Engine oil cooler feed line insert.

[Lynn Eades]

Hi Tony, Alistair, Thanks guys. When I said "full flow" I was talking about the std. system (95%) (where oil goes directly to the rear main and has the alternative option of going through the cooler (pressure is equal to both at any one time)
A bypass filter typically receives about 10% by volumne of total circulated oil.
I guess I just haven't established the reason(s) why Ford made that adapter with clearance around it, rather than having a completely sealed system of one definative flow path...... Or am I not understanding something?
I suspect only a percentage of the oil flow is supposed to (and does) go via the cooler because the hole in the adapter would be a restriction (little over 1/4") and much smaller than the main galleries in the block.
The Aussies plugged the cross drilling in the Aussie carriers (in the parts book) but used std fittings without the same sort of flow restriction.(seems better to me) This would be a real trap to someone changing the engine use, and would have caused a few "run" rear mains.

[ajmac]

The adapter directs all of the pump discharge oil that reaches that point out of the block, the rear main feed issue is just a Flathead design quirk that they couldn't get around and so had to live with. The problem is that the rear main feed is drilled from a gallery closer to the pump discharge than the tapping on the top of the Bell housing.
Any restriction in flow up to the block mounted PRV doesn't matter at all as the original pump on all British Flatheads has no pressure relief, so the oil velocity will be higher through the restrictions but the volume flow will be maintained. Pressure will increase before the restriction to the limit of the pump gear clearance or mechanical failure.
I'll try and measure the dia of the gallery from the pump up to the top of the Bell Housing, it isn't much larger than the fitting extension tube, I think the clearance is just that, rather than a design intent associated with partial oil bleed off.

The waisting of the tube allows the horizontal Bell housing port to see post cooler / full flow filter oil pressure if you wanted to pop on a sensor. The cross sectional area is just less than half that of the fitting extension tube on my version. I will test all this out with some additional sensors when I finally get the 24 stud in my Loyd.

[Tony Wheeler]

Originally Posted by Lynn Eades

When I said "full flow" I was talking about the std. system (95%)

Sorry Lynn, I thought you meant "true" full flow.

Originally Posted by Lynn Eades

I guess I just haven't established the reason(s) why Ford made that adapter with clearance around it, rather than having a completely sealed system of one definative flow path...... Or am I not understanding something?

Yes Lynn, it appears you and Malcolm have misunderstood the screw-in adapter. It's not designed to provide bypass flow to the motor. That function is performed by the external bypass valve. As Malcolm says: "The tubing extension on it is 3/8" OD, which is a fairly snug fit in the vertical passage coming up from the pump." In other words, just enough clearance to avoid binding when screwing in and out. Any leakage past the sides would be miniscule, as the pressure differential between the two passages is perhaps 5 psi at most. I believe the bypass valve is set at 10 psi (?) to ensure adequate flow to the motor when cold. Of course, it relies on the cooler being full, as you guys mention.

CTL7142 oil cooler adapater.jpg

Originally Posted by Lynn Eades

the hole in the adapter would be a restriction (little over 1/4") and much smaller than the main galleries in the block.
The Aussies plugged the cross drilling in the Aussie carriers (in the parts book) but used std fittings without the same sort of flow restriction.

This is one of those counter-intuitive situations where we need to resort to physics. It can be calculated that an adapter of 2" length and 1/4" ID will restrict flow by the same amount as 10" length of 3/8" oil gallery. In other words, it's insignificant. Which begs the question: Why do hot-rod books propose the grub screw method, when the screw-in adapter is so much simpler?

Originally Posted by Lynn Eades

This would be a real trap to someone changing the engine use, and would have caused a few "run" rear mains.

Actually it's the forward bearings which would fail, as the rear main is supplied direct from the pump. Not that it particularly matters! As you say Lynn I'm sure this trap led to catastrophic failures upon engine swap. Again, it begs the question: Why would Aussies booby trap their carrier motors in this way?

[Lynn Eades]

All very interesting, and nice picture Tony. This little trap is an area that has needed covering. I thank you guys for your collective input and I am a lot happier going forward with my carrier, now that I have had the benefit of your input. Thank you again Tony and Alistair.
I must say that Andrew R. said the Aussie cross bore plug has a hole in it. I have not seen the critter in real life ( carrier part no. 656-6) There is no picture (that I am aware of) and no ref. to a hole. Maybe one of the other LP2 guys can chime in to clarify the details of this (1/4 BSP) plug / restrictor.

Tony, the last line, of your last post, is that a pit trap for catching Kiwis?

[Tony Wheeler]

Originally Posted by Lynn Eades

Andrew R. said the Aussie cross bore plug has a hole in it.

Hmmm, very interesting....that would make it a partial flow oil cooler. This may be cold climate mod (to ensure oil gets hot) or to compensate for late production motor (original motor ran 40 psi, late production ran 70 psi).