0 oil pressure when cranking

[lonelydriver_95]

So my beloved 720 4X4 has an engine in it now and it cranks (yay) but it just has 1 very slight problem. it has 0 PSI of oil pressure. I found this out by seeing the mechanical pressure guage not move off its stop and also double-checked by taking off the oil filter and finding it bone dry. I would expect if an engine is insanely worn out It would have at least some pressure so it having 0 makes me think it may be something relatively simple. I looked it up and found a post on here from like 2008 where @datzenmike recommended filling the oil pump with oil to prime it and we haven't tried that yet and we will. But before we dig in is there anything else that it could be? 

[bottomwatcher]

Prime it. 99% the solution. Only worry about other stuff afterwards. Should be able to spin it without spark plugs fast enough to prime itself.

[datzenmike]

It will turn faster without the exhaust side plugs in. Why the exhaust side? They are the easiest to get at. Try that first. And you should half fill the oil filter too. My L20B will build enough pressure to turn the warning light off.

 

What do you know about this engine? Is it a replacement? Without a history it could be anything and why it was gotten rid of. Take the distributor cap off. Does the rotor turn when you use the starter??????

[Stoffregen Motorsports]

Yes, remove the plugs first. While the plugs are out, spray some WD40 into the bores. If it's been sitting long enough for the pump to have gone dry, then a bit of lubricant on the cylinders is a good idea. Might be a good idea to remove the valve cover and splash the cam with some oil too.

 

You could probably prime the pump by removing the oil psi sender and use a small funnel to get some oil into the galleys, but it's easier to remove the pump. Get a new gasket first, and be absolutely sure it's done on TDC, and pay attention to where the distributor shaft is located. I have used a pair of vise grips to hold the distributor shaft in place (from the top).

[lonelydriver_95]

I know almost nothing about the engine so it was a gamble, I got it cheap. What I do know is that it came out of an automatic 620 that has been sitting since the year 2000 and I was willing to take the gamble because of said automatic transmission. I was hoping the trans was the reason it was parked, as old Automatics are a weak point from a reliability standpoint in my mind and this engine at least turned over and didn't have any windows in it. It does at least crank over nicely without any "gallops" in it.

 

And I will for sure see if the rotor spins.