Oil leak at fuel pump

[Richard Farrant]

Hi Andrew,

From what you were telling me when we met yesterday, I have worked out a possible explanation. The oil will not flow to the cooler if it is cold, it will lift the relief valve in the remote valve block and return to sump, via dipstick tube. This might explain why when you drove the carrier, it did not show signs of leaking through the lift pump hole under the diaphragm, as it was hot oil and not flowing back via the tube. If I could find my T16 book I might be more sure but looking at a Windsor book at present.

[andrew honychurch]

Originally Posted by Richard Farrant

Hi Andrew,

From what you were telling me when we met yesterday, I have worked out a possible explanation. The oil will not flow to the cooler if it is cold, it will lift the relief valve in the remote valve block and return to sump, via dipstick tube. This might explain why when you drove the carrier, it did not show signs of leaking through the lift pump hole under the diaphragm, as it was hot oil and not flowing back via the tube. If I could find my T16 book I might be more sure but looking at a Windsor book at present.

thanks Richard. It has been very hot since the leak started so I think either the thermostat in the cooler has stuck, and reduced the flow causing the relief valve to operate, or as mentioned in my last post maybe I followed the schematic and hooked up the cooler pipe correct for the TM diagram, but the wrong way for my system which as you can see it exactly the oppostite way around.

Very odd!! On top of the Dingo playing up, I am not having a good few days!

[Richard Farrant]

Originally Posted by andrew honychurch

thanks Richard. It has been very hot since the leak started so I think either the thermostat in the cooler has stuck, and reduced the flow causing the relief valve to operate, or as mentioned in my last post maybe I followed the schematic and hooked up the cooler pipe correct for the TM diagram, but the wrong way for my system which as you can see it exactly the oppostite way around.

Very odd!! On top of the Dingo playing up, I am not having a good few days!

Andrew,
Are you positive there is a thermostat in the cooler? Not one in a Windsor, although that means nothing. The way it works is when oil is cold, it has higher viscosity and lifts the relief valve in the t-piece, then as the oil warms and thins, goes straight through the cooler.

[Michael R.]

Is there a cross section view of the relief valve in the T-16 Manual ?

Attached is the cross section view found in UC-F1, which shows the input flow direction and return. The second image is a standard set-up with an electronic oil pressure sending unit attached in the normal fashion for the Ford Canada UC Mk. I* and Mk. II*.

Note that for correct installation in the Canadian Carrier, the high pressure would be on the left side when facing forward, which is as you (Andrew) have it positioned on your block. Your oil cooler plumbing appears to have a direct connection to the return side of the engine block from your cooler.

[ajmac]

Great photos chaps, always nice to see detail.
Here is my take on the PRV: Originally Flathead V8s only had one PRV, that in the valley of the block. Oil passed up from the pump then turned right just under the tappings in the top of the bell housing and went into the valley on it's way to oil the bearings etc.. (not the rear main though), pressure was controlled by the PRV at the front on the valley. When you break into the oil system before the PRV, (which you do when you utilise the bell housing tappings) that oil pressure is unregulated. When they fitted the oil cooler, the additional PRV was added to protect the cooler from bursting due to over pressure in the event of a cooler / pipe blockage and possibly as a form of cooler bypass when the oil was cold and more viscous (not on Yours Andrew, that is just for safety) However on later wartime Flatheads ford came up with a proper PRV system as part of the pump, thus oil at the bell housing is regulated.
What pump did you fit Andrew? If you have the later one you can disable the cooler PRV as you are already protected. If not then I bet your main PRV at the front on the valley is set higher than the PRV in the cooler line causing the cooler PRV to be permanently off it's seat, it shouldn't be relieving in normal operating conditions. To be honest, the pressure transmitter should be mounted on the return from the cooler to give the true engine oil pressure, I would change yours asap if I were you. As it stands at the moment your engine oil pressure could be on it's knees and you wouldn't know a thing about it!
If your cooler never gets hot, remove the aforementioned pressure transmitter and use a thin screwdriver to check that your oil gallery blanking plug is installed. When you poke through the tapping you should bottom out after 1.5" or so, if it goes in much more then oil can travel up from the pump and right into the engine, it will have no interest in investigating the cooler :-)
Ps. Any more photos your your beautiful engine?

[horsa]

Hey Andrew,

Copied your image back in with an arrow pointing at the thing I was thinking might be a second breather since it looks really similar to the one on my rear deck going to the differential.

My coolers should be the 1st pattern but I have 2nd pattern as they were all I could source when I did the restoration. They don't have cut-off levers but I didn't realize that all of the later carriers omitted that feature.

Originally the T-16 had issues with oil coolers rupturing so the regulated pressure in the block being discussed might have been the fix. And also why they didn't need the cut-off lever anymore. My oil pressure has always seemed low to me being 15-25psi max even at full power for liftoff. Had thought it had something to do with my sending unit so if they run at lower psi by design, that makes me feel better. My jeep always has higher pressure right from the start and that's what I've been used to.

Your surge of high pressure could have been from a blockage in the line due to the by-pass being stuck. It broke free and is now stuck open so oil is going to your alternate route in the breather. I opened mine up before posting this and it contains a large metal ball at the bottom with a 1.5" long spring on top. A slotted plug down the well is screwed in over the spring and ball and then there is the large visible hex head on top of everything which is visible in my engine photo earlier in the thread. Don't have a diagram but it's fairly straight forward how the by-pass works. Pressure against the ball compresses the spring and allows the oil to take the other path.

In terms of direction, I think it flows from the line closest to where you and I have our oil senders attached. This is the revised location. Originally it was located on top of the housing beside the by-pass which would be reading pressure as it came back from the oil cooler as opposed to engine side oil pressure which is more important.