How big is the oil gallery?

[pooch]

I have a 46 239 Canadian block stripped..

I am considering making it external full flow filter equipped.

I see a cast round boss just inward from the oil pressure fitting.

I guess this is where one drills and taps for an external filter ?

What diameter is the oil hole that goes horizontally accross underneath ?

Whta size tap iis preferred for this external fitment?

[JSeery]

Are you talking full-flow or what's referred to as the 95% flow?

[19Fordy]

There are a bunch of threads on how this is done both on this site and HAMB.
Do a little SEARCH before you start drilling.

[JSeery]

Looks like your referring to the 95% setup.

[GOSFAST]

We do this mod all the time on almost every Flathead we do.

We do most of the drilling on the Bridgeport. The photo on the right below is where it's mounted on the mill.

Thanks, Gary in N.Y.

P.S. Here's a couple shots, I placed the same ones up here a while back. This particular build belongs to a friend of mine who's ride is in my signature!

[40cpe]

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Your question about the bore size: I forget the exact decimal, but it is about 7/16". Most use a pilot bit for 3/8" NPT and tap to 3/8" NPT. The existing horizontal hole will have to be drilled/tapped to 3/8" npt also to be able to tap the bore for the plug, assuming you are using the "95%" method.

Edit:after seeing the 7/16" plug in the galley, maybe it is not 7/16" but more like 3/8". I did my engine but have since forgotten the details.

[Ronnieroadster]

The actual internal diameter of the Ford cross passage is .421 any time I do the oil filter conversion I open up every fitting so it match's that diameter. Doing this eliminates any added restriction to how Ford designed the oil flow. Also something else to consider if the filter is placed at a great distance from the block A high volume oil pump would be a smart addtion.
Ron

[pooch]

Thanks all for info.

GOSFAST, I see your vertical drill into gallery, is this so when the drill breaks thru, it is straight on and not as likely to break the drill, as if it would if drilled obliquely, or is it so the right angle fittings you use are easier to fit ?

The cast boss is on an angle, I was assuming the drill hole would be square on to that .

JSeery's pic is on a slight angle.

[JSeery]

Mine is drilled at the same angle as the pad cast into the block (on some block and not on others). This location was used in military applications for filters or oil coolers. In the photos GOSFAST posted he is drilling the passages parallel to each other which allows the fittings being used to fit better. Also, he is doing the drilling on a mill so both passages can be drilled and taped without major changes to the setup. I have no idea if there is any difference in oil flow, but wouldn't think so as there are several 90 deg passages inside the block.

[GOSFAST]

Originally Posted by pooch

Thanks all for info.

GOSFAST, I see your vertical drill into gallery, is this so when the drill breaks thru, it is straight on and not as likely to break the drill, as if it would if drilled obliquely, or is it so the right angle fittings you use are easier to fit ?

The cast boss is on an angle, I was assuming the drill hole would be square on to that .

JSeery's pic is on a slight angle.

Hi "pooch", it's much easier on the Bridgeport to machine both holes "vertically", we don't need to worry about "tilting" the head.

We machine a "flat" register (for the inner fitting) for ease of machining and for clearance when using a socket to install the fitting, and having both vertically makes lining up the fittings/hoses much easier! Keeps it all very neat as shown in the photos above!

Thanks, Gary in N.Y.

P.S. The inner oil passage-way measures .420" (I believe mentioned above) and we tap this 1/2-13 to accommodate the "grub" screw. It gets tapped to a "fixed" depth only, to avoid the screw from being able to go all the through. We dyno these w/o the screw in place (no filter) but it's important to install before the final installation. Won't work well with the filter in play and no screw.

[pooch]

Great info, I feel more confident now to attack the block with a drill.

Why is this called a 95% flow?

Where does the other 5% go ?

[Ol' Ron]

I use a 7/16 14 tap. This tap will pass through the 14 NPT plug on the side with no problem. The tap does not make a very deep thread, but I've been doing this for the past 40 years with no problems. EXCEPT once I found the cross passage to be much larger, Gota check everything.

[40cpe]

Originally Posted by pooch

Why is this called a 95% flow?

Where does the other 5% go ?

It is called "95%" because all of the oil isn't filtered at every pass. The rear main gets it's oil before the oil leaves the block on the way to the new filter.

[JSeery]

See if this helps.