Johnson SS

[rustler]

Can anyone confirm the true displacement of the big case Johnson SS? I always thought it was a 33, but friend insists it is the small case Johnson which is 33.

[Bill Little]

Can anyone confirm the true displacement of the big case Johnson SS? I always thought it was a 33, but friend insists it is the small case Johnson which is 33.

The "Stunt Supreme" (small case) is a .33 (.32??) and only has "SS" on the side.

The "regular" (big case) is a .35.  I have one of those and a CS .35

[Garf]

The Stunt Supreme (SS), and Combat Special (CS) are both 35's. The small shaft Stunt (S), is a 32. I have them all.

[wmiii]

 I have one of each also, well maybe more than one, but Phil is correct.

 Walter

[Steve Holt]

Actually, the small case "S" stunt engine is a .33 rather than a .32.  The bore and stroke of the Johnson small case engine were:
  29   .718 bore and .718 stroke
  32   .750 bore and .718 stroke
  35   .770 bore and .750 stroke
   S    .770 bore and .718 stroke

The S was in fact a 35 piston and cylinder in a 29 case.  A by product of this combination was that the compression ratio was dropped from 11.2-1 on the 35 to 6.5-1.

The .32 compression ratio was 8.1-1, so it did have a better stunt run than the .35 but not as good as the S.

I have a .32 in an old Ringmaster, and it makes a lot of power but doesn't like running in a 4 cycle.  The S will run a 4 cycle.
Steve

[Bill Little]

The Stunt Supreme (SS), and Combat Special (CS) are both 35's. The small shaft Stunt (S), is a 32. I have them all.

Hi Phil,

Thanks for that, I got mixed up somewhere.  I don't have a "Stunt Supreme", just remember looking at them.

Odd thing is, I have a CS and another "Big Case" Johnson that is a .35, but it doesn't have the SS on it. ()

Don't know exactly "what" I have but it's a solid runing engine!

Bill <><

[rustler]

Thanks everybody.
For Bill - I believe most big case Johnsons have the model ID on the small raised circle, e.g. R/C, CS, SS. But the only ones I have seen with nothing on the circle are CS's. One like this is the first Johnson I ever bought. It was bought as a CS and from the way it runs it is definitely a CS!.

[Garf]

The ones with a milled plain circle are either the early 36BB or the Sport Special. They have rounded cyllinder fins.

[rustler]

There is a big case Johnson on e-b at the moment. Originally called a 29, now revised to 32. Was there a big case 32? Could it be the big case SS 33 I thiught existed?