Cam Phasing

[TT5.9mag]

That's not really how it works....


Modern engines, my foot. (other than that, DemonX2 is 100% right).
The key was never designed to carry load, ever.

The sprocket bolt that clamps the cam sprocket to the cam is what makes the spinny-magic happen. The clamp load from sprocket to cam is what locks the two together. I ain't doing the math but there's hundreds of pounds of force holding the cam to the sprocket when the bolt is properly torqued.

The keys are supposed to be weak. If something goes south, the intent is to shear the key and not eat up the nice expensive components (although on a small block Mopar you're likely going to trash the valves if this happens).

The key is an alignment aid only and carries no, I repeat NO load.

Can you explain why crankshaft manufacturers (Scat, Callies, Bryant, Manley, etc) all make cranks with multiple keyways?

 

[jos51700]

Can you explain why crankshaft manufacturers (Scat, Callies, Bryant, Manley, etc) all make cranks with multiple keyways?

I'm not a crank engineer, but just looking at it, I'd venture that it creates fewer stress risers than a single large keyway.

 

[TT5.9mag]

I'm not a crank engineer, but just looking at it, I'd venture that it creates fewer stress risers than a single large keyway.

Nope. It further reduces the strength of the shaft, and increases the amount of stress risers. Now why would they still do it?

 

[jos51700]

Nope. It further reduces the strength of the shaft, and increases the amount of stress risers. Now why would they still do it? View attachment 1716310139

As I read that, the line that says "in case the key way is too long..." kindda sums up my point and even elaborates that long continuous keyways contribute to shaft twist. A long keyway cut for single sliding key is pretty detrimental strength wise, where multiple half moon key slots is a much more rigid and robust setup.

That said, I'm not a crank engineer, and if you know some other reason, share it. As I said, keys aren't designed to carry loads and the furthest I 'officially' opined on.

You're welcome to slather your crank and cam bolts in red thread locker and leave them finger tight if you want to prove to me that the key carries the load.

 

[TT5.9mag]

As I read that, the line that says "in case the key way is too long..." kindda sums up my point and even elaborates that long continuous keyways contribute to shaft twist. A long keyway cut for single sliding key is pretty detrimental strength wise, where multiple half moon key slots is a much more rigid and robust setup.

That said, I'm not a crank engineer, and if you know some other reason, share it. As I said, keys aren't designed to carry loads and the furthest I 'officially' opined on.

You're welcome to slather your crank and cam bolts in red thread locker and leave them finger tight if you want to prove to me that the key carries the load.

And you’re welcome to leave your keyways out of the crank and cam if you think they don’t carry any load.

 

[TT5.9mag]

Shaft key & keyway | Key types | Keyed Joint application & benefits

Everything you’d ever like to know about keys and keyways and how they transmit load, reduce shaft strength, and are sized per application.

 

[TT5.9mag]

That said, I'm not a crank engineer, and if you know some other reason, share it. As I said, keys aren't designed to carry loads and the furthest I 'officially' opined on.

The reason they (crank manufacturers) sell cranks with multiple keyways is because when you drive more components from a hub or pulley, one key does not meet the requirement for strength. Supercharging is a very specific example where double keyed cranks and dampers (or hubs) are used.

 

[RustyRatRod]

The reason they (crank manufacturers) sell cranks with multiple keyways is because when you drive more components from a hub or pulley, one key does not meet the requirement for strength. Supercharging is a very specific example where double keyed cranks and dampers (or hubs) are used.

Yup. Even @Coyote Jack has talked about that before.

 

[Illahe]

Is the off-set woodruff key for the camshaft itself an acceptable way to adjust the phasing? I have a good older chain and gears. I have read the typical horror stories of the new stuff. The damned keys start a $30. Another $100 plus gets me an adjustable crank sprocket and new chain and gears. I'd like to stick with my old stuff. I need to advance 4 degrees and ebay has the key to do it.
Edit: ebay

I ran the offset Mopar performance keys to 6700rpm with 300# open spring pressure. No issues.

 

[Bewy]

I doubt crank strength on Chrys cranks around the keyway would be an issue because they are so beefy. Look how small the crank nose is on a SB Chev, & only a 7/16" bolt.