Yanmar ym3810d and 336d. I built one engine out of the two. New Rings and rod bearings new gaskets seals did valve job on head. Ive done probably a hundred different overhauls but never a 3 cylinder yanmar. My problem is no oil pressure. I'am hoping someone here may know what could cause this. After completing the overhaul I primed fuel system and it started right up and ran good. After starting I quickly looked at my oil gauge as I always do and no pressure. I checked gauge on something else and it works fine. I thought well maybe oil pump is bad since the other block had a rod through it and I was not sure which of the 2 oil pumps I put on the new motor. Took front cover off and put other oil pump on. Dropped pan and checked rod bearings just to make sure they hadn't been hurt and checked rod orientation thinking maybe I had them in backwards, grasping at straws. Only ran engine for a couple minutes. I went ahead and re lubed the bearings with engine assembly oil re torked and this is where I am now. Just don't see any reason to not have oil pressure. Any comments or suggestion is appreciated. Can the main bearings be installed wrong? Maybe block a oil passage.? I blew through oil holes on crank jornals. Everything seems open.
oldnslo
Super Member
Can you remove the filter and figure out some way to pump into the filter nipple with out the engine running to see if you build any pressure. You would need to be careful since I am not sure which side of the filter the relief is on.
This way you can start to isolate where flow is going without risk of damaging the engine.
This way you can start to isolate where flow is going without risk of damaging the engine.
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oldnslo
Super Member
Sully
Other option might be to feed oil into the fitting for oil pressure. This would backflow to the filter but still might provide a little insight on where the oil is going.
Other option might be to feed oil into the fitting for oil pressure. This would backflow to the filter but still might provide a little insight on where the oil is going.
Tinhack
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^^^ This. Use an old grease gun filled with oil and tube facing up. The hose thread is probably the same and you can feel any resistance if there's a blockage. The oil pressure gauge is typically on the main oil gally.
I use an old grease gun like this with Way Oil to lube my Bridgeport Mill. I sealed the plunger end cap since that's all I use it for now. I keep it filled with oil.
I use an old grease gun like this with Way Oil to lube my Bridgeport Mill. I sealed the plunger end cap since that's all I use it for now. I keep it filled with oil.
Pump was not setting very long. I put substantial amount of the sticky engine lube in the pump gears thinking that might help prime the pump.
Thanks, will try this.
