/ BX Temp Sender #11
A follow up to my old post. I finally replaced the temp sender and gauge on my BX2230. It took about three hours to do and about two months to make up my mind to re-tap the block.
The new Datcon water gauge/sending unit is a huge improvement. The OEM gauge would never get past the lower edge of the green zone in summer, and never moved at all in the winter. With new gauge, I can tell you that the Bota runs at 176ｰF at WOT with the MMM running. Sitting at idle, runs just under 170ｰF. Needle starts moving past 100ｰF about 40 seconds after start up. Reaches around 140ｰF in about two and a half minutes. Takes another 5 minutes or so to get up to 170ｰF. Can't wait for winter to see what is does then. Hmmm, single digit nights in winter...maybe I can wait.
Note, all of the above temps are pretty close to what I had measured with a thermometer in earlier tests.
I tried in vane for almost three months to determine the thread size/gauge for the existing sending unit. I can tell you it's smaller then 1/8 NPT, but just barely. Appears to be some variation of 10mm, but I've concluded the thread pitch is 26 threads per inch. It most closely matches my 27 tpi thread gauge (even better than any of the metric pitches) and it has 26 stamped on the side of it. To the best of my knowledge, 26 tpi matches no known standard. Not NPT, British pipe (parallel or tapered), Japanese pipe (which is just British), standard metric or SAE.
So in the end, I bit the bullet and re-tapped the block to 1/8-27 NPT. Took about an hour to tap the block. Would have been much shorter, but when I used the air gun on the compressor to blow off the newly tapped threads, I didn't realize the radiator cap was still off and shot coolant all over the garage. Even if I had pictures, don't think I'd be posting that scene. On the plus side, many dirty things are now shiny clean. Test run for 30 minutes cutting grass produced no leaks with the new sending unit in re-tapped hole.
Next project...ROPS lights.
Can you post the exact part number for the Datcon water gauge/sending unit you used?