74 year old needs help with 51 Chrysler Windsor

My dad bought his first new car from his brother, a Chrysler- Plymouth dealer in Russellville, Ky. A 1950 Plymouth wooden station wagon ***embled in Evansville, Indiana. I drove the car until I purchased an Austin Healey 3000 MarkIII in1970. I currently have a 1951 Windsor with the M6 transmission. My problem is that the engine stalls after about 15 to 20 seconds with the transmission in drive and the brakes on. I have no problem with the car in neutral.
Interrupter switch,resistor, loose connections?
Any help would be greatly appreciated.

 

@squirrel know anything about these systems??

 

Paging Rusty O'Toole........

 

Put the @ before the name and it will actually page him! @Rusty O'Toole

 

I had a 53 Chrysler with the same trans.

If I remember right there where 2 switches on the carb for upshifting.

The torque converter is filled with engine oil from two ports in the bellhousing where it mates to the engine block. Check your oil level.

Clutch is only really needed to shift gears but once it’s in d or l the clutch is not required.

If you depress the clutch while the engines running and shift selector in gear does it stay running?

The switches on the carb controlled upshifting only, the only down shift that was automatic was after you stopped, if you rolled forward a bit it would drop it from 3rd to 2nd.

Sorry that’s all I remember about this trans, had mine 3 years and never an issue.

There are service manuals available for decent prices

 

Engine should idle at 450 RPM in neutral and should not stall when stopped in gear. I would suggest doing a compression test and maybe a tuneup. If the engine is in good shape compression should be 100PSI or more with all cylinders within 10 pounds. A perfect engine would be 140PSI.

It could be the choke is not working if this only happens cold. The Sisson choke is an excellent unit but they do wear out after 60 or 70 years. New ones turn up on Ebay from time to time. They must be adjusted according to the manual.

These engines are foolers and will continue to run with no bad knocks or bangs in an advanced state of wear. They just get sluggish, down on power, hard to start and burn more gas.

I don't know anything that would suddenly make an engine cut out after 15 or 20 seconds of idling. I can only guess that it is idling badly and eventually stalls.

 

I messed with one of those 40 years ago...but I'd have to break out the book now to try to figure it out. Unfortunately I have lot of other stuff going on right now, and not much time or attention left over for this.

 

Thank you Rusty for your reply. When I said it stalls I should have said. It stops as if I have turned off the ignition. It immediately restarts. Is there any electrical issue that I might need to address ?
I also want to thank everyone who replied.


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This only happens when I have the transmission engaged.


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Just thinking a carb thing - set the idle up just a tad - and what Rusty said - do you have ant manuals ?

 

Man I know a lot of older engines idled low but 450 is real low. If like Rusty says it has a need for a tune-up, that would be an issue maybe when dropped into gear. WTH does it idle at in gear? The old cars had pretty loose trans setups so I would imagine 450 in neutral and 450 in gear also? lol. I can't imagine an electrical problem causing this. But automotive engineers back then were trying lots of weird stuff. Lippy

 

There are 2 wires that go from the coil to a small box on the air cleaner support. Try disconnecting the wires from the coil temporarily and see if that fixes the problem. If it does then the problem is in the trans control system. If you have a wiring diagram you could check that the system is wired properly and that the wires are not frayed or broken. If they are original the insulation tends to dry out and break off in pieces especially under the hood where heat and fumes take a toll.

Here is a wiring diagram for a 1950 model which should be similar to your car. To enlarge the wiring diagram move your cursor onto the diagram and right click. Then click on Open Link in new Tab. Go to the new tab, to enlarge diagram hold down the CTRL key on the lower left of the keyboard and roll the wheel on your mouse.

Look for the Coil near the distributor at the lower right of the diagram. See the 2 wires going from the coil to the resistor and circuit breaker box. That is the trans control wiring. Be sure it is wired correctly and check for broken, loose or frayed wires.

 

Rusty, not trying to **** into this thread, but as you seem to be the man on this stuff, why would it idle 15-20 seconds in gear before it quit if it was an electrical problem? Just curious, your thoughts? Just trying to understand. I like to learn. Lippy

 

Those old flatheads were beautiful, smooth, quiet engines and would easily idle down to 450 RPM in neutral, slower in gear. Of course an old engine that is worn out and out of tune is a different story. You don't often see one anymore that is in good shape and tuned correctly.
The idle speed must be low if the trans is to work correctly.

 

Damned if I know. Don't look at me, I'm not the one that says it does. I have offered a few suggestions but that is all they are, suggestions. A problem like this is something like texting a girl 1000 miles away that her nose is shiny.

One problem that comes to mind is a bare wire that shorts out intermittently as it moves around. I had a Chev pickup once that would stall out only when turning a corner slowly and only to the left. It turned out to be a wire that rubbed against a bracket on the firewall until it rubbed thru the insulation. But it only shorted out when the engine lurched a certain way which happened when you hit the gas taking off from a stop, if you were turning left.

1951 Chrysler still used cloth covered rubber insulated wire.The old rubber insulation dried out and flaked off when it got old leaving bare wires under the hood.

If the OP said the engine chugged and sputtered then stalled it might point to a weak fuel pump, plugged fuel filter or other fuel related problem. But if it runs perfectly then cuts out instantly it is more likely electrical.

OP also does not state if this happens only when cold, only after the engine is thoroughly warmed up, or what. If it only happened red hot I might suspect a weak condenser or coil. If it only happened stone cold I might suspect a weak choke.

It is also possible the OP forgot to mention some alteration or broken or missing part that could have a bearing on the problem. There are a million possibilities.

 

As rusty stated these flat head 6’s idle very low and run smooth.

My 53 after sitting one winter blew out the head gasket between 2 cylinders.
Other then being hard to start it ran perfectly fine.


So your car starts fine cold,
And hot.
Stalls after about 15 seconds in gear
Runs fine if left in neutral
And just dies?
No sputtering
Chugging
Loading
Etc?

See if you can get a tachometer or something else to check rpm and see where your is.
Could you have a vacuum leak that only effects the engine under load?
Low fuel pressure?
A weak engine, tight valves etc?

 

LOL on the shiny girl nose. And yes he didn't give much information. Sorry , it could be a bunch of things. I'm not familiar with these cars at all. Just was wondering what the wires from the coil have to do with the transmission. Or are we speaking of a different coil? Geez what did I get into. LOL. I will **** out now. I'd look at the schematic but ...... If we were speaking face to face my questions would probably come off differently. Lippy

 

The fact that it stalls intermittently and only when in gear makes me think it is a wire shorting out or maybe loose. If the engine has to move around in a certain way for it to happen then it restarts immediately it suggests ignition. Now that I think about it, it may be a fault anywhere in the ignition wiring, coil or distributor not necessarily related to the transmission.

 

I would suggest that the OP get in touch with the guys on the P15-D24 Forum...........there are quite a few who have had experience with the various types of transmissions that Mopar used in the 40's & 50's..........here in Oz we only got the standard 3 speed manual, O/d and a few of the Fluid Drives until the Powerflite came out............the P15-D24 guys should be able to help..............andyd

 

The transmission is controlled electrically. There is a solenoid that shifts the gears hydraulically. There is a governor to control the speed at which shifts take place. And there is an interrupter switch.

In addition there are 2 electrical switches on the carburetor. One is the kickdown, it is actuated at full throttle. The other is the regular shift, it is actuated when the throttle is closed.

The transmission itself is like any manual transmission. Except that it has a little oil pump and a hydraulic piston that shifts gears when a valve is opened by the solenoid. This hydraulic piston has only 2 positions, High and Low.

There is also a manual gearshift by the usual column mounted lever. It allows you to select High or Low range. So you have a total of 4 speeds forward, High range high and low, and Low range high and low. All normal driving is done in High range. Low range is for starting on hills or driving slowly in deep mud, snow or sand etc.

The transmission itself is rugged and trouble free. The electrical controls seldom give trouble and there are only a few wires. Of all the early automatic drives it is probably the simplest and most reliable and long lived. I would much rather diagnose and fix a Fluid Drive car than a Hydramatic car, for example. Troubles are few and far between and usually involve a simple cheap fix like replacing a broken wire or filling up with oil.

 

Now that was a great informative post! For us gearheads anyway.Thanks Rusty! Lippy

 

Yes.

 

Truck, your a bad man and we are going to put you in the corn field.

 

Several years ago I replaced the wring harness for the transmission. From the coil to the carburetor to the circuit breaker and resistor and ending with the governor, solenoid and interrupter switch. I think it’s an electrical issue but don’t know how to diagnose it. I do have a service manual.


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I would start by examining the wiring, points, coil, and distributor. If I saw no obvious faults I would disconnect the trans wiring from the coil and try it, if it still stalled I would suspect the distributor, points, coil, ignition switch etc etc. If the problem was cured I would suspect the trans control system.

Do this and come back and tell me what you found out.

 

Thanks Rusty and everyone for your input. Worst case, I’ll just shift into neutral at a stop light.


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I sincerely believe that whatever the problem is, it can be diagnosed and cured easily. But one of us is going to have to examine the car under the hood and do a few tests. You are closer than we are.

If you are not mechanical maybe you can find an old retired mechanic to help you out.

 

I’m somewhat mechanical. What should I be looking for?


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Could it be a weak interupter switch


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Could it be a bad neutral safety switch ?


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