Oil pressure question; zero oil pressure on install

[Mark Thompson]

I just put the engine in KMP625, fired it up, and had no oil pressure so immediately shut it down. The short history; the engine (Aluminum Shelby block 468) was build by a well known builder and was run on the stand/dyno with correct oil pressure. The install has the high pressure line from the oil plate going to the ring of oil filter holes, with the return coming out the center and then going to the cooler, then the lower return on the adapter plate.
Prior to firing the engine was cranked without spark for about 30 sec to prime the lines/filter/cooler. Has anyone run into this? Aside from a bad sender I can't think of what the issue is, and a bad sender seems improbable. Do I need to prime the filter/cooler longer? Even if the filter was plumbed backwards, would it result in no oil pressure? From my reading the filter only adds a few PSI pressure drop, so this doesn't seem likely.

many thanks, Mark

[CobraEd]

Originally Posted by Mark Thompson

Even if the filter was plumbed backwards, would it result in no oil pressure?

Yes, I have seen it before because of the anti drainback valve. you will end up with 0 presure if plumbed backwards.


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[RodKnock]

Mark, check the Kirkham gauge, grounding and connections. Before I had a couple electrical issues sorted out recently by Steve at Mustang Ranch, my oil pressure gauge once or twice registered zero oil pressure, even after driving it with normal oil pressure and then restarting it minutes later. My voltage gauge also had some issues once or twice.

Steve at Mustang Ranch knows his "you know what" when it comes to electrical and rewired, regrounded and reconnected things better on my Kirkham.

Sorry, my lack of electrical knowledge knows no boundaries.

[Keithc8]

This is why it is a good ideal to prime the engine with a drill before starting. Turning the engine over with the plugs out wipes what oil is on your bearings of and leaves them dry. Prime the engine to make sure that your lines are hooked up correct and to make sure that you are getting oil pressure before you start the engine. Double check your lines and the way they are routed.

Good luck, Keith

[Rick Parker]

Double check your lines and the way they are routed.

Look at the filter mount closely.

[Bob In Ct]

When the filter is connected correctly the oil goes into the filter through the outside holes and out of the filter from the center. The oil will not flow in the other direction.

Bob

[jhv48]

And, if it were me, I would check the dipstick first, hook up another mechanical oil pressure gauge to the block and then, after checking the flow is correct into and out of the oil filter, would prime the engine with a drill and watch the oil pressure line carefully for oil to start filling it. If it doesn't start filling immediately, shut er down and begin troubleshooting.

If new gauge works, you've found your problem.

[601HP]

FWIW -
The advice to prime and check for pressure is worthwhile. I've had the occasion to do this several times over the years. "Wifely" watches the gauge while the 18v Dewalt and I have at it. My Smiths gauge will register 60 pounds of pressure.

David

[Mark Thompson]

Thanks for the comments. I should have added to the background that I left the oil from the test work in the engine when I installed it, so the only priming was filling the external lines, filter, and cooler. The "out" line from the adapter plate is common with the sender and goes to the side of the filter mount, which feeds the in holes to the filter as you all have described.

I am increasingly suspecting the pressure sensor/gauge.

Mark

[Tom Cimino]

I'm sitting here with an adapter in my hand and the sender is on the return side of the adapter, not the "out" line. (I'm assuming when you say "out" you're refering to out of the engine to the filter housing). I would check your plumbing again to make sure you don't have your lines crossed. You can't be too cautious.

[Mark Thompson]

Tom

You are a prince. I have been assuming the pressure sensor was on the outlet. This all makes sense now.

Mark

[Michael C Henry]

I'd have an oil pump drive in hand and an 1/2' drill that turns counter clock wise before I really try to restart again. air doesn't take much power to turn up. If your moving oil you'd be surprised how much power it takes If it takes a bunch of powerfor the drill motor to drive the oil pump and no oil pressure I'd blame the plumbing arangement. Some oil filters have oil drainback check valve, if the oil filter is plumbed backwards the check valve would stop flow and most likely not show and pressure on gauge. Take a valve cover off and you'd be surprized how much oil is going to the rockers,

[Rick Parker]

Did you fill the cooler prior to firing? Spin the pump with the drill until oil is "Everywhere", then light it.

[PANAVIA]

These are all good ideas, priming the system with a drill and attachment makes sense , the remote oil filter and Cooler can suck up 2+ qts without issue.

If you have the inlet and outlet on the oil filter adapter to the block fliped in vs out, this can cause the no pressure condition ,as well.

As for electrical, thank you rodney for your kind words,--!

Electrical; the pressure sender operates on a set amount of voltage and it's resistance is the variable to that Voltage as read buy the gauge on the dash.

For instance , if you grab your handy ohm-meter, multi- meter and set it to ohms of resistance , and attach it to the lead and ground of the sender you will see one set of values at 0 psi oil pressure and the number of ohms resistance will change up or down depending on the design of the sender as pressure increases.

I did not review the ohm readings on the krikham gauges as of yet, but i am sure with a call to Arron at their mfr, I could get the specs if you are indeed in need.

Steve

[lovehamr]

Mike H.,

Did you get it working?

[Michael C Henry]

Did I get what working?

[lovehamr]

Sorry "Mike," I meant "Mark!" LOL

Steve

[Mark Thompson]

Steve

All is well with my oil pressure. Once I swapped the lines I had immediate OP. The flow valve in the filter took all the pressure drop and so there was no pressure at the sender. I guess there was never an oil pressure problem, just an indicator problem. Us EE types get confused by measuring on the drain side.

Mark

[lovehamr]

Don't feel like the Lone Ranger on that one man!! LOL