orsogrigio

hi guys, somebody can tell me what kind of troubles could raise using unleaded gas in a 73 350 engine without add leaded additives to the gas? Some says that better is to eliminate the valve stem seals to allow the oil to better lube the valves, some says to add additives, some other says that since 1972 engines were predisposed to run with unleaded gas and there is nothing else to do then fill the tank and drive. SinceI have the car I have done almost 10k miles, with no problems, engine turn and runs good, does not smell, not smokes nor black neither blue. the only thing that goes wrong is that when the engine is warm, if I switch it off and re- switch on in a few minutes it start with a half turn key, but if I re- switch it in an half an hour (about) it needs 4 or 5 turn keys, but the carb shop man says that is a matter of vapor lock, and I have not to be afraid to turn the key, but for few seconds it smell of gas

MDchanic

ALL cars sold in the US in 1973 were REQUIRED to be able to burn UNLEADED REGULAR gasoline.

No lead is needed. No octane booster is needed. Premium fuel is not needed.

I believe that Italy uses the same Octane scale as the rest of Europe (EU "Harmonization" and all that...), so you can use any gasoline that's about 91 or 92 octane by the European system (which is the same as the old US system).
In the US, these cars require about 87 or 88 octane.

- Eric

orsogrigio

Hi Hi Eric, thank you for all the right informations you're willing to give. I'm not sure as in Italy station service do not notice how many octanes in the gasoline, in Austria they notice it, so you can choose from 91, 95 or 98 premium gas, in Italy is avalable only one kind of unleaded in every station, then some company has avalable a premium gasoline, but not every company. But I do not care about it as I always used the one avalable in every station that is good enough for my needs. The thing that worried me was to worn the engine with a not appropriate kind of gas, but now you say unleaded is good I feel better. I thought, but I am not sure about it, that the lead in the gas served to lube the valve guides, don't ask me why, as the gas during the combustion fases pass through the intake valve only, or maybe, the unleaded has a different combustion that dry the valve stem seals and worn them, and because of this, oil leaks from the heads through the valves into the chambers and burns with the gas causing oil consumption. Am I saying bullshits?

oldcutlass

No it's not BS, the lead actually lubricated and protected the valve seat area from corrosion. It's primary function was to increase octane levels and keep the engine from pinging.

If you drive your car a lot then you might consider a lead additive, others here use it. I don't and have never used any additive in my cars and drive about 3000 miles a year.

orsogrigio

Hi OC, no, I don't use the car for more then 3/4000 miles a year, when I bought it odometer signed 82k, in february 2010, now it signs almost 92k, so, almost 10k in three years; not so much at all

MDchanic

Yes, he could use a lead additive, but he doesn't need a lead additive, as his engine was designed to run on unleaded gasoline.

You're confusing him, Eric.

- Eric

oldcutlass

Sorry my mistake, I thought it started later. Nix the additive.

MDchanic

Catalytic converters started later (1975, I believe), but the requirement to run on unleaded started either in '72 or '73. Therefore, a '73 can run on either leaded or unleaded with no harm.

In his case, he has no access to leaded gas, and the Italian pumps don't even list an octane rating.

On the other side of things, in Italy, they have "miscella" pumps that pump premixed 2-cycle fuel, with a dial to adjust the percentage to what you need for your machine. That's why those crazy old Italian scooters never had separate oil and gas tanks; where they were made, you could just ride up to the pump and fill it, like any other vehicle.

- Eric

oldcutlass

Sounds like Mexican liquor, I wonder if there is a worm in every liter?

MDchanic

Mezcal.

Nectar of the gods.

But they are ANGRY gods.

- Eric

orsogrigio

Yes, I remember, but it is a long time that "miscella" disappeared from gas station, I had a small byke when I was 14 that ran with a 5% oil fuel, but the Audi also, when was named Auto Union made a car with a 2-cycles engine but I don't know if they used a mix or had 2 separate tanks, I think they stop equiping car with those kind of engines in 67 or 68 as they had a high production cost so the cars where very expensive, thinks that a Auto Union 60L with a small 1,1 l engine had a higher price than a BMW 518. I had as my first car when I was 19 (mum marriage gift) a Audi 60 L with a 4-cycles engine already with a small 1,5 l engine that with only 60 hp could arrive at 100 Mph and had 80 Mph as cruise speed, it was fantastic, but it was old and I was young and it did not lasted too much in my hands

orsogrigio

no Eric, there were not any worm, but once I swallowed one of those ones you know, and after I drank a beer and I vomited my soul with the intestine twisted around my throat with a thousand knots and a truck wheel bolted to my head the morning after nomore worms please