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Flathead 6 Oil Pump / Flow / Filter Question


MBiggs

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Just picked up a 50 pilot house, the engine was stuck, but now spins freely.  My question is, I wanted to check if the oil is circulating, Plan was to empty the old and filled it back up with kerosene to clean up any old sludge etc. and spin it over using a 12 volt battery on the starter to get it to spin faster and flush the block etc., then empty and refill with new oil.  I took off the top to the oil filter canister to see if it had flushed through there and it was still holding old oil from before. With the top off and the filter removed from the canister, I spun it over some more expecting to see flow of some sort of flow, but saw nothing.  Should there be visible flow?  Is there other ways to check for circulation prior to start up after 20+ years of sitting?  Any other start up tips welcome and appreciated

 

Thanks

Matt

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The filter is on a bypass with a restrictor.  It gets about 30% of the oil that circulates at pressure.  With kero perhaps you didn't build enough pressure with the low viscosity fluid to put the filter into the flow circuit.  Just remove the filter assembly and bench clean it..  The bypass circuit will close the path to the filter should it clog, diverting flow to the engine, assuring the more important task of pressurized lubrication is maintained.

With 6V starter my engine will build 30 psi on the starter alone with oil, don't know what would happen with kero.

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Thanks!  Being new to the forum I appreciate the info.  Checked compression while I was at it and, all cylinders were about 60#.  What is acceptable and what should I be seeing? 

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Your oil filter is a by-pass filter. What that means is no oil goes through the filter until full engine oil pressure is achieved and then any excess oil over and above that pressure will pass through the by-pass filter. In a healthy engine that is usually 20% or so. Kerosene being less viscous than engine oil may not build any pressure.

This picture might or might not answer your compression question.

fromthebook.jpg

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1 hour ago, P15-D24 said:

Oil pressure wasn't high enough to open the pressure relief valve. That's why the old oil is still in the filter housing.  

That explains why the old oil did not exit the housing. It does not explain why is fresh/cleaning fluid did not get into the housing.

52 minutes ago, Don Coatney said:

Your oil filter is a by-pass filter. What that means is no oil goes through the filter until full engine oil pressure is achieved and then any excess oil over and above that pressure will pass through the by-pass filter. In a healthy engine that is usually 20% or so. Kerosene being less viscous than engine oil may not build any pressure.

The feed to the oil filter is from the main oil gallery, flow through the filter is controlled at the filter return by the second set of ports on the oil pressure relief valve. MBiggs stated "With the top off and the filter removed from the canister, I spun it over some more expecting to see flow of some sort of flow, but saw nothing." With the cover off it is possible to get fresh oil into the filter housing before the oil pressure relief valve opens as there is a place for the oil to go that is not stopped up.

However the oil filter inlet is the highest thing in the engine oiling system and if there is any restriction getting to it or if there is a easy way for fluid to return to the pan (loose bearings?) then maybe nothing will get that high. I'd remove the inlet tube to the filter from the block: If the oil pump is working at all you will get a lot out of the main oil gallery where it attaches for what its worth, the tube may be clogged and you might as well check that.

 

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1 hour ago, Don Coatney said:

Tod, Flow to and through the filter is controlled first off by the path of least resistance. Oil pressure relief valve comes into play only after the system has pressure. No resistance, no pressure, no oil to the filter.

Lets see. Oil pressure relief closed (zero or low pressure situation), so oil in the main oil galley is not being allowed to return from the filter or go directly back into the pan. Got that. If oil is being pumped then all the oil is finding other ways to move. Some goes to the bearings (cam, main and through the main to the rods), which if tight will have some resistance to flow, some ought to be going out the lubrication tube in the timing case but I think that has some flow restriction built in. Oil to the valve lifter area is by spray from the rods (though the bearings) so that is not a separate thing to consider.

What is stopping oil from taking the very low resistance path through the feed tube to the filter housing? Nothing, and it can't even pressurize as he has the cover off. But he is not seeing it there.

Maybe it is just gravity (filter inlet too high for the amount of pressure the pump is putting out while being turned over by the starter motor).

But it could be the filter feed tube is clogged. Could be the main oil galley or the plumbing leading to it is clogged, could be the pump isn't pumping, could be the screen in the sump is clogged. Pulling the feed tube to the filter from the main oil galley will help determine where the issue is.

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Thanks for all the responses, it gives me a direction to figure it out.  Now all I have to do is carve out some shop time and see if anything is plugged, think I'll go after the feed tube first.  I did notice that the bolt that holds the canister top on has a galley that exits out through two small holes at the top (which were plugged)  does the oil travel up and out the center tube?  I'll let you all know what I find.

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