CAM and Crank Alignment

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  #1  
Old 10-04-2010, 05:37 PM
rkiefer2's Avatar
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Default CAM and Crank Alignment

I recently installed a Comp Cam 274 into my 327 camaro. When I installed the timing chain to the cam shaft I alinged to two dots at the 12 o'clock position for the crank and 6 for the cam. I used the existing sprockets, which I hope doesnt screw me.

After getting everything together I'm getting gas shooting out of the top of my brand new edelbrock carb 18064. What the heck is causing this? Cam out of phase with crank?

Thanks,

Roger K.
 
  #2  
Old 10-04-2010, 10:16 PM
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Your distributor is 180 degrees out of phase. When the sprocket marks are facing each other like you had, the engine is at TDC compression stroke with the #6 piston. You needed to rotate the engine 180 degrees until both marks were facing up, which puts the engine at TDC compression stroke with the #1 piston. Then you install the distributor to point to #1.
This animated gif helps to explain it visually. http://shbox.com/1/cam_timing_ani.gif
 

Last edited by Camaro 69; 10-04-2010 at 10:20 PM.
  #3  
Old 10-06-2010, 12:55 PM
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That was a great explanation! I've been screwing that up for decades, and never could figure out why, I just always had to pull the distributor on almost every engine I built.
 
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Old 10-07-2010, 05:38 AM
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Thanks for the reply and pic for the timing chain. 90% sure that was the problem. I need to set the timing now. Called Comp cams and got 2 different answers on 2 diff occasions. First was 38 degrees second call they said th start with 8 degrees advanced. Based i my limited knowledge 8 seems closer.

327 SBC
World heads
Flat top pistons
Comp ratio 9.6:1
274 comp cam 488 230/236

What should i set my timing to at idle?
 
  #5  
Old 10-11-2010, 11:45 AM
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I'd start with the 8 to 10 degrees, at idle, with the vacuum line disconnected and plugged.

38 degrees would be more for the full advance, when the engine is revved up, if you have the capability to measure that.
 
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