SpeediFour question

[Steve Petschel]

My most recent SpeediFour was modified to look like a race motor (I don’t think it was ever run as built). The spark plug covers have been removed as has the front cowling to accommodate a racing vacturi carb. The spark plugs have been relocated from the front side of the cylinders to the end of the cylinders. I have heard or read that it was common practice to do this, but I also recall hearing someone say that it is not recommended because it could cause the pistons to burn. Can anyone shed some light on this subject?

Thanks in advance,

Steve Petschel

[George Emmanuel]

A racing class, Class E was created for engines in the Speedifour cu in/horsepower, but it wasn’t a popular class. Speedifours do not like to be run lean! Maybe the rumor you heard was related to running them lean? At a meet years ago one of our members brought an E runabout with Speedifour that had been raced. The rig was beautiful! He was getting it ready to take out for a run and I told him, “Bob, whatever you do, don’t lean that engine out”. So he got out there and was really running sweet, and I watched him at WOT turn around and reach for the engine and I said to myself, “He’s gonna do it”—and he did, –and it immediately stuck! When he got towed in he came up to me and asked if I had a spare powerhead. I told him that even if I did, I wouldn’t sell it to him……’nuff said!

I have a 1948 Lyman with ’48 Speedifour on it that I”ve done 2, 60 mile round trips. Never have run it hard and kept it in great condition.

George

[Steve Petschel]

Thanks George,

I wasn’t aware of lean issue and will keep it in mind. As to the spark plug location, you don’t see any reason not to leave them installed in the end of the cylinder vs the front of the cylinder?

Steve

[George Emmanuel]

From my limited knowledge, I see no reason position would cause a burned piston. But, I’ve seen engines where people ran way too much advance and caused damage.

George

 

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