View Full Version : A miniproject part 2: Trigger wheel adapter for B23 pulley

01-30-2008, 04:24 PM
A little while ago i made a bastard crank shaft hub piece, so that i could use the B23 pulleys on the B230 crank shaft.

Thread of that work can be found here: http://forums.turbobricks.com/showthread.php?t=121607&

The reason for making that was that i wanted to adapt a 36-1 trigger wheel to the front of the crank.

I already had one adapter piece for the trigger wheel made of aluminum, but i decided that i could do better than that, so here's the second part of that first miniproject.


This is what i had in mind. That section picture only shows one set of holes, but there actually are two sets of holes, the other ones going through the piece as shown, and other ones, which have been threaded to M8 thread.

I started by first machining the 50mm inner recess to the piece. Then i made a jig for the drill press, as is shown in the next pictures:



On the last picture you can see the jig. It's just a flat piece of steel, and it has a round protruding part which has a diameter of 50mm, same as the inner diameter of the aluminum piece.

Now i could just set the piece on the jig and set the bolt circle diameter to be correct. This way all the holes will absolutely be on the same circle.

The other set of holes are at a circle of 76mm in diameter, these are to be explained later. The other set are at a circle of 66mm in diameter, and these holes are the ones which will attach this piece to the hub. The B23 pulleys are fixed to the hub with the same 66mm bolt circle.

Once the holes were drilled i attached the piece to the lathe again and then machined the 30mm centering part, which is on the top side of this piece, as shown in the diagram picture above.


So then the piece was done. I actually made a few different ones. A shorter one will fit if the power steering pump pulley is not used, but for now i will be using that as well, so i made taller ones as well.



There they can be seen installed. The aluminum adapter is fixed to the hub with allen head bolts, and the pulleys are clamped with the same bolts.


And here's the reason for making the new adapter. The trigger wheel can be adjusted 20 degrees so that setting everything up will be easy. The trigger wheel is fixed to the aluminum part with M8 bolts.


The trigger wheel is 164mm in diameter, although i have a 147mm version as well. The 147 might work with the pump pulley, but will not work without it, because the teeth would stay below the outer perimeter of the water pump/alternator belt pulley. The 164mm will work with both. The bolt circle is 76mm., and the center hole is 30mm. The trigger wheel is centered to the hub by that 30mm center hole.

01-30-2008, 05:01 PM
Sweet dude! I just love nice shiny parts :)

01-30-2008, 05:05 PM
yea custom machined parts like that always look really sweet! nice work!

Karl Buchka
01-30-2008, 05:20 PM
Fasen vad gött det skulle sitta med en svarv. Snyggt jobbat!

01-30-2008, 05:41 PM
Fasen vad gött det skulle sitta med en svarv. Snyggt jobbat!

Tack, och jo, du har det rätt. Jag vet inte hur jag skulle klara mig utan en svarv.

The Aspirator
02-05-2008, 02:33 PM
Wow Wagner, you're a machining madman, that stuff is brilliant. I put a fjord 36-1 wheel onto my B23 with Dale's pulley and it's working great! Soooo much more resolution than just a 4 vane distributor.