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3.2L Carrera Timing Question

Hi everyone!

I know this topic has been beat to death but I have a concern about my timing that I just finished on my 3.2 Carrera. I do have three books (Bentley and two of Waynes) that spell it out but I must have mis interpreted something. To get to the point, Cylinder 1 at Z1 was easy, Bentley specs out 0.049 inches (on my dial I went counterclockwise to 0.049") for my valve overlap adjustment. I followed what I believed to be the right procedure for Cylinder 4 and had relatively no problems getting my Z1 around 0.049 (actual was 0.0481), but with both my Z-blocks on cylinders 1 & 4, I noticed that both intakes open at the same time and exhaust as well. Since my crankshaft is controlling my pistons going up isn't this right to have 1 & 4 operating in sync? I read on some other threads that 1 & 4 should be out of sync, I'm a bit tired and confused right now, please help.

Thanks,

Alex

Oh, some pictures attached.


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1974 Porsche 911 Coupe, RSR Project
1976 Porsche 911 Targa, Black
1986 Porsche 911 Carrera, Black
2006 Porsche Cayenne S, Black
Old 04-14-2007, 05:26 PM
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Cylinder 1 and 4 should be 360 degree crank rotation apart.
With two rotations of the crank ZI at TDC for cylinder 1 then rotate crank 360 deg and Z1 at TDC for cylinder 4 next rotation (720deg).
Looks like some of that plastic wrap needs to be removed to index one of the cams 360deg (crank position) from present position.
Paul
Old 04-14-2007, 06:26 PM
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Paul,

Thanks for your input, I believe that I did follow that part of the procedure, at least I hope so. So when pistons 1 & 4 are going upward toward the spark plug and near Z1 point, both of my intake valves are beginning to open. This is the point where my two gauges start registering a measurement and then when Z1 is lined up the the case part line they both measure identical values approximately 0.049 inches. Is this correct?

Thanks,

Alex
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Its easier asking dumb questions than fixing dumb mistakes
1974 Porsche 911 Coupe, RSR Project
1976 Porsche 911 Targa, Black
1986 Porsche 911 Carrera, Black
2006 Porsche Cayenne S, Black
Old 04-14-2007, 07:37 PM
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Alex
What you describe above is WRONG!!
If cyl 1 & 4 were to open inlet valves at the same time, we would expect that we would also provide ignition to 1 & 4 at the same time. This is not the case, e.g. plug wires from distributor are 180deg opposed which is 360deg of crank rotation.

You have the timimg for left side cam shaft set up. Leave left side as is. Rotate crank so Z1 at TDC with cylinder 1 just starting to open inlet valve. Take any tension of the cam lobes of the right side by backing off the rocket adjust screws cyl4, to prevent cam rotation. Now loosen off right side cam gear bolt, and locating pin, then rotate crankshaft clockwise 360 deg. Providing the right side cam did not move while rotating the crank 360deg this should provide the approximate location do re-start the cam timimg for the right side.

deg crank ------ 0 --- 120 -----240 ----- 360 ------ 480 ----- 600 ------720-
cylinder firing --- 1 ----- 6 ------- 2 -------- 4 -------- 3 -------- 5 ---------- 1 (back to 1 again)
deg camshaft---- 0 --- 60 -----120 ----- 180 ------ 240 ----- 300 ------360-
Z1 will line up with center of engine at 0 , 360 and 720 degree.
This is a four cycle engine. Where cylinder 1 is on the inlet stroke (moving away from the head) cylinder 4 is on the power stroke (moving away from the head.
Once this basic point is understood the logic of having the camshaft timing open the inlet valves of opposing cylinders (e.g. 1 and 4) some 360deg of crank rotation apart.



I will try PM you larger 1.4MB 911Engine.gif file of rotating engine.

Paul

Last edited by CruiseControl; 04-14-2007 at 08:46 PM..
Old 04-14-2007, 08:38 PM
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Paul,

Thank you very much, it's clear now. I appreciate your help and time.

Best Regards,

Alex
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Its easier asking dumb questions than fixing dumb mistakes
1974 Porsche 911 Coupe, RSR Project
1976 Porsche 911 Targa, Black
1986 Porsche 911 Carrera, Black
2006 Porsche Cayenne S, Black
Old 04-14-2007, 09:58 PM
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I got it Paul! I realized where I deviated, my mistake. I watched both of my dial gauges and they now read as they should. Cylinder 1 and 4 are in proper timing now and I can watch it hit the exact target of 0.049 inches (at Z1) 360 degrees apart from each other now.

Best Regards,

Alex

__________________
Its easier asking dumb questions than fixing dumb mistakes
1974 Porsche 911 Coupe, RSR Project
1976 Porsche 911 Targa, Black
1986 Porsche 911 Carrera, Black
2006 Porsche Cayenne S, Black
Old 04-15-2007, 09:48 AM
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