Author Topic: oil pressure  (Read 6427 times)

Rusty

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oil pressure
« on: March 30, 2010, 04:00:54 PM »
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.
rusty

chetbrz

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Re: oil pressure
« Reply #1 on: March 30, 2010, 05:42:30 PM »
Rusty,

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.
« Last Edit: March 30, 2010, 05:45:38 PM by chetbrz »
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29UJohn

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Re: oil pressure
« Reply #2 on: March 31, 2010, 10:22:41 PM »
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).
John
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Doug

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Re: oil pressure
« Reply #3 on: April 01, 2010, 11:54:30 AM »
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.

Rusty

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Re: oil pressure
« Reply #4 on: April 04, 2010, 03:59:48 AM »
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

29UJohn

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Re: oil pressure
« Reply #5 on: April 04, 2010, 02:31:37 PM »
Rusty,

It sounds like you may have a leak where the vac line connects to the oil pump.  If it is sucking any air there, it will not suck oil from the pan

The oil- pump is really an oil-vac pump.  If there is no fuel in the upper chamber of the vac-fuel tank, it could take a long time to seal and draw fuel, if at all.

Try capping the vac line to the fuel pump to see if that is the problem.  The best way is to make a sealed end with another 1/8 compression fitting and short piece of 1/8 copper tubing and solder it shut.  But, since you may not have that, you could remove the fitting and just hold something against the opening with your finger.

Do not use teflon tape - that is a compression fitting, so the tape will not help - it may actually make things worse.

As for the pickup line, you did the right thing replacing it with a compression fitting.  The original is what is known as a GM style fitting - it works great once at the factory, but is not designed to be re-used.  Sometimes they can be reused, but there is no garantee.  Best to repace with compression.

As for getting a prime going, it once took me 60 seconds twice to get a prime going.  That was a bit un-nerving.  I suspect that time it was a problem with my fuel vac pump tank.

 
« Last Edit: April 04, 2010, 02:42:16 PM by 29UJohn »
John
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Rusty

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Re: oil pressure
« Reply #6 on: April 04, 2010, 05:01:33 PM »
I am leaning to a vac leak also.  I pulled the pump (total about 20) and installed a fitting to a 3/8 clear line and that to a can of oil.  I hit the starter for about 10 seconds and that lifted the oil about 6 inches.  Please note, I had no line to the fuel pump.  I had installed about 6 oz of gas in the pump at the start of all of this as I planned on a easy project.   I took all apart the fuel pump (cannister) and replaced the one gasket.  Kind of hard to screw that up.  The top of the fuel pump seems to just sit in the main housing.  Is there a gasket that goes between the top "cap" and the main body?  Would it make a difference?  I think I may just need to crank her for a true minute.  That just seems like a long time.  rusty

If there is not enough gas in the cannister, would that cause a vac leak and then "disable" the oil pump? How much gas is enough?  Should I just fit it to the top?  I had only place 6 oz or so in it currently.
« Last Edit: April 04, 2010, 05:05:18 PM by Rusty »

chetbrz

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Re: oil pressure
« Reply #7 on: April 04, 2010, 06:46:39 PM »
Rusty,

I wouldn’t suspect the vacuum fuel pump.  Mine is hooked up for show only and while running the oil pump is just sucking air and has no negligible affect on the oil pressure.  With no spark plugs installed the oil pump should be able to pump up some pressure after a reasonably long crank.  Are you sure the pump gear is engaged and working properly. ?  If so you may have an air leak on the oil side or intake tubing.  If so even if the pump is working properly it would be easier to suck air then the heavy oil.

Just my thoughts,  Chet…
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29UJohn

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Re: oil pressure
« Reply #8 on: April 05, 2010, 09:28:59 PM »
Did you stop when the oil drew up about 6 inches in the tube, or was that all it would do?  It is a smaller hole, but it should have drawn it all the way into the pump.

As for the fuel vac-tank, there is no need for a gasket at the top.  The vacume is formed only in the top portion - the smaller top tank the sits in the top.  This cannister must have no leaks and be airtight, both fittings on top must be sealed tight.   Also, since you took it apart, the inside is dry.  normally there is always some fuel in the top tank - but there is no way to fill  it of check it.  IF the tank is airtight, but dry, it will take a little while longer for it to draw up fuel from the gas tank.  This is the same vacume that draws the oil up from the pan.  So, it will also take longer to draw oil from the pan. 

Adding fuel to the little tank just allows you to start the engine.  It does not affect the vacume.

You seem to have ruled all other problems out.  But, not sure I understand exactly the test you did.  If it only draws about six inches and stops, perhaps the pump is not very efficient for some reason (too thick of a a gasket on the cover? It should only be the thickness of about two pieces of paper.)  But didn't yoo say you bench tested it and it was pumping oil?)  If the pump is good, I would try and seal shut the small vac port on the pump and try again.
John
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Rusty

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Re: oil pressure
« Reply #9 on: April 06, 2010, 07:13:13 AM »
I had stopped cranking the engine once I saw the oil coming up the tube.  I did not have a line to the fuel pump, strictly oil for this test. The pump worked fine.  I was using 3/8 clear plastic tubing of about 12 inches in lenght to a can  of oil.  I just wanted to make sure that the copper tube to screen (suction) was working with out  a air leak and it seems fine, no bubbles seen in the oil.   I think all the lines should be clear, at least you can tell is fuild is present and moving. I am starting to wonder if the problem is with me as I am not patient enought to crank the engine long enought to have the suck oil up to the pump and then in to the engine.  Since the pump works, no leaks on suction side, it seemed tight as I "pressurized the block", the fuel pump is cleaned and tight, I may just need to crank a bit longer and starter her up.  rusty

I did remove the cover and the gasket is very thin so I reinstalled it.

29UJohn

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Re: oil pressure
« Reply #10 on: April 19, 2010, 08:34:13 PM »
Rusty,

You are keeping us in suspense.  Did you get the engine running and good oil pressure?

 ???

John
John
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Rusty

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Re: oil pressure
« Reply #11 on: April 20, 2010, 05:21:20 PM »
NO oil pressure.  I started it up as maybe the pump was not spinning fast enough.  It started right up and ran about 10-20 seconds, no oil pressure.  Turned off.  I removed the oil line from the block and tried again.  Just got a dribble out.  I adjusted the oil relief vavle all the way and all the way out, no change. My 41 chevy ruptured its oil line to the external filter once and that only used minimal oil pressure and that was like a artery, just shot across the engine compartment.  I triple checked the oil level.  I loosed the out flow on the pump and minial leakage around the threads.  I took the pump off and it was full of oil (so it was primed).  I benched tested and it will suck oil up but I am wondering if the volume is very low.   This was a rebuilt unit by  then n now  auto.  I plan on sending off to egge to test to see if volume/pressure is low.  I did have a proffessional hot rod builder help and he thinks it is with the pump somehow.  Will update once I know any more.  Rusty

I noticed that I was not getting fuel to the fuel pump from tank.  This could a lack of vacuum from the pump.  Does the fuel pump fill up fast from the tank?
« Last Edit: April 20, 2010, 07:49:19 PM by Rusty »

chetbrz

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Re: oil pressure
« Reply #12 on: April 20, 2010, 08:44:55 PM »
Rusty,

Have you tried a modern oil pressure gauge hook up?  Maybe your gauge is broken or the oil line to the gauge is clogged. ??

Chet...
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Rusty

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Re: oil pressure
« Reply #13 on: April 21, 2010, 08:03:31 AM »
Tried that.  The orginial worked , ???accuate before rebuild.  I used a new one also.  There seems no oil that is coming out of the hole that the oil send/gauge goes into.

A thought, the lower main cap on the center bearing is where the oil pick screen and oil line to mounts.  There is  steel pipe about 4-6 inches long that goes between the screen and the cap.  Maybe during the disassambly, a short pipe was used and the screen in no down into the oil pan far enough.  If the pump checks out OK,  I will need to drop the pan again and measure the depth of the pick screen.
rusty

chetbrz

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Re: oil pressure
« Reply #14 on: April 21, 2010, 05:12:49 PM »
Hi Rusty,

Just a ramble that probably has no barring on your problem but something that I have noticed with my car and I am not totally sure if it’s a problem or not.  When I first purchased my car I did my first oil change.  The Plymouth instruction booklet stated that the required engine oil content was 1 gallon.   After adding the required amount I noticed that my dipstick only registered to the half full point.  I didn’t want to over fill the oil pan so I assumed that maybe the dipstick was not the original stick.  When driving, if I was down a half a quart I would start to loose oil pressure.  So consequentially I started adding additional oil but still the oil level doesn’t come to the full mark.  I have since wondered if maybe I have a non stock oil pan that maybe required additional oil, but I have not yet figured out what the problem is or if there is a problem at all.  I was wondering if there is any adjustment on the oil input tubing that may be out of adjustment ??  I still don’t totally understand why my dipstick only registers half full with 1 gallon of oil in the pan ???



Just a ramble,  Chet…
« Last Edit: April 21, 2010, 05:29:01 PM by chetbrz »
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