In an effort to remedy a no-start, no-spark condition on my '65 544 with B18 I discovered that the oil pump drive bushing has worn to the point that it drops down into the block far enough to allow the dogs on the bottom end of the distributor to no longer engage with the slots on the top of the oil pump drive gear. In this position the distributor rotor no longer turns creating a no-spark condition. If I grab the top of the oil pump drive gear with a pair of needle nosed pliers and gently lift it up (twisting as it engages with the cam gear) it will stay in place long enough for me to gently install the perfectly aligned distributor and the engine will start and run until such time that it then drops back down---usually when shut off again or when I turn the rotor by hand.
The top end of the outside of the bushing measures 17mm, the bottom end slightly less. When I pull the oil pump drive gear completely out, the bushing comes out with it quite easily. It seems that the only thing keeping the bushing from falling off the shaft altogether is a bit of crusty oil sludge caked on the lower end.
I have a junk block with the bushing still in it (quite tightly, it appears) so how do I go about getting the tight bushing out of the junk block without damaging it? And what are the correct measurements for the bushing? Is there a specified height above the block opening that the bushing should sit in order to hold the drive gear in the correct position or is it one of those 'try it till it seems right' kind of things?
Any help on this is GREATLY appreciated!