Dino Saga 070422 _ Alternator Pulley Again

Dino Saga 070422 _ Alternator Pulley Again

Week went by with quiet alternator fan but then noise started again. Something was seriously wrong and the alternator had to come out. Again. Oh well!

This time I loosened the oil heat exchanger after pulling the lower water hose and draining the cooling system. Swung the exchanger to the right and alternator came out with fewer curses. Fan was wobbling on shaft and locking nut was tight. Pulled nut and lock washer and could see the problem. There was about 0.010” clearance fit of pulley on shaft and the length of pulley bore was about 0.020” less than the mating shaft surface. There is the shaft OD through the front bearing, a step down to the pulley bore diameter and then a step down to the threaded shaft end where the lock washer and nut go. Nut was tight against the last step but 20 thou. end-play and 10 thou. radial play let the pulley rock and roll. And fret, and collect water, and rust, and generally make a mess. The Woodruf key was really beat-up. Things had been like that for years. My tightening of the nut a couple of weeks ago prevented immediate catastrophe but I should have known better than to put things back together before I found an original cause of a problem.

Had a time pulling the pulley because of the beat-up key but once all was apart, things didn’t look all that bad. Cleaned up shaft and pulley bore. Still pretty round. Slipped some 0.005” stainless shim stock into the bore gap and things stiffened up nicely. Shoulder that pulley rides against was still square so all that was necessary was to get a washer of pulley bore ID and a thickness greater than 0.020”. That washer would force the pulley square against the shaft shoulder when the retaining nut was tightened. Took some digging and some work with a Moto Tool but made a washer about 0.040” thick. Got a new key and put all back together. Looked good so an hour later the car was back together and bingo, no more noise.

The inspiration for these Sagas came out of my attempts to find out what all was fouled up after my engine rebuild of 2004. The alternator problem is just the latest of these foul-ups. The alternator was rebuilt at that time and the rebuild shop returned the alternator with the wrong pulley. I caught the error and took the alternator back. Shop found correct pulley and put it on. Forgot a washer in the process. Fretting and corrosion finally got things loose enough for me to hear the problem. Oh Boy!

Was real busy and didn’t take time to take pictures this week. Had a party for old employees of my old company. German friend likes my Dino and took some shots. Had folks from Europe and all over the US. Fun to hash old times. Santa Barbara got an inch of rain on Friday and might get the same today. In April? Funny weather patterns. We usually get all of our rain from December to March and don’t plan on anything from April to November. My canopy is holding up pretty well but I sure do envy Jon’s beautiful new shop. Having your own powder coater is just too much.

Hope for sun next week.

John
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