9 Apr 2014

With the alternator mount fixed and our near nonexistent winter, what better than driving Midlana down the coast, or that was the idea…

Some background is in order:
When I pieced together my engine, I needed a way of mounting the alternator, but no air compressor or power steering pump. The catch was that the various mounting brackets tend to “lean on each other” such that it’s not easy to remove two while keeping one. So I bought an alternator adaptor kit which allows bolting a K20 alternator onto a K24 block. For whatever reason, the tensioner – also needed – had a 6-rib pulley, while the alternator and crank pulley both have 7-rib pulleys. When I fixed the alternator mount and reinstalled the water pump/alternator belt, I couldn’t remember which side of the 7-rib pulleys the 6-rib belt rode on. Eyeballing it, it appeared it needed to go to “this” side, and all was well.

About 15 minutes from home, the little voice in my head said that there was a new noise, “oh yeah, so there is.” In a home built car, you have to listen to the little voice, because it’s trying to watch out for you. The other part of me thought, “meh, it’s nothing, I’ll keep going.” However, I’m old enough now to listen, pulled over, and removed the engine cover, and sure enough, the belt was in the progress of disintegrating. Worse, while doing so it throws off flailing threads which whip around things and grab onto them, just like Indiana Jones’s whip. Fortunately it didn’t grab and rip the hose out of the header tank, which was right there, but it probably would have if I’d kept going.

So I limp the car back home, get a new $26 Gates belt and replace it, offsetting the belt to “that” side. All was well – for about 30 minutes and a lot further from home, sitting at a long red light, when I heard it start breaking up again… huh? Then it made an unhappy noise and the coolant temperature jumped up, uh oh. However, the saving grace was that the electric water pump at the front of the car kept the cooling moving, so there was no overheating. Got it off the road and sure enough, the new belt was torn up as well. I managed to rip off the flailing bits, get it back on the pulleys (it had hopped off) and got it home.

The mystery is why it worked fine for a year, including racing, and now doesn’t. The only thing I can think of is that since there are three pulleys, maybe I got it right on two of the three and not the third? Somewhat related, over the last year I’ve noticed how the water pump pulley (which rides on the backside of the belt) was polished clean right through its anodize coating. It had been in the back of my mind but didn’t seem to be a big enough deal to change. So I went back to the vendor of the alternator and tensioner adaptors, and learned that with the combination of parts I had, there was a small misalignment in the belt path – ah hah. So I’m going to start with a clean slate in order to make things right (reliable), so a new setup was ordered: updated alternator mount, different alternator pulley, updated tensioner design, and a new belt. It’ll be here next week, so this weekend I’ll try to get everything apart – again. It’s probably also time to bite the bullet and also remove enough stuff so that the oil/coolant heat exchanger can be updated as well. If I’d left the engine dead stock like I did on Kimini, I don’t think I’d be having to do all this…