Priming oil pump before assembly, whats the procedure?

[Jonasand]

Hi!

I'd like to know what you guys do with your oil pump before assembly, say that you have cleaned all the parts with carb cleaner and everything is dry... what do you use for lubing it up before assembly?

I'm thinking that maybe its good to do a light touch of engine oil and then pack with assembly lube? Or would the oil cause the assembly lube to break down therefore making it wiser to go with pure assembly lube and no oil?

And would rotating the engine (after oil pump is back in case) pump out the assembly lube from the pump?

If so then perhaps it is better to wait with putting the pump back in till you know its time to rock n roll?


Any wise words on this from the experts?

Thanks
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79 Baywindow, currently rebuilding engine
Type 4 2.0 L FI
Hydraulic lifters

[Brian]

I pack it full of Vaseline.
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[SGKent]

as soon as you spin it whatever is in there gets pushed out and new oil will be pulled in. On late T4 cases there is a loop where excess oil gets pushed back into the oil pickup. Any air and the pump cavitates. On a late case you leave the oil filter off, put a pan under it and spin it for a second no plugs until it dumps oil. Then put the filter on, try again and see if you get pressure. If so then put plugs in and start it.

On T1 engines and early T4 engines you crank it with the plugs out until it gets pressure. If so then put plugs in and start it.

Some people use vaseline, others like me use a thick oil with the red assembly lube in it. Don't use grease because it can clog oil passages.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[Jonasand]

Is it a bad idea then to put the oil pump (with the assembly lube) in the case before the cylinders are installed... I mean would the pressure from turning the motor over by hand (for example when installing cylinders and pistons) cause the assembly lube to move out of the pump causing it to not prime as well?

Or am I overthinking this?

Perhaps there is still enough gooey stuff in the pump when it is time to actually start the engine, even though the pump has been turned by hand a few times during assembly of the rest of the engine?
_________________
79 Baywindow, currently rebuilding engine
Type 4 2.0 L FI
Hydraulic lifters

[SGKent]

The assembly lube and oil is really sticky so it won't all drain out. You can also pour some into the oil pressure hole and it will drain down a bit to the pump. Just remember that if it is a late T4 case then you have to spin it with the filter off etc until it gets oil coming out. Make sure when you bolt the case halves together that you also seal up that extra inlet.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[Jonasand]

Where is this oil pressure hole situated?

I’ve got a GE engine case, so thats a late type 4
_________________
79 Baywindow, currently rebuilding engine
Type 4 2.0 L FI
Hydraulic lifters

[SGKent]

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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[Wildthings]

One trick you can do is before installing the engine, fill the crankcase with the specified amount of oil and then rock it towards the oil pump to about 30° from the horizontal and then turn the engine over a few turns by hand. This would make the oil pump awash with oil so it would prime easily.

[Jetfxr69]

[SGKent]

[aeromech]

[Jonasand]

[Wildthings]

With the engine steeply tilted and the pump at or below the oil level it should prime easily.

When trying to get a pump to prime on any rig, I will often loosen the filter so it will not put backpressure on the pump. Prefilling the filter can be a detriment when trying to prime a pump.

I have found pouring oil into the port for the oil pressure switch to be effective. I use a plastic Coleman funnel with a fine mesh screen that will actually screw into the port and dump in a fair amount of oil. If nothing else this give you full oil galleys and oil to the bearings.

[SGKent]

late cases have an issue where they often take time to build oil pressure when they sit. No one really knows why, and there are lots of theories. The one that seems to make the most sense is that on the late case, any oil that gets pumped by the pump is pushed back to the oil pump pickup when it goes thru the single pressure relief. Once air gets into the pump, it foams up and the pump doesn't pump properly. If you crank the engine, let it sit for 5 seconds or so, crank again, let it sit for 5 seconds or so, then about the 3rd time it will get normal pressure. The first GD engine I built, I did not seal that passage really well, and could not get oil pressure on the engine while just cranking it. I pulled the sender off the hose (I have a dual sender) aimed it at a can, cranked it and had oil instantly almost. Put the sender back on and the engine had oil pressure perfectly like every one of the thousands of engines I have built. Let it sit for a week and I have to go thru the 5 second thing. The new case I have does not do this but I sealed that passage really well. Considering the number of late cases that have lifters that get air in them, I think it is all together possible this loop is the cause. Before that, the engine dumped any overflow out into the case. So if there was air in oil system up high it had no way of getting back to the pump inlet. Late cases it does. So I don't know if I have confused you or answered your question. If you ask why did VW do that loop, the only thing I can figure out is that any oil that bypasses from over pressure goes back thru the oil cooler over and over until it is used. That would help control oil thickness on the oil going to the hydraulic lifters, and hence control the lifter bleed down rate. Solid lifters didn't need that control. Earlier cases you are dumping cooled over pressure oil back to the case to help with sump temperature. Late case you are cooling the oil over and over before it is used regardless of the sump temperature.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[Jonasand]

Thanks for the info Steve, not confused, well maybe, but this problem is good to know about.

For me that would be two problems then;
1. Below normal oil pressure if the engine has sat for a while
2. Air getting into my hydraulic lifters

I'm guessing you have a oil pressure gauge with where you can get more numerical readings. I just have an oil pressure light, the one with the oilcan symbol.

Will the regular gauge be enough to warn me about this scenario that you speak of?

What harm can this lower then normal oil pressure do?

Is there anything else I could do to mitigate this problem without sealing that passage?

Would using synthetic oil do anything?
I have heard this its good for hydraulics. Perhaps different oils are different with regards to how they behave when air gets into them? Just taking wild guesses here...
_________________
79 Baywindow, currently rebuilding engine
Type 4 2.0 L FI
Hydraulic lifters

[Jetfxr69]

stick the pump in the hole, fill engine with oil, and crank till light goes out. then put in plugs and let ‘er rip. its NOT rocket science for christ’s sake. unless your engine is made of porcelain, it will be fine.

i work on jet aircraft and dont know shit, my advice to you is to take a train.
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‘77 westy Seamus
‘76 tintop Crusher
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‘72 tintop bastard westy Hudson

[SGKent]

If the light doesn't go out for 20 -25 seconds when a bus with a late engine case has been sitting, it probably means air has gotten into the oil pump via that passage VW added, and it is foaming the oil so no pressure results. Crank or let it run for max of 4 - 5 seconds if the light is on. Wait 7 or 8 seconds and do it again. Usually the 2nd or 3rd time the light will go off. Waiting 8 - 12 seconds for oil pressure is far more desirable than 20 - 25 seconds. If you drive the bus every day you'll never see this issue. It takes 4 to 5 days of sitting for it to appear. Has been reported many times here on the forum and there are many people who propose different fixes.

As to hydraulic valve lifter clatter on start up, VW said in a tech bulletin to instruct the client to ignore it and wait until it goes away after driving a short while.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[Jonasand]

Thank for clarifying! I’ll try to remember this when the time comes to start her up... hopefully soon...
_________________
79 Baywindow, currently rebuilding engine
Type 4 2.0 L FI
Hydraulic lifters