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oil pressure

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I tried starting up the engine but have no oil pressure.  The gauge worked before I took it all apart.  I removed the vacum connection on the oil pump and squirted in about 4 oz of 30 weight into the top of the pump.  I pulled the spark plugs and put some oil down the cylinders.  How long of cranking should I go before seeing results on the gauge?  How long can I crank before I would cause any ring wear?  The pump is rebuilt by Tom at then n now auto.  I did not adjust the oil pressure relief valve.  I do not know if someone "tighten" this as the oil pressure dropped due to wear over the years.  I was going to get it running and then adjust if needed.


I would check the oil pump by disconnecting the oil input line and cranking the engine for a short time with your finger over the input to the oil pump.  It should present some suction pressure.  If not you can remove the cover and put some grease around the exocentric chamber to produce a better seal.   Fire the engine up using some starter fluid and if the pressure doesn’t come right up shut her down and troubleshoot the pump.  I wouldn’t run her longer then 3 - 4 seconds to fill the input tube.  If the pressure doesn’t come right up something is wrong.   If this fails, squirt some oil into the cylinders to protect the rings and cylinder walls.  I said fire the engine up in that cranking might not be enough to bring the oil up the tube to the pump.

Another thing you could try is removing the spark plugs this way you can increase the cranking RPMs without straining the engine.   This may allow you to bring up some oil pressure.

You could always tighten the pressure relief valve a turn or three by screwing it into the engine so that any oil pressure developed would be applied to the engine parts rather then the oil pan but I wouldn’t expect this as a problem in that the spring should keep the valve closed even at the lightest setting.  

My 2 cents, doesn’t mean it is correct ?  Just what I would do.

My thoughts,  Chet…

PS,  You could remove the oil pump front cover and make sure the exocentric is turning.

You must prime the oil pump first. 

I would do the following:

1) pack the oil pump with vasaline.  That is how the old timers primed the pumps.  (While the cover is off, check the inside to see if the two vanes are in there with their springs pushing them out against the sides.)  The hot oil will wash the vasaline out.  Do not use grease.  (Another method is to remove the pump, submerge it in a bucket of oil, and turn the gear by hand until all the air bubbles come out and only oil is moving through the pump, then reinstall it.)

2) Be sure the small air line from the oil pump to the fuel pump is tight on both connections.  If not, the oil pump will not pump oil.

3) Remove the spark plugs.  Shut off the gas so no indavertent sparks start a fire.

4) Now with the clutch in, run the starter.  The engine should turn over very fast.  Try it for no more than 60 seconds at a time, to allow the starter to rest and cool.  Sometimes it takes more than one time to get the pressure to come up.  When it does, you should see about 20 lbs of pressure.

You will not harm the engine, since there will be no compression load in the cylinders.  The bearings should have enough oil on them to handle turning without a compression load.

If you have any doubts about your gage, test it on something else first.  Better yet, use a substitute new gage, even if only temporary.

IA few other tips. I go two steps further now.  I disconnect the oil intake tube from the oil pump and sweeze some Lucus oil into the draw tube to prime that, then reconnect.  I also remove the pump and force lucas oil into it while turning the gear by hand (vice packing with vasaline - which does work well.)

If you still have no luck, remove the pump and place a draw tube from the intake to a can of oil and turn it by hand to see if it is working.  You should be able to tell quickly.

After you have oil pressure, reinstall the spark plugs and turn on the gas and start her up. 

If the oil pressure goes above 40 lbs under any cicumstances, shut her down immediately.  (Be sure you have a good gage.  Suggest using a temporary mdern gage.) Then remove, clean and check the oil pressure releif valve.  Reinstall and start again.  If the pressure is still above 40 lbs, turn the screw counterclockwise to relieve some pressure and lower the oil pressure to about 30-35 lbs.  Then let the engine run a while and get good and warmed up.  Then rev the engine.  If the oil pressre goes above 40, turn the relief valve some more. What you are looking for is a max of 40 lbs hot at full rev RPM (~2000 RPM), and about 15-20 lbs (sometimes less if very hot) at idle (800 RPM).

I have had my 30U do that twice, Once after sitting a long time, the second time was after changing the oil. I just took an oil can, put a rubber hose on it, took the vacum line off the oil pump, put the other end of the hose on that fitting, pump some oil in it. Hooked the vacume line up, crank her up every thing was fine. Have no idea why it lost it's prime.

This is what has happen. I pulled the pump and primed with lucus oil.  All spark plugs are pulled.  I cranked for 30 seconds. Nothing. I then added a new gaugae with clear plastic line.  Nothing , clear line.  I removed the pump and put in oil and turn to no bubbles.  Again, no luck.  No oil ever going into the gauge line.   I removed the cover plate gasket on the pump thinking that it was too large and there fore no shuction.  NO luck.  I removed the pump, put in the vice, ran a hose to a oil can and used the impact wrench to turn the pump.  That worked, so the pump itself works.  I then connected a hose to the end of the cropper line that come out of the block, suction line.  I used mouth suction and got oil.  I then took a oil suction gun that is used to remove or install grear oil in trans cases.  I filled it with oil and under pressure in to the block.  I was hard but I got oil to the gauge, up the line, I could not get the gauge to move but at least I primed the block.  Reinstall, all, no luck.  I then remove the discharge side of the pump and had wife hit the starter, no oil flowed out.  It must be getting air somewhere on th suction side.  I pulled off the oil pan.  I removed the pick up screen and houseing.  I thought the suction end of the copper tube has tight but maybe not.  I could really put some juice to that nut to tighten things up.  It the process of orginally removing the line,  I bend badly the orginial fitting.  I could not get a replacemet so I converted it to a modern compression fitting.  I wonder it I had not tighten has much as I should and this casused a little air leak.  I tighted everything and will try again sunday.  The vacum line seems tight but will use teflon tape.  rusty


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