“B” Grind Cam

J

jeepguy1948

Well-known member
“B” Grind Cam

I recently purchased a motor from another club member and installed it in my ‘30 Phaeton. The motor has a “B” grind cam in it. What is different about a B cam and a stock A cam?
 
Re: “B” Grind Cam

jeepguy1948 said:
I recently purchased a motor from another club member and installed it in my ‘30 Phaeton. The motor has a “B” grind cam in it. What is different about a B cam and a stock A cam?
Click to expand...

Most notably, Valve lift, ...and the Duration the Valve is open. Depending on which 'B' Camshaft you have, roughly 0.017" for Intake Valve lift. The compression ratio, and the Carburetor and Intake Manifold sizes were increased over the Model-A, and so with all three working as a package, the Model-A made about 25% more horsepower over the Model-A engine.
 
Re: “B” Grind Cam

I wouldn't use a Model B head, they use the 3 bolt water pump that is hard to get parts for. To answer your question, a Model B has a compression ratio of 4.6.
 
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Re: “B” Grind Cam

Key Specifications Comparison


  • [*]Model A Cam (A-6250):
    • Lobe lift: 0.302" (intake and exhaust)
    • Duration: 236°
    • Separation angle: 112°
    • Valve lift: 0.287" [1]


    [*]Model B Cam (B-6250):
    • Lobe lift: 0.334" (intake) / 0.341" (exhaust)
    • Duration: 244°
    • Separation angle: 114°
    • Valve lift: 0.319" (intake and exhaust) [1]
The B cam also had a larger 1.187 tappet v the 1.117 A one
 

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Re: “B” Grind Cam

So here’s what I have:
A block .100 over
5.5 head (maybe 5.6-5.7 with .100 over?)
B grind cam
Stromberg 81 downdraft on Burns intake

I am guessing maybe 60hp?

I have never driven an A with any motor other than this one so I can’t make a comparison. I do know that it has plenty of poop.

I also have a Ryan OD and the motor pulls it quite well.
 
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Re: “B” Grind Cam

What muffler? The old reproductions are more restrictive. Recognize them by the curve from vertical to horizontal having a smaller diameter than the straight parts of the pipe, caused by the tooling that bent the curve into the pipe. The Aries ("Authentic") muffler costs more, has less back pressure, is quieter and is the only type now sold by Snyders or Bert's. The tube around the curve the full diameter and the parts inside the can are made to Ford's original plan.

With that good balanced set of hop up parts you have there you would really notice the difference switching from the lousy reproduction to the authentic. For the most total airflow through the engine you want a set of parts that all support the desired performance.
 
Re: “B” Grind Cam

You and I are in agreement here Philo, I already have an (SS) Aries muffler (I actually made a presentation at one of our club meetings about the differences between the old knock off’s and an Aries muffler (nobody cared however, I seem to be the only one interested in performance LoL)).
 
Re: “B” Grind Cam

"You have to use the right gas.......
A Los Angeles icon. The whole area still has oil seeping out of the ground and into basements. La Brea tar pits about 3 blocks away is part of the field."

I heard that they found an early Model A at the bottom of the La Brea Tar Pits. Only the bones were left. I think it is on display in the museum besides a saber tooth tiger.
 
Re: “B” Grind Cam

All B cams are not the same! The first ones had .305






All B cams are not the same, the first ones had .305" lobe lift, second series .315" (not many of these were made) and the third series had .339". The .339's also had about 5* more duration and make a great touring cam.
 
Re: “B” Grind Cam

Since cams are being discussed, My A has an early 5 bearing cam. I'm just curious as to that comparison as well. The engine is fast.
 
Re: “B” Grind Cam

J Franklin said:
Since cams are being discussed, My A has an early 5 bearing cam. I'm just curious as to that comparison as well. The engine is fast.
Click to expand...


Far as I know, the 5-bearing A cams are identical to the 3-bearing cams except that they have two extra journals.
 
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