HELP!! sbc with NO oil pressure!

I went to fire my freshly rebuilt SBC up today, I fired it up ,then walked back to check the oil pressure and I had none. I started with a bare block, so everthing is new, I had the block cleaned(baked). The engine is a old small journal 327 block (63 or64), I had to use one of those canister to spin on filter adapters and I thought that might be it or the oil pump, so I pulled the filter and all the adapter **** off and everything looked good. I then stuck my drill thing in the block and spun the oil pump drive, it blew oil out from under the truck, so I know the pump is working. So here I am, the pump is working, oil is getting to the filter, everything looks good as far as the adapter goes and there is no reason for oil to not be going back up into the block from the filter. Can anyone think of what the problem might be? I was thinking that there may be a restriction somewhere or ??? Any help would be appreciated.

 

Could be a bad sending unit, remove it and spin the oil pump again and see if oil comes out where the sending unit was. Is it a manual or electric gauge?

 

Did you check the distance from the oil pick-up to the bottom of the pan?

 

Did it sound out of oil pressure??

is it an electric or mech gauge


Also Make sure the distributer is all the way in, my 2c

 

I'd pop a valve cover off to see if you're getting oil to the top,if you are, do an oil pressure test,if you don't have an oil pressure tester,run down to your local franchised auto parts store and they'll usually let you "rent" one for free

 

The distributor is all the way in (for sure), and the pickup is picking up oil, because I can spin the pump over manually and it pumps oil out of the hole in the block where the filter goes. The gauge is a elcheapo trio gauge from wally world, it was working fin a month or 2 ago with the other engine in, but it could not be working now, I guess. I just bought the cheap unit to get by till I stepped up with some cash for some good gauges. I will take the oil sending unit line loose and see if oil pumps out. The engine sounded perfect, I had it revved up to about 2000 to start the cam break in, there were no funny noises or anything. I was thinking the gauge might be bad also, but I am not taking any chances, I have a lot of money in the engine. I do not see how the engine would have pressure to the filter, but not past it?? any other thoughts??

 

Are you sure you have the correct length drive shaft between the distributer and the pump? With the distributer in the hole, pull the sending unit out behind the distributer, roll over the engine . You should immediately get oil out the pressure switch hole. If you do, screw a mechanical gauge (that you trust) into the port and fire up the engine with someone looking at the gauge. If no pressure in less than 3/4 seconds shut the engine off and proceed with other checks.

Frank

 

by chance did you use a lot of silicone/rtv around any gaskets that may have separated and fell into an oil p***age?

 

Did the spin on adapter have a seal that went in the center? I had a problem once with a 327 where a spin on adapter had a soft seal in the center that got ****ed into the oil jacket and blocked oil flow. Same type of results, spin the pump, it worked fine, but no pressure. Also, check the presure guage. If it is mechanical, make sure that all the air is out of the line. Hope this helps

 

Pre-oil the motor again with your dummy shaft...and make sure you are getting oil right on up through the pushrods and rockers. Your shaft needs to have the "collar" that goes down into the block (Or use an old dist. housing) or the lifter galleys will never pressurize.Try removing the oil pressure line from the block to see if you have pressurized oil there...or plumb that line to another gauge. If you are using an electric gauge you might want to try a manual one just to eliminate the gauge as a source of the problem. If you are not getting oil to the top end it's time to check and see if all of the galley plugs are there...and that none have blown out. I usually thread these p***ages and use threaded plugs instead of the ones you drive in. Also I seem to remember that there is a galley plug at the rear of the block that is sometimes removed during rebuilding...and if it's left out you will have no pressure. Perhaps someone else can be more specific, but I thought that was a Chevy small block issue. Also check to see that you are engaging the pump with your distributor. The pump pickup might be too close to the pan bottom as well. You did not say if you had pressure and subsequently lost it...or never had it at all. The best test is a static pre-oiling to make sure that system works before you fire it. That will also save some "stress" on the new parts, since they are not spinning while the pump fills all the dry galleys etc. and you have no immediate oil pressure. Best of luck to you.
-Scott

 

Yea could be the soft plug under the rear main cap was left out or have heard of guys driving three behind the cam gear in too far and blocking oil off to the lifters and mains also theres a threaded plug in the rear of #7 cylinder on the lifter valley side of the deck under the head that some shops forget to put in but it would leak oil out all over the ground if it wasnt there.would check gauge first.Just a few ideas for you to ponder on

 

You said that the gauge WAS working, I take it that this was before you pulled the engine.

Sometimes those plastic lines with br*** ferrels will collapse after the first use and prevent a gauge from working. That's where my money is.

But to be on the safe side do as several others have suggested, remove that line and crank the engine over to check for oil...better yet and safer is to pull that line and the dizzy and check with a drill first.

pulling a valve cover and checking for oily rockers is a good idea also, but not a guarantee. I'm still betting on a collapsed plastic sending unit line

 

sometimes the nylon line from the gauge gets pinched with the crush sleave (where you screw it in the block fitting). go to autozone/pep boys/kragen get a new crush ring, cut the line, put the top fitting on then pu the new ring on and screw it back into place. also on sbc (not sure about the early 327) above the timing cover there is a port to check oil pressure along with the rear port.

 

Ok, read all the posts and have got your problem solved ...I am reasonably sure....... take the oil line off the rear of the gauge and put it in a can. Fire the motor and let it run for 10-20 seconds and make sure you 1) are getting oil through the line, and 2) make sure your catch can ( a bottle is best) is catching the oil. Now you have just burped the air bubbles out of the oil line. It happens all the time when it is disconnected and reconnected. I would think you now have some pressure showing on the gauge. That's an old one.

 

There is a 1/2" plug that has to go in the oil p***age hole in the block above the rear main cap. That directs the oil from the bottom end through the oil filter to the top end. If that is not installed you wont show pressure.

 

If your using a remote oil filter you have the oil lines crossed. I did that once by accident.

 

Thanks for all the opinions guys, that is why I love the hamb! I am using a mech. gauge with the plastic line and I did notice that it has air in it. I will check that out first, tommorrow. The half inch plug above the rear main cap, I would have to pull the pan and rear cap to check that , correct? Hopefully I will not have to do that. Right now I am leaning toward the gauge or the plug, I will be sure to keep you guys posted, for sure!

 

Rear cam bearing holes lined up ?
302

 

I just checked and I am getting NO oil to the rear sending unit port, I took the line off and spun the pump with a drill. So, now what? Pull the motor? How do I check for the plug at the rear main cap? The guy that put the cam bearings in has been doing it for 30 years and only fools with chevy stuff, so I would have to ***ume that they are in right.

 

The soft plug under the main cap was probably left out,to check you almost have to pull the pan and cap.Suppose you could use a piece of small rod or all thread and run it down the rear sending unit oil port behind distributor and see how far down it goes before it hits the plug or cap, would have to get measurements on that though. .

 

you didnt forget the little galley plug below the rear main cap did you?i forgot it once..i primed and primed and primed..and i got nothing.the pump will pump away,and it spews the oil right back into the pan without goin through the motor.it's approximately 7/16 diameter.you'll only forget that one once.i had a customer build a fancy 9000 rpm 327,forgot the plug.fired it,ran it for a while,and burned er up.a simple tear down found his primary oil feed galley to be UNPLUGGED!!ouchie.thats ok..teardown,block flush,new brgs,ONE LITTLE PLUG,and some labour got him on his way.i think he even bought an oil guage after that....

 

Why should air bubbles stop a gauge reading? Doesn't air transfer pressure the same as oil? It compresses a bit, but it'll still p*** the pressure on.

I earn my crust working on and operating 2000psi air compressors, 1500cfm, and I've never 'burped' an oil line for a pressure gauge or transducer.

The gauge on my car has bubbles in, transparent plastic pressure line, I can see 'em. That still works.

 

Does anyone have a diagram as to where exactly the plug is? I pulled the engine out of the truck , pulled the pan and rear cap and I do not see anything. My bearings are shot to hell, I am going to tear the engine completely down and check everthing out then go back up with it, but I want to make sure I get the no oil problem fixed.

 

The plug in question is a small, 1/2 inch device, like a freeze plug. You must drop the oil pan. Pull the oil pump & rear main cap off. Deep down ( couple of inches ) into the oil galley on the drivers side by the filter is where it resides. If you look carefully you will notice that the galley goes up and out to the top and back of the block and another goes over to the filter. Go to Napa and get a 1/2 inch freeze plug a drive into this galley till it bottems out ( ***uming it's been neglected.

 

use a flashlight

 

Ok, I checked and the plug is in there, it is not new either. So the machine shop or the guy that put the engine togther did not clean the galleys out. I ran a piece of wire from the filter hole over toward the crank and it came back filthy, that makes me think that the oil galleys are stopped up. I cannot find anything else. i messed up and let a buddy of mine put this motor together(because he wanted to), I should have done it myself. I sure am glad I had to pull the pan off, because he left a spiral lock off a piston and the pin was about to come out of the piston and hit the cylinder!!! I am going to start over and clean eveerything up GOOD and put it back together with all new bearings. Is there anything else that could make me not have oil pressure, I want to make sure this does not happen again??

 

Maybe it's good that you never got oil pressure, else you could be looking for a new motor instead of just bearings.

While it's stripped down you can now go through the oiling system, follow it, gallery by gallery, drilling by drilling, using an airline to blow in through where the pump is and then the filter feed and return holes, to see where the air comes out. Or doesn't!

 

Jeez I learned this leeson a long time ago...bought a short block all machined and ***embled. It looked nice but the workmanship was ****. It was an expensive excersize to put it right. After that I bought some used mics and measuring tools and taught myself how to use them. Now I have my machine work done, measure all the clearances and ***emble myself. I also do all of my own cleaning too-you would be amazed at the grit that comes out of a block...
Anyway, you can (before you ***emble that motor again) use a good rifle cleaning kit. It will have long brushes and wipes that you can shove through the galleys, etc. I always pull all of the galley plugs out (or ask the shop to leave them out) and run brushes through all of the galleys, oiling holes, lifter bores, etc. Clean the holes in the crank too, and wipe your cylinders down. I usually stop when a white paper towel will stay white after a wipe. You can never get it clean enough. THEN I ***emble it...and before I fire it I pre-oil it by spinning the pump. You probably lost the bearings due to the trash in there...not the short run without pressure.
-Scott

 

yes, I am glad it did not have pressure or it would have tore everything up.. when I tore the engine down, I could tell that it oiled for a few seconds. The oil hole in the rear bearing under the crank was stopped up with junk. The crank is at the machine shop, they are going to polish the rear main journal and the rear rod journal, those 2 are the only journals that got any trash to them. They are pulling all the plugs out of the block and boiling it out, and they are going to run all the oil p***ages out with brushes. when I get the block home, I am going to wash all the oil p***ages out, just to make sure. I am going to end up with a nicer engine.

 

Don't ya hate having to do things twice?

I probably don't have to say this , but when you get your block back from the machine shop wash it with soap and water repeatedly. Especially the oil p***ages.The first time I did it I was amazed at the amount of trash that was still in there after the block was tanked. Good luck.