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Setting TDC? on new motor

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Old Sep 27, 2006 | 09:18 PM
  #1  
Wishmaster's87IROC's Avatar
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From: Winston salem, NC
Car: 1987 1SICIROC.....1999 TransAm
Engine: 385 HSR.....LS1
Transmission: 700R4 with Midwest 3400 2.4str...M6
Axle/Gears: SLP Zexel Posi unit 3.42's...3.73's
Setting TDC? on new motor

Is this correct way to set TDC? I have number1 piston all the way to the top and the cam gears are dot to dot...6 top and 12 bottom.

What I dont know if its on the compression stoke or exhaust..does it really matter? any time I roll the motor over and get the keyway on the crank snout at 2 oclock and the cam dowel pin at 3 oclock the piston comes to the top...so I assume Im right.

you can see in the picture

atleast thats what it say on theComp timing set instructions.
Attached Thumbnails Setting TDC? on new motor-dsc01931.jpg   Setting TDC? on new motor-dsc01933.jpg  
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Old Sep 27, 2006 | 09:39 PM
  #2  
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Yes, you have it. The cam is properly timed.

FWIW, that position is probably firing on #6, but it doesn't matter. When you install the distributor, you can adjust as necessary to get the cam/valves in the correct position.
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Old Sep 27, 2006 | 10:21 PM
  #3  
Wishmaster's87IROC's Avatar
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From: Winston salem, NC
Car: 1987 1SICIROC.....1999 TransAm
Engine: 385 HSR.....LS1
Transmission: 700R4 with Midwest 3400 2.4str...M6
Axle/Gears: SLP Zexel Posi unit 3.42's...3.73's
why would that be?...comp timing instruction that came with the timing set says to set it up that way...

why you say Im on #6? should it be top to top?

how would I adjust as necessary to get the cam/valves in the correct postion..I dont understand what you mean
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Old Sep 27, 2006 | 10:50 PM
  #4  
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Dot-to-dot is #6 firing. That's a perfectly right way to put it together though, even though it's NOT #1 firing; in fact it's better than trying to line it up at #1 firing, because it's easier to see and get right.

Both dots at 12:00 is #1 firing.

Put it together dot-to-dot, and then rotate the crank EXACTLY one complete revolution. The dots will then both be at 12:00, and it will be at #1 firing (or more accurately, #1 TDC.... #1 firing should be a few degrees before that).

Or, if you feel like living dangerously, just leave it at #6 firing, and put the dist in at that position. Either way you can easily enough get it set up right.
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Old Sep 27, 2006 | 11:09 PM
  #5  
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From: Calgary, AB, Canada
Car: 1982 Trans-Am
Engine: 355 w/ ported 416s
Transmission: T10, hurst shifter
Axle/Gears: 10 bolt, true-trac, 3.73
yea, you've got the cam and cranked lined up to each other.

The fact that you're not on #1 firing isn't used yet because:

you can't fire up the car yet, you still have to set your lash right? So you put on your timing chain cover, then go and lash your valves, meaning you rotate the engine over by hand like 10 times. By this time you have no idea where those pesky dots are anymore. So you stick your little pinky in the #1 plug hole and rotate it over till you feel the puff of air. Apparently your dots will be both pointing to 12 o'clock, but I never had the curiosity to pull my cover off again to check. Anyway, then you set up your dist.
clear as mud?
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