Fuel [Post-War (1946-54)] - Packard Motor Car Information (2024)

What does everyone run for fuel??? I was running premium, but have been trying, unsuccessfully, to tune out a bit of a ping that would occur when pulling a hill. We just did a 400 mile round trip and I ran Shell regular, and no ping.

53 Cav, your engine is only 8.0 compression. Unless you have ungodly amounts of carbon buildup, then 87 is plenty of octane to run that. In fact, many lawnmower engines today use 8 or 9 compression ratio engines:https://jackssmallengines.com/equipment/lawn-mower/Engines/

Though the max compression ratio without pinging depends on fuel mixture preheat, which would be higher in our cars than a modern small engine with its shielding and plastic intakes, it's still pretty comparable, and people generally report up to 8.5 compression being fine on 87. Point is, I'm not surprised that premium fuel is making little difference as to your pinging issues. I would start checking out TxGoat's list.

1955 400 | Registry | Project Blog
1955 Clipper Deluxe | Registry | Project Blog
1955 Clipper Super Panama | Registry

A stuck manifold heat valve could contribute to pinging and lost power.

Shell 87 non-ethanol is an excellent choice.

I overlooked the possibility of excessive carbon buildup, which is not uncommon in older cars, especially if they are not driven regularly on the open road. See below:

*Another thing to consider is that simply by driving the car on an extended trip on the open road you may have cleaned out carbon buildup, thus reducing or eliminating ping*

Short trips around town and extended idling can allow carbon to build up in the cylinders, which can cause pinging under load. Shell is probably a Tier One gasoline, with better quality control and a more complete additive package than some other gasolines, which can help prevent carbon buildup and help remove it if it has occurred.

Older cars can benefit from an occasional open road run of twenty miles or more at speeds around 50 to 55 MPH or more, if appropriate for your particular car. Running at highway speed for a few tens of miles with fresh gasoline and clean oil can help keep the engine running well, and it's good for the tires and drive line units as well as for the battery.

Thank TsGoat, I always appreciate your comprehensive replies!

Manifold valve is functioning.

Was in my engine last summer and it's clean.

Car has been on extending trips before, running both Esso and Shell premium fuels with the same pinging. Not it's first Italian tune-up! LOL

Getting out for a good cruise is when I enjoy driving my car the most. Floating down the highway is more pleasurable that puttering around town.

In Canada all fuels "may contain" up to 10% ethanol, I don't think we can get any fuel any more that is ethanol free.

Just don't buy gas from Walmart, in the US it's called "Murphy USA".

People with modern cars complain of getting lower gas mileage using it.

1955 400 | Registry | Project Blog
1955 Clipper Deluxe | Registry | Project Blog
1955 Clipper Super Panama | Registry

Quote:

Until this spring the vacuum advance on my car was not the correct one, which I knew, and thought maybe it was contributing to the pinging, but the pinging didn't go away when I put on the correct vacuum advance, so much for that theory. But the pinging has gone away at the same time as I changed fuels, but hadn't made any other changes. Causation or just coincidence? I'm not sure. Maybe I'll put another tank of premium in sometime to see if the pinging comes back.

We had a Dodge van with a 360, a long time ago, and it used to ping anytime we put Esso fuel in it, not sure why.