Jim,
I found in either one of my books or online (cant remember where exactly) that the Canadian Mercury vehicles were exactly the same as the Ford sisters in the US. So your M1 originally came with the same engine as my F1 which was the 239ci.
However, the US version of the Mercury cars had the 255ci. With your guys' help and a little research on my own I think I've answered my own question. Yes, everything between the 255ci and the 239ci engines from 49 to 53 are basically compatible. Besides the crank being larger, the oil pan is also bigger (makes sense) along with a few other little things. Essentially, if I put this merc in my F1 with new heads on it, no one would know it wasn't a 239! :-)

This is my first flathead and I'm totally digging it! It's like taking a trip to the moon!

Sean Kelly

 

I don't know that the Merc car oil pans are bigger, they are different tho. Merc cars in certain years (50 - 51 as I recall) used a sheet metal bellhousing, and to brace it they put three studs on the bottom of the sump on the oil pan. My truck came to me with one of these oil pans, and had car mounts, so I initially thought I might have a Merc 4"-stroke engine in it. No such luck!

 

Sean,
I think that is mostly true, except for superficial differences... i.e. my heads were cast with a raised "MADE IN CANADA" on them

 

I would also have expected the block and other castings to be "C1BA", and the intake and timing cover to be aluminum.

Quickest, surest way to tell if it's a Canadian engine: see how many ports there are back where the oil galley ends at the rear of the block. Canadian engines have an "extra" plugged connection, facing rearwards, that can be used to create a "95% full-flow" oil filtering system very easily.

 

Here is a picture of a part of the driver's side head.


OOPS I seem to be hijacking this thread... sorry Sean. Back on topic, I hope you get that Merc engine in your F-1. I understand your new fascination with flatheads. I am finding that in myself.

 

The deal with the oil pans has to do with the 49-53 flatheads which differed quite a bit from the 41-48 (59A) flatheads. The 49-53 flatheads had 3 main designations: 8BA for Fords, 8CM for Mercury, and 8RT for trucks.

The cooling systems were changed so that the water outlets on the heads were at the front and used thermostat housings. Water pumps, which also mounted the engine, were different for the trucks, and the intake manifolds were different, the distributor was a conventional style, and the transmission mounting was different. Mercury engines had a 4" stroke, which with the 3 3/16" bore, gave them 255 CID over the Ford and Ford Truck 239 CID.

All of the early flatheads had the same bellhousing pattern, the transmission had a large round pattern which bolted to the engine and oil pan. When the 49 cars came out, they changed to a conventional pattern, so the engines had a bell housing that was made from sheetmetal and provided a flat area to bolt the regular Borg Warner bolt pattern transmission on. The Mercurys used transmissions with the old style bolt pattern, so they looked like the old 59A pattern. The Trucks used the passenger style bell but also had bells for the 4 speeds. To use a 49-53 engine in a early car you would use a Mercury bell housing.

The oil pans, because they formed part of the bell housing, usually had a three bolt brace for the bell housing bottom plate. If the engine was a 4" crank or not made no difference to the oil pan used. Either the early or late engines could be built with bores up to 3 7/16 and strokes to 4 1/8 ".

Truck Oil pans were made which held an extra quart and had a step in the sump. The 49 and up cars had a big front crossmember for the A-Arm suspension, so the front of the oil pan was made to clear it.

So if you had an engine bored to 3 3/8 with a Merc crank, it was 286 CID and if it was 3 3/8 by 4 1/8, it was 295 CID. You got a 4 1/8 crank by offset grinding a Merc Crank. An engine that was 3 3/8 by 4 1/8 was called 3/8 x 3/8, referring to the bore of 3 3/8 and the increase of stroke by 3/8 of an inch. Boring to 3 3/8 was relatively safe and was a bore increase of 3/16 of an inch. Some of us opted for a safer bore of 3 5/16 and the Merc crank of 4" called 5/16-quarter. Cubic inch wise was a bit smaller at 276. Today, you can sonic test the cores to detect a block with a shifted core that shouldn't be bored very far.

Dang, I love flatheads. They ran so well, and had loads of torque. The Y blocks which replaced them were such turkeys......Ford tried, but didn't have anything until they came up with the FE 390s, and didn't have a light engine again until the 289/302. And although the 351W was a good truck engine it had lousy heads, and was too big for passenger cars like the Falcon, Fairlane, Comet and Mustang, and can't hold a candle to the current 347 conversions of the 302. Of course, if money is no object, you can build great 351Ws with aftermarket heads, or 347s and so on, but to have a great 3 5/16 by 4" flattie is to have an engine that puts out a lot of horsepower and torque, sounds great and runs a long time. You can get a lot of gas mileage with the compression at 9.5:1 which is practical even at sea level with aluminum heads. This is important with $4 a gallon gas.

Regards,

Alan

 

No man, you guys keep going! I'm learning a lot here!!! I'm a complete virgin to the flathead world and am finding myself completely obsessed with them!

Sean Kelly