This was a pretty straightforward job. Even so, it still took me about three hours all in.
Firstly I unplumbed all of the bits that were attached to the manifold. That's throttle cable, idle bypass, heating pipe, brake vacuum pipe and oil breather pipe. After that I dismantled the fuel injection rail, finally removing the injectors themselves. In order to depressurise the fuel rail I pulled the FI fuse whilst the engine was running. The only thing that got knackered was the brake servo connection. The plastic had gone a bit brittle. It was temporarily repaired with insulation tape.
The Irmscher manifold has runners that are a bit shorter and straighter than the standard ones.
The diameter at the manifold is a bit larger as well, more like 37mm rather than 33mm.
Reassambley was also pretty simple. I spent some time sorting out the studs since some of them came out as bolts.
I used a new inlet manifold gasket. Really a new throttle body gasket
was needed. The throttle body had a fair bit of oil on it so it was cleaned up with carb cleaner. The Haynes
manual talks about replacing the injector seals but I found refitting the old ones to be fine.
Top tips: 1) disconnect the battery negative...there was a big spark when I dropped a spanner onto the starter motor. 2) remember to connect the fuel pipes up before trying to start the engine.