Black Ariel timing side crank bush
Posted: Wed Jan 17, 2018 5:16 pm
I have my 1928 Model C's crankshaft back together and trued so soon I'll be ready to start putting the engine back together. However, I have a question about the timing side bush.
The bush that came in the engine when I bought it has a long slot at the top of it (0.046"x0.046"x1.9"), which is ~2/3" below the "official" drain hole back into the crankcase of 0.086"-dia. Although the area of the slot is only 29% of that of the hole, and the slot is quite a bit longer, which also would slow the flow, it still represents a drainage path into the crankcase so it could cause the level to be too low in the timing chest. Of course, if the flow of oil into the timing chest is faster than that out through the slotted bush, the timing chest would fill to the proper level in steady state when the engine is running. However, even if this were the case, the oil still would drain through the slot and bring it down to that lower level when the engine is stopped overnight.
Having no slot would eliminate the draining problem, but it would mean the oil would have to travel a long way through the ~0.002" clearance to lubricate the entire 1.9" length of the bush. How have others dealt with this?
The bush that came in the engine when I bought it has a long slot at the top of it (0.046"x0.046"x1.9"), which is ~2/3" below the "official" drain hole back into the crankcase of 0.086"-dia. Although the area of the slot is only 29% of that of the hole, and the slot is quite a bit longer, which also would slow the flow, it still represents a drainage path into the crankcase so it could cause the level to be too low in the timing chest. Of course, if the flow of oil into the timing chest is faster than that out through the slotted bush, the timing chest would fill to the proper level in steady state when the engine is running. However, even if this were the case, the oil still would drain through the slot and bring it down to that lower level when the engine is stopped overnight.
Having no slot would eliminate the draining problem, but it would mean the oil would have to travel a long way through the ~0.002" clearance to lubricate the entire 1.9" length of the bush. How have others dealt with this?