What GS camshafts are interchaingeable?

[hannibal]

Since the duration of the 79 and 80 850 cams are the same, don't they use the same cam just timed 10? differently?

In other words, couldn't you just advance the 79 cam a few teeth and effectively have a 80 cam?

[Chuck78]

Yes, just like the 1000G/1100G models, same cams, various cam sprockets year by year, altering the timing, searching for more low-mid grunt.

[Steve]

Since the duration of the 79 and 80 850 cams are the same, don't they use the same cam just timed 10? differently?

In other words, couldn't you just advance the 79 cam a few teeth and effectively have a 80 cam?

You have a plausible idea, it just needs a bit of "refinement".

I don't know if the difference is in the cam itself or the sprockets. The lobes themselves might be offset 10? or it might be the offset between the bolts that hold the sprockets to the cams.

Either way, there are 30 teeth on the sprocket, so moving just ONE tooth will change the cam 12?.
I certainly would not go "a few teeth".

.

[TeamDar]

You have a plausible idea, it just needs a bit of "refinement".

I don't know if the difference is in the cam itself or the sprockets. The lobes themselves might be offset 10? or it might be the offset between the bolts that hold the sprockets to the cams.

Either way, there are 30 teeth on the sprocket, so moving just ONE tooth will change the cam 12?.
I certainly would not go "a few teeth".

.

This is not correct. When measuring camshaft timing and duration, the numbers are referring to crankshaft degrees of rotation not camshaft degrees of rotation. While moving the timing chain one tooth on the cam sprocket is actually 24 not 12 degrees of advance or retard as measured at the crankshaft since the cams run at half the speed of the crankshaft. In other words, if you were to retard the camshaft one tooth on the cam sprocket, you would have to rotate the crankshaft 24 degrees to rotate the camshaft to its old position. Dar

[Steve]

Very correct, Dar, thanks for the reminder.

.

[hannibal]

Thanks all around for the clarification.

[Big T]

Slotted cam gears will provide better cam timing

[GregT]

Slotted cam gears will provide better cam timing

Only if you then put the cams in the right place.....

The smaller fours like 108/108 lobe centers regardless of which cams you use.