Thread: Vaseline the Oil Pump Gear wheels

yes,

vasaline, snow white jelly are the preferred options, but any non moly grease will be fine although it will screw with the stats on your first oil change if you do monitoring and checking.

Don't just coat the gears but pack the oil pump full.

Are these comments applicable to any rebuild or just LR? I’m putting together an engine now and have the oil pump in bits wondering how to prime it but also told you don’t need to prime it will just pump.

It is general practice with motor mechanics to do this with all motor rebuilds . What I do is fill pump body with Vasaline then fit the gears , wipe off excess Vasaline then bolt the pump together. The pump will self prime with out it but you will need to be cranked over a lot longer before getting oil pressure.

Oil pumps are designed to pump oil, and while they will pump air, they are not particularly good at it because the clearances between gears and between them and the casing leak a lot of air, especially at cranking or idling speeds. Packing the pump with vaseline simply blocks most of these leaks long enough to prime the pump with oil and also dissolves in oil.

How necessary it is depends on variables in the engine design such as how far above the oil level it is to the pump, and how tolerant the engine design is to bearings running without oil pressure.

you can also back fill the pump and the oil system by flooding the oil system through the oil pressure gauge port.

there are some engines that have a time limit on the oil drain and filter change as the pumps wont re prime if allowed to drain.

So the issue is the pickup is in the oil but the gears are above oil level?

The first filling of the engine fills the sump via the return drains from the head but doesn’t fill the pump body.

I can see that being an issue untill the gears are wet.

The oil pressure switch is first point of call beyond the pump hence topping from there wets the gear teeth.

In addition remove fuel or spark and crank engine over till pressure builds relying on oil and grease used in assembly process? Then start for real.

Originally Posted by PerthDisco

So the issue is the pickup is in the oil but the gears are above oil level?

The first filling of the engine fills the sump via the return drains from the head but doesn’t fill the pump body.

I can see that being an issue untill the gears are wet.

The oil pressure switch is first point of call beyond the pump hence topping from there wets the gear teeth.

In addition remove fuel or spark and crank engine over till pressure builds relying on oil and grease used in assembly process? Then start for real.

thats about it, some larger engines have a port for priming the oil system or an electric prime pump that wont let you start until a certain pressure has been reached