Flathead oil gallery

[m606paz]

Hi Boys!
I have doubts about the lubrication galleries in my flathead, since I am not going to disassemble this engine now.
The motor has a hole with horizontal outlet pressure, with outlet to the left. Then there is a hole in the middle, with vertical outlet, to install the oil pressure sending unit. Those last two communicate.
There is a third hole that we normally see covered with a plug, but in my case, it was the oil filter return.
There is no communication between outlet and return holes...
Does this last return hole need oil pressure?
My engine no have valve relief.... is a 1944 model.
Thanks in advance!

FullFlow.jpg

Maintenance manual C0 - copia.jpg

[Jacques Reed]

Hi Mariano,

Your diagram shows a factory full flow oil filter set up. I have never seen that relief valve setup other than in diagrams. Every WW2 Flathead V8 that I have seen in Australia has the bypass type filter. Hot rodders have for years modified the system on Flatheads to incorporate a full flow oil filter utilizing those three inlet/outlets.

Most early factory Ford flathead oil filter setups are the bypass type. This type does not filter all the oil but only a small proportion of it which is returned to the sump (i.e. oil pan) from the filter outlet.

The inlet orifice size on the bypass type oil filter container is critical to maintaining oil pressure within the system. Under no circumstances should it be enlarged in the belief it will filter a larger volume of oil. to do so would cause a substantial drop in oil pressure in the system.

Would be curious to know if anyone has one of those relief valves.

Cheers,

[m606paz]

Jacques , thanks for your reply!
How about grub screw,Does it have to be screwed into the hole or not?
Does the third hole need pressure oil?
Regards!

[rob love]

The grub screw will usually have a small hole running through it to allow some oil in case the filter gets plugged or the lines get kinked. There is no pressure relief built in to those old filters, and dirty oil is still much better than no oil. Besides, even that system is not a full flow oil filter since oil goes to the rear main before it goes up to those fittings.

Without the grub screw, you have all the oil (less what already went to the rear main bearing and into the back part of the crank) going across to the main gallery. The CMPs I have worked on take a small portion of that oil into the oil filter and dump it back into the pan.



I cannot say what was in use in late war vehicles, because the bulk of Fords in Canada are 43 and earlier. I don't see many 44 or 45 dated Ford CMPs around here. I think they were needed overseas. However, the system shown in the second photo you show I believe would have had a fitting that reached down into the hole and blocks transfer across to the main. If you blow the photo up much larger you can make it out. The external bypass looks like that used in the carriers. Again, I have not run into that in the domestic CMPs, but then again I have not seen it all.

[Jordan Baker]

This previous thread may answer your questions.

http://www.mapleleafup.net/forums/sh...ad.php?t=20460

[Jacques Reed]

Thanks Jordan, Rob, and Lynn,

That makes it all very clear. I have never seen a bypass valve on the oil filter lines a CMP truck here in Australia even though it is shown in the Truck Maintenance Manual. Just a carrier requirement perhaps with a semi full-flow system? My mistake calling it a relieve valve.

The Parts List for an F-15A makes no reference to that bypass valve either. It only shows the bypass filter setup and oil filter lines from the block and to the sump.

Very good information which could prevent a lot of damage and heartbreak.

Cheers,

[Lynn Eades]

So Mariano, tell me what you intend to do with regards to an oil filter in your truck?
I assume you intend to run a bypass filter?
If this is your plan, then just tap into anyone of those 3 holes. All you are doing there is receiving oil under pressure.
I doubt that there is a plug (or restrictor) inside the horizontal gallery (where you picture shows the grub screw) If so, TAKE IT OUT.
You bypass filter will have (or should have) a restrictor in it somewhere(see Jacques post)
You need to return the oil from the filter back into the sump (Robs post) or through an oil filler tube with an oil return fitting in it.(Ford made them)

There is absolutely nothing wrong with a bypass filter. They normally have a finer media and remove more nasties. About once every 10 or 15 laps of the oil, it all gets to go through the filter, so over time it is all nicely cleaned.

The war time engines were swapped around a bit between trucks and carriers. This was o.k because there was nothing (no restrictor or plug) in there, in a Canadian or British carrier (the clever fittings did the job of restricting the flow, and sending it via the cooler). The complications came along with the Australian pattern carrier set up (same plumbing, different fittings, which required the restrictor plug) and the hot rod boys fitting full flow filters.
I hope that helps.