Ferrari 412 - Failed Inspection. High HC and CO Values

Nobody wants to argue with you!

OP has been recently struggling with the injection "on his own" for one year (https://www.ferrarichat.com/forum/threads/ferrari-400-412-k-jetronic-metering-head-rebuild-myths-and-advice.653663/page-2#post-148385052). I really think he should perform extensive tests on his prior work, before messing with the camshafts(as long as they are aligned with the factory markings).

It is also my understanding that OP has virtually zero access to anything like a knowledgeable vintage Ferrari mechanic or Bosch Service where he lives...

 

Where is ... here?

 

Some basic reference information - PM 1/6 is top dead center for cylinder 1. With correct cam timing, both the intake and exhaust valves on cylinder 1 should be completely closed. For the other bank, PM 7/12 is top dead center for cylinder 7. Again, both the intake and exhaust valves on cylinder 7 should be completely closed. These flywheel mark are not used for setting the intitial timing. There are two AF 10 marks on the flywheel which are used for setting the initial timing of each bank. These marks give a 10 degree distibutor advance at idle. It's very common to put white paint on the AF 10 marks so they are easy to see with the timing light.

 

I read PM | 1-6 in your photo, not AA 16.

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TDC is translated in Italian as PMS, so "PM | 1~6" in your photo should be what @wmuno suggested. So using this mark seems appropriate, although the workshop manual recommends to use a tool to identify top dead centre (see section B42 for the detailed procedure).

The other marks are used with a dummy timing light. If you do have an adjustable timing light you can use the same TDC (PM16) mark to check ignition timing. As your ignition is relying on a modern hall sensor, there is not much to do, except to check that both banks do have the proper advance at idle.

 

There are both Cam Timing marks and Ignition Timing marks on the Flywheel. In your photo:

CS 10 = Exhaust closes 10 deg ATDC
PM1-6 = TDC for #1 and #6 (and the cam marks are intended to align in this position, but can be off some as Brian indicated).
AF 8 = Warm idle ignition occurs at 8 deg BTDC (as you noted, not adjustable, but useful as a check to make sure things are working correctly)
AA 16 = Intake opens 16 deg BTDC (not in your photo, but it's there)

Usually the mechanic uses a degree wheel mounted to the crank snout for the cam timing events rather than using the cam timing marks on the flywheel (but they should agree, and, if you don't have a degree wheel, they can be used to check things when "closes" and "opens" are defined correctly).

 

On other cars I have, using the wrong hall sensor (eg: sensor at the edge versus sensor in the middle of the bracket), would offset the ignition, but I doubt several sensors were made for the 412.

From memory the 412 does have vacuum compensation, maybe your ignition does not receive a proper vacuum signal?

In any case just check ignition with a timing light. Less guesswork.

 

Your black-box does not appear on the "standard" ignition diagram (54). This being said, cars equipped with catalytic converters do have specific parts not shown on the diagram (coil-pack is different).

Overly retarded ignition can cause black soot on the spark plug (see How To Read Spark Plugs by NGK : https://ngksparkplugs.com/en/resources/read-spark-plug).

I stand by my comment that the Ferrari recommended spark plug heat range is very cold (equivalent to NGK BP8ES), and not suitable for prolonged idling (low heat range + idling > cold combustion chamber > same effect as running overly rich). With all this soot, I am not even sure your engine is firing properly. A set of BP6ES (last resort a BP5ES) would handle all these deposits more easily. This will not cure your problem, but at least will make your life less miserable while you tune the car.

 

Always fun to learn a little technical Italian.
(Please correct me if I'm wrong)

CS = Chiuso Scarico (shut exhaust)
PM = Posizione Massimo (position maximum)
AF = Avanzare Fuoco (advance fire)
AA = Aspirazione Aprire (intake open)

 

I just know the technical Italian that I've come across in the various F technical documentation (where they often have the same thing in 4 languages) which most often shows:
CS = Chiusura Scarico (Exhaust Closing)
PM = Punto Morto (which, I believe, literally translates as "Dead Point" so can see how that corresponds to the English expression "Top Dead Center")
AF = Anticipo Fisso (Fixed Advance)
AA = Apertura Aspirazione (Intake Opening)

 

For your car the AF 8 would be the timing marks indicating a 8 degree advance at idle. Since you can't adjust your distibutor, you could use these marks to check the distibutor timing. The AF marks are not used used for cam timing. You are correct in using the PM 1/6 mark for cam timing..

 

Are you saying that (using the correct definitions of "exhaust closing" and "intake opening") the pointer is not aligning well with the CS10 and AA16 flywheel marks?

 

Let me ask "how did you verify that it was off-timed?" Did you use a degree wheel or something else?

 

The 400i inlet camshafts are retarded 4° compared to the 412, and we even see 400i with overly stretched timing chains (i.e retarded on both inlet and exhaust) that still run without all the soot seen on the previous pictures.

Just wondering how many degrees off we have here?

 

you cannot be off that much or you would bend a valve. The cam is specified for a certain valve clearance. Did you adjust the valve lash for that clearance before you checked it?