JD B Oil Circulation

[Michael St John]

I am rebuilding the engine on my 1942 BN. I have just put the head back on and took the opportunity to check all was working as it should. I have the engine cover and the fan shaft off. Turning the engine I get oil coming out of the two outlets in the governor housing. There is also plenty of oil coming from the mains and bigends. I then blocked of the two outlets on the governor casing and continued to turn the engine over. Plenty of oil was dripping from the top of the governor housing and draining into the crankcase. What I cant get is oil to come from the oil pipe that supplies the two exhaust rockers. I assume I should get oil to the rockers or is it low pressure that turning by hand wont supply. I dont want to put the rocker cover on without being sure that oil is getting to the rockers and valves.

 

[johns48jdb]

its ok. only two of the rockers get oiled. the rest get a few fumes or a little splash ever now and then. that part is ok.

 

[Anonymous-0]

The rockers only get one brief pulse of oil from the oil pump with each turn of the oil pump shaft. There is a flat spot on the shaft that once each revolution aligns with a passageway in the pump housing so ONLY while aligned can oil flow to the tappet oiler tube! They do NOT receive a continuous flow.

You probably have not rolled it enough to get oil all the way to the oiler tube given the brief time the passage is actually open. I don't know exactly how much of the time it is open but it is likely closed around 75% of the time. In addition, the oil pump turns at or near camshaft speed which means you'll have to do a LOT of hand cranking to see oil at the tappet oiler drip tube!

I hope that helps.

Later.

 

[Mike M]

Make sure that someone hasn't broken the oil line that feeds into the back of the block to supply oil up to there. Lots of people yank the block out and don't unhook this line. Not until the late pressed frame models could you just yank the block out.

 

[aggie jon]

and if you do yank your block out and break that oil pipe that runs through the block, a good hardware store can fix you up. Ask me how I found out.

 

[Lee B]

As buck eye al noted you have a diminished supply problem to begin with what with the flat ground into the pump shaft only letting the oil go by in spurts. The A has hole thru the shaft doing the same thing. Be sure to double check that your pump is delivering the spurts.

And then use compressed air with the line loaded with oil to test your thru the block connection and your head bolt/lead washer/rocker arm configuration that would deliver the oil when it finally gets there. I also wouldn't want to button it up until I knew that the oil would eventualy get there. The compressed air should make plenty of noise and leave lots of dripping oil behind to indicate that you don't have a chunk of a lead washer blocking a critical passage for example. It might also show leaks from areas where the oil shouldn't be found like leaking directly from underneath the odd washer that gathers the oil into the distribution pipe.

Also be sure you have oil squirting on the fan drive gears from the bottom of the oil guage supply hole. This one goes straight forward into the governor housing and ends with a tiny squirt hole aimed at the fan drive gears. It's small enough to be overlooked and not cleared out all too often. I've use a grease gun directly connected to force it open but a very fine wire inserted right into the bottom of the tapered hole works as well.