Fuel Storage

[mordecaibrown]

For a 1977 2.7 911S Is it safe to put fuel storage in the gas tank as I store the car over the winter and some gas in the tank may be a year or so old. And if so what brand? I see a brand called STA-BIL. Storage I did add close to a half a tank of fresh gas when I pulled it form storage this year.


Sam

[Mark Salvetti]

I think you should be OK with at least a half-tank of fresh. Does your fuel have ethanol in it? I think probably yes.

Sta-Bil 360 Marine (it's blue) if you have ethanol fuel. Add it before your final fill so it mixes well and it gets distributed through the fuel system.

Mark

[Quickstep192]

I have used Startron in ethanol gas on the boat for years and never had problems with phase separation or other ethanol maladies.

Fortunately, the marina now sells ethanol free.

[EC900]

There’s a Sta-Bil 360 for ethanol not labeled for marine use that I use along with regularity Lucas Injector Cleaner, I use this stuff in motorcycle and small engines. Ethanol really gums up and swells the old rubber hoses when it sits inside the hoses, and be sure to use the proper ratio when mixing stabilizers.
Gasoline is said to begin to deteriorate after 6 months. A full tank is better than an empty tank when it comes to long term storage as it keeps moisture and rust from forming inside. Seasonal draining the gas if you want but the StaBil eliminates this, but if you want to drain 1/2 of old gas out, just dilute it with new gas and put it in another car engine is a way not to waste it.

Nothing wrong with winter driving, but don’t do short 15 minute driveway-warmup starts and then shut it down for another few weeks. So long as there’s no salt or water pools of salt water and spray, I go for a 30 min/ 30 mile highway drives in dead of winter.

[Marc Bixen]

+1 For Sta-bil Marine. But even better is 100 octane lead-free race fuel plus Sta-bil marine. Race fuel is much cleaner, no water or ethanol, and doesn't break down anywhere near as fast as pump fuel. We deal with a lot of collectors and find this the best solution.

[mordecaibrown]

Thank you everyone on the advise!!!!

Sam

[PeteKz]

You don't need to go get race fuel. For a year storage, "Premium" ETHANOL-FREE is fine. The 10% ethanol contamination turns nasty in that time and will gum up your fuel system, no matter what you add to it. Yes, I know, some of you "haven't had any problems" but I have.

[safe]

I prefer to store my cars during winter with 1/4 tank or some thing like that. Then in the spring run it down to the gas station and fill it up.
Use whatever fuel you like, doesn't matter, as long as the octane rating is right for your car.

[Schulisco]

Originally Posted by safe

I prefer to store my cars during winter with 1/4 tank or some thing like that.

The problem on the 911 is: The tank is made of steel without any surface protection - it can rust and it will if there's too much water/moisture in it. For storing the car just a few months is not a problem. But the longer the car sits with only half or less full tank of gas, the more air and moisture is in the tank which can force detoriating fuel and rusting, especially when the fuel contains ethanol which attracts water...

If you use fuel storage be aware that it takes some time to mix with all the fuel in the system. The fuel pump in a SC pumps 1000cc in 30secs. To pump a full tank of gas of 80l it takes at least 40mins. This is a ride of at least 20mls...

[safe]

Originally Posted by Schulisco

The problem on the 911 is: The tank is made of steel without any surface protection - it can rust and it will if there's too much water/moisture in it. For storing the car just a few months is not a problem. But the longer the car sits with only half or less full tank of gas, the more air and moisture is in the tank which can force detoriating fuel and rusting, especially when the fuel contains ethanol which attracts water...

If you use fuel storage be aware that it takes some time to mix with all the fuel in the system. The fuel pump in a SC pumps 1000cc in 30secs. To pump a full tank of gas of 80l it takes at least 40mins. This is a ride of at least 20mls...

Air isn't circulating the tank when stationary over the winter. If you store the car relatively warm and at a constant temperature there will be no water or rusting.

Ethanol doesn't magically make water, if there is water in the fuel system the ethanol will absorb it and purge it when you run.
Without the ethanol the water will "pool" at the bottom of the tank and rust it.
In cold climates we used to add ethanol in the winter to remove water.

No ethanol does not deteriorate gasoline. Gasoline looses its "flammability" over time, that's why I keep the level low so I can fuel up in the spring, but 6 months is really nothing to worry about.

Pretty confident that pouring 60 liters of fuel, with some force like at a gas station, into 20 liters will mix it pretty good. Non issue.

[HarryD]

If it was me. Fill tank with StaBil 360 added. Go for a 49 minute drive to get the treated fuel into all parts of the fuel system. Top up tank and put her to sleep. Some good recommendations here. https://forums.pelicanparts.com/porsche-911-technical-forum/183215-winter-storage-checklist.html

Posts 20 and 21 should not ignored.

[Schulisco]

Originally Posted by safe

Air isn't circulating the tank when stationary over the winter. If you store the car relatively warm and at a constant temperature there will be no water or rusting.

Ethanol doesn't magically make water, if there is water in the fuel system the ethanol will absorb it and purge it when you run.
Without the ethanol the water will "pool" at the bottom of the tank and rust it.
In cold climates we used to add ethanol in the winter to remove water.

No ethanol does not deteriorate gasoline. Gasoline looses its "flammability" over time, that's why I keep the level low so I can fuel up in the spring, but 6 months is really nothing to worry about.

Pretty confident that pouring 60 liters of fuel, with some force like at a gas station, into 20 liters will mix it pretty good. Non issue.

Only few people have the opportunity to store their cars in constant warm and dry ambient temperatures.

I also didn't wrote anything about ethanol is making water. It detoriates and attracts the water, e.g. from the tank ventilation and from the air what's already inside the tank.

Anybody is free to do what he wants to do. But: Recent experience showed that storing the car with a full tank together mixed up with a fuel storage is the best way to store it a longer time. The longer, the more important. Storing the car for les than three months or so you can waive this.

See this three parted article series in a german classic cars magazine due to the introduction of E10 (Gas with 10% ethanol) in Germany back in 2011.
https://www.oldtimer-markt.de/ratgeber/grundlagen/oldtimer-und-e10-%E2%80%93-die-fakten
At the bottom of the article page there are the links to three parts of the article as PDF files, I let Google only translate the 2nd part. The pictures are self explaining. Mostly on carburettors, but also the aluminium and steels parts of the CIS would be affected in the same way.
https://uploadnow.io/f/S4rjby8

Thomas