Reviving my P18 after PO gave up!

[Hook47]

Hey Gents! First post! 

 

I'm mighty proud to own a beautiful 1949 Plymouth Deluxe! The PO gave up on it because he couldn't get it to run, and when I took it home it had a significant portion of the vehicle in the trunk! 

 

Fast forward to now and I've made a lot of progress, but I've got a couple odd issues I could use some help chasing down. The car will run, drive and stop (thankfully) but after about 5 to 10 minutes it will loose power, possibly due to a loss of spark. I've been wrenching on cars for years, but this is the furthest back I've gone aside from some tractors and motorcycles. Here is what I've found:

 

Compression is good on all six. She isn't smoking or burning oil, and the engine honestly looks like it was rebuilt before PO gave up.

 

New wires, 6V coil, 6V battery, points (yes, aftermarket... I know... but NOS ones coming in the mail!) and new condenser. 

 

Gas tank flushed, new ethanol free fuel

 

Carb and fuel system are in good shape. Nice strong jet of fuel, choke is set and functioning as God intended. 

 

Used a timing gun (off a 12V battery) and realized the car is 21 degrees advance of the #6 cylinder. I tested the #1 and the timing marks weren't even close to showing up with the gun. Am I on the right track with the #6? 21 degrees seems like a LOT but I wanted to ask you guys before I mess with timing. 

 

Here is another weird symptom- I'm noticing a spark maybe under the points? It's weird. Hard to see where it is coming from. On other vehicles I've seen similar issues when the condenser was bad, so I installed a new one and noted it does crank easier, but occasionally it fires through the intake! I'm assuming the 21 degree advance has something to do with that! 

 

I want to do a better job diagnosing what is going on when it dies. After it cools down she will run again. Next time she dies I'm going to check thoroughly for spark and for maybe fuel in the intake incase she is flooding out? 

 

Any ideas? Am I on the right track? 

 

 

Edited June 15 by Hook47

[Loren]

A spark?

One of the problems I have seen on other cars is the ground wire between the breaker plates is missing.

The points have to be grounded ( or is it “positived” on a positive ground vehicle? lol ). The car will run because the current will find a ground if it will start but not always.

What usually happens is a progressive decline in ignition performance. Each time the points open there’s a spark. The points are made to last a long time with these sparks but the breaker plate is mild steel and it erodes a little each time a spark is made.

I have seen breaker plates so eroded that when the car reaches cruise speed the vacuum advance pulls on the breaker plate and the ground is broken causing a miss until the vacuum advance returns to it’s former position.

So I’d pop the distributor cap and look for the ground wire for starters.

[Plymouthy Adams]

check to ensure you are not running a 12 volt coil with internal resistor erroneous installed by the PO.....if it measures 3.4 ohms across the terminals...chunk it for a 1.4-1.7 ohm coil.

[keithb7]

Great suggestions! Pulling the distributor is a great idea. Take it apart and replace any old wires. Mentioning the spark you are seeing down behind the points, is a good clue to chase. Check the vacuum advance pot by pulling a vacuum on it. Replace the wire from the coil to the distributor housing while you are in there. Then you put the distributor back in when engine is set #1 TDC compression stroke. Turn your distributor shaft until the rotor sits at about 7 o'clock. Then mesh distributor shaft gear to the oil pump gear. Put spark plug wire 1 in the cap socket right over the rotor. Proceed with 5, 3, 6, 2, 4 clockwise. Then you'll have it set up right. Your crank pulley timing mark should be at, or very close to 0 degrees. If its not, someone probably put a different pulley on it. Draw your own line with a white paint pen. Then fire it up and check your timing with your timing light. 2-3 or so degrees advanced should be good to set it at. You can hear it, when its right. A vacuum gauge off the intake manifold is also a great way to set timing at idle. Rev the engine up a bit and watch the timing mark with your timing light on it. The timing mark should be advancing. Check and set your dwell by adjusting the points with a dwell meter, as per the manual specifications. 38 degrees dwell for my old Mopars.

Edited June 15 by keithb7

[Hook47]

Thanks for all the awesome input, fellas!

 

She's on a 6V coil WITHOUT internal resistor! I've made that mistake before.

 

Well like I say, she was at 22 degrees advance which seemed really agreesive. Guess what I found out today? The bolt to tighten down the distributor was TOTALLY LOOSE! No wonder she was so advance! I set her to about 8 degrees before TDC and she was running better. Started warm and on a short 5 minute drive didn't lose spark! Are we getting closer? 

 

I've noticed my oil pressure gauge starts at 40 when cold, then goes between 10 and 20 when warm, up to 30 or 40 under load. Is this normal? Could be it a worn out transducer? 

 

One step closer fellas! I have Petronix 6V electric ignition NIB. I've decided pulling the dizzy is a good call just to make sure she is road ready, in line with advice above, I'm going to replace the suspect ground (er... positive?) Wire from dizzy. Any recommendations between keeping her stock or going Petronix?

 

Thanks again guys! 

[Doug&Deb]

I had a bad experience with Pertronix. It worked three times and burned up. They did reimburse me quickly but I’ll stick with points. Of course you have to be careful about that also. Lots of junk available.

[Plymouthy Adams]

rule of thumb on oil pressure, 10lbs per 1000 rpm.....

[Sniper]

4 minutes ago, Plymouthy Adams said:

rule of thumb on oil pressure, 10lbs per 1000 rpm.....

That rule is invalid with our flatheads in fact it's pretty much invalid for anything not a small block chevy. If you read what the service manual says about oil pressure with the op is seeing is what is expected. 40 PSI at 30 miles an hour or so Road speed and any indication of oil pressure warm idle. That is what the factory service manual calls for

[Hook47]

Copy above on the oil pressure! 

 

Guys, am I on the money timing this cat off the #6 cylinder? Using the xenon timing gun it's the only cylinder that even makes since on timing. With the number one I'm flashing on the opposite side of the crank pulley from the timing marks! 

[Dave72dt]

You can use # 6 for timing. You'll need to figure out why the # 1 plug indicates it's firing that far away from TDC since both 1 and 6 are paired and rotate to the top of their cylinders at the same time.  1 and 6 should be opposite each other on the dist. cap.  Check the condition of your wires where they come through the wire locator and your cap itself for carbon tracking.

 

 

[Hook47]

Hey fellas, more progress, but more questions! 

 

So I dug into why the #1 was firing off the TDC gauge, and I think I found it... I went back to the basics. I put #1 on TDC, compression stroke, determined by me feeling compression through the plug hole and feeling pressure. I cannot get the pin hole bolt out of the number 6, as that bolt is cammed to hell and back! My understanding is plugs fire over the valves, so putting a wire in the plug hole to help find TDC is pointless. 

 

Once I reached TDC I noted the rotor was at the 5 O clock position, rather than the 7 as the service manual calls for. As I understand, this means the oil pump was installed and timing out of spec, but isn't critical if the firing order with the wires is at spec. And therein is the issue. The rotor is on the #4 wire! This seems way off! My understanding is the rotor should be at the #1 wire at TDC, #1 compression stroke. My question is how was this thing even running?! Can they run with the wires out of order? Maybe this explains backfires through the intake during crank! 

 

The #1 plug is clean as a whistle too. Doesn't look like it's been firing in spite of me DRIVING the car a couple times like this! 

 

My understanding is the firing order is 153624. Right now it's something like 423651... wth lol. 

 

Am I on the right track? Set to TDC on #1 compression, then set the wires in the DIRECTION of dizzy rotation to 153624? 

[Dave72dt]

Is it opposite the # 6 wire when on TDC?    If it is and your timing marks on the crank pulley line up put the wire for cyl 1 in that hole and follow the firing order around in direction orf rotor rotation.  1 will be opposite of 6, 5 opposite of 2 and 3 opposite of 4

 

Yes it can run with an incorrect firing order, poorly and no doubt with backfires while cranking.

Edited June 20 by Dave72dt
spell check and grammar

[keithb7]

One could really mess with the major timing adjustment located under the distributor. Crank it way out spec so it fires for cylinder 4, before cylinder 1. Lol. Lack of reading and writing skills makes a very dangerous tinkerer. 
 

Pull distributor out. Remove cap, and all wires.  Set #1 piston at TDC compression stroke as best you can.  Your pulley markings should confirm. With rotor in place, pointed to 7 o’clock try and drop distributor down in place. If it won’t go, turn rotor to where it drops into place. Seating in the oil pump slot. You have a choice to make. This is where #1 wire sits on your distributor cap. Followed by 5,3,6,2,4 wires.
 

Or better, take note where your rotor sits in relation to 7 o’clock where it should sit. Remove oil pump. Note the slot position in oil pump shaft. Turn pump drive gear with your hand to where you think the slot should line up with your distributor shaft. Re-insert oil pump but don’t bolt it down yet. Re-insert distributor. Seat it in the oil pump groove again. Is your rotor at 7 o’clock now? If not remove oil pump and adjust it again.  Once rotor and pump are in proper place you’re done. Insert plug wire #1 in the distributor socket directly over where the rotor is sitting.  Followed by proper firing order. 1-5-3-6–2-4. My Mopar head has the firing order cast into it. Hook up your spark plugs.
 

Set your static timing with a simple go-no-go type of light. Or digital multimeter set to continuity beep. Start with your major timing adjustment under the distributor base. Lock it down as close to zero degrees as you can. Then set your minor adjustment, (easily seen at the side of your distributor) to about 2-3 degrees before TDC, static. If you can. Use your pulley markings for reference. If all the other parts in the ignition system work, voila! You should have it nailed down. Fire it up and listen to it purr. Season to taste. 

Edited June 20 by keithb7

[Hook47]

Thanks fellas, I'll try the above! I think I've found the root cause of the PO giving up because "it just won't run right!" 

 

I'll report back on my success/failure/both after doing the above recommdations!

 

Hope I didn't hurt the poor thing running it for short durations. God, it must have been preigniting and detonating like a mother. I can very much see why it was losing power and dying on me!

 

One last clarification- barring some actually insane foul up when the last guy or guy before the last guy rebuilt this motor- can I trust my crank pulleys TDC mark? I'm assuming it's keyed to where it would have to align to the engines crank shaft to properly represent TDC. It was interesting that the number 6 cylinder did show me believable timing when I used the timing gun. PO did say his Dad (before he passed) had the motor professionally rebuilt, and it looks it. Compression is also great. When PO tried to make it run it the dizzy and several other parts were not installed. 

Edited June 20 by Hook47

[soth122003]

3 hours ago, Hook47 said:

When PO tried to make it run it the dizzy and several other parts were not installed. 

Sounds like the PO tried to get it running by memory and offset the timing. Try what Keithb said and static time it. It should start/run with little to no adjustment on the dizzy.

3 hours ago, Hook47 said:

can I trust my crank pulleys TDC mark?

Yes and no. If the pulley has a harmonic balancer on it, it is possible for it to have slipped and moved, meaning the timing marks are no longer aligned.  If there isn't one the normally yes the timing marks can be trusted.

 

The little plug above the number 6 cylinder is a pipe plug with tapered pipe threads and can be removed with some penetrating oil and a pipe wrench. Just take it slow and steady and maybe some heat and it should come out fairly easy.

 

Joe Lee

[Hook47]

We got it, fellas! BIG WIN! 

 

So following the above advice, I got my motor back to TDC and dug in. 

 

The distributor is off the factory spec position. The rotor is at the 4 o lock position, meaning the oil pump is off a few teeth. Swapping the rotor has it in the 10 I clock which was still out if spec, so I decided I don't care as long as it works. At this juncture I do not plan to pull the oil pump to reset it. That sounds like a two man job and I'm 1 short! 

 

Instead, I determined the firing order to see if that was a issue. Following the wires I found I was at TWO five three six ONE four.... two wires were swapped to the wrong place! I swapped them to 153624 and WHAT A DIFFERENCE! Prior to today I had only been hearing a flathead 4, that flathead 6 really purrs in comparison! On a test drive I had great power, no missing, no loss of power when hot, and great oil PSI! SHE EVEN FIRES RIGHT BACK UP WHEN HOT! 

 

Thanks a bunch for the help, fellas. Next step is new wheel bearings, maybe looking over the brakes, and she is ready to go to town! 

[soth122003]

Glad to hear it. As far as the oil pump goes it can be a 2 man job, but only to make it easy. One man has to go back and forth to each side of the engine, but only a few times. (I can see why you don't want to do it. It runs fine now an if it ain't broke don't mess with it LOL).

 

As far as the wheel bearings go, I would order them by the old wheel bearing part numbers and not the car they are attached to. Ask me how I know. Lol

 

Joe Lee

[keithb7]

The rear wheel bearings and inner axle seals is a fairly time consuming job. You’ll need a dial indicator. A brake drum puller, & ideally a slide hammer for the inner seal. Someome with a press to remove bearings off the axle, and press new ones on.  Plus the concentric brake shoe tool. Possibly more shims and new outer grease axle seals. 

[Hook47]

2 hours ago, keithb7 said:

The rear wheel bearings and inner axle seals is a fairly time consuming job. You’ll need a dial indicator. A brake drum puller, & ideally a slide hammer for the inner seal. Someome with a press to remove bearings off the axle, and press new ones on.  Plus the concentric brake shoe tool. Possibly more shims and new outer grease axle seals. 

 

Funny thing is I have no reason to believe it needs wheel bearings, I was just going to check them out! Are the drums that bad to get off? Saw a YT video where they came off fairly easy with a few taps of a hammer around the radius!

 

 Brakes actually work, so I was considering more preventative work!

[soth122003]

3 hours ago, Hook47 said:

Saw a YT video where they came off fairly easy with a few taps of a hammer around the radius!

Newer model cars. The 49 has tapered rear axles and a key to keep the drum from spinning on the axle. In other words the drum and axle are like a mated fit. You'll need the proper drum puller to remove the rear drums.

 

The fronts have bearings that the drum rides on and come off easy.

 

 

Joe Lee

[keithb7]

@Hook47 if you just want to check wheel bearings jack up the rear end. Wiggle the rear wheels. Spin the rear wheels. Any thing feel a little granular? Push and pull drum and axle in and out towards center diff. Should be a little play. Not much. If I recall .008-.012” or so? Don’t quote me on that.  Get a mechanic stethoscope. Place the tip on axle housing where the wheel bearing sits. Spin the wheel. Listen for excessive noise.  What would be excessive? Have a listen to your other bearings and compare.  Remove the grease plug. Is there any grease in there? Get a horse syringe. Fill it with grease. Pump grease into hole. Fill it up. Spin bearing. Fill it up again. DO NOT USE A GREASE GUN. 

 

 

[Hook47]

Well, she is throwing another curveball at me! 

 

Did an oil change today and decided to confirm timing now that she is firing on all six. I've noticed the last couple runs she is idling high... like 2 to 2500 RPM! Not sure why this started. The lean/rich screw has no effect (probably because its not on the idle circuit), the throttle linkage is set correctly and the choke is open and not stuck. 

 

I put the timing gun on and the damn thing is saying it's at like 35-40 degrees advance!!! How is that even possible! Is that because the RPM is high? Here is the kicker... I loosen the distributor and went full retard (I know, never go full retard) by turning it all the way clockwise. She is still idling high and showing about 30 degrees advance at the fill retard setting! 

 

I'm pretty stumped. 

[Hook47]

Any guesses, fellas? Still playing around with it but I haven't figured out why it's idling high yet. 

[keithb7]

To control idle speed you need to control air intake as well. If your carb has air leaks where it should be sealed, it’ll idle high. The only air entering into your carb needs to enter down through the top air horn only.  Other points of air entry means you don’t have control of the air. Your engine is running-off on its own.
 

This is also why your air/fuel mixture screw has no effect. It only works when you have proper control of the of air entering the carb. You don’t have that. 

Edited June 28 by keithb7

[Dave72dt]

Check the fitment of the throttle plate in the bore, especially if has been removed.  A little misalignment or bent plate will hold it open enough to give a high idle.