Oil leak at fuel pump

Lynn Eades · #1 04-08-12, 00:35

Yes the pcv valve can be unscrewed. It has a piston (valve) and a spring in it. back then , there were all the same. Note the arrow on the body showing flow direction.
The cooler bypass cap is soldered on. underneath is a screw plug that loads the spring against the ball. this is adjustable.

andrew honychurch · #2 04-08-12, 10:45

I am going to check the PCV first thing this morning. I am a bit reluctant to disturb the oil relief valve, but of course I can check whether this is allowing oil back down the filler tube by looking down the filler tube itself when the engine is running. Will report back. thank

andrew honychurch · #3 04-08-12, 20:55

ok, pulled the PCV and cleaned it not really a problem.

However the oil is flowing continually out of the relief valve into the tube directly above the fuel pump. Hence the problem. Broke the seal on the relief valve and checked it , all good. Turned it two extra turns, which stopped the flow but put the engine oil pressure up to 80 lbs!!!! Broke for lunch and a think. Back on it tommorrow. Maybe the oil cooler is plumbed incorrectly and restricting the flow??/

Edit; there are two fleible pipe that then join onto the steel pipes upto the cooler. If I was half asleep when I assembled it I may have crossed these, but I would think I have checked this was correct at the time. More confusing is the T16 manual which shows the relief valve on the side of the crankcase opposite to mine. In other words, it may be that good old British Army have assembled my engine with the relief valve on the return pipe not the outlet pipe.....Not sure what effect this would have until I can sit down and think about it. so to be clear, my valve assembly is on the pipe on the clutch housing/crankcase nearest the outside of the engine, whereas in the book it appears to be on the union nearest the middle of the engine......Would it matter?? Must do surely

horsa · #4 04-08-12, 23:57

Post some photos showing how you have the lines routed Andrew. It'll make it easy for us to understand what you have going on.

andrew honychurch · #5 05-08-12, 09:44

ok, so here goes, fist the photos then the explanation

in the top photo this is the set up as the vehicle came from the British Army, as far as I know. I have not altered it and the soldered seal on the pressure relief valve was stamped with an inspectors mark. It would appear to me, that the British, or a later Ford modification, has directed the oil relief flow to the point above the fuel pump as you can see in the photo. It is this oil flow, that I believe is finding its way into the fuel pump and flowing out of the petrol relief hole.

The set up as seen in the photo from the TM is quite different. It would appear that the relief valve is on the other side of the two pipes to mine. In other words either the pick up pipe has been changed on my engine, about 12 months later than the date of the TM, or it has been muddled by British Army when they made this mod.

So in the TM photo, it would appear that the pipe nearest in the photo is the return to the engine and the outlet pipe to the oil cooler has the oil pressure gauge and the relief valve attached to it. I assume if there is a restriction in this circuit it returns through the brass interconnection back to the return into the crankcase.

On my engine , you will see that my pressure gauge and relief valve are on the other pipe and the relief has been redirected to the oil filler pipe.

It may well be that I have followed the schematic in the TM ( another diagram not illustrated here) and connected the pipes on the flexible section of the oil cooler lines the wrong way around. I can check this today, but it still does not explain why these pipes are completely different from the set up in the TM. Go figure, and if you can work it out, please let me know.

Meanwhile, I plan at some stage to remove both pipes and check which way the oil flows from my engine left or right pipe then I can connect the cooler pipes the right way around for sure.

horsa · #6 05-08-12, 20:33

Attached a shot of my oil cooler lines even though its a different setup. Yours appears to have a second breather on the driver side of the rear engine. I've got that part connected to the top of my differential and don't have another breather on the engine other than the one where the oil enters the engine at the fuel pump where you are having the leak.

From your routing, the by-pass is open and sending the oil to the upper line. It's leaking is probably related to either the engine having too much internal pressure or air is coming in from the second breather and exiting from the higher original factory one and causing issues with the oil trying to flow inward against it.

Not real sure what the purpose of the alternate oil route would be since I've never seen that on another vehicle so far. If it was providing essential oil, they wouldn't have made it only functional when the valve was in by-pass mode.

Can you open the lines up front and confirm that oil will flow from the oil cooler lines? Or do you have the oil cooler shut off by manual lever if still installed? I don't have the levers on mine so can't turn them off if I wanted to.

rob love · #7 05-08-12, 21:26

I believe that the reason for the bypass was to protect the engine in the event of a plugged oil filter or crimped cooler line. If that situation occurred then it would simply bypass the cooler/oil system and still lubricate the engine. Your system would not do that. Rather the oil would just dump through the filler/breather tube back into the pan, doing nothing for the bearings.

Is there any chance your filter or cooler lines are partially blocked? Can you get a mechanical oil gauge on the return side, just before the engine, and confirm what the oil pressure is coming back into the engine?

80 psi at the relief would indicate to me that there is a flow problem either coming back to the engine. The flatheads generally would not generate that much pressure.

andrew honychurch · #8 05-08-12, 23:10

Quote:

Originally Posted by horsa

Attached a shot of my oil cooler lines even though its a different setup. Yours appears to have a second breather on the driver side of the rear engine. I've got that part connected to the top of my differential and don't have another breather on the engine other than the one where the oil enters the engine at the fuel pump where you are having the leak.

From your routing, the by-pass is open and sending the oil to the upper line. It's leaking is probably related to either the engine having too much internal pressure or air is coming in from the second breather and exiting from the higher original factory one and causing issues with the oil trying to flow inward against it.

Not real sure what the purpose of the alternate oil route would be since I've never seen that on another vehicle so far. If it was providing essential oil, they wouldn't have made it only functional when the valve was in by-pass mode.

Can you open the lines up front and confirm that oil will flow from the oil cooler lines? Or do you have the oil cooler shut off by manual lever if still installed? I don't have the levers on mine so can't turn them off if I wanted to.

Which extra breather are you referring to David? I have the breather in the usual place above the fuel pump and thats it. I do have two pipe elbows on the crankcase as you do.

I have not had any opportunity to look at it today, as we have been watching Olympics...family things. But will check this all out tomorrow.

One thing to bear in mind is that this oil was not pouring out on the 20 mile road run. Maybe the oil cooler has fouled up and is causing a restriction. Although I have blown air through and it pushes oil back out pretty easily.

I really appreciate ALL your help and ideas. I will report back asap when I have got to look at it in more detail.

ps David, no taps on the later oil coolers to shut off supply.