Fuel

[pco122]

Hi

Greetings from the other side of the Atlantic. I recently bought a 1970 911 T that should be arriving from the USA next Tuesday.
Do you use unleaded fuel with or without those lead substitute additives that can be found in gas stations?

Thanks

Fernando

[NeunElf]

Porsche started using hardened valve seats in the mid-1950s (I have personally paid for new valve seats for a 1958 Porsche engine). Porsches built since then can use unleaded fuel with no problem. That's assuming--of course--that other properties of the fuel, like octane numbers are ok.

There are many, many variables in gasoline formulations, but lead is required for its lubricating proerties only for engines with "soft" valve seats.

[72targa]

Here is a general statement from Chevron:

How will unleaded gasoline affect my older vehicle with an engine designed to be operated on leaded gasoline?
Pre-1971 U.S.vehicles were designed to operate on leaded gasoline. The original exhaust valve seats in these engines were not hardened or were not equipped with metal alloy inserts. The lead in the gasoline not only functioned as an antiknock additive, but served as a lubricant which kept the exhaust valves from wearing away the valve seat (exhaust valve seat recession) under certain severe operating conditions.

Leaded gasoline is no longer available in the U.S. because it was completely banned from on-road gasoline in 1996. Other areas of the world have also banned lead. Driving around town or at normal highway speeds with unleaded gasoline will not result in exhaust valve seat recession. Exhaust valve seat recession may occur with unleaded gasoline at higher engine operating temperatures generated by an extended period of high-speed or uphill driving or towing a heavy load. If a trip is going to involve one or more of these situations and your pre-1971 vehicle hasn't been equipped with metal alloy exhaust valve seats, consider adding a lead substitute aftermarket additive to the gasoline in your tank during the trip. Consult your engine manufacturer before using the additive. In some countries, a lead replacement gasoline (petrol) is offered that contains protective additives.

As I have always understood, though, this did not apply to Porsches as even in 1970, the exhaust valve seats, as with the rest of the cylinder head, was already an alloy material.

[sithot]

Generally, the guides in 911's from the early period were "gone" by around 60,000 miles.
Top end overhauls only cost $1,200 "then" *mid-late 70's*. Long hair, bell bottoms, platform shoes and big friggin' collars. ( Fortunately, I never succumbed to the call for the platform shoes )

I'd run an additive like Techron or similar or just buy Chevron gasoline. I keep racing fuel in my old cars and bikes (when they are dormant) for stability reasons. 30-45 days on todays pump gasoline and it's going bad.
We're now getting 10% Ethanol on the East Coast in major cities. PITA if they go higher. E85 is being pushed in the midwest but only a "handful" of cars are able to use it.

Off topic but here goes:

Excuse this blasphemous comment but I hope Audi kicks the living hell out of everyone at Lemans. I'm waiting for a hotrod diesel and I know it's coming. Gale Banks has a full race diesel truck that spins to 5,000 rpm and he's shooting for higher numbers than that. Only 650 hp and 800 lb/ft of torque.

Ethanol, schmethanol. I want diesel.

Tom

[72targa]

I'd run an additive like Techron or similar or just buy Chevron gasoline.

Just remember that Techron is an additive designed to clean out the injection flow system (fuel injectors to upper valve surfaces). It's not designed to supply the "cushion" that tetraethyl lead used to. That's what the aftermarket additives (lead substitutes) are designed to do.

[sithot]

Yes.

http://www.knowyouroil.com/california/octane_boost.htm

http://tetraboost.com/info/

http://www.redlineoil.com/products_f...p?productID=64

And more...

Best,

Tom

[pco122]

Thank you all for the information

[scargo70]

any info on the effects of ethanol on these cars?

[72targa]

Time to go to school...

http://www.deh.gov.au/atmosphere/fue.../chapter6.html

http://www.choice.com.au/viewArticle...ld+you+care%3f

http://www.chevron.com/products/prod...soline/pg2.asp

http://www.mnsu.edu/news/read.php?id=old-1115755777

http://www.ncga.com/ethanol/main/your_car.htm

[sithot]

any info on the effects of ethanol on these cars?

If they start serving it in stronger dilutions it will have a negative effect as it is corrosive to the fuel system, plastic and metal lines. E85 is widely available in the mid-west and I wouldn't go near it. There are but a "handful"
of cars that can use this "technology". Your antique Porsche aint' one of them.

At 10% I wouldn't worry too much although you might want to check your fuel filter more regularly as it will pick up water out of your tank which usually has all the "good stuff" floating in it.

Tom