Carbureted warmup procedure?

[smiles11]

What’s the consensus for warm up procedure on carbureted longhood cars? I normally start mine & idle for a minute or two. Then drive conservatively until temp reaches 180deg. I've been told its good to idle a couple minutes with carbureted cars, but I've also been told it's best for a dry-sump car to turn the key, wait for oil pressure & go while keeping RPM's low to warm up. I'm in California, so temps are mild in the winter & hot in the summer. So I assume it would be best to start her up for 30 seconds & just go. Thoughts?

[edmayo]

Basically what you're saying is correct about start and drive easily until oil temp comes up. However oil pressure does not come up when you turn the the key, you must have meant fuel pressure.

[Noah]

Start it up and drive, just don't beat on it until up to temp. I would not leave the car idling. What's the point, exactly?

[fizeus]

Basically what you're saying is correct about start and drive easily until oil temp comes up. However oil pressure does not come up when you turn the the key, you must have meant fuel pressure.

I think he meant to turn the key and let the starter turn the engine (and the oil pump) until you see the oil pressure needle moving up (pausing every 10 / 15 seconds).
The rationale of this tip is to let oil circulate and lubricate cylinder walls and cam lobes avoiding the engine to start up completely dry (piston rings are prone to premature wearing if not lubricated correctly).
Once you see oil pressure needle moving up you can hit the gas pedal and let the engine start up normally.


Then you should keep it at low RPMs until oil pressure start to rise up and slowly increase the idle to reach about 5 PSI on the oil pressure gauge (1500-1700 RPMs if you use 20W50 oil) for a minute or two.
Now ok to drive the car conservatively until at temp.




This was an suggestion (from Grady Clay if I remember well) and I admit I do this when the car has been in the garage for a long time.

[Haasman]

Grady always started engines this way. "It's all about the oil pressure ..." he used to say. "You want oil throughout the engine completely before raising RPMs. Watch the oil pressure. Then drive off easily until engine temp starts to show"

We used to have many discussions about all this during the summer I turned wrenches for him. Very unusual person. Still miss him.

[66S]

The motor scavenge circuit is pumping just oil for about 45 seconds I have been told, after that it pumps air and oil at lower pressures. More of a concern for 911s with aux oil cooler and no thermostat in the scavenge circuit. If the car runs well I don’t warm up a 911 just drive it to warm it up. My cars with a turbo or supercharger get warmed up before driving.