empty fuel tank before engine drop?

[andyt11]

The first snow has started to fly here and its time to put the car away for six months! If I'm planning to drop my engine in a few months time, should I do the usual routine and fill it to the brim and a drop of stabil, or should I leave it empty. I guess what I'm asking is will the fuel come running out at some point during the engine removal process.....

in which case, whats the best way to remove the half tank thats in there right now....?

[tharbert]

With today's blended fuels, I wouldn't store it for the winter even with stabil.

[Aurel]

Originally Posted by andyt11

in which case, whats the best way to remove the half tank thats in there right now....?

The absolute best way to remove gas from the tank is to drive the car a little more: it puts a smile on your face and does not waste the gas .

[Grady Clay]

EDIT
DISCONNECT AND REMOVE THE BATTERY FIRST.

Since you are removing the engine, I would drain the tank and use the opportunity to clean the tank and the fuel screen filter (fitting if pre-‘74).

Not only will you get done some necessary periodic maintenance but you get fresh, high octane fuel in the spring.

While everything is still running, have a small amount of fuel in the tank and add lots of Stabil and some Marvel Mystery Oil.
Circulate this mixture through your fuel system.
Then drain the system.

Better still, for the last fuel use aviation 100 octane no-lead or gasoline known to have no ethanol.


Why is the engine coming out?
Why not take it out this weekend and get a jump on whatever is needed?
Springtime comes all too soon – even North of the border.

Best,
Grady

[andyt11]

Its coming out for valve guides. I have easy access to ethanol free fuel locally so I'm not too worried about that.

Driving the car further isnt really an option due to weather, so does the tank need to be empty before I disconnect the fuel lines and if so, how does one drain the fuel tank?

[Grady Clay]

What year 911?

Generally speaking, with the rear in the air, you don’t need to worry about fuel running out if fuel lines are disconnected at the engine.

When you lower the car, the hoses should be sealed for safety.

Draining the tank is easy by siphoning the fuel after removing the fuel level sender. Have a replacement gasket for the sender.

I would still add some preservative and oil so the system never dries without some surface oil.
This will make putting it back in service easier.

Be VERY careful around gasoline and gas fumes – particularly indoors. The life you save may be your Porsche’s.

Best,
Grady

[andyt11]

thanks Grady. its an 88 911.

I'll put a drop of stabil and a drop of oil in anyway and let run a little.

When i drop the engine I'll clamp the hoses tight.

Sounds like I shouldn't bother filling it though. Just more fuel to deal with when it all goes wrong.

Whas the benift of filling it to the brim anyway?

[Grady Clay]

Andy,

I edited above:
DISCONNECT AND REMOVE THE BATTERY FIRST.



I’m still in favor of draining the fuel.
I would also add more than “…a drop of stabil and a drop of oil….“
Any remaining Stabil and oil will be very dilute when you add high octane fuel next spring.
The goal is to preserve your fuel system all the way to the nozzles.
You will have the FI off and exposed to air.
Having a bit of oil and any remaining gasoline with a bit of preservative will preserve these sensitive parts from atmospheric corrosion or just dried fuel remnants.


I’m not in favor of clamping fuel lines.
There is bound to be damage – perhaps not showing up for a decade but why risk it?

Someone here can measure the two fuel fittings you disconnect to remove an ’88 engine. They should be something like 14x1.5 and 16x1.5, more-or-less.

Find a local salvage yard and get some similar mating fittings off some salvage car (MB, BMW will do fine ).
Make yourself an ‘adaptor’ that connects the two chassis lines together.
This ‘seals’ your fuel system.
Even if you forgetfully re-connect the battery and turn the ignition on with fuel in the tank, there won’t be a fuel spill.



Who do you intend to have refurbish your Carrera cylinder heads?
This is not usually a DIY operation or one for those lightly experienced with Porsche.
Reconditioning 911 cylinder heads requires serious expertise and experience.
I don't say this lightly - this is a BIG DEAL!
Correctly done heads will let your 911 perform great for another decade or more.
Improperly done will be a constant problem.

I implore you to find the ‘right’ vendor.
Done properly, they can be better than Porsche delivered them new – and last longer.

Best,
Grady

[andyt11]

Thanks Grady. I'll drain it before I start.

There is a shop in town that is capable of reconditioning the heads, but I've also been in touch with Flat 6 in Minneapolis and Johnson Motorsports. I've even been considering sending them to Steve Weiner.

I'm going to do the grunt work myself. I've started reading Waynes book but like I said the snow has arrived and now I'm wondering, if I get a dry day next week do I fill it up or leave it be. I'm going to leave it be, run some oil though and empty the tank when I start.

Wanna come to winnipeg for a "holiday"...?!

[Walt Fricke]

Andy

You can do what you want, but: you won't get any fuel spillage of consequence when you disconnect the fuel lines back by the engine. Without the pump running, nothing is going to move from the tank through the lines and up and then out. I just wrap the open ends with masking tape to keep the dust out while the motor is out. The only spillage is what you use a rag for when you break the lines and the little gasoline nearby necessarily spills.

An easy and pretty clean/safe way to drain a tank is to use your fuel pump. Fabricate something to lengthen the fuel line (not the return line) back by where you disconnect it at the engine, and pump the fuel into a fuel jug. You want to listen to the pump when doing this, and turn the key off when you hear the pitch change, as that indicates you are starting to pump it dry. Don't want to run the pump without the cooling/lubrication of fuel for very long. You would be surprised how fast you can fill a jug (so caution if you have more than 5 gallons in the tank).

If you fear your tank has a bunch of crud in it, this might be a little riskier, but I don't think it really is, as the pump already draws off the bottom of the tank, where the crud is most likely to be. The tank has a rather coarse filter in it. The pump has a nice fine one, but it is inside and you can't really clean it so you don't want to count on that.

It is when you want to swap out a fuel pump that spillage is a trickier issue. You have to pinch closed the rubber line to the pump. But you aren't doing that, are you?\

As to draining the tank, I bet you are recalling the advice for cold weather that you should always keep your tank as full as you can. That's to reduce the amount of air, with its attendant moisture content, so you have a minimum of water condensation.

Me, I like to empty the tank down pretty much and put the fuel in another of my cars where I will use it sooner. But I have had no bad experiences with leaving gas in the tank over the winter. Now leaving it in for 15 years produced some very peculiar smelling gasoline. But that's another story.

Walt

[andyt11]

Thankyou Grady and Walt. I think I'm going to leave it be. I see a fuel tank cleaning coming on prior to engine drop. Its a good time to do it.

But even if I don't, it sounds like I'm going to have too much spillage on my hands regardless.

Needless to say, extinguisher on hand and battery off from start to finish.

[Grady Clay]

Walt,

You and I are good friends so we can disagree.
Everyone may learn from the discussion.

(You know that I occasionally argue an opposing view, just to make a point.
Argument is the ‘spice of life’.)
This is an issue I feel strongly about.

A fire injury is one of the most devistating injuries - ever.
We don't want to go there.




I agree that our race cars are configured to pump the fuel tank (fuel cell) dry.
In fact we are required to have a “fuel sampling port” for many organization’s tech.
Even with this situation, we are extremely careful with fuel and potential spills.


For someone with a normal 911 engine removal, the situation is different.
There isn’t the level of care as with race cars.
Any fuel spill or vapors are potentially explosive.
Extreme caution must be exercised.


Carefully siphoning fuel outside and away from structures reduces the risk.
There is no need to have electrical ‘assist’ to draining the fuel.
The “electrical” only adds to the risk.



So….

I disagree with using the fuel pump to drain the tank under ‘normal’ circumstances.
That means for a ‘regular’ 911 engine drop.
Even breaking the fuel lines into a rag poses a significant risk of fire.
Disconnecting and removing the battery reduces the risk.


I agree with removing the fuel over the winter.
The fuel can be used in other vehicles.
If there is no fuel in the gas tank, then water (humidity) won’t be absorbed.
Condensation becomes a non-issue.
I fill empty tanks with dry Nitrogen or Carbon Dioxide.
There is even less corrosion issue if there is oil residue from protective oils prior to draining.


I like the offering “free gas” for 15-year old gas (even 1-year old).
That gas needs to be used in some farm machinery and not a Porsche.



The reason why start-up fuel is so important when putting your 911 back in service after (winter) storage is octane and ring seal.

When you let your 911 set for a long period, the rings quit sealing as well as they do with regular driving.
That allows engine oil to pass past the rings and into the combustion chamber.
Engine oil in the air-fuel mix reduced the octane rating significantly.
It is common for a ‘stored engine’ to knock from 'low octane' due to this issue.
Bad idea.
Detonation damages engine components – like rod bearings.

When re-starting a stored engine, you should use the highest octane fresh race fuel available.
This mitigates the oil-in-gas reduction in octane.


Re-starting a stored engine is far more stress than starting a ‘fresh’ engine after a rebuild.
We all pay lots of attention to fresh starting and ‘brake-in’.
We need to pay more attention to re-starting after storage if we want long-lived engines.

Best,
Grady