Oil pressure not coming up

I am cranking my engine for the 1st time after being rebuilt. But The oil pressure isnt coming up. How long should a crank before the pressure starts to come up? I filled up the oil filter before putting it on and my oil pressure sending unit and gauge are the new updated kind that I got from this and share and was working perfectly before I took the engine out.

Don’t panic. It will come up when the engine fires.
I had this on my recently rebuilt Mk9 engine.
I must admit I had a bit of a sweat on waiting . It took about 8 seconds.
You could prime the oil gallery with a simple pump connected into one of the oil gallery plugs.

Thanks I was getting very nervous, of course now also the tachometer doesn’t work. This car could take some years off my life

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Don’t forget, if it’s got a new filter, that’s gotta get filled. It took me 10-15 seconds to do the same to mine today with a partially filled filter

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On a fresh engine I would take the plugs out, disconnect fuel pump and do 3 or 4 10 second starer runs. Engine turns super fast and you should get around 20lbs of pressure. I did this today on my freshly built engine. After primed she started right up and the pressure was around 50 pounds.


I did take all the spark plugs out, actually never put them in, disconnected the fuel pump and disconnected the coil and spun it for a while and still no pressure

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It takes me three trys of about 15 seconds each, without plugs, after sitting all winter with fresh oil and a new empty filter to see the pressure come up.

Are you sure the sender is working ?

try unscrew the oil filter and crank until it oozes out of the filter assembly

I would say that if you crank it for a total of 60 seconds and no oil pressure comes (or no ooze of oil out of disconnected filter) then there may be a problem that requires the sump to come off to inspect that 1) the pump is coupled to the gear drive and 2) that no o-rings are missing from the pump and 3) pump tubes are all properly connected.

I would suggest to check that the distributor rotor is turning when you are cranking as the oil pump is driven off the bottom of the distributor drive (via a coupling)

Dennis 60 OTS

I put an external pressure gauge

The distributor rotor is turning I checked that. But mommy I don’t wanna drop the sump. I also had filled up the oil filter with oil before I put it on the engine I will check with the guy that built the motor to see what he thinks I’m going to speak with him tomorrow. I loosened the oil filter but while cranking no oil drips out. If I get any sleep.

You didn’t say how long you cranked.

I’m thinking mine took more than 30 seconds - but that was the longest half minute of my life.

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How many seconds total have you cranked it so far??

Cranking on the starter, especially if it is the original one and not a hi torque unit, it can take forever to get oil pressure up. The starter is only cranking the engine very slowly; maybe 10% of idle speed.

If you are particularly concerned you could pressurise the system by removing one of the oil gallery plugs.

Personally I wouldn’t bother. Just start the engine, you won’t do any damage. This is what all that assembly lube is for.


Seconded… with 20 dittos!

I agree that starting the engine is a reasonable way to bring up first oil pressure after a rebuild but I would still turn it a time or two by hand and then run it a bit on the starter just to be sure all seems well before firing it up.

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Finally, the pressure got up to about 17 psi. Thanks so much for all your help. You people are the best

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And now, I have the same issue with my engine.

The engine is freshly built and on a test stand with no spark plugs and no carbs. I pressurized the system through an oil gallery plug with a garden sprayer (thanks Allen). I pumped about 2 quarts through the gallery and watched oil ooze out of the cam lobes. There are 9 quarts total in the sump now with the dipstick registering about halfway up the cross hatch. I have a mechanical OP gauge teed into the feed line. I am also using a CJ spin on oil filter adaptor. Here’s the set up.

The starter is the original and spins the engine at about 120 RPM with a fresh battery. The dizzy is not installed but I can see the drive spinning. After 60 seconds of spinning I still have no pressure. I’ve tried it a couple of times. The gauge is known to work since it registers about 20 psi as I pre-charge with the sprayer. I thought this was maybe normal until I watched this video (should start at 37:50):

They get oil pressure in about 15 seconds. I notice they have the OEM cartridge filter. Any chance the CJ spin-on is delaying the pressure build up?

For reference, here’s my pump and plumbing installation just in case I have missed something.

Thanks for your help
Rick OBrien
65 FHC in FL

I believe the CJ adapter is made by Rob Beere and takes a PH16 filter which is a bit smaller than stock, so if anything it should pump up faster. If you don’t mind a bit of mess you can crack open the oil feed pipe at the block while cranking. If you see the mess then you have oil flow and the problem is either sender or gauge. It does take a long time normally, and it must be cranked with the plugs out to stand a chance of even seeing the needle move.

My gauge pegs over 60 when started, but with cranking only I might only get 5psi after 45 seconds.

That’s a good idea Erica. I removed everything back to the tee and tried again with an open line. Nothing. Either it’s a dead pump or just refusing to prime…so far. The pump should be good. It’s NOS British Leyland and never used. It spun freely and seemed fine coming out of the original box.

Very disappointing, but a funny thing did happen. If you really want to scare the crap out of yourself, try spinning the engine with rubber stoppers still in the spark plug holes. Compression is good!

I’m thinking now to just proceed with the build out (waiting on carb bodies from Mr. Curto) and try to run it. How long do you think it can run with no OP?


I just can’t imagine a new pump being literally dead. I don’t know if you’ve ever looked inside one but there’s basically nothing to it. The 5 things that come to mind are the pump drive dog, the pump drive gear, the o-rings on the pipes, the gasket where the pipe meets the block (not all blocks have this I think), and the worst of all, blockage in the channels or bad rear bearing seal.

If you saw the dizzy spinning that lets out the gear and dog I think.

Ooh one more the big plug on the back of the block being missing. But that would make a huge mess very fast…ask me how I know. Sorry this must be frustrating :frowning_with_open_mouth: