Degreeing cam ?

Is it possible without a multi index crank gear to change the cam timing by jumping a tooth at a time on the cam gear ? I never thought about it before but why would'nt it work ?

You can do that if the degrees per tooth are the range you want to advance or retard the cam. But not the best method.

Thanks i thought you could but i wondered how many degrees jumping a tooth would be ? Mmmm way too much time on my hands

nuclearcobra wrote:Is it possible...to change the cam timing by jumping a tooth at a time on the cam gear ?

Yes, of course. That's how it used to always be done. The multi-keyway crank gears are simply a convenience that came afterwards and in later years. In fact, in the case of the 460 aftermarket double-roller chains 1 tooth on the cam gear equals approximately 8-camshaft degrees.

Divide 360 degrees by the number of teeth on your cam gear to get the degrees-per-tooth. (Or by the number of teeth on your crank gear if you're jumping a tooth there.)

Paul

p.s.: Remember, camshaft timing is normally expressed in crankshaft degrees, so if you're playing with timing at your cam gear don't forget to factor for the crank degrees.

1 tooth on a "Double Row" timing set which has a finer number of teeth than a stock "silent chain" set is between 16 & 17 degrees.
That's a LOT to be moving a camshaft.

Thanks for the input guys. the cam i degreed is a lunati flat hyd, it called for 106 i/c and i got 107.5 thats as close i could get it with a 3 way gear, its advanced 4 degrees.

get a 2*crank key,thats how i always done it with stock gear way back in the day.

rmcomprandy wrote:1 tooth on a "Double Row" timing set which has a finer number of teeth than a stock "silent chain" set is between 16 & 17 degrees.
That's a LOT to be moving a camshaft.

Indeed! These days there's really no need to go from one extreme to the other when we can now dial in cam phasing "just right."

One thing that is neat about the ol' chain jumping trick is when the current cheapo keyways are all over the map, meaning not exactly broached where they are supposed to be AND perhaps not even broached in equally spaced increments (regardless of manufacturing automation). Sometimes, you can work with both the chain tooth and and keyway position and find a happy medium with a chain that would otherwise be way-the-hell off. Such as a supposed +4 keyway putting you +6.5 and so you advance the cam gear a tooth and the put the lower gear at the supposed -4 keyway and thereby get closer to the desired cam phasing. Most people overlook that because the crank gear will always have half the tooth count of the cam gear and so they believe that moving the chain on one gear and backing the chain on the other will simply cancel each other out....but those KEYWAYS on the multi-keyed lower gears are broached all over the place. I think it damn well justifies the existence of the 9-position keyway chain set (read: convenient). The days of jumping teeth are pretty much gone, lol.

Paul

Paul Kane wrote:

rmcomprandy wrote:1 tooth on a "Double Row" timing set which has a finer number of teeth than a stock "silent chain" set is between 16 & 17 degrees.
That's a LOT to be moving a camshaft.

Indeed! These days there's really no need to go from one extreme to the other when we can now dial in cam phasing "just right."

One thing that is neat about the ol' chain jumping trick is when the current cheapo keyways are all over the map, meaning not exactly broached where they are supposed to be AND perhaps not even broached in equally spaced increments (regardless of manufacturing automation). Sometimes, you can work with both the chain tooth and and keyway position and find a happy medium with a chain that would otherwise be way-the-hell off. Such as a supposed +4 keyway putting you +6.5 and so you advance the cam gear a tooth and the put the lower gear at the supposed -4 keyway and thereby get closer to the desired cam phasing. Most people overlook that because the crank gear will always have half the tooth count of the cam gear and so they believe that moving a tooth on one gear and backing a tooth on the other will simply cancel each other out....but those KEYWAYS on the multi-keyed lower gears are broached all over the place. I think it damn well justifies the existence of the 9-position keyway chain set (read: convenient). The days of jumping teeth are pretty much gone, lol.

Paul

thats where the 2*key comes in handy too,lol. i had a name for one brand i used "one"time,china gear.

Paul Kane wrote:

rmcomprandy wrote:1 tooth on a "Double Row" timing set which has a finer number of teeth than a stock "silent chain" set is between 16 & 17 degrees.
That's a LOT to be moving a camshaft.

Indeed! These days there's really no need to go from one extreme to the other when we can now dial in cam phasing "just right."

One thing that is neat about the ol' chain jumping trick is when the current cheapo keyways are all over the map, meaning not exactly broached where they are supposed to be AND perhaps not even broached in equally spaced increments (regardless of manufacturing automation). Sometimes, you can work with both the chain tooth and and keyway position and find a happy medium with a chain that would otherwise be way-the-hell off. Such as a supposed +4 keyway putting you +6.5 and so you advance the cam gear a tooth and the put the lower gear at the supposed -4 keyway and thereby get closer to the desired cam phasing. Most people overlook that because the crank gear will always have half the tooth count of the cam gear and so they believe that moving the chain on one gear and backing the chain on the other will simply cancel each other out....but those KEYWAYS on the multi-keyed lower gears are broached all over the place. I think it damn well justifies the existence of the 9-position keyway chain set (read: convenient). The days of jumping teeth are pretty much gone, lol.

Paul

Paul,
You're telling one of the secrets of the engine building business, LOL ... actually tell someone to do that, (put the crank gear in the retarded position and advance the whole gear a tooth), and by word of mouth you'll be known as a "fly by night" engine builder in no time.
Ask me how I know - I tried to HELP someone years ago and paid deeply in local reputation for a few years.
Those who think they have a little knowledge, really have no clue.

rmcomprandy wrote:Paul,
You're telling one of the secrets of the engine building business, LOL ... actually tell someone to do that, (put the crank gear in the retarded position and advance the whole gear a tooth), and by word of mouth you'll be known as a "fly by night" engine builder in no time.
Ask me how I know - I tried to HELP someone years ago and paid deeply in local reputation for a few years.
Those who think they have a little knowledge, really have no clue.

Ha! Just laughed hard over here. Yeah, it's too bad when someone with little understanding believes himself to have a grasp on the big picture when he doesn't....and then mis-represents your expertise based on his limited perspective.

-P