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ralphnof49

Engine oil pressure again

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Last year I had issues about oil pressure in this rebuilt 47 Lincoln Club Coupe engine. The pressure would drop to about 5 lb when the engine got well warmed up, but lifters were usually quiet. Now as we try to get on the road this year, the pressure, with a new sending unit, is over 50 when cold but drops to 0 when hot and the lifters are tapping away. I'm not sure how concerned to be about going in a parade on Saturday and I would like opinions on the nature of this problem. I have straight 30 weight oil in the engine and perhaps should change to 15/40 diesel oil. I would appreciate any advice. Ralph.

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Hey try Bi-passing the filter, and check the in line restricter to the filter, other wise it maybe the oil pressure relief valve that maybe restricting oil flow to the lifters.

zman

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The restricting orifice is part of the inlet fitting that screws into the side of the filter. The pressure sending unit screws into the same fitting. Oil flow is also restricted by even a smaller orifice on the outlet tube ( in the filter) so I doubt that the low pressure is due to the filter circuit.

These 12's are notorious for low oil pressure if the bearing clearances are too great, wear or otherwise. If the tappets are in good shape they will be function as long as there is oil supplied and the tappet oil circuit is limited to 20 psi regardless of the main system pressure. There are some things other than worn bearings that could cause trouble; like a fuel pump push rod bushing that is worn thru into the main oil galley or even the cam bushings intalled upside down.

You might try using 20-50 oil as many folks do with these engines.

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Thanks peecher. I did by pass the filter unit and the lifters quieted down. The small oil exit hole in the center tube of the filter seemed to be partly clogged. I haven't checked the inlet orifice. After installing the filter unit back on the pressure jumps up when cool and then drops down, but increasing the rpm raises the pressure again. The lifters are now quiet. I will check the inlet orifice to be sure it is OK. I had tried 20/50 oil last year and still had oil pressure issues, but it could work better now. Ralph

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zman and peecher, there is no restricting orifice at the inlet. It must not have beeen there as long as I've had the car. It's absence explains the problems I have been having up till the latest, which added clogging of the small filter exit hole.

Now, where do I obtain a new in line restricter orifice? Do you know who supplies these?

I sure appreciate your help. I don't know how else I would have found the problem.

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Harell or Earl Brown, both in PA and listed in the on this web site,shouldn't cost much, Then put some "Lucas oil treatment to replace a quart of the oil you use.

I put some in a Jubalee tractor that sat in a field for 30 years drained the oil and put 15 W 40 with the Lucas.After 100 hours of run time with an oil pressure of 40 psi at around 1200 RPM. and at idle 15 PSI.

Zman

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when you bypassed the filter did you just run a line around it or block the existing line. i have a simular problem. when i bought my lincoln it had a aftermarket spin off filter and oil cooler setup on it. i have changed it back to original. i now have a lot of lifter noise. thanks for any help. lyle

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Hey guys, think about this. The small orifice in the verical drain tube is really the "restricting" orifice. Oil, under pressure, will fill the filter cannister but must exit thru this small hole. The exit (drain) line enters the oil passage ( on the block) that feeds oil to the left side hydraulic tappets. By-passing the filter circuit really has little effect on the main oil pressure.

I wouldn't worry about any additional restricting orifice in the inlet fitting.

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lyle, I connected the two lines together to run oil through into the engine and then the lifteres had oil and ran quiet. Then cleaned the tiny exit hole well in the center pipe of the filter cannister along with the whole thing and put it back in with oil in the filter cannister and the filter.

peecher, the only thing I notice is a little longer time to see pressure on the gauge than I think it should be. I have Lucas Oil in now. Ralph

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ralph does the line that comes out of bottom of canister go to the side of the oil pan or does it go back to the rear of engine near where the inlet goes into the oil canister.being that i installed the original canister without any pic or such iam trying to see if i have the plumbing right. i now have the outlet hooked to the side of the oil pan. i have a plug in the hole in rear of engine thanks lyle

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lyle, I don't know if the lines vary for different years. On mine the coiled tube originates from the back of the engine and enters the side of the canister and the oil pressure sender is on that line. The exit line out of the bottom goes to the back of the engine and enters the block lower down than the first line. This line needs to feed oil to the lifters.

peecher, I wonder if the pressure restrictor is needed before the canister to reduce pressure on the filter. I also wonder about oil flow since these engines apparently needed better oil flow that they had. Perhaps the restrictors were too small?

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Lincoln Zephyr motors 36/37 have only 2 oil holes on top of the block / bellhousing at the rear, they are both oil supply holes, one for oil pressure gauge the other to supply oil to the filter, this filter is only a By-Pass filter. The main oil supply is inside the motor, and is unfiltered. The return oil from the Filter is piped straight into the side of the sump. All filters have a built in Restrictor in the center pipe. On L/Z motors 38 onward all have Hydraulic Lifters, the bellhousing has a third oil hole lower down beneath the other two supply holes. "Some very early 38 L/Z motors dont have this third hole." This third hole has the oil return pipe from the filter connected to it on these models and not to the sump. This supplies Filtered Oil to the Lifters. Lifters love filtered oil. Inside the valley under the Inlet Manofold at the rear under a 1 inch. screw out plug is a 12 LB. oil regulating valve, it is screwed in too, it regulates the oil flow to the lifters under cold start conditions and if the filter gets clogged This valve may be missing or has been replaced with a plug on Ralphsnof49 L/Z motor. This could reduce oil flow to lifters or allow loss of oil pressure, depending whether its missing or plugged, especially if the 1 inch. plug above it has been left out as well. This 12 LB. regulating valve only supplies oil to the lifters during a cold start, for about 20 secs. until the filter has filled up, because the filter drains back when parked up, once the filter has filled the oil flows over the 12LB. valve and shuts it down and the oil flows to the right hand lifters, it already has flowed to the left hand lifters on the way to the valve.The oil galleries are complex. So the pipe work has to be right and the correct valves in place. there is also a different relief valve at the front of the block, this distributes any oil left after passing thru. the lifters to lubricate the Cam gear.

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Ralph, The oil filter cannisters are stout enough to take any pressure the system can put out. Some Ford V8 applications used a small restrictor orifice at the inlet, about .040" I think and the filtered oil drained directly into the oil pan. On the 2 Post-war engines I just rebuilt there is no specific restricting orifice in the inlet fitting for the filter nor in the filter on my '46.

The oiling system on these engines is marginal at best; the lines are too long and too small. Circulating the "cleaned" oil from the filter back into the lifter sub-system was a step in the right direction. The description above of the hydraulic lifter feed system is not quite accurate. The early '38 engines had a metering plug at the rear ( next to the fuel pump push rod). this was replaced with a by-pass valve set to open at 4 psi. The hydraulic lifter line pressure was regulated by a ball and spring valve at the front of the engine and set at 20 psi. The hydraulic lifter feed system was thus regulated to not more than 20 psi no matter what the the cold engine oil pressure was.

You will notice that the small orifice on the vertical drain tube in the filter is fairly high up. They did this to prevent drain-back when the engine was shut off so the filter stays almost full at all times.

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Thanks peecher. I could not find a place for an inlet restrictor in my 47, so am happy to hear there isn't one. I also checked my parts catalogue and none is listed. I looked for the bypass valve at the rear of the engine under a 1" cover, but couldn't find it. Is it near the fuel pump push rod and accessible without removing the intake manifold? I hope the engine rebuilders set the bypass valve and the lifter line pressure properly. Ralph

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The hydraulic lifter by-pass valve is under the large hex-head cap next to the fuel pump push rod bushing. You must remove intake manifold to gain accesss.

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OR REMOVE THE FUEL PUMP AND CLIMB UP IN..STRADLE ENGINE..THE CROSS MEMBER MAKE GREAT FOOTHOLD TO STAND ON. CAP IS REMOVED AND INSIDE IS A LITTLE BRASS "PLUG" THING THAT IS AN ORFICE TO LIMIT PRESSURE TO LIFTER GALLEYS....IN THE FRONT IS A BALL AND SPRING THAT DETERMINES PRESSURE...AND CANNOT BE SEEN WITHOUT MANIFOLD REMOVAL. THE

BALL IN FRONT ACTS LIKE THE SOAKER HOSE IN YOUR GARDEN REMOVE THE END CAP NO PRESSURE.....TAKE IT OUT OR LESSEN THE TENSION...PRESSURE RUNS OUT THE END AND ONTO TIMING GEAR....HIGHER TENSION AND LIFTERS STAY PUMPED AND LESS FOR THE T GEARS...

LOOK FOR A FORD SERVICE BOOK OR V-12 GUIDE..OR MAYBE PHIL WILL SCAN A PIC. THERE IS A GREAT ILLUSTRATION IN THE LITERATURE OF THE OIL PATH FROM THE PUMP TO GALLEYS AND FILTER...HELPS TROUBLE SHOOT..

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Thanks guys, I'm not sure how soon I can do more checking. One thing for sure is to make sure the small exit hole in the center pipe of the filter is kept clean. If the filter became plugged, theoretically, would a bypass take place and the oil pressure drop because of the bypass?

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ok to sum this up i have a 36 or37 motor because i have a place to hook the filter drain to the pan. the lifters are lubed internally. the filter is just a bypass flow. is this right? thanks for any help lyle

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You may have a 36/37 pan on a later L/Z. motor. What year is your car? If you have only 2 oil holes at back on top of bell housing its likely to be 36/37, 38 onward motors have 3 oil holes out back, except very early 38 motors, we wont go there, information overload. 36/37 motors dont have hydraulic lifters, they have solid lifters and dont have the same oil gallery system the hydraulic lifter blocks have. The oil filters are Bi-pass on all L/Z motors even when drained into the pan. The oil passing thru. the filter is bi-passing the motor, thus its called a Bi-pass filter not a bi-pass for the hauldraulic lifters or anything. The filter can be by-passed if it becomes blocked thru. lack of changing, this is done automaticlly under the inlet manifold by the metering valve which senses the lack of oil flow over it so opens up and delivers unfiltered oil from the main gallery direct to the hydraulic lifters.

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my car is 37 and has only two holes in the bell housing so most likley is a 37. it runs realy well but not real quiet like the old v8 flatheads run. it has some ticking. is there anyway to find out if it has hyd lifters without pulling it apart. thanks lyle

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As your car is a 37 with only two holes on bellhousing its more likely to be a 37 motor with solid lifters. Hydraulic lifters Can Not be fitted to 37 motors, they do not have the oil galleries to lubricate the Hydraulic Lifters. Solid lifters do sound clickey as there are 50% more than in a sidevalve V8,thats why hydraulic lifters were fitted to 38 onward L/Z motors to get rid of the tappett noise. If you remove the fuel pump and look down the hole in manifold you can see if theres a metering valve 1 inch. plug, there shouldnt be, that means solid lifters.

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Lyle, by some chance your engine might be equipped with adjustable tappets? The Johnson style adjusable tappets used in the Flathead Fords may have been installed in your engine years ago if it was rebuilt? You should be able to tell by removing the fuel pump stanchion and take a look at one of the valve/spring assemblies near by. Look for a hex head cap screw between the bottom of the valve stem below the spring and on top of the lifter. This adjusting screw screws into the top of the lifter.

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My problems continue. I have a new oil filter and 15/40 synthetic oil and a clean filter canister. The oil pressure is high when cold and drops after warming up, but can be raised again by higher rpms. But after a few more miles the pressure will not come up again and the lifters start tapping away. I assume the next step is to check the rear bypass next to the fuel pump push rod. I thought it would be in good shape as the engine rebuilder seemed to know what he was doing and I had given him the engine manual for reference.

Ralph

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