Need Help "No Oil Pressure

[Labrauer]

Hi gurus of the forum,

 

I have rebuilt a Flathead 218 and installed it in the car. I got it started and have no oil pressure on the gauge in the dash. I have checked a few things I thought might be wrong like checking the Oil pressure relief valve, the oil pump, the floating oil strainer, the Oil pump outlet pipe and also put air through the oil galley holes with not any luck on pressure. On the oil pump I checked the clearance on the outer rotor, measured depth of the pump body and also checked the body cover for flatness. I also checked the clearance between the inner and outer rotor. I also checked the end play on the drive shaft and all was good within specs in the book. I primed the oil pump again after pulling it a second time before installing. On the floating oil strainer I pulled the screen and made sure it was clean. On the pressure relief valve I checked for scratches and polished it to a shine. Checked the relief valve spring and it is good and the right color. Turned the engine over with it out and oil came spurting out of the hole. I took off the return tube from the block at the oil galley and put a plug in and still no pressure. I have dropped the pan and checked to make sure the oil pump outlet tube was tight and it was. Looking at the crank and camshaft with the pan off there is oil on both dripping off. I have an oil filter in the oil canister. I have no external oil leaks. I have the recommended viscosity of oil in the crankcase. I am missing something to check I just can't find what could be wrong. I checked for oil in the valve tappet galley and there is very little if not any being pushed out there. 

 

Question I have is that on the connection rods I can move the rod from side to side a tad on the crankshaft is this suppose to be right or should they not move at all? When the engine was assembled I checked the bearing clearance with a plastic gauge and was in specs so I am feeling good about the right bearings being installed although I haven't checked the oil flow at the bearings by using a bearing leak detector and I'm not really sure if I have the right equipment to do it. 

 

Any body have any suggestions on what to check next? One thing I forgot to mention is that on the tube that goes to the gauge I had to replace the brass fitting that screws into the block. I don't know if I remember right or not but the old one seems to have had a smaller hole in it and if it did does it make a difference?  

 

Thanks in advance for any suggestions and answers,

Larry

Edited March 25, 2016 by Labrauer

[White Spyder]

Mmmmm, sounds like yo have oil moving and flowing in the engine and all within spec. I would try to attach another gauge at the outlet and turn the engine over and see if it might be the gauge or a clogged tube.

[Don Coatney]

I agree. Install a temporary gauge on any unused port on the oil galley. Remove the spark plugs to un-stress the bearings and crank the engine with the starter until you see pressure. Re-install the spark plugs and start the engine.

 

[dpollo]

I would suspect your gauge.  The reason for the smaller hole in the gauge fitting is to maintain air up at the gauge end of the line and reduce pulsations of the needle but that certainly is not what is wrong here.

 

Side to side movement on the con rods is normal.     

 

One thing to check is the pump cover seal.  This must be a square cross-sectioned O ring.  A standard O Ring will hold the cover away from the rotor which vastly reduces the pump's effectiveness.  Only the older gear pumps used a gasket and it was very thin.

Easy to check.  An effective way to prime the pump instantly is to pack vaseline into the spaces. on assembly.

  Also, Is the pump gear pinned to the pump shaft ?

[Plymouthy Adams]

dpollo, on 25 Mar 2016 - 09:13 AM, said:dpollo, on 25 Mar 2016 - 09:13 AM, said:

I would suspect your gauge.  The reason for the smaller hole in the gauge fitting is to maintain air up at the gauge end of the line and reduce pulsations of the needle but that certainly is not what is wrong here.

 

Side to side movement on the con rods is normal.     

 

One thing to check is the pump cover seal.  This must be a square cross-sectioned O ring.  A standard O Ring will hold the cover away from the rotor which vastly reduces the pump's effectiveness.  Only the older gear pumps used a gasket and it was very thin.

Easy to check.  An effective way to prime the pump instantly is to pack vaseline into the spaces. on assembly.

  Also, Is the pump gear pinned to the pump shaft ?

as the car is running, the pump turns the distributor I would say the gear would be properly affixed..first rule on oil pressure....always check with a second device..

Edited March 25, 2016 by Plymouthy Adams

[dpollo]

quite right, P.A.  in my early morning stupor I was thinking the slot for the distributor drive was part of the gear, but it is in the end of the pump shaft.

[suntennis]

On the driver side of the block there is a oil passage that goes from the front to the rear where the oil gage is connected. If you put pressure on the front of the block where there should be a plug, you should get pressure out of the oil gage hole. If there is nothing coming out, the oil passage is blocked and the reason for no pressure indication. I had this happen on a rebuild because the engine builder did not check it out before assembly. Ran the engine shortly and wiped out the rear main due to no oil.

[Dodgeb4ya]

I just replaced a partially plugged oil gauge 90 degree brass fitting that was partially plugged causing very sloe to rise oil pressure.

Cleaned it out... now gauge is normal.

Edited March 25, 2016 by Dodgeb4ya

[Jeff Balazs]

Just an idea. You could simply remove the line from the block to the gauge and then turn it over without starting it. You should get a fair amount of oil there relatively quickly. If you do then you know for certain what is actually going on.

 

Jeff

[Labrauer]

Thanks guys for the great information. I will put an external gauge on the block and see if I get any pressure. I didn't know about the small hole in the 90 degree fitting needed to be there or not. Now I have to get another pan gasket set to reinstall the oil pan. 

All feedback is greatly appreciated,

Larry

[Don Coatney]

I used sealant compound on only one side of my oil pan gasket and used grease only on the other side. I have removed my oil pan 2-3 times without having to replace the gasket. I used grease only on the front and read end pieces.  

 

[Labrauer]

Sounds like a good idea Don. I'll have to try the sealant compound and the grease this time when I install the pan gasket. 

[Labrauer]

Hey guys I have oil pressure now. With the engine idling I have 40 to 43 pounds of pressure. I don't quite know what the problem was but I replaced the rubber hose that goes to the tube that connects to the gauge as it was pretty well cracked in many places. I also noticed that when I replaced the oil pan it wouldn't go on straight. I looked at the oil pump strainer and it was cocked a little where it wouldn't go down to the bottom of the pan. So it was one of those two things I believe that was causing the problem. Now for the next problem I have an oil leak on the fitting above the Oil pressure relief valve. The fitting is brass and I may not got it tight enough down into the engine block but I didn't want to strip it out as I seem not to know my own straight when it comes to getting bolts and fittings tight. I am about to my wits end on one thing or another going wrong. If it's not one thing it's another. 

 

I want to thank each and every one that has chimed in on this problem and I surely appreciate all the comments and ideas on what to check and do.

Larry 

[White Spyder]

Torque wrench and thread tape.

[Jeff Balazs]

You may want to try Permatex thread sealant or event just #2 sealant on these fittings. I have used these products for years and they do the job. Check the brass fitting for thread damage when you remove it.

Jeff

[Labrauer]

There is no thread damage on the fittings as I have checked that and I put some of the plumbers tape wrap on the threads before the install. The brass fitting is threaded into the block as far as can be as it is bottomed out on the block. I am going out of town tomorrow and will be back the following Friday I will get some Permitex and try that when I get back.

 

As always thanks for the replies,

Larry