Octane and fuel pumps in vintage iron

A mechanic in Atlanta told me the other day that unleaded is probably OK for these older cars as long as you use the LOWEST octane that does not ping, on the theory that the lower octane ignites at a lower temp and is easier on the engines.
[I've been running unleaded REGULAR in my 330 GTC for the last ten years. No sign of any problems - I had one cylinder head off in 1998 and the valve seats were like new]


Also, in a 330 GTC he ran the elec fuel pump just long enough for it to stop clicking, then cut it off prior to ingition.
[That's just what I do - the electric pump fills the float bowls then, upon starting, the engine driven pump takes over]

Are you supposed to keep the elec pump on all the time, or is it just good for priming the carbs? [It wont hurt to keep it on - there is an overflow/return line so that it can't overfill. Once when my mechanical pump was malfunctioning, I drove for two years with the electric pump. The later cars had ONLY electric pumps]

Would running the elec fuel pump all the time be a risk for fire? [Only if you leave it on after the car catches on fire]

Be gentle on me here, I'm new at all this!

You are asking very good questions - the vintage cars are a ball to drive and with proper care can be used as everyday cars - except that I would not recommend driving them in salt - VERY BAD!
Hope this helps.

By the way, don't let anyone scare you with requirements for exotic fluids in a vintage car. You can get everything you need at the local "Pep Boys" type store.
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The only thing that I would add to what Bob said is based on my experiences with vintage motorcycles. Namely, be careful using synthetic oil unless the motor has been rebuilt using modern sealents. Actually, that you'll get using slippery oil leaks, which is really no big deal. Remember oil cost, what, 15 cents a quart back when these cars were new. Who cared if you had to add oil every third tank?

And yes, you're driving an older woman, so go slow initially. You might want to skip 2nd and go straight to 3rd. Tapping the brakes is not a bad idea to set up the pads. But once you get her warmed up, drive her! Go back and read Napolis words on driving a 275 in the Italian tune up thread.

Dale

 

Hi, Dr - My oil of choice is Kendall 20/50 GT-1. Of all the oils I've used, it is the most durable.

I have NEVER used synthetic in a car. I use a semi-synthetic in my Piper, Aeroshell 15W/50.
Bob

 

I've never had a problem w/ lower octane - I once added a little bottle of the lead subsitute, but that was probably 2000 miles ago. Remember that these are fairly low-compression motors - around 8.8:1 - so pinging shouildn't be a big issue.

The elec fuel pump can also be a life-saver if you get vapor lock on a hot summer day.

 

My 365 is wired so that the electric pump runs all the time that the key is on. All the switch does is turn the Autoflux light on and off.

 

I think the problen in running the fuel pump all the time is in flooding. On my 250 I am constantly plauged with sticking needle valves and floats. With the electric pump going all the time you can really load up easily.

 

I think the "Atlanta Mechanic" is wrong - the fuel mixture burns when the spark ignites it, and at that point it does not matter what the octane is, unless the begining of combustion in the cylinder causes an uncontrolled ignition of the mixture in another part of the combustion chamber, which is a ping. This is undesirable since it amounts to an explosion, rather than a smooth burning with a controlled pressure increase. A lower octane gas will "self ignite" at a lower temperature, and if this is a problem a HIGHER octane gas is called for. The total BTU's released will be the same, the difference is whether the combustion is controlled by the spark, or uncontrolled, resulting in excessive peak temperatures and pressures. Who wants a hole in a Ferrari piston?
He is right that the lowest octane fuel which works without pinging will work just as well (BUT NOT BETTER) than the higher octane fuel.

Cheers
Warren

 

I have always stuck with Castrol. I guess I'm kinda an old dog.