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Parts, Repair

The fuel tank conundrum!

A 924 tank is a 924 tank, right?

Not quite. Not even close. It seems that trying to match the fuel tanks on a 924 is like trying to find a bone marrow donor. Correction, like a layperson trying to find a marrow donor! But why would you need a donor tank? Well, the tanks are made of steel and for a 924S that makes them up to 26 years old. There are a couple of weak points, hairline cracks in the top of the tank and corrosion; usually along the seams or the straps (which hold the tank in place).

Judging by the number of people searching for fuel tanks I guess others are having similar issues. This post will cover the different types of fuel tank, another, to follow soon, will cover the refurb. So there are different types of tanks, and I must stress this is what I know so far, so is not complete! Firstly, the ones I do know that don’t fit, without modification.

The oval dash 944 plastic tank, this is the wrong shape and will only fit with some modification to the cross member, which I know of but have not looked into in depth. There are write-ups on other blogs and forums.

The 924 Turbo tank. Again this is the wrong shape to fit NA 924s due to the shape of the gearboxes.

So, now I’m onto the tanks I’ve bought (the first one leaked, the second has gone in), and what little I know about them. Although, no one has quite been able to tell me exactly what I’ve been buying, but this is an idea of what to look for.

This was the first tank I bought… I believe it was from a NA 924 2.0. This tank has an internal fuel pump, but this can be swapped for the filter.

Porsche 924 2.0 NA Fuel Tank

The tank below was my second purchase. I believe this was from an early 944. You will notice that the breather pipe along the top of the tank is different and where there is a thin pipe on the top of the 2.0 tank this is inside the 944 version. With the 2.0 version, to fit the S you need an intermediary pipe to match the internal diameter of the hose from the expansion tank.

Porsche Early 944 Fuel Tank

I have not seen a 924 S tank outside of the car, but from what I can see on the diagrams the design is the same on the top as the 944 tank above, however there is a difference on the bottom of the tank, where the pipes connect. The fuel filter housing appears the same but the return pipe comes out of the opposite side on the 924 S (left) to the 924 2.0 and early 944 (right)…

Porsche 924 S 1988 Fuel TankPorsche 924 944 Fuel Tank Filter Housing

I don’t know what the difference is between the two designs? I am aware that there was a fuel starvation problem, but I think that was between the design at the top of the tanks.

There is another difference between the early and later tanks, but that’s with the expansion tanks and breather system. For the 924 S this change was made in 1988 (for the 160bhp model) but I believe it may have come in sooner for the 944. Firstly, there is an additional breather hose attached to the tank, see below on the 944 tanks (this was not on the early 924 one)…

Porsche 924 S Fuel Tank Breather Hose

This is purely a breather hose that runs off of the expansion tank, if you don’t need it it can simply be removed. The other difference, quite obviously, is with the expansion tank, the one in my early 924 S has only two connections, as shown in the photo below.

Porsche 924 S Fuel Expansion Tank

The extract in the parts diagram shows a possible third connection on the expansion tank which runs down to this breather hose (29A).

Porsche 924 S Fuel Filler Config

That is about all I know on the fuel tanks, at the moment. If I learn more I will update the post. Feel free to add info in the comments, on the proviso that you know it is correct 😉

My next post will be how to refurb an old fuel tank, which I have done [successfully] already.

Discussion

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  1. Pingback: “Petrol”-head No More « #Project924 - September 27, 2012

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