my flathead 59 is down for gasoline diluted oil and I am about to dive into it. I was a professional mechanic for over 40 years but that don't mean spit when it comes to Flatties as I have found. This engine came to me " rebuilt " It has 165 lbs compression per cylinder and only generated 13 inches of vacuum at idle. Mind you this was with about 10 qts of gasoline diluted oil. Now we come to floating bearings, Huh what? never heard of such a thing, no laughing. is there a book that would help me with this? Any advice would be greatly appreciated.
You don't have the shop manual for the engine? Or an old Motors manual? should be enough clues in one of them to get you started, at least, then ask questions about the tricky areas.
how long did motor run with oil/gas mix? how did it hold 10qts? flushed motor more than once? corrected gas in oil problem?
There are very few ways for gas to get in the crankcase on these engines. Example: leaky fuel pump diaphragm , too many 10 minute runs with the choke on, Choke stuck shut or bad adjustment, bad or incorrect power valve in the carb, missing main jets, leaky float full of gas, clogged air filter. A leaky float will not float if it has gas in it. Floating rod bearings were used in these engines for many years. They do not have the tab that holds them still while running. They have bearing surfaces on both sides of the insert and are free to turn in the rods and the crankshaft. They can sometimes be a pain in the**** to set up correctly. Clearances are 2 to 2.5 thousandths of an inch between bearing and rod and the same for bearing to crank clearance. Total 5 thousandths combined. A little less (4) won't hurt. These don't carry much oil pressure at hot idle, so don't depend on the gauge. The oil pump and relief are 50 lb items but these engines depend on lots of flow. Precision fit bearings started in '48 trucks and ''49 passemger car engines, if memory serves.
The Jalopy Journal
