Fuel Transducer Mount
One of the first things to do when starting to mount the engine is to mount the fuel flow transducer (red cube). The plans call for hose clamps and a plate with cube mounted on the intake runners. I am changing this and am not the first to do it. There has been discussion regarding the wisdom of mounting the transducer on the vibration-prone engine. The way the plans would have you do it, adds some vibration resistance through the adel clamps on the intake runners. So, my plan is to isolate the transducer, somewhat, using rubber or silicone gasket material between the transducer and bracket and between the bracket and the sump. So,to document the process, here goes.
Prototype I:
First, fabricate the support out of 2x2x1/8" AL angle to fit the two 1/4-20 tapped holes on the left side of the sump. I called Jeff Schans at Lycoming re the purpose of the 1/4-20 tapped holes in the sump. He said they are for mounting baffles or other sundry thingies that end-users might need, so they will be 'red cube' mounts for me.
Second, get some 1/8" rubber gasket material. (1/4" would provide better isolation)
Third, cut #6 holes for the cube and 1/4" holes for the 1/4-20 bolts to attach bracket to tapped holes in the sump.
Fourth, put it on the engine and see what changes are needed.
Changes for Prototype II:
1. Get some silicone gasket material 1/4" thick to replace 1/8" rubber purchased at Ace 'Aircraft Supply' (which might degrade because of heat). 1/4" provides more isolation, too.
2. Get aircraft 1/4-20 bolts with holes in heads for safety wiring to sump.
3. Use #10 hex head bolts with holes for safety wire to secure cube to tapped holes in angle. (I countersunk the bracketI for some flat head machine screws with washers and lock nuts like the plans indicate, but the bolts can't be put in from the bottom of the bracket due to interference with intake runner.
The red Thunderbolt engine block matches the "red cube" rather nicely, don't you think? That is why I ordered the red block, of course. Those of you with grey blocks have a nice contrast, though.