24 replies to this topic

[BaronVonchesto]

So i've finished refitting my newly rebuilt engine and am just about ready to start it up for the first time! Excited! but i cant get the oil pressure up and was wondering if im doing anything wrong.

 

I'm cranking the engine in 10s bursts, and i did this about 5 times but the oil pressure gauge didnt budge from 0.

 

I did fill the oil filter with oil, but not the oil pump when i put it on the crank. all i did was take the oil pump out of the box, squirt in some assembly lube, slap on the gasket and bolt it straight to the cam.

 

also i've removed the oil pressure bullet and spring. and of course i've ensured that i did pour over 4 litres of engine oil (dipstick is slap bang in the middle). no spark plugs fitted.

 

am i missing anything?

Edited by BaronVonchesto, 12 July 2019 - 05:29 PM.

[unburntfuelinthemorning]

You won't get any oil pressure with the relief valve not fitted.  Do you mean there's no oil coming out when cranking?

 

You can remove the banjo bolt above the oil pressure switch and insert oil here to reach the pump.  Replace the bolt and try again.

Edited by unburntfuelinthemorning, 12 July 2019 - 09:15 PM.

[BaronVonchesto]

oh! for some reason i thought that the pressure relief valve should NOT be fitted when trying to prime the pump.

i shall put it back in and crank it again. how long should i crank it for you reckon

in the past i only needed to crank my engine for about 10-15 seconds before oil pressure would rise, but this was with my engine sitting for weeks without being started.

 

for a newly rebuilt engine it might take longer no?

[cal844]

10-15 seconds running while waiting on pressure is ok, I wouldn't go any longer.

Are you using the ball and spring or thimble and spring relief valve?

[Spider]

I have always done as Unburnt suggested and prime the pump via the Banjo Bolt hole, an Oil Can is helpful here to avoid a mess.

 

Then I wind away for what ever it takes to get the Oil Pressure up, 20 - 30 - 40 seconds, but rare it needs any longer than that. I doubt from new you'll get it up in 10 seconds, but without priming the pump first (and after filling that hole with oil, put the car in gear and roll it back a few feet to draw the oil in to the pump), you can crank until the cows come home and still not get oil pressure up.

[BaronVonchesto]

so just to be clear on what to do here:

 

1) put pressure relief thimble and valve back in.

2) remove banjo bolt and squirt oil into the pipe. to fill it up (do i squirt into the block too?)

3) put it into 2nd gear and roll the car backward 2 or 3 meters

4) then crank the engine for 20-40 seconds to build pressure

 

did i get that right?

[DeadSquare]

so just to be clear on what to do here:

 

1) put pressure relief thimble and valve back in.

2) remove banjo bolt and squirt oil into the pipe. to fill it up (do i squirt into the block too?)

3) put it into 2nd gear and roll the car backward 2 or 3 meters

4) then crank the engine for 20-40 seconds to build pressure

 

did i get that right?

 

 

N0.

 

Fill the block.

[DeadSquare]

 

so just to be clear on what to do here:

 

1) put pressure relief thimble and valve back in.

2) remove banjo bolt and squirt oil into the pipe. to fill it up (do i squirt into the block too?)

3) put it into 2nd gear and roll the car backward 2 or 3 meters

4) then crank the engine for 20-40 seconds to build pressure

 

did i get that right?

 

 

N0.

 

Fill the block.

 

 

 

And replace the banjo.

[gazza82]

If you can turn the engine over backwards a couple of times it will suck oil back into the pump too.

[timmy850]

There is a nice summary here

https://www.7ent.com...ni-storage.html

[DeadSquare]

There is a nice summary here

https://www.7ent.com...ni-storage.html

 

If you look at picture 4, cranking the engine is going to be difficult.

[Magneto]

I've had them still not prime after all this, so I go ahead and light it off, if it doesn't come up after 5 sec or so I shut it off and tear it down again. I've only had to do this once, and the pressure came up the instant it started, just wouldn't do it on the starter motor. Every other one I've done comes up in 20-30 seconds maximum. I then continue to crank it for 10 sec or so after the pressure comes up. With no plugs you're not going to overheat the starter motor in 30-40 seconds.

[Rorf]

Start a newly built engine without without oil pressure and bearing damage is done, taking off 1000 of miles of useful engine life.

 

If an engine had been correctly built and the oil pump fitted correctly oil pressure should come up after about four ten second bursts on the starter. You will actually hear the engine slow down slightly as the oil pressure builds up.

 

I have always put a bit of multipurpose grease in the oil pump before fitting. Of course the new pump should be dismantled and cleaned up - the odd casting burrs here and there etc to be filed off.

[DeadSquare]

Start a newly built engine without without oil pressure and bearing damage is done, taking off 1000 of miles of useful engine life.

 

If an engine had been correctly built and the oil pump fitted correctly oil pressure should come up after about four ten second bursts on the starter. You will actually hear the engine slow down slightly as the oil pressure builds up.

 

I have always put a bit of multipurpose grease in the oil pump before fitting. Of course the new pump should be dismantled and cleaned up - the odd casting burrs here and there etc to be filed off.

 

Every car that comes off a production line, is started and driven off while the oil pressure builds up.

[unburntfuelinthemorning]

Every car that comes off a production line, is started and driven off while the oil pressure builds up.

 

Many engines have oil pumps in the sump submerged in oil which eliminates priming problems.