Losing Oil Pressure

[TomT/Williamsburg]

Thanks, Phil - I like the zipper idea - LOL! No - another pump will be installed this time around ...

[41ford1]

Originally Posted by trainguy

These problems will drive a person to drink.Do you have another oil pump?If so why not try it.Over filling is just a bandade,not to be a wise ass but these flatheads are not rocket science.Your problem has a simple solution all you have to do is find it.You have eliminated the bypass valve,the pick-up,baffle,oil level.Whats left?The oil pump.why the pressure drops on hard turns and braking,who knows,but pressure dropping when warm is symptomatic of excessive clearance in the pump,bearings or both.The fact that you build oil pressure when cold pretty well eliminates the by pass valve.Normally bearing wear doesnt happen suddenly same with a oil pump.With the many times you have removed and inatalled you pan maybe you should consider a zipper or velcro. Phil

I know first hand. Velcro (registerd TM) won't work in this application . Maybe you aught to install the pan with 1/4 turn fasteners.
Your best shot is to change the pump. I figured you had it nailed down with the baffle find. Now I'm baffled! If the pump change doesn't cure the problem the next thing is the pump drive system. Thats the 3 gears at the rear of the cam. I can visualize an issue with quick stops but not turns.

[cmbrucew]

Could something be blocking the return passages?
Next time pan is off, weld/solder elbows 1" and 5" up on the sump. Clear tubing in between. You can see the oil level available for the pump.
Afterward solder/weld patches over the holes.
Bruce

[BILL WZOREK]

Tom:
I know we are all shooting in the dark here, but what about the oil line, could it be getting pinched upon hard stops or sudden turns.
How about running a 2nd gauge maybe a electric one & watch both to see if you get the same reading on both.

Let us know what you do & what you find.

[chuck stevens]

Tom,
I have the same exact problem on the 40 I just finshed. Good oil pressure when cold- 55+, running down the road it is fine but, zero at an idle when warm. No bad noises, I have pulled the pan, and checked the pump out, looks fine. At the moonshine fest I talked to a guy who suggested under sized cam journals, my cam is a new Schneider, running on new bearings. I have two oil pressure gauges, both read the same. The engine is a 8BA with 2000 miles on a fresh rebuild. Tried extra oil, blocking the oil filter, running 20-50 Rotella, and still nothing at idle. I will pick up this challenge after my winter hiatus. Good thing I have other rides, Chuck S.

[George/Maine]

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It almost seems like to little pressure at idle and loosing what the pump is putting out.
My guess your crankshaft is worn loose bearing, rods worn and losing pressure.
Back in the day would drive with the light on and had no problems.
I don't even have and oil pressure gauge on my 8ba or a filter

[VeryTangled]

Hi Tom, We're really pulling for you on this one.

To lighten things up (but hopefully not get this thread off topic)...

I'll never forget the smile on your face when you drove up in this:

[trainguy]

Originally Posted by VeryTangled

Hi Tom, We're really pulling for you on this one.

To lighten things up (but hopefully not get this thread off topic)...

I'll never forget the smile on your face when you drove up in this:

Hey,I've seen that car somewhere!Phil

[chuck stevens]

That is one sweet running flathead, I'm still smiling! Hope to see you guys in a couple of weeks, Chuck S.

Originally Posted by VeryTangled

Hi Tom, We're really pulling for you on this one.

To lighten things up (but hopefully not get this thread off topic)...

I'll never forget the smile on your face when you drove up in this:

[TomT/Williamsburg]

Man - you guys really to know how to kick a guy when he's down, huh? Thanks Jeff! LOL - yep I would have driven that car home in a heartbeat! What a fun little ride .... I might have stolen it but there were too many witnesses!!!! LOL ... a great little ride, Phil

OK - so the saga continues. We "unzipped" the pan to remove the oil pump and install another when we noticed the pickup canister (which is connected directly to this oil pump) had no gasket where bolted to the pump. Taking it apart it appeared this is where we were sucking air and the mount surfaces were not flat. So, we flattened out the pump and pickup canister mount surfaces, I found a gasket in my box of gasket goodies, we opened up the pump and inspected everything, packed it, and reinstalled it figuring we got the problem licked. But no - she did the same thing again ....

Now get this - when the oil pressure drops to zero we bled the gauge line, raised the rear of the car to an upgodly height, depressed the clutch figuring the crank main bearing end play may be loose, and nothing changed it and it stayed at zero for over 20 seconds. So we got the engine to drop to zero pressure again and raised the idle speed to 2000 rpm during the entire time it was at zero oil pressure - almost 30 seconds - and the engine ran like a swiss watch - no knocks, noises or anything bad !!!

I spoke with Chuck, 41ford1 and we'll check the gear that's in the block tomorrow as we install an 8BA pump that I have. If it has movement it could be coming away from the pump gear giving us the zero oil pressure reading. John and I do not think changing oil pumps will change anything but we have to try it.

I will keep you posted ....

[Cecil/WV]

With the pan off, you can put a pressurized canister on the back of the block and look for excess leakage from the bearings.

[john mullen]

just to add in hear some info. engine running at operating temp at idle carry's 18-20 lbs pressure, At 55 mph and 2000 rpm the oil pressure is around 55- 60 psi. it only looses pressure when you stop for a light and or turning a corner at slow speed. after 15 to 30 seconds the oil pressure returns to 18-20 psi and as long as you do not move the car it stays there. as Tom stated we jacked the car up as high as possible from the rear and nothing happened. he backed it up the hill at my garage and let it cost down and applied the break with moderate to light pressure and it did not fall below the 18-20 pressure. backed it back up the hill and let it cost down again and applied the brake with panic like force and boom, oil pressure 0 for 15 to 30 seconds.
the pump we took out today was inspected with a fine tooth comb and found it impeccably perfect in every way. the bushings were tight the gears were meshed nice and snug. the clearance between the gears and the bottom cover is well within specs.
Anyway I just wanted to add my 2 cents hear as I do not believe it has any thing to do with the pump. Just my 2 cents we will replace the pump tomorrow and see what happens. I am baffled for sure as well as TomT

[TomT/Williamsburg]

Hey, Bill - we ran another gauge - #3 - and a new line to that gauge. Same result with all 3 gauges and supply lines ...

[BILL WZOREK]

Boy ~~ I wish you gave us something Hard to figure out >>>

[Cecil/WV]

What if you added more oil, temporarily, to see if that would make a difference??

[chuck stevens]

Tom, If you are going to pull the pan again, I agree with Cecil- put a pre-luber on the main oil gallery, with the pan off, you'll see where the oil is going. Some other ideas... the pressed in oil tube that runs down the valley may be leaking, maybe a small casting flaw in the pump itself. At any rate putting oil to it with the pan off is the way to go. I'm very interested as I have a similar problem, Chuck S.

PS I have a homemade pre-luber you're welcome to borrow.

[john mullen]

Cecil/WV.. We have had as much as 6 quarts in the oil pan with no help. The pressure lube idea is great however the thing is it doesn't lose the pressure until you break hard or turn. Otherwise the oil pressure is perfect. I have been building Flatheads for a long time and never have I come across this bizarre problem. keep those ideas coming guy's we need help for sure....

[Willit Stop]

I had the same problem/symptoms with my '36 21 stud,as I stated before.Our pumps may be completely different...I don't know.Anyway,my pump has a teapot looking spout for the pick up and the other end is soldered to a tin cup that surrounds the gears.Inside the cup is a steel plate that is between the gears and tin cup bottom.With the plate in the cup,there was a gap of about 1/8 inch between the top of the cup and pump.In other words,no seal.My problem could've been solved by moving the plate to the outside bottom of the cup but the gears would then ride on the tin cup.The solution was to install a big fat o-ring where the cup meets the pump.If you have the same type pump with a space between the two you will loose pressure at times.In this situation,your pump will produce pressure but will draw air if the flow of oil through the tube can't keep up with the pump. Hoping this helps John.

[TomT/Williamsburg]

Well, we resolved it. I changed the oil pan to one with no baffle for an 8AB pump which had been in another engine and was known good. I am running 5 qts of oil, 20-50, 80 lb relief valve in the engine along with the relief valve that is in the oil pump. I am now running 20-30 lbs of oil pressure at idle, 40-45 around town, 50-55 lbs at speeds of 70-75. No loss of oil pressure on a hard stop or hard l/r turn. In checking crank clearances and anything else we could reach with the pan off there was one rod cap that was on backwards - I never knew one side was different from the other - and had been this way since I put the engine in the car before Bonneville. The bearing had no signs of abnormal wear so that was good.

We have not yet done an autopsy on the pump we removed - all I can think of is that the accident last year somehow damaged the pump that only manifested itself on hard turns and short stops. I was standing still when I was rear ended, my car was picked up, the other car going underneath me, the rear end was shoved forward messing up the tranny and the hit actually broke my motor mounts pushing me forward 20 feet. So it is entirely possible something happened to the pump at that time.

I will keep you posted on what we find out but that's the story for now. It was a tuff haul but John was really great helping me get this thing resolved. Thank you, John!

Thanks for all the help and support guys - it's good to have friends like y'all -

Now, on to my 40 Ford starting issues but I'm taking the rest of the day off!!!!

[Mart]

Thank God you have it fixed! now I can sleep nights!

Mart.