Low02

iTrader: (14)

Okay i know this question comes up quite a bit but i want to be 100% sure i get this right. When i reinstall the cam all i need to do is get # 1 at TDC (doesnt matter if its intake or compression, right?) As long as the crank gear is at 12 o'clock and just line the Dots up. So the computer will correct the timing if its 180 out? TIA.

BlackScreaminMachine

iTrader: (17)

If I am not mistaken (and if I am, correct me) the alignmnent pin the cam ensures the cam is matched up to the DOT on the cam sprocket, as long as the crank is set to where it's dot is at 12 o'clock and the cam is at 6 o'clock then your fine.

The crank's timing even depends on the cam, since the cam has a alignment pin to keep it where it needs to be at all times thats whats determines in essesnce the compression or intake stroke.

eallanboggs

iTrader: (1)

Crankshafts don't know about things like intake and exhaust strokes. All they know how to do is move pistions up and down in their bores. Cranks are forced to learn about this stuff the hard way by the cam. Camshafts keep track of the complicated stuff like what cylinders are performing certain strokes at any given point in time. When you put the crank DOT at 12 o'clock the crank doesn't know and doesn't care what stroke #1(or any other cylinder for that matter) is on. This only comes into play when you decide to marry the crankshaft to the camshaft with the timing chain. Once you mate the crank and cam dots in the DOT to DOT relationship strokes and timing get involved in the process. Computers are powerful these days, but not powerful enough to correct for a 180 degree mistake. No computer is that powerful at least not yet. If you align the dots in the DOT to DOT relationship BEFORE you remove your old camshaft and leave the crank at 12 o'clock you'll find that this whole process becomes less complicated. Using this method all you have to do is remove the old cam and install the new one in the same postion you removed the old one(crank has not been moved). Now spin the crank over 2 times(4 strokes) to verify that the dots still match up.

RIDINFILTHY

iTrader: (10)

x2 good way to explain

LS1Silverado05

iTrader: (41)

Yea..x3...Good job

Fratsit

iTrader: (1)

Aw heck.... I'll x4. Great explaination. Well said.

R/

Frat

quadman

iTrader: (3)

yes, excellent explanation. here's a pic:

Low02

iTrader: (14)

Great information and thank you, but I've already removed the cam. I wish i would have thought about doing that before i took it apart.
Since i didn't do that I've got to get #1 at TDC right? And does it matter if it is on comp. or intake?

mrhzk35404

iTrader: (7)

No, the cam sensor deals with that. All you have to do is put it dot to dot. The crank doesn't determine what stroke your engine is on the cam does.

97MysticZ

iTrader: (16)

Just put it dot to dot. It's impossible for you to them 180 degrees out. Like stated above, the crank just controls the pistons. If you have the crank sprocket dot at 12 o'clock and then you turn the motor over 360 degrees so that the dot is at 12 o'clock again, the pistons will all be in the same place.

eallanboggs

iTrader: (1)

Apparently my explaination wasn't all that great since even after having read it you still don't realize that the crank does NOT know about stroke events until AFTER you have installed the timing set. The crank starts doing what the cam tells it to do once you marry the crank to the cam by installing the timing chain, but before the timing chain is installed the crank doesn't know what a stroke is. With the DOT on the crank spocket at 12 o'clock there is no such thing as a compression or exhaust stroke(strokes when crank sprocket DOT is at 12 o'clock) until after the timing chain is installed. Try reading a little more about the 4 stroke cycle to get a better grasp on this stuff. Most books don't explain it the way I have here, but it's not that complicated. If you want to get youself even more confused try learning the 2 stroke cycle. No cam, valves(except for a reed) or timing chain to tell the crank what to do with piston porting and power on every stroke. Got to love that.

forcd ind

iTrader: (7)

i think you pretty much answered your own question-being 180 out was a concern on dist engines (gen 1) most people thought dot to dot was #1 when it was really #6 firing-both dots at 12 o'clock was #1 firing-the cam runs at 1/2 the speed of crank, so dot to dot, turn 1 time, now their both at 12 o'clock, then 1 more turn and back to dot to dot-the sensors will pick up where stuff is

Low02

iTrader: (14)

Thanks again everyone. I'm just used to working on Gen 1 SB's.
Its so simple, i was having a hard time seeing it. Ive rebuilt a few top ends on 2 stroke Quads and bikes, and yes it makes my head hurt thinking about how they work. Lol.
Thanks again for the info.