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Running rough


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I had my car out  for a spin today and on the way home it started running rough .At 50 MPH it started hesitating felt like it was going to backfire .

IT idles just fine, it had the hesitation through a three gears .Any ideas would be helpful I thought of replacing the spark plugs they are three years old .

the carburetor  has been rebuilt .

 

 

Thanks 

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ALSO could be a condensor going bad also check the points gap and also the condition of the contacts in the top of the dizzy cap to see if there is any pitting and also the rotor.  When the car is just started is there any type of sputtering when cold or only the sputtering when the engine has gotten hot?  do you still have the original coli in the car. This also might be starting to wear out.

 

Also check the little wires in the dizzy to make sure they have not lost the clot covering.

 

Rich Hartung

desoto1939@aol.com

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The plastic rub blocks on modern points without proper grease .... or even with! .... As it wears away, it will close the gap on your points changing the dwell affecting the timing.

 

When you adjust your points, you rotate the engine til the plastic rub block is on the peak of the distributor cam for the widest point gap.

Then you set the points to whatever it is suggested for your car.

If the plastic rub block wears away because it has no grease, the point gap will get smaller & smaller .... to the point they no longer open the points.

 

Naturally you want to check the point surface to see they are wearing flat & smooth with no pits burned into them.

Example would be, If you leave the key on & walk away, the points are closed ... there is electricity passing through them & possible to weld themselves closed.

When you start the engine, the weld breaks away but leaves a pit on one side and the points wear uneven because of the metal on the other side.

 

Of course could simply be a screw that holds the points in place worked loose. Just need to re-adjust the points and tighten it.

 

Just a few reasons why points were replaced with electronic ignition .... They work great but they require maintenance. All above could explain your issue.

 

Could be many other things like a coil failing .... points would be the first thing I looked at.

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Here is a photo of a generic rub block .... many others have a different opinion on the name.

 

The distributor has a cam gear that opens & closes the points.

Right here circled is the rub block that opens & closes the points & maintains the timing or dwell of the car.

 

Seems obvious that if this area wears away, it changes the amount the points open ....

To the point you can not even adjust the points.

 

This may or may not be your issue, just something to look at.

 

I remember back in the day I use to burn out a set of points every few weeks because I was a idiot & running a Mallory super coil ....  A set of points was $3 then.

I sure was a cool kid though with the fancy coil.

 

Future times the quality of points have been degraded & you need to check the rub block.

 

 

 

 

 

 

 01011_BOSCH_POINTS.jpg.cfd161268793b46397c050149cee92b8.jpg

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3 minutes ago, keithb7 said:

If anyone has a favourite “points grease” please share. What are you using? Where do you buy it?

 

Thx. 

My buddy gave me a tube of Blue Streak lubricam grease SL-2 (Standard Motor Products) haven't been able to find it on line. This tube will last me my lifetime!!!!

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Life time supply of points lube!!

 

Put it your will for future generations!  🤧 🙂

 

DJ

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I was at Chryslers at Carlise and pickup two small  tubes of diaelectric grease for $1. I purchased 4 tube. Hopefully will never run out.

 

As the old Brilcream ad state a little dap will do ya.

 

Rich Hartung

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An update on my car running rough . 

I had a friend come over to help with this problem he reset the point gap and changed the rotor which was warn. 

e started the car and test drive no hesitation  at all and as a added bonus it starts much easier .

 

Thanks for all your suggestions 

PS I had just purchased a electric fuel pump to help with the starting problem.

I will hang onto it but hopefully it won't be needed.

 

 

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Since you have the El feul pump I would suggest that you still install it near the fuel tank. This acts as a backup to the mechanical pump. Hook a toggle switch up to the el FP so you can turn on/off as required.

 

Rich Hartungu

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If you are using an electrical fuel pump, I suggest you install an oil pressure safety switch so that if you have an accident the fuel pump will shut off and not start a fire.  I have replaced my electrical fuel pump and bought a new mechanical.  Don Coutney suggested the safety feature. 

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3 hours ago, pflaming said:

If you are using an electrical fuel pump, I suggest you install an oil pressure safety switch so that if you have an accident the fuel pump will shut off and not start a fire.  I have replaced my electrical fuel pump and bought a new mechanical.  Don Coutney suggested the safety feature. 

 

The disadvantage of the oil pressure switch is that you can't use the electric pump to prime the carb for a cold start. I much prefer an inertia safety switch so the pump will start running when the key is turned on. If the car takes a hard collision the inertia switch should shut off the pump. I use a common Ford switch, it's the red-topped gadget on the firewall, you reset it by pressing the red button.

 

wilwood-3.jpg.a80aacad64635925061cbbf7bbd6134d.jpg

Edited by Sam Buchanan
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I ran my P15 with an electric pump and no safety switch for about a year, just wasn't totally sold on the benefits of introducing a failure point in the voltage circuit for the pump (no mechanical pump). Even though the odds of needing the switch are extremely low, they seem to be pretty reliable on modern cars. So I mounted the inertia switch on the firewall for easy access on a dark night....BUT.....ran it for a few weeks hooked up to nothing but an indicator light. I wanted to see if false-trips were going to be an issue before going all-in. I also wired the switch with a combination of male and female connectors so I could quickly hot-wire around it if necessary.

 

No false trips so I inserted it into the fuel pump circuit and it has been fine. I can trip it by delivering a hard blow to the firewall, maybe that simulates a hard collision....who knows. The switch is based on a metal ball being held in place with a magnet until a collision dislodges it and breaks the circuit.

Edited by Sam Buchanan
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On 8/22/2022 at 12:33 PM, Sam Buchanan said:

The disadvantage of the oil pressure switch is that you can't use the electric pump to prime the carb for a cold start

 not so, you can wire in a prime switch that will make the circuit for you.  A momentary toggle or pushbutton would be best so that it is off when you take your hand off it.

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Exactly.  I bought  double throw switch that's momentary contact one way, off in the middle, and constant contact the other way.  Momentary for priming, usually with the key at ACC, constant contact for full-time, with the key at IGN and the engine running, but subject to the safety switch.  

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1 hour ago, Sniper said:

 not so, you can wire in a prime switch that will make the circuit for you.  A momentary toggle or pushbutton would be best so that it is off when you take your hand off it.

 

That's true. I was stating how priming is possible without the need for the pump switch if the inertia switch is used instead of oil pressure switch. Turn on key, carb primes, ready to start, very transparent. I don't have a mechanical pump.  :)

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