shaft-driven cam

bone

"bangle for president"
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i cam across this pic of the engine found in a bugatti type 37
37%20engine.jpg


look at how those camshafts are driven from the crank!
i've seen belts, chains, gears, but never a shaft like this
why don't they use it anymore?

if the concept is good enough do drive a bike, why not to drive the cams?
 
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According to wikipedia those upright shafts are pretty expensive, at least compared to belts, chains or gears. Other than that idk.
 
I saw a Packard Merlin in an air museum a few weeks ago and it also used a shaft-driven cam. I wonder if there's a noise issue that wouldn't fly (so to speak) in more typical road cars.
 
A friend of mine's Type 40 don't seem to produce any untoward noise from the upright shaft. They're lovely sounding engines. The 40a which has a 49 block sounds fine too.

(Type 40s have the same engine as Type 37)
 
Ducati used to use shaft-driven cams back in the bevel head days. They stopped using them, and switched to belts with the Pantah motor, because they were extremely difficult to assemble correctly, with many major assemblies needing careful shimming. To give you an idea, famed Ducati tuner Guy Martin (no relation to the famously incomprehensible motorcycle racer) was quoted as needing ~20 hours to rebuild a Pantah motor, and 40+ hours for a bevel head (It actually takes longer still, but no one would be willing to pay for the actual time it takes him).
 
I saw a Packard Merlin in an air museum a few weeks ago and it also used a shaft-driven cam. I wonder if there's a noise issue that wouldn't fly (so to speak) in more typical road cars.

probably many issues why it isn't unsed in typical road cars. i was more thinking about high reving bike engines. in my head the shaft seems better than a belt or chain...

A friend of mine's Type 40 don't seem to produce any untoward noise from the upright shaft. They're lovely sounding engines. The 40a which has a 49 block sounds fine too.

(Type 40s have the same engine as Type 37)

you have friends who have a bugatti? damn, you realy hang out in a cool environment!

Ducati used to use shaft-driven cams back in the bevel head days. They stopped using them, and switched to belts with the Pantah motor, because they were extremely difficult to assemble correctly, with many major assemblies needing careful shimming. To give you an idea, famed Ducati tuner Guy Martin (no relation to the famously incomprehensible motorcycle racer) was quoted as needing ~20 hours to rebuild a Pantah motor, and 40+ hours for a bevel head (It actually takes longer still, but no one would be willing to pay for the actual time it takes him).

that makes sense :)
 
Totally expected another DEI thread when I came in here. I could buy a Zeus gear set for my timing but it's apparently very loud and wears out (it isn't lubricated like a gearbox), you can't just replace it like a belt.
 
Ducati used to use shaft-driven cams back in the bevel head days. They stopped using them, and switched to belts with the Pantah motor, because they were extremely difficult to assemble correctly, with many major assemblies needing careful shimming. To give you an idea, famed Ducati tuner Guy Martin (no relation to the famously incomprehensible motorcycle racer) was quoted as needing ~20 hours to rebuild a Pantah motor, and 40+ hours for a bevel head (It actually takes longer still, but no one would be willing to pay for the actual time it takes him).


I imagine most of that time is adjusting the gear for proper clearances. Think of it like adjusting a ring and pinion gear in a final drive, encased in a block with no room to work in.
 
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