Well it happened again, both large alternator and PS belt derailed during 6000 rpm shift point running up through the gears. This happened several years ago, I thought that I had solved the problem by shimming the PS bracket square with damper pulley, but apparently not.

This particular run was a running start where I had coasted to 20 mph or so, dropped into first and went up through the gears. During the run I detected an odd momentary feel in the steering, and a bit of a pop of sorts. I suspect this is moment when belts were shed, the problem is I don’t recall if it took place directly after the down shift to first with a large instant rpm change, or when the engine was approaching 6000 rpm in first or second. This was the first time I have pulled her into first while rolling along at more than a few miles per hour which add to the confusion.

Once replacing the belts after a cool down, and hosing down the engine compartment from the old teakettle boiling over I noticed some non linier belt movement as if one of the pulleys were slightly bent, and the PS pulley pump shaft showing end play.

Water pump pulley appears to have some wobble not from shaft play, but probably from when I striped its paint and some energetic sanding as the center of the pulley appears to be true. Or, outer rim of pulley distorted during one of the derailments; can’t tell for sure. I first realized something was up when steering correction required a lot of effort to keep centered in lane some distance down the road when a curve came up, and temperature gage was moving to right.

I can’t figure out which belt started the chain reaction; the large one which would have the most flutter at speed particularly during an abrupt rpm change from a down shift or the PS belt. My thought is that large belt was first to jump its pulley, which tangled with PS belt causing it to pop off. None of the belts were loose.

Anyone had this belt derailment problem, and do you have a fix?

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Shift at 5900 RPM?

Sorry, couldn't resist.

- Mac

Pulley alignment and wobble is critical. I have mounted my alternators down low and on the driver side to avoid this issue with 6000+ RPM motors. A new/better water pump pulley might be in order. I have some...

Lou

_________________
Home of Slant6-powered fun machines since 1988

Lou was at the track when I starting losing my belts religiously (like after every race...not when idling). I'll be crossing that bridge this winter along with a new clutch...I'm definately looking at the smaller belt and passenger side mounted alternator.

-D.Idiot

Don't they usually have a passenger side alternator?

Been a long day at work...That should have read driver's side alt mount, but I'm working on another project in my shop for something else to mount in the passenger side area...

I think I'll hit the hay, tomorrow more fun is on the way...

-D.Idiot