cam ?'s

[1988nissan300zx]

haha it still didnt copy right i put a picture of it up.

 

[Gen1Pat]

No. You do not use that black dot for the stock timing location. Been so long I forgot how the damn thing worked. Got my numbers and letters all ass-backwards. The numbered holes changed the cam timing in degrees. The letters near the teeth are the timing marks you align with the mark on the head.

 

[1988nissan300zx]

i still dont see how it works cause for example say for 2.5 degrees you would use 2 and timing mark C, well the C is straight up from the 2. so that would be just like stock stock setup. so that is not moving the cam any, i dont know i am confused, i just can get a grasp on how it works.

 

[Gen1Pat]

Letter C is the timing mark for hole number 2. They do that so it is easier for you to time the cam with the mark on the head. Every hole has it's letter, that letter is the hole's timing mark you line up with the mark on the head. Making more sense? Lol. Don't over think the gear's function. The reason how the timing is changed is because of how the teeth are laid out in relationship to the center of the gear. Really dude, you don't need to know how it works, only that it does, hahaha! Trust me, I'm one of two people on here that has degreed in a cam on this bike.

 

[1988nissan300zx]

haha yeah i guess i am just over thinking it. so say i wanted the 2.5 degrees i would put the gear on the cam with the pin in the 2 hole and then line the C up with the head?

 

[Gen1Pat]

In theory, yes, that would advance the cam timing 2.5*. HOWEVER, without first degreeing the cam with the gear in the stock location to get a baseline, you do not know what your cam timing is. You may advance it further then what you want to, and suffer either a power loss somewhere in the power band, or worst case, bend a valve. Doubtful you'd bend a valve with just a 2.5* advancement. But, it is possible. No cam is 100% true to their profile.

 

[1988nissan300zx]

man this is kind of irritating that i grasp this, i just don't see it all that does is just spin the gear on the cam don't it? so with that said it didn't move the cam any, so then there is no change.

 

[Gen1Pat]

Trust me man, there IS a change in the cam timing.

 

[1988nissan300zx]

ok one thing and I will just let it be lol. so maybe I am going at it wrong with the cam in the head lined up with stock settings I would just unbolt cam gear and pull it off then reinstall gear on cam in desired spot, then since the new timing will mark will be straight up from where the pin is now it will already be lined up with the head mark, and I didn't move the cam I just spun the gear then reinstalled.

 

[duneracerweston]

the cam timing is all in relation to the crank. so it doesnt seem like a change but it doe change it, just a tad.

 

[Gen1Pat]

the cam timing is all in relation to the crank. so it doesnt seem like a change but it doe change it, just a tad.

Thank you Weston. Forgot to mention that.

 

[1988nissan300zx]

ok another stupid question to you do anything with the crank or timing chain when change position of cam gear, like roll the motor over or anything?

 

[Gen1Pat]

Nope. Leave the piston at TDC.