light that clips inline to the plug wire will work.

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OK...here are all of the steps I just did:

#1 - put a rod in #6 cylinder hole and a pencil on the intake lifter of #1 cylinder spark plug hole. Turned crank, #6 (rod) came up, #1 pencil went down, stopped at DC on the pully.

#2 - purchased a "OEMTools In-line ignition spark plug tester" (Auto-zone $8). Put it in between the plug wire and plug of #1 cylinder. Loosened distributor bolt. Turned ignition key, rotated distributor until light came on. Repeated several times to make sure. Stopped when light came on. Tightened down distributor bolt.

#3 - put In-line tester on all plug wires, turned engine by had with starter. All six light up.

#4 - Put everything back together, add gas, ignition key turned, rotate engine with starter. Nothing.

#5 - brought back to DC on pully, flipped distibutor 180, repeated step #2, repeated step #4.

Nothing. No start. (And yes, if I ground a plug directly to the battery there is a spark, just in case no one reads back to my previous posts).

Thank you again for the assistance.

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You need three things for an engine to run.

 

Air, Fuel and spark.

 

You obviously have spark and it appears to be close to where it should be. 

 

The cam appears to be opening and closing the valves at approximately the right time, you have air.

 

That leaves fuel.  Did you look down the carb and work the throttle lever to see if you get a shot of fuel?

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Yes, agree on all of that. Air, fuel and spark. That is why I am quite frustrated. All I did was replace the spark plugs (well and rebuild the starter, generator and re-paint the whole car - but that is unrelated)

 

The carb has been dry for over a year and was always run from a gas can to the fuel pump (unknown Gas tank condition - hadn't gotten to it yet). For recent test starting, I've just used a spray of starting fluid or a little gas down the carb barrel. 

 

 

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1 hour ago, Quest Master said:

Yes, agree on all of that. Air, fuel and spark. That is why I am quite frustrated. All I did was replace the spark plugs (well and rebuild the starter, generator and re-paint the whole car - but that is unrelated)

 

The carb has been dry for over a year and was always run from a gas can to the fuel pump (unknown Gas tank condition - hadn't gotten to it yet). For recent test starting, I've just used a spray of starting fluid or a little gas down the carb barrel. 

 

 

 

I'd suggest you might not have hit on the right fuel/air combination to get the old girl to fire up. Hook up the gas can again, get the pump to filling the bowl, pull on a bit of choke, and make it start.  :)

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   I would pull all the plugs, prop the throttle wide open and do a compression test. If the numbers are low, put a squirt of oil in each cylinder and repeat compression test. If the pressure is better, put the distributor back to where you got spark and put the throttle back to idle, install plugs and wires. Your cylinders could be dry from all your previous attempts.

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I'll refer to Sniper's comment, you've got air, and you've got spark...you're not getting fuel to the cylinders.  You've exhausted all means to ensure you have the right timing and ignition to theoretically get the car to start.  You also said you had some "minor coughs".  Sounds like a fuel issue, or lack thereof.  You mentioned your car(buretor) sat dry for over a year.  Hooking a gas can up to the carb does not ensure proper fuel delivery to the cylinders.  You're carb sat dry for over a year, it's quite possible something in there dried up, loosened up some crud, clogged jets, accelerator pump, etc.  I'd remove the carb and ensure everything is clean and clear, and the gaskets are good, i.e., rebuild it.  You could look down the throat to see if there is a spray of fuel when the accelerator is opened, but that is hit or miss.  Or, and this can be a bit dangerous, just pour a shot of gas down the throat and try to start it right afterwards.  If it starts (it won't run long) then you have a carburetor problem.

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20 minutes ago, Dan Hiebert said:

  Or, and this can be a bit dangerous, just pour a shot of gas down the throat and try to start it right afterwards.  If it starts (it won't run long) then you have a carburetor problem.

I watched as my dad almost loose his eyebrows looking down the throat while I was cranking.  It was great.  Recommend doing this in the late evening when the light is low because its a great show when the flame shoots up.  Perhaps you can try this July 4th in place of fire works.  

  • Haha 2
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Went through similar with mine.  Finally rechecked the plug wires for the 13th time and found evmn erything correct but one cap tower off.  So do the static timing procedure again ( I'm sure you are now expert on it) then remove the dist cap and assure the rotor is indeed point to where you hàve the wire for number one cylinder.  When I did mine, it started so quickly it scared me. 

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I'm going to go back to the one thing I changed - the spark plugs (no I didn't not keep the old ones). This car ran previously just fine. 

What spark plugs are you using and what gap did you set on them at? I have a 1941 P12 with a P20 engine.

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   And on the other hand, you could use Autolite 295, set at .028”. A non-resistor plug. That’s what I run, with solid core plug wire.

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