Flathead Ford vs Mercury

H

hogluvr

Junior Member
I'm planning on putting a flathead in the '40 coupe I'm buying (yes, I know it's a long dark road). I know very little so I have been trying to educate myself. I was looking at rebuild kits and they are plentiful for the '49-53 Ford 239, anything else not so much. I am looking at a '51 Mercury motor. So my question is, what is different on the internals between the 2? I know the Merc has a longer stroke and a hotter cam but what about everything else, are the pistons etc. different? Is the increased stroke responsible for the extra displacement in the Merc motor, or is there more to it? And for that matter, what is different between the '38-48 Fords and the '49-53 internally, as I can't seem to find a kit for that one either? I know about the different water passages and the bellhousing but what else changed? I know the heads are interchangeable, what about everything else? Thanks in advance for your help, from a noob! :p
 
hogluvr,
I wont be able to help you on your questions, but Welcome! The experts will be along shortly! So much knowledge on here. Love the 40 Coupe cars and the trucks too! We need some project pictures, and back story!
Regards,
Chris
 
This will help answer your questions.
http://www.vanpeltsales.com/FH_web/flathead_specs-90to125late.htm

The 1949-53 Ford/merc engine blocks are interchangeable. Merc had a different style carburetor. Ford and Merc engine mounts and water pumps are different. 49 and 50 Mercs are wide belt. 51 to 53 Ford and Mercs are narrow belt. Merc and Ford flywheels and clutches are not the same. Some connecting rods have oil squirt holes and some do not.
Memorize all the info. on this Goggle search.
https://www.google.com/search?q=194...ome..69i57.18888j0j4&sourceid=chrome&ie=UTF-8

Tubman is correct. Getting proper fan clearance is a big bump when installing a 1949-53 Ford or Merc engine in a 40 Ford. Be sure to read all about this and more in the following thread and the links contained there in. It is solid gold. I have a Corvair fan hub if you need one.
https://www.fordbarn.com/forum/showthread.php?t=301956&highlight=1940+ford+fan+clearance
 
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The Mercury pistons are different because the connecting rods are the same. While the earlier engines have an extended bell and the later ones don't the later engine can be installed into the earlier chassis by using a late model truck or '49- (early) '51 Mercury bellhousing and mixing and matching clutch disks and pressure plates. The early and late heads are not interchangeable without some modification. One needs a hole in the head plugged, while the other needs a hole in the block plugged. The main difference is in the front of the engine. With the post distributor and dual fan belts, the late engine is a bit longer than the early engines. This can be approached in one of two ways : either modify a bunch of stuff to fit the later engine in the early chassis or swap the front end components (cam, timing cover and distributor) for the early units. Late truck pumps use a single wide belt and have mounting ears like the earlier pumps, so they make the job a whole lot easier. As I understand it, getting a proper fan in a '40 when using a late engine is also a large bump in the road.
 
The 40 fan will fit the Merc engine with no alterations. I have one in my 39 and with a fan shroud it cools very well. I have a stock 39 radiator and have no cooling problems after installing the shroud.
 
1951 was a transition year for the 8BA family of engines. The change came in early 1951 for both Ford and Mercury cars. Modern fuel formulas were such that Ford decided to change the valve train to the modern rotator type valves. The engineering thought of the day was that the hardened stellite valve seat inserts would no longer be necessary when using the rotator valve set up. The hardened seats were phased out slowly. First the intake and later the exhaust were phased out over time. Trucks kept the exhaust insert though the end but passenger cars didn't. The other change was the modification of the crankshafts to fit the new automatic transmision. The bore on the crank flange had to be changed to fit the torque converter so they changed all of them at once.

The change can be noted in the valve chamber on most engines by the 1BA casting number in there. The Mercury 255 engine only changed in the type of cam, the cylinder heads, the intake manifold, and the pistons in the long block assembly.

Folks have a tendency to ID engines by the numbers that they can see which are mostly on the heads and the intake and are both easily replaceable. The only way to tell for sure between the 239 and the 255 is by either measuring the stroke of the piston or by measureing the width across the cheek of the crankshaft counter weights.

Mercury components can be an advantage when an 8CM (1949 through early 1951) engine is going into an early Ford car. The oil pan is rear sump and the rear half bell and clutch will both work to fit an early Ford 3-speed. The late 1951 1CM can also work but the bell housing will not fit the early transmission. The EAC of 1952/53 has a different pan and bell housing for swing pedals.
 
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flatjack, I am not sure if you have posted photos of your Merc engine and the 40 fan adaptation on your Merc engine but, if you haven't please post photos of how you made the 40 fan fit so it clears the upper radiator hoses on your Merc. with an explanation of the details. Also, what is the dia. of a 40 fan? I can't recall. Thanks, JIM
 
19Fordy said:
flatjack, I am not sure if you have posted photos of your Merc engine and the 40 fan adaptation on your Merc engine but, if you haven't please post photos of how you made the 40 fan fit so it clears the upper radiator hoses on your Merc. with an explanation of the details. Also, what is the dia. of a 40 fan? I can't recall. Thanks, JIM
Click to expand...

I would also appreciate seeing pictures of your '40 FAN/UPPER HOSES solution. Did you just mount a '40 FAN on your Merc crankshaft, or something else entirely? DD

.
 
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Why not just put the crank, rods and pistons from the Merc into a 59AB block and every thing should work like a 40 engine. All that will bolt into the 3 3/16 59AB block.
 
The 40 fan mounts on the crankshaft, so it comes nowhere near the hoses. My car is a 39 DeLuxe. If it was a standard, that would be a problem. I'll see about getting picture.
 
flatjack9 said:
The 40 fan mounts on the crankshaft, so it comes nowhere near the hoses. My car is a 39 DeLuxe. If it was a standard, that would be a problem. I'll see about getting picture.
Click to expand...

Jack ....I don't need a picture of fan on crank. We've all seen at least a couple of them, but THANKS anyway! DD

.
 
My '41 pickup with an 8ba is the same as Flatjack's '39 del. Basically I cut the spot welds away from the fan mount pulley and pushed the pulley forward to align with the
water pumps. The only wrinkle is some motors have a sleeve the front seal rides in some do not. That must be accounted for. I'm certainly NOT advertising anything but I have upon occasion supplied these fan mount pulley's. Best to indicate for min runout
and concentricity in a good lathe during reweld.
The shroud is a great idea....gets temp into the green zone.

Charlie
 
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The second part of my question is what changed between the '38-48 and '49-53 229s? I'm assuming a rebuild kit for an 8BA won't work for a 59A-B, just wondering why? And yes, I'm learning a lot too!
 
Almost all details changed 48 to 49 engine styles. For the sake of shortening the nomenclature, I will use "59" for earlier engine stuff and "8BA" for 49-53 stuff. Also be aware there are non-USA engines that confuse the issue a bit. If you live in the states you probably don't need to worry about those, but our Canadian and overseas friends have more to worry about.

59 blocks include the upper half of the bell housing in the block casting.
8BA blocks have bolt on bell housings.

59 blocks from the factory have split valve guides (2 piece) and mushroom stem valves. May of these have been changed to later style over the years.
Early 8BA have solid guides and normal looking valves. This setup is what is frequently installed in earlier motors.
Late 8BA also has solid guides, but the valves have extra bits in the keepers for the exhaust valves to allow the valves to rotate when off the seat.

59 motors have the distributor on the front mounted to the timing cover.
8BA have a much more typical looking distributor coming up to the front of the right head.

59 engines have the water exit on the heads in the top center of each head.
8BA engines have the water exit on the top front of each head. Water passages in teh deck are changed for improved cooling too.

59 engines have "floating" rod bearings where one set is for a single rod throw (2 rods).
8BA engines have normal locked in rod bearings where a set does one rod.

59 crankcase vent system: air enters at the back of the intake above the fuel pump and exits through a slot in the front of the oil pan (there are internal passages to make this work decently).
8BA crankcase vent system: air enters through a tube at the front of the intake, and exits through a road draft tube that runs from the front of the intake down the front of the motor and exits next to the oil pan. Again, there are internal passages to make this work.

Other detail changes, but the complete list will get really long.
 
38 coupe said:
Almost all details changed 48 to 49 engine styles. For the sake of shortening the nomenclature, I will use "59" for earlier engine stuff and "8BA" for 49-53 stuff. Also be aware there are non-USA engines that confuse the issue a bit. If you live in the states you probably don't need to worry about those, but our Canadian and overseas friends have more to worry about.

59 blocks include the upper half of the bell housing in the block casting.
8BA blocks have bolt on bell housings.

59 blocks from the factory have split valve guides (2 piece) and mushroom stem valves. May of these have been changed to later style over the years.
Early 8BA have solid guides and normal looking valves. This setup is what is frequently installed in earlier motors.
Late 8BA also has solid guides, but the valves have extra bits in the keepers for the exhaust valves to allow the valves to rotate when off the seat.

59 motors have the distributor on the front mounted to the timing cover.
8BA have a much more typical looking distributor coming up to the front of the right head.

59 engines have the water exit on the heads in the top center of each head.
8BA engines have the water exit on the top front of each head. Water passages in teh deck are changed for improved cooling too.

59 engines have "floating" rod bearings where one set is for a single rod throw (2 rods).
8BA engines have normal locked in rod bearings where a set does one rod.

59 crankcase vent system: air enters at the back of the intake above the fuel pump and exits through a slot in the front of the oil pan (there are internal passages to make this work decently).
8BA crankcase vent system: air enters through a tube at the front of the intake, and exits through a road draft tube that runs from the front of the intake down the front of the motor and exits next to the oil pan. Again, there are internal passages to make this work.

Other detail changes, but the complete list will get really long.
Click to expand...

Thank you for the reply, very thorough!
 
All the internals from the 49-53 engines will fit in the early 59AB bocks. While the late engines had a different dist. some folks do use the late camshaft, front plate and dist. Another advantage of the early block in a 40 or earlier frame is that the stabalizer rods will attach to the block.
 
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