Here is a description on how to install a 3-port oil breather system on an Escort RS Cosworth, or a Sierra Cosworth for that matter.

There is quite a lot of work involved but nothing is difficult. Just make a mental note (or maybe a drawing too ?) of where everything goes back.

1. For your own convenience it's a good idea to jack up the car and put it on stands so that you don't have to bend over so much when working in the engine bay.
2. Remove the wiring loom from intake side of engine and bend it back so that it goes towards the windshield and the middle of the car. You'll have to separate the two big multiplugs above the left wheel, unscrew the bracket that hold two other plugs to the front left of the engine and separate those plugs, remove the plug from the idle speed control valve and the plugs to the injectors.
3. Remove the throttle cable from the throttle housing.
4. Loosen the hoseclips on the hose from the intercooler to the throttle housing. Loosen the 4 screws that holds the throttle housing to the plenum chamber and remove both the throttle housing and the hose from the engine.
5. Loosen the fuel rail from the plenum chamber and bend it out of the way, not removing the fuel lines to the fuel rail. Be sure not to loose the o-rings on the injectors.
6. Remove the vacuum pipes to the plenum chamber.
7. Split the plenum chamber and remove the cover from the intake.
8. Remove the old breather system with all hoses, the valves and the adaptor which sits in the block below the inlet.
9. Fit the new adaptor in the block on the inlet side and secure it with Locktite.
10. Fit the hose that goes from the adaptor to the separator to the adaptor and tighten the hose clamp with the hose in such a position that it will fit correctly onto the separator. Feed the hose though the middle hole in the intake.
11. Fit the drainback hose to the return pipe to the sump and tighten the hose clamp in a height so that the separator will sit correctly in the engine bay.
12. Remove the screw that attaches a wire to the hexagonal plug on the exhaust side of the engine. Then remove the hexagonal plug. This will open up a passage to the sump.
13. Screw the threaded adaptor into the passage and attach the hose to the separator to it. The threads in the passage might be shallow so take care not to destroy the new adaptor.
14. Let the hose pass behind the engine to the separator.
15. Reassemble the intake, throttle body etc with new gaskets. The injectors should also have new o-rings. These needs to be greased to slide into place.
16. Reassemble the vacuum hoses on the intake and plug the end of the one which is left over from the old breather system with a suitable screw.
17. Attach all hoses to the separator and tighten in such a way that the separator sits with it's longest axis pointing towards the ground and so that it doesn't touch any parts of the engine or auxiliaries.
18. If you have the original box for the airfilter this needs to be removed and replaced by a conefilter to make room for the catch tank.
19. Fit the catch tank where it should sit and mark where you need to drill holes. Remove the tank and drill holes. Fit tank in place and secure with chassis screws.
20. Fit the hose from the separator to the catch tank and the hose from the catch tank to the atmosphere.
21. Check that all connections are securely tightened.
22. Fasten the hoses to the chassis and to other hoses with zip-ties so they don't dangle.
23. Check that the braided hoses don't rub against any part that is painted or could wear through, if they should rub against each other. If they do insulate them with some old bicycle tube or similar.

Check that everything is still in it's correct position after the first few drives after the installation.

Breather connection on the turbo-side of the engine. Turbo in the upper part of the picture.

Breather connection on the intake side of the engine. Circled in red. Loctite the adapter securely in place in this hole after removing old adapter.

Finished installation.

Tightening torques:

Throttle body to plenum intake elbow	8 - 10 Nm
Plenum chamber to intake	8 - 10 Nm
Intake to cylinder head	18,5 - 21,5 Nm
Fuel rail to plenum cover	8 - 10 Nm