Refitting the plenum is a simple task that’s made frustrating by the inaccessible location of the five bolts that hold it. I have watched the Caterham Cars mechanics remove a plenum before, and they used a long wobbly extension and a ball-ended hex driver. Unfortunately, I don’t own a ball-ended hex driver (and actually don’t like them because they can damage the cap head), so I was forced to locate the bolts and tighten them to the Ford workshop manuals 6 Nm with the limited access I had.

My first task was to clean off the residual glue from the masking tape, and ensure all the plenum bungs where tight. Getting the plenum into position was simple enough; I found I could rest it on the top hose while trying to locate the bolts. I found the bottom rear bolt was accessible by moving the top hose, the bottom middle was accessible from underneath, and the bottom front bolt was just about reachable around the tensioner to start the bolt by hand and there was room for a 1/4” drive ratchet for tightening.  

Once secured, I reconnected the MAP sensor, and while connecting the throttle position sensor I noticed a simple improvement I could make to the wire routing and fuel line clearance: I reversed the P-clip on the block, hopefully the picture tells the story.

I am going to investigate a way to secure the throttle position  sensor wires, maybe with a small P-clip.  For some reason, it seems to me as if the connection to the throttle position sensor is shorter on this build than it was with my 360R.    

UPDATE – The have now fitted P-clips to support the throttle position sensor wires. To do this I purchased some M6 x 40mm fully threaded set screws to replace the bolts holding the throttle body to the plenum. The P-clips are M6 with 6mm diameter for the wires and a M6 nyloc nut completes my modification. I got a bit carried away and also used the P-clips for the ECU engine temperature sensor. Only time will tell if I don’t get throttle position sensor wire breaking problems.

Tools used

  • 6mm hex 1/4” socket
  • 1/4” drive ratchet
  • 6mm to 8mm adapter
  • 8mm ratchet ring spanner
  • 1/4” drive extensions
  • 10mm ratchet ring spanner