I considered mounting the transaxle thermostat to the top of the rear-chassis cross brace, but the routing of the four oil lines was messy. It eventually occurred to me to mount it to the bottom of the cross brace, which solved the routing issues, but increased the complexity of the mounting tabs. Specifically, the tabs are at an awkward angle on the tube’s radius and sunken into the small triangle which made it difficult to take accurate measurements. To solve that problem, I used diagonal cutters to keep shortening the end of a welding rod until it fit. The next challenge was to figure out how to fixture the tabs so that they would be properly spaced, aligned and planar. (i.e., not twisted or bent). Rather than fabricating two separate tabs, I designed a single piece with openings to facilitate cutting the center section out after welding was completed. I then fabricated a temporary plate to enable the fixture to be clamped to the cross brace.
Welding jig; tabs with disposable center section (front) and temporary clamping plate (rear)
Jig clamped to cross brace and ready for welding
The thermostat is a well-engineered unit from Improved Racing. I used a higher-temp version for my engine and in both cases the laser-etched side wasn’t visible. I contacted them and they laser etched the other side of both thermostats at no cost. They have great products (I also have one their oil coolers with integrated shroud, fans and isolation grommets) and excellent customer support. No affiliation, just a happy customer.
Tabs welded, center section removed and thermostat installed
After fabricating the oil lines, I wanted to mount two of them to prevent them from flopping around. The transaxle has a bunch of thoughtfully-designed inspection ports. Their covers seal via an O-ring and feature a tapped M5 boss in the center for mounting stuff. One of the cover plates provided a perfect location to mount a hose separator. The issue was that the hose separator was designed to be freestanding (i.e., the one piece bolts to the other) rather being mounted and it used a screw that was small than M5. The solution was easy. I used an end mill to enlarge the recess on the piece that accommodates the head of the socket head cap screw and I drilled a M5 clearance hole on the tapped piece.
Three of the inspection port covers; note the threaded boss in the center
Hose separators; stock (top) and modified (bottom); yeah the recess isn’t perfectly centered, but that’s what happens when you eyeball things rather than taking the time to do it the right way with an edge finder.
Two of the oil lines held in place via a modified hose separator mounted to an inspection port cover