I'm putting air conditioning in my bj73 that never had it before. Easiest way to do this is to put an extra pulley on the crank to drive the compressor. The factory pulley is not readily available here in the states. And expensive if you find it. I decided to fabricate a pulley starting with an all-purpose pulley from tractor supply.
Started with a 6 inch OD solid steel centered pulling with a keyed bore .75.
Second was to lock it down on a 3/4 to 3/8 inch steel bushing.
Put a 3/8 by 3 inch bolt through the steel bushing as per the pictures below. This bolt will be used to check the pulley into a drill press and spin it.
Measure bolt circle diameter on the factory pulley with a caliper subtract this from the. Inner diameter of the tractor supply pulley. Divide the difference by two and then make one center punch mark that distance from the outer edge of the flat face of the tractor supply pulley. Chuck the pulley into drill press turn it on and with a scribe make a scratch line on on the pulley while it's spinning in the drill press right where your punch mark is.
Drill your first bolt hole on the center punch mark. use that hole to put a bolt in and line your factory pulley up with the tractor supply pulley. use the circle you scribed wHole spinning in the drill press lined up by eyeball centerline on all of the bolt holes in begin putting punch marks for the other 5 bolt holes.
Drill all your bolt holes slightly larger than factory.
at this point the pulley is usable and you can sandwich it between your crankshaft balancer pulley and the accessory pulley just remove the spacer the new pulley will function as this spacer. you will however not be able to access the crankshaft bolt for setting the valve timing without removing the outer accessory pulleys.
I chose to cut the center out so I would be able to access to crank bolt.
Line up your factory pulley on the tractor supply toy and Mark a circle for the interval of the factory pulley on the face of the tractor supply pulley with a permanent marker.
Chuck the pulley your fabricating back into the drill press and turn it on.
While it is spinning use a 4-inch angle grinder with a cut off blade and cut down into the face of the tractor supply pulley on the circle you drew while she's spinning. the cut off wheel will make a beveled edge on your cut be careful not to cut into the bolt holes you drilled.....continue slowly changing out cut-off wheels as necessary it took me 3 cut off wheels. Eventually you will cut through and have a nice round hole centered on your pulley for the center bore.
clean up the sharp edge on the inner bore if your new pulley with a drill drill or Dremel grinder of some sort.
You could completely eyeball this without spinning it but spinning it in the press gives you nice round circles and helps you line things up so it's not off center.
Started with a 6 inch OD solid steel centered pulling with a keyed bore .75.
Second was to lock it down on a 3/4 to 3/8 inch steel bushing.
Put a 3/8 by 3 inch bolt through the steel bushing as per the pictures below. This bolt will be used to check the pulley into a drill press and spin it.
Measure bolt circle diameter on the factory pulley with a caliper subtract this from the. Inner diameter of the tractor supply pulley. Divide the difference by two and then make one center punch mark that distance from the outer edge of the flat face of the tractor supply pulley. Chuck the pulley into drill press turn it on and with a scribe make a scratch line on on the pulley while it's spinning in the drill press right where your punch mark is.
Drill your first bolt hole on the center punch mark. use that hole to put a bolt in and line your factory pulley up with the tractor supply pulley. use the circle you scribed wHole spinning in the drill press lined up by eyeball centerline on all of the bolt holes in begin putting punch marks for the other 5 bolt holes.
Drill all your bolt holes slightly larger than factory.
at this point the pulley is usable and you can sandwich it between your crankshaft balancer pulley and the accessory pulley just remove the spacer the new pulley will function as this spacer. you will however not be able to access the crankshaft bolt for setting the valve timing without removing the outer accessory pulleys.
I chose to cut the center out so I would be able to access to crank bolt.
Line up your factory pulley on the tractor supply toy and Mark a circle for the interval of the factory pulley on the face of the tractor supply pulley with a permanent marker.
Chuck the pulley your fabricating back into the drill press and turn it on.
While it is spinning use a 4-inch angle grinder with a cut off blade and cut down into the face of the tractor supply pulley on the circle you drew while she's spinning. the cut off wheel will make a beveled edge on your cut be careful not to cut into the bolt holes you drilled.....continue slowly changing out cut-off wheels as necessary it took me 3 cut off wheels. Eventually you will cut through and have a nice round hole centered on your pulley for the center bore.
clean up the sharp edge on the inner bore if your new pulley with a drill drill or Dremel grinder of some sort.
You could completely eyeball this without spinning it but spinning it in the press gives you nice round circles and helps you line things up so it's not off center.
