Front Pulley Size

[chrisjamescox]

I'm at the end of a rebuild of my PI TR6 and I've noticed that the alternator bracket is of the homemade variety, it's a little longer.  Further investigation has revealed that the root of the problem is the size of the front pulley.  The pulley wheel is about 2 inches less in diameter than the rotating back plate (the bit with the timing marks scribed) this is 6.5 inches in diameter so the pulley wheel is circa 4.5 inched in diameter.  I understand that the smaller diameter will result in slower rotation of the alternator and water pump which I guess is of limited concern especially in this cold whether.  I wonder if anyone out there has any idea of what car my pulley may have originated from, why it's been changed, and whether it actually matters.  Chris