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So I was installing the new timing set and I wanted to verify what I thought was the correct alignment, cam gear 12 o'clock, crank gear 12 o'clock, #1 piston at TDC on compression. So I did a quick search here on CO and yes, several folks verified what I thought.
But I ran across this diagram in my '71 CSM. It doesn't, however, state the #1 cylinder position, as far as compression stroke or exhaust. It does say for ALL V-8's.
The cam turns at half the speed of the crank. BOTH orientations are correct as far as installing the timing chain. If you align them at 12:00-12:00 and turn the crank one full rev, guess what? They will be at 6:00-12:00. Turn it one full rev again, and they are at 12:00-12:00 again.
If you are changing the timing set on an existing motor and the distributor is not touched and nothing is rotated, it DOESN'T MATTER. If you do turn the crank one rev while doing this, other than potentially smacking the pistons into some of the valves, you will have the distributor 180 deg out.
Yeah Joe, I get all that. I should have specified that I don't have the distributor in yet (it's a new build) and I'm assuming when I do got it in, I will point the rotor at the #1 spark plug (and so ,compression stroke). So in that case, it would be crank at 12 and cam at 6?
Yeah Joe, I get all that. I should have specified that I don't have the distributor in yet (it's a new build) and I'm assuming when I do got it in, I will point the rotor at the #1 spark plug (and so ,compression stroke). So in that case, it would be crank at 12 and cam at 6?
My memory isn't that good any more.
I just stuff a piece of paper towel in the no. 1 spark plug hole. When it gets blown out, you're on compression stroke.
I was just having a look at the lifters (No heads, no intake, just the short block) and it's easily visible that 12 and 12 are the compression stroke. I guess the CSM (picture above) threw me for a loop. No difference for small and big blocks, true? I'm building a 455 (but I thought I'd find you and Eric (MDchanic) in this forum
Crank at 12 and cam at 6 is firing #6. Crank at 12 and cam at 12 is firing #1.
Thanks for the verification, Eric.
Originally Posted by joe_padavano
Considering that they use the same cams and timing sets.
The only valve train difference is in the deck height and resulting pushrod length.
And Joe, you asked above about "why are people continually mystified by this?" Someone in my "undersized timing set needed" thread is looking at my 12&12 picture and telling me I've got it wrong. There's your answer
What position would the intake and exhaust valve be in? Open and closed or closed closed?
Since I'm still working on my short block (no heads, intake, front cover, etc.) here's what I did; I turned the crank until the marks were 12 and 12, all the while watching the cam and the two lifters I installed on the #1 cylinder. Like you I thought it would be simple. But it wasn't. I could certainly tell the compression stroke because the lifters didn't move. But the intake and exhaust were a little harder. I suppose because of the built-in advance on the cam. It wasn't like the exhaust lifter was up with the piston at TDC; that happens a little before the piston reaches the top.
But all in all, it was fairly easy to tell the difference between the intake/exhaust and compression strokes.
I always go off the balancer at 0, which puts the marks at 12 and 6 at TDC. I degreed everything and the Cloyes set is accurate, I guess over or under thinking this one, however you want to look at it.
I always go off the balancer at 0, which puts the marks at 12 and 6 at TDC. I degreed everything and the Cloyes set is accurate, I guess over or under thinking this one, however you want to look at it.
Um, if you rotate the crank one full rev, the balancer will be at 0 again and the timing marks will be at 12:00 and 12:00.
Just a side note, I replaced a 2 chain(long chains) timing set on a 4.6 Ford. Did it just as the manual said, but 2nd guessed myself and complicated things. I ran it thru 2 revolutions thinking it would be aligned again- wrong! Come to find out it takes many revolutions to line up again. So I put it together and all was well. You are second guessing yourself Mac. It will be fine.
Nah Greg, not 2nd guessing. 3rd and 4th guessing, but not 2nd, lol. That's just the way I roll. BTW, I got the billet Cloyes set from cutlassefi (Mark) and it fits perfecto!
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