Ferrari 412 - Failed Inspection. High HC and CO Values

If the PM7-12 mark is 60 deg of crankshaft/flywheel rotation after the PM1-6 mark (edit: raemin's figure confirms that), then use cyl #7, but the order of the marks would be:

AA16 (for #1), PM1-6, CS10 (for #1), AA16 (for #7), PM7-12, CS10 (for #7)

A cylinder fires every 60 deg of crankshaft rotation so the PM mark for the "other bank" cylinder should be (60 deg * the number of steps in the firing order away from cyl #1), but this can be in either direction in the firing order (for example, on a TR, the PM1-6 mark and the PM7-12 mark are 180 deg apart on the flywheel, but cyl #7 fires 3 steps before cyl #1 in the firing order, not after). You've always got the final double-check that the cam cap marks on the 7-12 cams should be reasonably close when the flywheel is at PM1-6.

 

Since that is the other one with the 0.5 mm clearance, that is the one you are using for cam timing.

 

Is the flywheel not a degree wheel? Have you ever done it both ways? I have. Now explain the advantage of a degree wheel for me please.

 

Makes no difference. Most of us use 12 because it is at the front and easier to access.

 

This is what I was wondering looking at my cranckshaft the first and last cylinder of a given bank do seem quite aligned: do you mean cyl 7&12 are at tdc at the same time, (just firing at a different rotation)?

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And? Its a 4 cycle engine. TDC happens every engine rotation but cams turn at half that speed. Turn engine one more rotation and it will be at overlap, the position where cams are timed.

 

On an inline 4 1 and 4 piston are always at TDC at the same time. 2 and 3 are as well. On an inline 6 1 and 6 are the same, 2 and 5 are the same and 3 and 4 are the same.
On a V or Flat 12 1 and 6 are the same, 2 and 5 are the same, 3 and 4 are the same, 9 and 10 are the same, 8 and 11 are the same, 7 and 12 are the same.

Been that way forever.

The basics should come at the beginning and the details and nuances later but its way too late now I guess.

Look at the crankshaft. If that does not define self explanatory I don't know what does.

 

One is called "TDC compression", the other "TDC overlap". Ferrari in print refers to overlap as "at the crossing".

 

Years ago, I found it helpful to take a few courses on “basic” principles of combustion engines at our local community college. This video is great and you can see how someone might accidentally set things up at TDC on the overlap not the compression stroke.

 

Lets not confuse the issue any more than it already is. Overlap is exactly where cam timing is measured.

 

In Aston Martin tech data, that is known as "decoking the cylinder heads".

 

Bad timing and bad fuel mixture ..the same thing this whole.thread is above

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With cam timing so far off it was probably aspirating a lot of combustion byproducts back up the intake tract.

In a suit I was a retained expert in I showed how cam timing led to catalytic converter particulates being in the intake plenums.