late flathead oiling?

[derek costello]

I have a 1952 Canadian Mercury engine it came with the metal can oil filter mounted on the head, this has small 1/4" lines.
I wanted to change it to a modern spin-on oil filter with 3/8" lines but all the info I have been reading on this forum suggests I have to do machining on the block
which I don't want to do as the engine has already been rebuilt.
I recently read that very late ? Canadian blocks are already drilled and tapped
for the horizontal plug that goes between the oil pump delivery outlet and the return line that goes back into the block. So I tried a 7/16" fine thread set screw
screwed into the side of this fitting it was very tight so I tried sanding the threads on the set screw down and it fit all the way in to the area between the two vertical outlets. I have installed the filter fittings and am now ready to put
on a new filter, I have enclosed a picture what do you think ?

[40cpe]

What is the internal diameter of those fittings?

[Ol' Ron]

there also should be a grub screw between the two. this forces the oil through the filter. If you don't use a filter, you must remove the screw or you'll prevent the oil from getting to the bearings. On another The canadian system sues a special fitting on the output of the pump.. THere might be a photo of this some where on the barn.

[JSeery]

Need to be sure you understand how this works and you have it correctly, a mistake will lead to a new rebuild! It is my understanding that this OEM arrangement did not have the horizonal passageway threaded, they used a special vertical fitting and an external valve arrangement. The ball and spring is a relief valve if there is an obstruction in the filter itself. The modern modification (often referred to as a 95% filtration) involves tapping the horizonal passage and installing a grub to block oil flow. This setup does not have a by-pass valve except for one within the filter itself.

Sounds like that is where you installed the 7/16 grub, just interesting how the threads got there in the first place and why you would need to sand the threads down.

[derek costello]

The existing horizontal hole is factory drilled and tapped for 1/4" pipe thread, but just inside that it narrows down to 7/16 20 (bolt size) thread. I could not get a 1/2" 20 set screw in there but 7/16" seems to fit OK ??

[derek costello]

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I had to sand the threads down on the 7/16" grub/set screw because it was so tight to thread in I was afraid to force it. By sanding a bit it went in tight but I got the end of it just past the pump output hole which is where I think it should be.

[JSeery]

Yes, I understood that part, I was just curious how the 7/16 threads ended up in the passageway to begin with. I didn't think it was a factory procedure to tap in, I don't see why they would have.

And by the way, welcome to the Barn!

[derek costello]

My question is now, if I have a pressure relief valve on my oil pump why would I need one on/in the filter?

Also a modern filter...spin-on doesn't have valves in it, that I know of ??

[derek costello]

the book "Flathead Fever". said that "Canadian blocks were drilled and tapped this way at the factory, any body confirm that ?

[JSeery]

Yes, modern filter do have by-pass valves in them, at least some do. Without a by-pass how is oil going to reach the engine oil passages if the filter becomes clogged? The by-pas in the engine is to regulate oil pressure, but the oil has to get to it first. If you connect the fitting on the spin on bracket backwards you can also end up with problems in short order. Just keep in mind that this arrangement much be setup correctly and maintained or you run the risk of not supplying oil to the engine main oil galley. There will be some oil to the rear main as that oil does not go through the filter (that is where the 95% name comes from.

[JSeery]

Originally Posted by derek costello

the book "Flathead Fever". said that "Canadian blocks were drilled and tapped this way at the factory, any body confirm that ?

Maybe so, but sure wouldn't see why. This is a copy (somewhat difficult to read) of the information I have. Guess it really doesn't matter how the threads got there, just interesting.

[40cpe]

If you successfully blocked the flow through the horizontal passage, you have to provide full flow through the barbed fittings you have installed. The horizontal passage was 7/16", Are those barbed fittings screwed into 1/4" pipe threads? How large is the internal ID of those fittings?

[derek costello]

I have tried to keep all tubes and fittings 3/8" ID and filter hoses 1/2"ID.

[Ronnie]

Originally Posted by derek costello

My question is now, if I have a pressure relief valve on my oil pump why would I need one on/in the filter?

Also a modern filter...spin-on doesn't have valves in it, that I know of ??

There are many oem filters that have a bypass relief filter in them. It is there to stop oil starvation in cold weather starts and if filter becomes plugged.


R

[RalphG]

I'll have to take a look at the seized 53 Mercury engine I have sitting on a stand in the shed and see what it has. I know it had the original filter arrangement. Same as the 52 that I drive. For simplicity's sake I will leave mine all original as it seems to be working fine.

[Ol' Ron]

I use only Wicks filters

[derek costello]

I have continued my installation of the revised oiling system and am posting a picture of how I had to relocate the oil pressure gage sender as their was no room for it with the new lines
at the rear block holes.

[kiwitony]

I think I read on here some years back, that there were some cheap Chinese copy filters about without the bypass valve that caused many engine failures. Not trying to hijack your tread. cheers Tony.

[derek costello]

Thanks Tony, I will make sure the filter type I use has a pressure relief bypass..............

[JSeery]

Originally Posted by derek costello

I have continued my installation of the revised oiling system and am posting a picture of how I had to relocate the oil pressure gage sender as their was no room for it with the new lines
at the rear block holes.

Looks good!