Cam install question

[shatar4]

After searching this site several times,I am more confused then ever. When putting the timing gear set on, does the marks go 6 and 12 or 12 and 12? Also, does #1 have to be at TDC while setting the marks or is that while installing the dist?

[Changin Gears]

The crank gear needs to be at 12.  The cam gear can be at either 12 or 6.  The reason is the cam turns at 1/2 crank speed, so if you turn the crank 1 revolution the cam will turn 1/2 revolution.

[shatar4]

So if I install it at 12 or 6 it wouldn't matter but when I install the dist. the #1 piston must be at TDC to be correct for timing?

[cwestra]

Yes, install the gear with #1 piston at top.  There is valve timing and ignition timing.  You are setting valve timing here.  Ignition timing is set when you install the distributor.

[Aussie Challenger]

Set the crank at 12 & the cam at 6 o'clock, there is less likely of you getting the cam 1 tooth out that way.   

[72cudamaan]

            

[Strawdawg]

Set the crank at 12 & the cam at 6 o'clock, there is less likely of you getting the cam 1 tooth out that way.   

X2....when crank is at 12 and the cam gear at 6, this will automatically be Top Dead Center for number one.   

[shatar4]

Thanks! That help clear it up for me.

[Chryco Psycho]

with the cam @ 6 & the crank @ 12 you will be on firing stroke for # 6 cylinder

[shatar4]

Ok, confusion again. So if the crank is at 12 and the cam is at 6, it's firing on #6. So why have the dots line up at 6 and 12?

[Chryco Psycho]

I never said anything just go back to what you are doing !
#1&6 piston are oth at TDC at the same time , one is on exhaust stroke & 1 is firing , remember the cam turns at 1/2 the speed of the crankshaft so with the cam gear @6 oclock #6 is firing with the cam gear @ 12oclock #1 is firing

[shatar4]

So if I install the cam at 6 and the crank at 12, turn half way and I should be at TDC with #1 and then I can install the distributor.

[cwestra]

So if I install the cam at 6 and the crank at 12, turn half way and I should be at TDC with #1 and then I can install the distributor.

When I did mine, as a check I rotated the assembly while watching when the intake and exhaust cam lobes would lift the push rods on #1.

[Chryco Psycho]

So if I install the cam at 6 and the crank at 12, turn half way and I should be at TDC with #1 and then I can install the distributor.

Yes 1 full turn of the crank will line you up with TDC #1 firing

[Aussie Challenger]

As a precaution you should rotate the crank 2 full turns clockwise and re check to make sure the dots line up, don't turn the motor anti clockwise when doing the timing checks.