Technical Just what is the difference in the "A" & "B" 4 cylinder Ford engine?

Being new to original 4 cylinder Ford engines and trying to educate myself share with me what you have learned over the years.

This is my introduction to the 4 in a row. HRP

 

And not to steal the thread but were the "B" 4 cylinders in '32 and '33?

 

Yes sir,the one pictured is in my '32 coupe. HRP

 

Interesting Thread and the fact that you can bolt a 1939 Ford transmission to the "B" engine really helps...note vibration dampener that bolts to firewall...

 

No...you can't. But you can put the 39 guts and tower in a B case.

 

Model A's were 40 HP, B's are 50. A's were a splash oil system. B's have pressurized mains and dipper rods. A's had mechanical advance distributors, B's had centrifugal. Some B's had a counter balanced crank shaft. B's have a fuel pump, and fuel pump lobe on the cam. The heads, block, crank, rods, ect are different. Honestly, nearly every part is different, although you can bolt a B into an A with the correct parts. I put a B inti my 30 coupe, using a Clings adapter and 39 trans. Worked great.

 

Even the timing cover is different, as the hole you stick the dowel in to find TDC is in a different location.

 

Some things I'm aware are the addition of a fuel pump and a distributor with centrifical advance, cam timing was a bit hotter and the rod and main journals are larger and the water pump was improved.

 

Thanks Chris,I'm taking notes! HRP

 

Main bearings are larger in B. B engine went from 32-34

 

Didn't the head on the '33-34 have a C cast onto it rather than the B to denote "commercial"?

 

I was always told crank main journals were larger.

 

With the headers, downdraft carb and if you up the compression to 6-1 with a new head and lighten the flywheel to 42 pounds or less you might decide to keep that banger.

 

Water pumps are different. 3 bolt on B, 4 on A.
Oil pans are different at fly wheel housing. B is one piece with attached sheet metal bottom half cover, A pan has no sheet metal cover, flywheel cover is cast one piece with the top half.

 

If you're interested in hopping up the "B", Id recommend you get Jim Brierley's book, good info there. Take a look at the monthly 4 banger thread, the first post has a lot of good links to alot of good information. Good luck.

 

Thanks for all of the excellent info and that is how we progress...

 

Here's my Model B Trans with 39 guts!

 

Now I see the difference...Thanks...

 

From everything I have read building a hot banger involves cubic yards of cash. HRP

 

Think of the satisfaction of doubling the horsepower on an 86 year old engine! I think that it's safe to say that you could buy three SBC crate motors for the price of building an A or B. Here's mine on the Dyno showing 60HP at the rear wheels.

 

Reminds me of what you used to hear on the ol CB, " You be got that shot right ,driver". And when you get finished, it still wont outrun much on the road, for a long distance. Pretty quick across the intersection, though.
I will give you a little tip, dont be snatching it around. When I first rebuilt the motor in my A, I was going to be cute and try to spin the tire. I revved it up a little and dropped the clutch and nothing happened. I got that sinking feeling in my stomach you get after you really screw up. As it turns out, all I had done was shear the axle key between the hub and the axle, which wasnt a big deal to fix, but there were a few anxious moments.
Running it hard after you get it rolling is an entirely different matter. Good Luck

 

Get the rebuilt carb back on it yet Danny?
Does the B engine have manual timing inside the cab like Model A’s?

 

At this point in time I just want to get the car running smoothly.

I am familiar with the key ways,I sheared a few when I had 40 Fords,It took a couple to realize dumping a clutch is not too smart. HRP

 

Rick,I have joked about it saying we put 4 old carburetors in a bag, shook them up,dumped them out and ended up with one good carburetor.

My pal Earl cannibalized several carburetors for the best parts and the car is running pretty darn good,there wasn't a timing mark but that has been addressed and it's set at about 5 degrees before TDC.

The fan belt was too narrow and I found a green industrial belt that fits properly and doesn't slip when you rev the engine,it's still loose like it should be.

As far as having manual timing in the car,it doesn't nor did it have a choke cable when I traded for the car but a universal cable is now laying on the seat and that is the next thing to be installed.

Playing with the choke when the car is first fired up it runs a little rough while it's warming up but when it choke is closed it idles down and runs great.

All the lights & signals work great,the brakes have been converted to juice and work like you would expect.

I added some water a few weeks ago and after running the car it puked out what I had added I realized the radiator is not pressurized and it doesn't need to be filled to the cap.

I now have a tag on the car and it went down the road to the gas station about a mile away and back with no problem. HRP

 

Your right,it can't hurt to ask over there. HRP

 

When you say there was no timing mark, are you looking for an external mark or were you looking for the divot in the timing gear? If you find an experienced "A" guy, you can just about listen to it and tell if the time is right, or pretty close. If its retarded, and as the rubbing block on the points wear this is the way it heads, it wont run down the road the way it should.
Here is another place you can go:
https://www.vintagefordforum.com/forum/model-a
Sharp bunch of guys there, a lot of them left the Fordbarn because of difference of opinion, but still know their old Ford stuff.
Good Luck

 

I guess I was looking for what is familiar to me,I am hoping to have it running well enough to start driving it around town and get comfortable with the engine,if all goes well I would like to drive it to the McDonald's cruise-in at 81/85 next Saturday,it's about 40 miles round trip from where I live and would be a good confidence booster. HRP

 

An old initial timing trick.
Hook up a vac gauge.
Advance the timing to the gauges highest reading.
Then retard it until the gauge drops a “few” pounds.
Always worked for me.
Funny about your carburetor story.
Glad to hear it’s getting close. This is the fun part.

 

You know as well as me I that these old carburetors have been subjected to many different hands monkeying around with them,changing jets ,needles,gaskets,different parts and I doubt very seriously that there are 5 parts that are original to that carburetor that is on the car now.

I'll check with a vacuum gauge this weekend. thanks HRP