1931 Ford Roadster with Model B Engine?

[Fairview]

Hi All,

Greetings from the snowy Shenandoah Valley.

My first post here, so please forgive my question if it is very basic.

I have a 1931 Roadster that came from a family friend's estate. It is in unrestored but driveable condition. It was told to me that the family had a Model B engine installed 60 years ago. I don't know enough to verify whether this is correct. Can you help distinguish the Model A engine from the Model B engine?

If it indeed does have a Model B engine, is that a good thing, or not? I usually am in favor of all things original, but I don't plan on restoring this roadster, we enjoy it just like it is.

Many thanks!

Jeff

p.s. I'd post pictures of the car/engine but have it stored for winter in a hangar at the local airport, so I won't be there for a few days

[ken ct]

"B" engines have a fuel pump. "A" is gravity feed to carb. ken ct.

[Fairview]

Originally Posted by ken ct

"B" engines have a fuel pump. "A" is gravity feed to carb. ken ct.

Thanks, Ken.

There is no definitely no fuel pump on my Model A.

Jeff

[Brian SATX]

The pump may have been removed a a blanking plate put in. Look under the carb and see if there is a plate on the block. IF it has a B head, the water pump configuration is different also. It will only have three bolts instead of 4.

[Artiki]

It could've been blocked off and your engine could be running gravity feed, enough though a B.
Is there a pipe running from the left hand side if the tappet cover diagonally down to the sump, behind the carb & header? If so, it is an A.

[BRENT in 10-uh-C]

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Jeff, to answer the other part of your question, years ago this was considered a good thing because restorers/owners felt the Model B was more durable. I think it was an situation of 'He Said/She Said' that it was better and it was believeable to the unknowing, --so a myth was born. I personally am of the opinion that in most applications, the reliablity & durability of an A engine is equal to a 'B' engine. I will also say that having one over the other is not IMO worth the trouble of switching them unless it was time to be rebuilt.

.

[Fairview]

Originally Posted by Brian SATX

The pump may have been removed a a blanking plate put in. Look under the carb and see if there is a plate on the block. IF it has a B head, the water pump configuration is different also. It will only have three bolts instead of 4.

Originally Posted by Artiki

It could've been blocked off and your engine could be running gravity feed, enough though a B.
Is there a pipe running from the left hand side if the tappet cover diagonally down to the sump, behind the carb & header? If so, it is an A.

There is a small plate with two bolts on the right hand side of the block, near the front. There is no pipe running down the side of the block. However, I replaced the water pump several years ago with one of the newer pumps with seals. I'm sure it is a Model A pump as I would have remembered having to find a Model B pump. It never crossed my mind at the time.

So it sounds like I've got a Model B block with a Model A head? Many thanks for the help.

Jeff

[Fairview]

Originally Posted by BRENT in 10-uh-C

Jeff, to answer the other part of your question, years ago this was considered a good thing because restorers/owners felt the Model B was more durable. I think it was an situation of 'He Said/She Said' that it was better and it was believeable to the unknowing, --so a myth was born. I personally am of the opinion that in most applications, the reliablity & durability of an A engine is equal to a 'B' engine. I will also say that having one over the other is not IMO worth the trouble of switching them unless it was time to be rebuilt.

.

Brent, That makes sense to me and fortunately this engine seems sound. Incidentally, there is an oil pressure gauge mounted inside the car- it maxs out at 5 pounds per square inch! (Well, it is on a scale from one to five and I assume it is pounds per square inch). My engine carries about 4 pounds of pressure it seems.

Thanks for the guidance. Jeff

[Roadster62]

Welcome to the Forum! I put a B engine in Dad's '31 Roadster over 30 years ago, it is a good move IMO.

[Tom Wesenberg]

If you have a B block with an A head, then you have less horsepower than a straight B engine would have. This would be a good time to install a high compression head for a considerable power gain.

[BRENT in 10-uh-C]

Originally Posted by Fairview

Brent, That makes sense to me and fortunately this engine seems sound. Incidentally, there is an oil pressure gauge mounted inside the car- it maxs out at 5 pounds per square inch! (Well, it is on a scale from one to five and I assume it is pounds per square inch). My engine carries about 4 pounds of pressure it seems.

Thanks for the guidance. Jeff

Yep, the only thing you need now is warmer weather so you can get it out of the hangar and start driving again. Tom is right about having less horsepower than the original 'B's ratings. Technology and parts availability is of such that you can nearly double the horsepower in a Model A engine over 1931's ratings and it still look totally stock from the exterior. Again, go enjoy it as-is and have a great new year!!

.

[ken ct]

Originally Posted by Fairview

Brent, That makes sense to me and fortunately this engine seems sound. Incidentally, there is an oil pressure gauge mounted inside the car- it maxs out at 5 pounds per square inch! (Well, it is on a scale from one to five and I assume it is pounds per square inch). My engine carries about 4 pounds of pressure it seems.

Thanks for the guidance. Jeff

I have a rebuilt "B" fuel pump if you want one. PM me. ken ct.

[Ron in Quincy]

Brent,

I have an article that was writtem by George Riley shortly after he developed the 4 Port. He states in the article " if you want to port and relieve your block, then use an A block as they have much more meat in them in comparison to a B block ".

Ron

[Model A Fan]

Originally Posted by Tom Wesenberg

If you have a B block with an A head, then you have less horsepower than a straight B engine would have. This would be a good time to install a high compression head for a considerable power gain.

Originally Posted by BRENT in 10-uh-C

Yep, the only thing you need now is warmer weather so you can get it out of the hangar and start driving again. Tom is right about having less horsepower than the original 'B's ratings. Technology and parts availability is of such that you can nearly double the horsepower in a Model A engine over 1931's ratings and it still look totally stock from the exterior. Again, go enjoy it as-is and have a great new year!!
.

How would you do this if the block is an A block and not a B block?

Sounds like a sweet find. What color is it?

[BRENT in 10-uh-C]

Originally Posted by Model A Fan

How would you do this if the block is an A block and not a B block?

Sounds like a sweet find. What color is it?

I am assuming the question is how would you increase the horsepower. To answer that you would first need to travel back some 50-55 years ago when my dad was just getting into restoring Model A's. When he & his friends were joining the club and wanting more power or performance, they could not order a "stock-appearing" Brumfield or Snyder hi-compression head, nor could they order a new Stipe cam. Naturally there were guys racing Model B's in 'Big Cars' but they were pretty tite-lipped about the speed or performance mods, ...AND in the Model A clubs, it was heavily frowned upon if you used a downdraft carburetion set-up, an aftermarket speed head, --or any visible speed equipment on a restored Model A. The only alternate engine that was accepted was the Model B, --or Model C engine as some people called it.


Back in that day, most Model A's I was exposed to were using worn cams or poorly reground cams so most of them were not even producing a true 40 horses ....but when someone opened their hood and showed a 50 horsepowered Model B engine, that was 25% more horsepower over their counterparts. Then if someone had a Model C engine in their car, OHHH they had the Holy Grail of engines because of the counterweighted crankshaft! It seems funny to me now but 40-45 years ago as a kid walking around at swap meets, I was taught to turn over every Model A head to check for a heart shaped combustion chamber indicating a higher compression ratio over stock (i.e.: 5 or 5¼:1). It was such a big deal when we found one, --and such a sneaky deal when Dad had one on one of his cars!! Now when I drive a Model A that has a stock 4¾ compression ratio head, it seems like a slug, --and even the "Police Head" is considered by most as a "has been"

Now, fast forwarding to today's world we have commercially-available, stock-appearing cylinder heads in 7:1 (or more) compression ratios, new camshafts with much superior performance over the Model B, new counterweighted crankshafts for the Model A, new commercially-available oversized valves along with good R&D data to know what mods work in the port areas. Couple that to a few other tricks and a builder can make a stock appearing L head engine double its original horsepower rating and produce extended reliability results too. The venerable Model B (--or even the 'C' as some ole timers incorrectly called it) engine's performance has now been surpassed and its once-upon-a-time advantage has kinda dwindled.

.