12 Valve Engine and Drivetrain Talk about the 12V engine and drivetrain here. This is for 1994-1998.5 engine and drivetrain discussion only.

TDC for timing

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Old Mar 22, 2007 | 10:20 PM
  #1  
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From: Sacramento
TDC for timing

Can anyone explain how to find TDC by using the drop valve method. Can't seem to find it with the timing pin and everyone seems to think the drop valve method is a more reliable.
Thanks
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Old Mar 22, 2007 | 10:23 PM
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From: fryeburg maine
tighten exhaust valve 2 turns. rotate engine in reverse till it stops (piston hitting valve) mark the harmonic balancer using the pickup sensor is easiest.

now rotate engine forward till the piston hits valve in this direction and mark the harmonic balancer using the same side of speed sensor.

now measure 1/2 way between these 2 marks and u have tdc for #1 cylinder.
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Old Mar 22, 2007 | 10:39 PM
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From: Sacramento
Thats easy enough. Now thats two turns on the exhaust valve nut correct? Once I rotate the valve down will the piston only come up high enough to just tap the valve or will it start to push the the exhaust valve back up?
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Old Mar 22, 2007 | 11:19 PM
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You will feel it. If you go too hard you could bend the valve (from what I here).
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Old Mar 23, 2007 | 07:58 AM
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From: dfw texas
before you run down the exhaust valve, make sure you are on the compression stroke. turn the motor over forwards till you see the intake valve go down and back up. then i like to crank in 3.5 turns or so in the exhaust valve. then rotate forward till you see it hit the exhaust valve, then make your mark. then use the alt. nut to rotate it back wards till it hits the exhaust valve again. then mark it again. you can't get tdc with the motor on the exhaust stroke this way.
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Old Mar 23, 2007 | 10:33 AM
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Thanks guys
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