Newbie question

[HemiRam]

Hey All- I recently picked up a 70 Challenger, 440 with a 6 pack. I never had a muscle car in my younger days and plan on enjoying mine now. I took it out on the freeway and ran it up and down a few times which was friggen awesome. I got home, shut it off and the engine knocked pretty bad for a few seconds before shutting off. Is that just a type of gas I used issue? I used the mid unleaded, should I be using premium?
Thanks

 

[Katfish]

Yes on the premium, and probably need to adjust the timing.

 

[tonysrt]

Could also be too lean, caused maybe by a vacuum leak or carbs being lean. Check the plugs to see condition.

 

[Ricks72Chlgr440]

Hey All- I recently picked up a 70 Challenger, 440 with a 6 pack. I never had a muscle car in my younger days and plan on enjoying mine now. I took it out on the freeway and ran it up and down a few times which was friggen awesome. I got home, shut it off and the engine knocked pretty bad for a few seconds before shutting off. Is that just a type of gas I used issue? I used the mid unleaded, should I be using premium?
Thanks

Several things could cause that. Idle speed too high. Engine timing is off. Engine valves and pistons have deposits that cause a hot spot. Pull a couple of plugs and look at their condition. That will tell a lot. Definitely use higher octane fuel if you can get it in CA. Until you get this resolved you can help prevent this by turning the engine off while in gear, if automatic.

 

[Challenger RTA]

Just a thought.

Function of the Idle Solenoid​

Purpose​

The idle solenoid is an electrical device used in carbureted engines, particularly in the 440 Six-Pack setups. Its main function is to prevent "dieseling," which is when the engine continues to run after the ignition is turned off.

Operation​

• Ignition On: When the ignition is turned on, the solenoid is energized. This causes a pin or plunger to extend, which pushes against the throttle linkage.
• Idle Position: The plunger adjustment allows the throttle blades in the carburetor to open to a preset idle position, typically around 900 RPM.

Ignition Off​

• Throttle Closure: When the ignition is turned off, the solenoid retracts the plunger. This action fully closes the throttle blades, preventing air from entering the engine and stopping it from running on.

Installation and Wiring​

Wiring​

• The solenoid requires a specific wiring setup. A wire connects it to the ignition system, usually exiting the harness near the distributor area.
• If the original wiring is missing, a new wire can be run from the ignition coil to power the solenoid.

Mounting​

• The solenoid is typically mounted on the intake manifold, and it may require a specific bracket for proper installation.

Benefits​

• Improved Street Performance: While some enthusiasts argue that the solenoid is not necessary, it can enhance street drivability by preventing unwanted engine run-on.
• Emissions Compliance: The solenoid also helps meet emissions standards by ensuring the engine shuts down cleanly.

In summary, the idle solenoid plays a crucial role in managing engine idle behavior and preventing dieseling in 440 Six-Pack setups.

What are the benefits of using an idle solenoid in a 6-pack setup?
Using an idle solenoid in a 6-pack setup can help prevent "dieseling," where the engine continues to run after being turned off, by ensuring the throttle valves close completely. It can also improve street-ability by allowing for better idle adjustments, making the vehicle easier to drive in everyday conditions.

What are common issues with idle solenoids in carburetors?
Common issues with idle solenoids in carburetors include difficulty starting the engine, stalling shortly after starting, irregular idle speed, poor acceleration, and increased fuel consumption. A faulty solenoid may fail to open or close properly, disrupting fuel flow and affecting engine performance.

How does the idle solenoid affect engine performance in different conditions?
The idle solenoid helps control the engine's idle speed by adjusting the throttle position, which can prevent issues like stalling or "dieseling" when the ignition is turned off. In different conditions, such as during deceleration or when the engine is under load, it ensures the engine maintains proper airflow and fuel mixture for optimal performance.

 

[MOPARMITCH]

Welcome to the Madness. !!!!

 

[Mopar Nut]

Post some pictures of your Challenger when you can, we would like to see it.

 

[mrmopar340]

Welcome waving from Virginia. You'll get it sorted out and be able to enjoy your car.

 

[Challenger RTA]

friggen awesome

Welcome to FEBO. I would venture to guess. When you think about that moment. A moment later when your back on earth. The smile comes right back!

 

[540HemiCuda]

What was your ACTUAL engine temperature when you shut it off? That is the most likely culprit although other things like too high an idle and carbon build up can contribute.

Not to start an argument here, but improper timing can contribute to an over temp situation. But it won't play any role AFTER the ignition is cut.

Octane is your friend, but since you are already running mid, adding a couple of points of octane will not likely be enough given your description of the 'run on' which is sometimes also called 'dieseling'.

Monitor your engine temp with an accurate gauge. Post up what it is. And go ahead and run as high an octane pump gas as you can find.

And it often helps to just shut the engine off with the car in gear.