Won't Rev 2.0

[DonaldSmith]

Update:

I could see getting the car to run well enough to get on and off a trailer and back and forth to a designated parking spot.  My son-on-law suggested that we rent a car-hauling trailer, and trailer the queen to the convention, using his half-ton truck.  U-Haul's standard offering came very close in size and capacity, but the total load is just a little over his towing capacity.  And the car would be hanging forward too close to the truck for sharp turns.  He'll be looking into truck rentals, etc. 

 

My plan is get the car running well enough to drive.  I'll methodically diagnose and adjust the ignition and carburetion systems, after having rested for several days. 

 

Ignition:  I'm working with the points system.  The car wants to run, since I put the two plug wires back into the distributor cap.  (I had knocked the wires out earlier, when I switched out the coils.  A result of working when over-tired.)  I can get the vacuum to 15 psi; the goal is 20.  I'm going to use a timing light and follow the instructions. (e.g., disconnect the vacuum line.  It makes it easier to rotate the dizzy, etc. ) Also  I can check things like the centrifugal advance.  I think the ignition system is basically OK.  

 

Carb:  Mike's Carb has been responding well to my questions.  They think there is a blocked passage somewhere in the high speed system.   For one thing, I never looked at the passage that is cast into the air horn.  I'll also check the step-up piston again. 

 

Slowly but persistently; methodically; per instructions and recommendations.   Stay tuned for occasional updates and intermittent breaking news.     

 

[DonaldSmith]

Worked on the ignition today.  Tried to follow the timing light instructions.  Disconnected and plugged the vacuum line. 

Started the engine, with the help of a shot of fluid.  (Make note:  End of battery cable gets hot after prolonged attempts to start.)

Started idling at 15 inches of vacuum, got up to 20 within ten minutes.  Isn't 20 my goal? 

 

Starts easy now.  Ran timing light off a 12 V car.  Still too dim; marks hard to see.  But I could see timing change with acceleration.  

Loosened and moved the dizzy.  Got up to maybe 21 inches of vacuum.  Good enough for now.  (Yes, I reconnected the vacuum line.)  I felt a little tingle moving the dizzy by the body, so I grabbed it by the vacuum advance thing.  The cap and rotor look good - no trails. 

 

Should I start working on the carb?  Could a gap between the air horn (top) and the body cause my problems?  No visible gap.  Tightened the screws quarter to half turn.  Could that do it?  Should I put the air cleaner on and do a test run, or go directly to taking carb top off?  NO driving until the opiate wears off.

 

Took two Tramadol this morning, for back and shoulder pains.  Feeling better, but sleepy.  No way getting behind the wheel.   I could take the air horn off and blow out some passages, without getting in too much trouble.  Take it easy, think things through.   Maybe fall asleep in the magic chair.  

[Sam Buchanan]

53 minutes ago, DonaldSmith said:

(Make note:  End of battery cable gets hot after prolonged attempts to start.)

 

You have a faulty cable.

[Young Ed]

Has anyone mentioned checking the spring piece for the points?

[kencombs]

23 minutes ago, Young Ed said:

Has anyone mentioned checking the spring piece for the points?

I did, a few posts back.   Don't know if he checked or not.

[DonaldSmith]

Breaking News!  We can confidently RULE OUT the carburetor. 

 

I popped the air horn, checked passages, checked the step-up-piston, and buttoned up the carb.  I ventured out into the neighborhood. The road test showed the same bogging, around 25 PH, full acceleration in 3rd gear.  That would translate to bogging down around 45 mph in 4th gear.  Back to the garage.   

 

On to the distributor.  I'll pull that sucker, and go through the suggested things to check.  I'll have to review the posts in this thread, and in its predecessor.  School daze.

[9 foot box]

   Your Pertronix ignition required carbon core plug wires. I run points and prefer copper core wires with 295 non resistor plugs set @ .028”. Go start your car when it’s dark out and see if the plug wires are showing any arcing. If you are able to that tonight, it might point to why you are having this problem. I don’t know what plugs you are using, only that you gapped them at .035”. Tomorrow you can do an ohm resistance test with each wire and the coil wire. You can buy copper core wires for a six cylinder tractor. Rick D.

[DonaldSmith]

Breaking News!  We can confidently RULE OUT the carburetor. 

 

I popped the air horn, checked passages, checked the step-up-piston, and buttoned up the carb.  I ventured out into the neighborhood. The road test showed the same bogging, around 25 PH, full acceleration in 3rd gear.  That would translate to bogging down around 45 mph in 4th gear.  Back to the garage.   

 

On to the distributor.  I'll pull that sucker, and go through the suggested things to check.  I'll have to review the posts in this thread, and in its predecessor.  School daze.

[DonaldSmith]

My last post must have ben hiding in my computer overnight.  Sorry for the double post. 

 

I've got new Wally World lawn mower plugs in the car now, gapped around 0.027 - 0.030.  The wires look like resistance type. 

 

Dizzy on the bench.  Going to dig into it today.  The big spring is anchored properly, but the points don't line up.  The moving point is higher than the stationary point.  Offshore wonder?   And then there are condensers to learn to check.  Crunch time.   

[Kilgore47]

20 hours ago, DonaldSmith said:

I felt a little tingle moving the dizzy by the body

You shouldn't feel a tingle when moving the distributor.  Could be a cracked cap or bad wires.  Check to make sure the plug wires are pushed all the way down onto the cap.  When I got the P15 the plug wires were just barley into the holes.  This caused arching and the cap was destroyed.  The previous owner said they couldn't keep it running.  After I went through the ignition system I couldn't believe they got it to start.

[Ivan_B]

Guys, why are we still troubleshooting the ignition if the car runs okay on idle/slow speeds? How much do you think an incorrect ignition timing, etc., will mess things up at higher RPMs?

 

Did you actually take the carb off the car and completely gone over it? Are you able to obtain a spare carb for testing purposes? Does not even have to be the same, just close-enough for this engine... Just put it on and see if it makes a difference. You've also mentioned that you need to use starting fluid, at times. This only further points toward the fuel/air issue, in my opinion.

 

For the hot cable, remove/clean/lubricate the battery/alternator contacts if you have not already done so.

[DonaldSmith]

Kilgore47:  The cap and wires look good.  Could the cap leak the voltage but still look good?   I'll make sure the wire ends are in the sockets.  I'll check for fireworks at night. 

I have the dizzy on the bench.  It looks good.  I looked at the centrifugal advance, and it seems to move freely, with good spring tension.  

I filed the points and will set them at 0.017 to 0.020. I'll make sure they are aligned. 

I tested the condenser with my new meter.  (The black lead has to be pushed in all the way.)  0.24 uF (that's a mu, a small "u" with a long tail..)  The old condenser tested at 0.27.  Is that better or worse? 

 

Ivan B:  I completely removed the carb and went through it per Mike's instructions.  Occasional starting fluid helps when the cable gets hot and it cranks slowly,. after I've been messing with stuff.  I know, replace the cable.   It's on my list. 

 

(One Joker in the deck:  Transmission interrupter circuit.  If the interrupter switch is sticking, it can interrupt the ignition.  On the upshift?  Once I get the beast running, I can try disconnecting the circuit.       

[TodFitch]

30 minutes ago, Ivan_B said:

Guys, why are we still troubleshooting the ignition if the car runs okay on idle/slow speeds? How much do you think an incorrect ignition timing, etc., will mess things up at higher RPMs?

The higher the pressure in the cylinder, the more voltage it takes to make a spark. The pressure in the cylinder goes up the more the throttle is opened, so a weak ignition system can cause performance issues at higher speeds, climbing hills, etc. There was a P15 on a tour a few years back that I was convinced had a fuel pump problem. Turns out it was actually a bad coil. But the symptoms were nearly identical.

[Ivan_B]

25 minutes ago, DonaldSmith said:

Could the cap leak the voltage but still look good?

Yes, of course. There could also be a break in one of the wires, which is shorting to your hand when you get too close. As suggested, looking at the operating system in the dark should demonstrate where the problem is.

 

Also, don't recall if you've tested this or not, but the car would not rev in 3-4, right? How about the low gear or idle? Are you able to obtain the maximum driving speed (per the user's manual) in first?

 

  

3 minutes ago, TodFitch said:

The higher the pressure in the cylinder, the more voltage it takes to make a spark.

Okay, this makes sense. But we've probably already checked the spark quality with an indicator, right??

Edited July 11, 2023 by Ivan_B

[DonaldSmith]

Check spark quality with an indicator - You have my attention.   What's an indicator?

 

[desoto1939]

On the dizzy cap pull each sparkplug wire one at a time. Check that the end contact is clean and also tight on the end. Check the hole for the wire and make sure there is no corrosion in the contact area for the wire.  Check all the wire ends at the dizzy and then check the ends to make sure they are clean and tight at the sparkplug end.

 

If you are running a petronix unit then you need resistor sparkplugs capped at 35.  If non petronix then regular A7 or A9 Autolite plugs would be gapped at 25. The correct gap for the dizzy would be 20 but any gapp between 18-20 will work just fine but means the dwell is bigger if the gap is smaller.

 

Check for end play in the dizzy shaft also check the breaker plate assembly to see if you have a lot of play between the top and bottom half. Sometimes the grease that is in the small ball bearings between the two halfs harder up and these might need to be cleaned out and lubriplate grease them again.

Or get a totally new breaker plate assembly.  Check the springs for the weights in the dizzy

 

I might have a few of the NOS breaker plates for your car. They should be the same as the one used in my 39 Desoto.

 

 

 

Rich Hartung I am member of the NDC so you can find my contact info in the Membership Directory.

 

 

Edited July 11, 2023 by desoto1939

[Ivan_B]

1 hour ago, DonaldSmith said:

What's an indicator?

Oh, it's just this simple thing:

https://www.amazon.com/Deal】OriGlam-Adjustable-Ignition-Circuit-Diagnostic/dp/B06X9RC3PF/ref=sr_1_6?hvadid=409940613264&hvdev=c&hvlocphy=9011574&hvnetw=g&hvqmt=e&hvrand=10617054610227163456&hvtargid=kwd-951276676&hydadcr=24658_11410762&keywords=spark+plug+tester&qid=1689100930&sr=8-6

"Real men" just hold a spare plug next to the block, with their bare hands, you know... ?

 

You connect it instead one of the plugs and ask someone to crank the engine to see how strong and large the spark is. For the modern 12v engines you should see a long and blue spark. Not sure about these older 6v systems, but is is probably the same. If the spark is yellow or does not fly very far - this could indicate an issue.

 

BTW, since we are talking about spark, there are also see-thorough plugs available for the engine itself. It allows you to see inside the combustion chamber and adjust the carb ail/fuel ratio based upon the color of the burning fuel. I need to get myself one of these...

[DonaldSmith]

Thanks, Ivan_B.  i just had to order an indicator.  Thanks, DeSoto 1939 for the tips.  

 

I found an anomaly with how I had installed the points.  There is a curved metal piece that fits around the curved spring.  Somehow, I had two of these pieces.  Sometimes on the bench the points wouldn't even close.   Nice and free now, and set at 0.19 or so. The condenser checks out.  

The dizzy is back in place, and I can connect and adjust things . . . . after an extended break. 

It's hot out, and my back hurts from standing and walking.  I would love to get this over with, but the body says, in good time.       

[Ivan_B]

You'll get it, eventually. Just bear with us, here

You did not need to order the indicator, unless you work with ignition issues frequently, you could've just done a quick spare plug test. Do not hold it with you bare hands, though, just attach the plug so its base is grounded to the engine, and see how the spark fires. You can even bend the side contact 1/8-2/8 away from the center electrode to see if the spark will go that far.

[nonstop]

You might have just found the issue!  If the points aren’t closing, you have a point bounce and a miss.  If you get a chance, can you post a picture of the spring set up?

[DonaldSmith]

Here'd the breaker plate with the two metal thingies around the spring.  When I first checked things out yesterday, the points were misaligned.  At some point in handling today, the spring would not close the points.   I can see high speed problems with points closing.   I took out the second metal thingie and carefully assembled everything and set the gap. 

 

 

Tomorrow I finish reconnecting everything, setting the timing, etc.  Then road test.  Fingers crossed.  

Son-in-law just rented a 3/4-ton truck to haul a trailer to haul the DeSoto to the Convention, just in case.    

 

 

[9 foot box]

   Your points return spring isn’t installed correctly. You only need one. It goes under the copper strap and puts tension on the points arm. Hope this picture helps. Rick D.

[DonaldSmith]

Silly me.  I thought the copper strap was the spring.  Back to the bench.   

[FarmerJon]

Lucky for us, these old mopar distributors are easy to take out and set back in! Glad you have finally found a likely cause.

Edited July 12, 2023 by FarmerJon

[soth122003]

With pulling the dizzy more than a few times on the same job, make sure you don't install it 180 degrees out. Done that once or twice pulling the dizzy and installing it and then wonder why it won't start, or worse yet backfire and scare the crap out of you.

 

Joe Lee