Escort Body Tank

Escort Upgrades - Mk3 to Mk4 Fuel Tank

You ay be wondering why you would want to bother swapping the fuel tank in your mk3 for a tank from a mk4 but there are a few possible reasons why you may be considering this:
1) You want to fit the EFi tank with its built in high pressure electric pump to supplement a Zetec conversion.
2) You have converted to a mk4 steering column as part of the mk4 dashboard conversion and want to use the same key for the filler cap but have found that the mk4 cap is not interchangeable and you have to fit the mk4 filler neck which is also different (as explained below) meaning you are now facing replacing the entire fuel tank with the mk4 version.
3) Your tank is rusty and you are looking at the mk4 as a possible alternative.

Well, although it does fit it is not quite a straight swap.

Differences

Although they share the same basic shape, there are numerous differences between the fuel tanks fitted to the various models of Mk3 & 4 Escort.

The main differences are Carburettor fed engines and fuel injected engines, and Mk3 and Mk4 Cars.The carb fed Escorts use a mechanical fuel pump attached to the engine and take there fuel from a pipe welded to the forward face of the tank. Fuel injected cars however use an electric pump mounted behind the fuel tank and so there fuel feed pipe is on the rearward facing wall of the tank.
Then there's the differences between the Mk3 tank and the Mk4 tank.
Although they can both be physically fitted to either car there are differences that make complete instillation a little more involved than a straight swap.

The picture on the left show's the fuel tank from a fuel injected Mk3 Escort where as the picture on the right show's the equivilant tank for the Mk4.

Mk3

Mk4

It can clearly be seen that the fuel level sender has been relocated on the Mk4 tank and is even of a different design with a bigger base plate. The other difference is the filler neck attachment.

Mk3

Mk4

The Mk3 filler neck attachment is shown on the left and compises of a collar onto which a flexible pipe is attached via a jubilee clip. The Mk4 tank however uses a one piece plastic moulding for the filler neck which slots into a hole in the tank with a rubber bung as a seal.

This of course means that should you wish to fit the mk4 fuel tank to your mk3 (as I have done) you will need to fit the corrosponding filler neck.

Fitting the Mk4 tank to the Mk3 Escort

The mk4 tank is mounted in exactly the same way as the mk3 item with a couple of bolts and a strap. However, the mk4 filler neck isn't quite such a simple swap. It is of a larger diameter than the mk3 item and so the hole on the bodywork that the filler neck protrudes from needs to be opened up slightly. This is achieved with the use of a rotary grind stone and a sanding flap wheel in a power drill. There's also a supporting screw half way along the pipes length which will require a pilot hole to drilled into the cars structure in the area of the rear suspension. Because of it's location access with a domestic power drill is very difficult with the suspension still in place. I was fortunate enough to have access to a right angled air powered drill.

I would have liked to have included photos of the filler neck fitted but I cannot find them so must assume that they have been lost. But it is not a difficult job and is pretty self explanatory when you come to do it.

The contents of this website are purely a reflection of my own experiences and knowledge gained whilst working on my various projects. Anything you do based on what you have read here is done so entirely at your own risk.
Personally I wouldn't trust someone like me with a lawn mower! You have been warned! Flapper-bat!