Got a Problem Need Advice

[Labrauer]

I have got the 48 Plymouth coupe ready to go on the road again but I have one problem. The car is still on the jack stands and I have run it idling and with the throttle cable pulled out running. It runs great at this stage of the game but when I go through the gears and in high (3rd) revved it up to around 45 mph the engine starts to spud-er and back fire and seems to loose power. I have checked the timing and it is TDC. Put the timing light on it and revved it up to see if the vacuum advance is working and it is.  Everything seems to run great until I get up to the speed of 45 and then all heck breaks loose. Checked the compression and it is great on all cylinders. Put new spark plugs in. Check the gap on the points several times and they are right. Changed the points and condenser in the distributor checked the wires inside the distributor all looks to be fine. The car has been changed over to 12 volts with a new 12 volt coil and also everything in the distributor 12 volt. I just don't understand what's the problem or how to fix it.  

Any suggestions or advice please. 

As always thanks in advance,

Larry

[bluefoxamazone]

7 minutes ago, Labrauer said:

I have got the 48 Plymouth coupe ready to go on the road again but I have one problem. The car is still on the jack stands and I have run it idling and with the throttle cable pulled out running. It runs great at this stage of the game but when I go through the gears and in high (3rd) revved it up to around 45 mph the engine starts to spud-er and back fire and seems to loose power. I have checked the timing and it is TDC. Put the timing light on it and revved it up to see if the vacuum advance is working and it is.  Everything seems to run great until I get up to the speed of 45 and then all heck breaks loose. Checked the compression and it is great on all cylinders. Put new spark plugs in. Check the gap on the points several times and they are right. Changed the points and condenser in the distributor checked the wires inside the distributor all looks to be fine. The car has been changed over to 12 volts with a new 12 volt coil and also everything in the distributor 12 volt. I just don't understand what's the problem or how to fix it.  

Any suggestions or advice please. 

As always thanks in advance,

Larry

hello Larry, you seem to be concentrating on the ignition/timing.. sure it's not a carburation problem...?grtz

 

[Labrauer]

No I am not sure it isn't a carburation problem. I would think that if it runs fine until I run it through the gears it wouldn't be that but maybe I just don't know. I guess that could be the problem I am just wondering because the carb came off the old engine and it was doing fine although it has set on the shelf for about 6 months before reinstalling. 

[knuckleharley]

How "fresh" is the gas? If it has been in the tank more than a  few months,I would drain it and replace it with fresh gas.

 

The second thing I would do would be to check fuel pump pressure.

 

If the fuel pump pressure test shows it to be working correctly,I would then soak,clean,and rebuild the carb.

[Plymouthy Adams]

have you checked the points to ensure that the springs are properly installed so to prevent point bounce?

[Don Coatney]

Are your points floating due to the heavy metal spring not installed or installed incorrectly? When you say everything in the distributor is 12 volts what are you referring to? On 12 volt cars the points and coil still run on 6 volts using an internal or external resistor on the coil. 

 

 

 

[Merle Coggins]

Quote

...until I get up to the speed of 45 and then all heck breaks loose

 

When "all heck breaks loose" what does the timing light do? Does the timing become very erratic? That would indicate points bounce as Don mentioned. It happened to me once. Didn't get the spring hooked right and the points would bounce/float at higher RPM. Timing would go nuts. Engine would stumble and loose power. Redid the points with the spring properly hooked and all was right with the world.

[Plymouthy Adams]

you mentioned two things of interest...converted to 12 volts and 12 volt coil....are you running a ballast resistor with this set up....and what 12 volt coil do you have...could it be the internal resistor model coil?  As you are truly not under a full load condition by free wheeling on stands..your breakdown would probably occur very early with weight on wheels.  If running both a resistor coil and the ballast, you are reducing the voltage to the coil and limiting it ability to saturate and the fact you are not under load will allow the engine to perform a bit better than if you tried to drive it.   Just something you need to confirm and rule out on here.  

[bluefoxamazone]

mmm. I'd put my money on Plymouthy and mr Coatney... ?

 

[sser2]

Likely a distributor problem. Tension of points spring (17-20 oz) should be tested with dynamometer. Shaft bushing wear is also a likely cause of erratic performance at higher rpm. Shaft free play measured at shaft's end should not be more than 0.008". In most old distributors, it is way more than that.

[JerseyHarold]

Have you checked the exhaust for restrictions?  The flow might get choked-off after a certain RPM.

[Labrauer]

Well guys this is all great advice. I have not checked the timing when this happens. I will do so as soon as I get back in town Monday. I have to leave town in about one hour so it will be Monday or Tuesday before I can report back. I take all of your commits and check each one I'm sure someone hit the nail on the head.

Thanks a lot,

Larry

[Labrauer]

Don what I am saying is the car was converted over to 12 volts from the 6 volts so I got a 12 volt coil, condenser and points. 

[48ply1stcar]

I have been dealing with this all year. 

Yesterday I used a can to feed the fuel pump from a splice on the drivers side under the front door.  After still having a fuel to carb issuse I odered a new pump which I have been blaming all summer.  Then before pushing the car back into the garage I placed the gas can under the fuel pump.  Now I have more gas getting to the carb.  Now I have to make adjustments to my carb, replace the fuel-line under the radiator, the only part of the fuel line that hasen't been replaced.  Or it could be because the gas can is closer.  Started to replace fuel line, too hot and humid to finish.

Edited September 3, 2018 by 48ply1stcar
Additional information

[knuckleharley]

I hope if you are replacing rubber fuel lines that you are using new rubber fuel lines built specifically to handle ethanol? If not,you will be sorry because ethanol will eat regular rubber fuel lines like acid.

 

If you are replacing any hard fuel lines because you suspect they might have rust causing a restriction inside,or they might have pin holes sucking air,do yourself a favor and use the new nickel/copper fuel lines. You can bend them by hand without them kinking,and they will never rust inside or out.

[classiccarjack]

I bought ethanol resistant fuel line from Amazon.  It's tough to slip over the nipples to the fuel line and the pump, but I would love to quit seeing my fuel lines looking like Jaws attacked them!  The modern fuel is BRUTAL to the fuel hose.  They just dry rot inside out...  

 

May be worth looking into.  I hope this helps.

[knuckleharley]

4 hours ago, classiccarjack said:

I bought ethanol resistant fuel line from Amazon.  It's tough to slip over the nipples to the fuel line and the pump, but I would love to quit seeing my fuel lines looking like Jaws attacked them!  The modern fuel is BRUTAL to the fuel hose.  They just dry rot inside out...  

 

May be worth looking into.  I hope this helps.

You can also buy it at any auto parts store.

[Labrauer]

Well guys it will be a few days before I can get to the car now because I had to put the wife in the hospital Monday morning with possibly of surgery so please bear with me and I'll get back on this as soon as possible. Thanks for all the replies and I'll let you know how it goes 

[48ply1stcar]

Good thoughts and prayers, for you and your wife.

 

[knuckleharley]

8 hours ago, Labrauer said:

Well guys it will be a few days before I can get to the car now because I had to put the wife in the hospital Monday morning with possibly of surgery so please bear with me and I'll get back on this as soon as possible. Thanks for all the replies and I'll let you know how it goes 

It's all about priorities,and in the end,cars are just cars. Hope she doesn't need surgery and returns home soon.

[classiccarjack]

17 hours ago, knuckleharley said:

You can also buy it at any auto parts store.

They don't supply it here.  Believe me I wasted a lot of time and gas to find out the hard way... 

[classiccarjack]

16 hours ago, Labrauer said:

Well guys it will be a few days before I can get to the car now because I had to put the wife in the hospital Monday morning with possibly of surgery so please bear with me and I'll get back on this as soon as possible. Thanks for all the replies and I'll let you know how it goes 

You are most welcome, family first...

 

Our cars always wait patiently for our return.

[bluefoxamazone]

we have thumbs up...

[knuckleharley]

6 hours ago, classiccarjack said:

They don't supply it here.  Believe me I wasted a lot of time and gas to find out the hard way... 

I don't know why not. It is standard fuel line for every car made for the last 10+ years. It's hard to find rubber gas line anymore that ISN'T ethanol-proof because federal law requires ethanol in gasoline.

[classiccarjack]

On 9/5/2018 at 4:15 AM, knuckleharley said:

I don't know why not. It is standard fuel line for every car made for the last 10+ years. It's hard to find rubber gas line anymore that ISN'T ethanol-proof because federal law requires ethanol in gasoline.

I took pictures by phone, but the files from my phone are to big to upload.  And this subject is not worth the trouble of downloading to my PC, then resizing the files to get them small enough, then logging in on my work computer to post it.  

 

Perhaps you feel that I am some incompetent guy with no clue.  But here, where I live, no local auto parts store carries "Gates Greenshield Multifuel & Bio-fuel compatible Fuel hose". 

 

I found it online, after looking for fuel hose that is "Ethanol" resistant.  After finding the part number, I could order it from O'Reilly's Auto parts.  But, it was cheaper to buy it on Amazon and ship it in. 

 

I had to do this, because of the fuel line that you suggest, that is sold at the local parts house, failed after two years.  This happened on my motorhome, and it took me a couple of days to drop both tanks and replace the fuel hoses. 

 

The Gates hose that I am mentioning, has a inside special liner, I had to stretch the hose over a larger cirular wedge to expand the inner liner to fit over the barbed fittings.  If you have ever used this hose, you too will realize that it is a PITA to install.  If the hose that you are using slips on easily, you better keep an eye on it.  If you have better gasoline than we have at your pumps, then you have nothing to fear, and most likely won't suffer the same fate as I...