Cranking oil pressure

[dn010]

Does anyone know what the oil pressure should be while cranking the engine? I'm having what could be an issue where I'm getting oil to the filter and the other side at the pressure switch, but no oil is flowing to the rockers. I was trying to circulate oil throughout the system prior to first start even though I did use assembly lube. Now I am not sure if I should fire it up briefly to see what the pressure is or take it apart and see if I have an issue somewhere first. Pump is a known good pump, O ring is between the upper and lower crankcases. Not sure what else it could be unless there is an issue with an oring in the pickup that is causing a lower pressure issue. Or maybe there is no issue at all and this is just how it is.

[82DMC12]

You can run the engine briefly without the valve covers on.

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[dn010]

You can run the engine briefly without the valve covers on.

Thanks. With that, it looks like I'll move forward with firing it up and go from there.

[82DMC12]

Thanks. With that, it looks like I'll move forward with firing it up and go from there.

I've seen, at at least two vendor locations, cut up valve covers with the intake-side cut away so they can temporarily mount them and run the engine to check cam lubrication. I've seen a video, there might be a little splatter but it's not shooting up everywhere. Never actually done it myself though.

[Helirich]

Are you cranking without spark plugs? It should give you oil pressure if you are. I wouldn?t start it until you do. Lots of people do with no problems, but I wouldn?t.

[dn010]

The problem is not that I have no oil pressure, it's just that I'm not sure how much I "should" have while cranking with no spark plugs in. I am getting enough to fill the oil filter and at least the lower passages since I have oil pour out of the oil pressure switch hole when I remove it which I think is a good sign, but the rocker arms are still dry after repeated cranking cycles. How much oil pressure I have while cranking I don't know yet, my sensor is not working (not like the dash gauge is of any use anyway) and I don't have the adapter for my oil pressure tester - both should arrive to me tomorrow so I'll have actual numbers.

[Helirich]

The problem is not that I have no oil pressure, it's just that I'm not sure how much I "should" have while cranking with no spark plugs in. I am getting enough to fill the oil filter and at least the lower passages since I have oil pour out of the oil pressure switch hole when I remove it which I think is a good sign, but the rocker arms are still dry after repeated cranking cycles. How much oil pressure I have while cranking I don't know yet, my sensor is not working (not like the dash gauge is of any use anyway) and I don't have the adapter for my oil pressure tester - both should arrive to me tomorrow so I'll have actual numbers.

I suspect you?re fine, but I would wait till you get your gauge on there.

[David T]

There is no spec for cranking oil pressure. On a running motor the rule of thumb for a running motor is a minimum of 10 psi and for every 1,000 RPM at least another 10. You should see *some* oil pressure during cranking after a few minutes. On first start-up it can take a while till you fill all of the oil passages, bearings, etc. Some builders will hook up a supply of oil to the motor and force oil in while cranking the motor over without the spark plugs. Some motors you can pre-oil by removing the distributor and running the oil pump with a priming tool (not Deloreans). If you used assembly lube, crank the motor without the spark plugs till you get some pressure. As for seeing oil on the rockers, that can take a while.

[dn010]

Just to sort of post an ending to this- although I couldn't get oil up to the rockers from cranking alone, I went ahead and started the engine. I could see oil finally make it up to the rockers once it had idle RPM. The engine is a 3.0 that I just finished rebuilding, hydraulic tappets are now happy. Luckily it also has an oil filler on the driver's side valve cover so I was able to just remove the cap and look down in to see what was going on inside the valve cover. So, first start was a success - oil going where it should be and my car is back in service.

71040

[JBaker4981]

Just to sort of post an ending to this- although I couldn't get oil up to the rockers from cranking alone, I went ahead and started the engine. I could see oil finally make it up to the rockers once it had idle RPM. The engine is a 3.0 that I just finished rebuilding, hydraulic tappets are now happy. Luckily it also has an oil filler on the driver's side valve cover so I was able to just remove the cap and look down in to see what was going on inside the valve cover. So, first start was a success - oil going where it should be and my car is back in service.

71040

I have so many questions about that motor... 3 Liter Eagle?

[dn010]

It's the 3.0 Eagle engine using the Volvo 780 Bertone fuel rails (because I can still get fuel pressure regulators for that car) and throttle body (because I already had everything set up for that one as opposed to the Eagle TB). It obviously needs the DeLorean lower crank case but everything else is 3.0 parts. It is running Ford EDIS and I use a MAF sensor. It is pretty quiet with the hydraulic tappets compared to mechanical ones.

For a little back story, I think it was around 2015 when I originally swapped in the Volvo 780 Bertone engine (B280F) and went EFI. After many years, the engine was dripping some oil slightly and I keep getting some smoke out of the exhaust now and then so I pulled it in the beginning of this year to see what was going on. What was supposed to be a quick clean up / seal up and a week later drop back in - turned into a months long process after I removed the cylinder liners and found the aluminum was corroded, (https://dmctalk.org/showthread.php?19987-Coolant-Corrosion-in-Block). The only other thing I found wrong with it was an exhaust valve had grooves worn in it from something that made its way down there.

Long story short, I found the 3.0, cleaned it up both internally and externally, rebuilt it with all new parts and you see the end result. There were challenges finding certain parts and adapting certain things to work, but in the end it dropped in and started right up on the B280F tune I was running prior.