Part of my rewiring project involves installing and wiring a working set of useful gauges (and senders) to monitor important functions. Here is what I have installed so far:  Most of these have come from my stash of 1980's Audi parts. The voltage gauge is simple to set up, it runs off the main coil/fuel pump "on" switch (so I can monitor battery condition as soon as cranking). I obtained an hour meter so I can keep track of "fuel economy" and service intervals, all it requires is 12 volts, too. I have it running off the secondary "on" switch, along with all the other gauges and the alternator field winding. All the gauges that have built in lighting are hooked up the main light switch I installed, even though I don't have lighting wiring or lights set up yet. For oil pressure, I scavenged a two-terminal sender (one is a variable pressure connection, one feeds the oil pressur idiot light on the Audi), which although a 10x1 mm thread, threads smoothly into the 1/8 FPT hole in the block with some plumbing tape to seal it. This gauge made me pour out the runny 5w30 oil I had in the machine, since I was barely seeing 10-15 PSI (one bar or under). Replacing it with 20w50 yielded a more convincing and acceptable 30 PSI (2 bar).  The torque converter has a place for a temperature sender (high TC temperature is a "stop and turn things off" warning in the owner's manual). I used an old Audi oil temperature sender and gauge. I got a brass 1/2" MPT plug that fit the hole, and drilled a clean 5/8" hole through it, then I put the sender with its metric thread in the lathe and carefully cut it down until it was a press fit into the plug. This assembly is then screwed into the hole in the TC, again using plumbers tape for a good seal.  Water temperature gauges on my old Audis are always in the instrument cluster, and so did not lend themselves to fitting in the dashboard of this beast. Luckily, somewhere along the way, someone gave me or I acquired what I believe to be a Scirocco oil temperature gauge and sender (I think it's for oil because it goes to 150 C, way to high for coolant). I broke the first sender, and substituted a random Audi one I had, screwing it into a tapped 10x1 mm hole in a 1/2" MPT plug to fit the hole in the side of the head. On my 15 minute idle test, the needle moved, so I ought to be able to get used to whatever is "normal" and watch out for anything "abnormal."  I have run a wire from the coil to use for a tachometer, but haven't bothered to install one yet, even though I do have one kicking around. I think I am holding out for one more appropriate to this machine, with, say, a 4000 rpm full scale. This engine idles at about 1000 rpm, and is governed to something like 2500, so it's not like I have to keep eye on the red line while drag racing. There is also supposed to be a pressure gauge for the hydraulic (forward/N/reverse) clutch system - but right now the old copper line that went to it is just cut off. And it is supposed to run at around 200 psi, so something is not right there - it would spray all over if it had much pressure. Perhaps this is why I have trouble finding the "neutral" position between F and R. |
