You will literally never find one of those centering guides.
Your harmonic balancer tube is just shy of 1 1/4 inch inside diameter. Your harmonic balancer tube is right at 1 3/4 inch outside diameter.
Your centering tool inside diameter is most important. Your outside diameter is least important because you are dealing with a soft rubber seal, simply a snug fit will do.
A simple solution is to find a rubber hose which about 1 1/8 inside diameter, about 1 5/8 to 1 3/4 inch outside. Cut off a couple of inches, slit the hose lengthwise, grease it up inside and out, then slip it over your crankshaft end. This will work just fine.
A little imagination and work, you can find what you need at a Home Depot store in the plumbing department. Look around at 1 1/4 plumbing fittings and gaskets for sinks. Some white PVC tubes are very close, like the ones with a "swedged" end, a larger diameter end designed to slip over a pipe. There are large flat clear soft plastic seals, type you use to join drain fittings, which are just about right. You can "imagineer" together something which will work. Kinda Mickey Mouse but will work with a little imagination.
Anything which will slip over your crankshaft end and is about a 1/4 inch thick will work. Some large rubber "O" rings from an auto part store are suitable, bit frustrating to align an O ring with your seal, but can be done. I think Home Depot has those O rings in a multi-drawer bin box in the "fasteners" section.
Other possibles are rubber tips for chair legs, rubber sleeve pipe adapters in the ABS / PVC pipe area of Home Depot, oddball metric size radiator hose, air filter to valve cover hose and the old standby, a deep 1 3/16 - 1 1/4 ratchet socket. Try some metric sizes as well.
Best bet, costs a bit, buy a cheap used harmonic balancer off Ebay, have a machine shop lathe off the tube and bore the inside diameter out a few thousandths of an inch. Explain what you are doing, the machine shop will know what to do.
Final analysis is you will discover using a centering tool or not using a centering tool makes diddly-squat difference. There are so many screws around the edge of a timing gear cover, centering is virtually guaranteed, hard to get this wrong.
You know your timing gear cover will move around and tweak as you tighten down the bolts. Kinda pointless to work at keeping it perfectly centered on the crank.
I have installed with a centering jig, installed without one, no leaks either way; truly does not make a difference while your timing gear cover is in good condition and not a sloppy fit.
Billyray
