A battery charger was attached to the alternator "B" lead and turned on. This confirmed that the ammeter sender was the wrong way round so it was then just a case of unbolting the two connections and reversing them. A repeat test with the charger confirmed this was now correct.
The CHT/EGT gauge was unscrewed from the panel and the connections of the two thermocouples reversed. Looking at the Westach instructions I can easily see why I got this wrong - the pinout in the instruction sheet doesn't really match my version of the instrument. The change was then tested successfully by using a heatgun on the two thermocouples.
The oil temperature sender was removed from the engine and the heatgun used directly on it - nothing. A 1K ohm rheostat was then connected in its place and the gauge responded as expected (low temperature=high resistance and visa-versa). Checking the sender with a multimeter showed it was open circuit so a new one has been ordered. This will take a week to arrive.The intermittent fault with the fuel gauge was more of a problem. I had fitted a co-pilot PTT switch to the panel a few days ago. This required removing the KMD150 GPS and then reaching though the side of its rack to get to the back of the extreme left of the P2 side of the panel. I suspected that I must have disturbed a connection in doing this. The only way to find it was to remove all the instruments and the radio from the right side of the panel. In each case they had to come out through the side of the GPS rack. Once they were out I was able to establish that the problem was the positive voltage supply to the fuel gauge so this connection was re-made and the gauge started working again. Then everything had to be refitted. I just hope I haven't disturbed anything else! Next time the engine is run I will see if the vibration causes any more problems.
Once everything was back together I could get on with some new jobs. The lower cowl was test fit with the spinner and propeller in place. In no way would it go on because of the way the baffles fit under the lower edge of the airduct and into the spaces either side of it. I'll think about this some more but at the moment it looks like the propeller will have to come off any time I want to remove the lower cowl. This is less than convenient but certainly not a "show-stopper".
Then a hole was drilled in the cowl, just visible in the bottom right in the picture, to allow a fuel tester to be applied to the gascolator drain.
Pieces of baffle material were pop-riveted to the front of the airbox. These will fit over the internal extension to the port I made in the front of the lower cowl airscoop to roughly seal it and create a small ram-air effect.
Finally, pieces of heat resistant material were glued to the cowl using high temperature tank sealant where the exhaust pipes are closest. The edges were sealed with self-adhesive aluminium tape.
The lower cowl was then fitted in place and the propeller and spinner backplate re-fitted. The backplate only has 1/8" clearance from the cowl which confirms that without a different approach to the baffles it cannot be removed and refitted with the propeller in place.
I'll next run the engine once the new temperature sender arrives in about a week, Then I'll also look to adjust the vacuum regulator and further diagnose the low compression on cylinder 4. I've decided that the rear of the exhaust pipes are short enough not to require any further support so I've removed that item from the to-do list. New items have been added in red.
