1998 550 Maranello "sorting" thread--DIY

Brian's points are well-taken. I for one hate the degree wheel. Its a pain in the ass, and then if you hit the pointer stalk it is so much more work to go back and find TDC again.

When I time bank 7-12, I will illustrate how to do it without a degree wheel.

 

Now that correct timing has been set on the intake cam, the next step is to set the same bank's exhaust cam.

To do this, leave the engine AT TDC on the non-firing stroke, where you had just stopped it to measure intake cam lift.

Move your dial gauge over to one of the two exhaust tappets, applying the pointer as parallel as you can get it to the direction of tappet travel. As was alluded to earlier, this is why I have a solid curved pointer.
Once the pointer is applied to the tappet, zero the gauge.

Continue to rotate the engine in the driven direction beyond TDC of the non-firing stroke. As soon as the crank begins to turn the dial gauge will deflect and eventually stop as you rotate the engine further. Exhaust timing is correct if the gauge reads 0.69mm +/- .05mm.
The process is the same for adjusting the exhaust cam as for the intake, with the exception of the fact that you cannot tap the cam into place while watching the dial gauge like you can with the intake cam. You have to trial and error it repeatedly, making fine adjustments in a systematic manner, until you have the exhaust cam torqued in spec.

Perfectly in spec, the assembly marks of my 1-6 exhaust cam look like this (Photo 1)

NOT spot on.
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Sark...refer to post 298 in this thread. That's where I defined what I am referring to as "firing" versus "non-firing". Maybe the WSM says it differently.

The way I am using the terminology, TDC on the "non-firing" stroke is where the intake valves have just begun to open and the exhaust valves are just about finished closing.

 

John,
Thank you for the diagram. Is it a general one or one specific to the 550?

It is a very good diagram because in the timing check description in the WSM they refer a couple of times to the "crossing" without defining what that means to us laymen.

Sark, I know that the timing description in the WSM states "with cylinder 1 at TDC during COMBUSTION", but that is just the place they are telling you to zero the dial indicator for reference. At that point the cam lobe is not touching the tappet. They then tell you to rotate the engine over 360 degrees, approaching the "crossing", which is what I am referring to when I say "TDC of the non-firing stroke".

 

Is there such a thing?

I will now time the 7-12 bank without using a degree wheel, using only dial indicators.

The first dial indicator is placed into the spark plug hole of cylinder 12, and a second dial indicator is placed onto one of the intake tappets of cylinder 12. With the cams in a position approaching the "crossing" (intake cam lobe is almost ready to start exerting pressure in the intake tappet but the tappet can still rotate freely in its seat), you zero the gauge on the intake tappet. (Photo 1).

Continue approaching the crossing, until the dial indicator in the spark plug hole indicates you have just reached TDC (the Ferrari way). I had previously set this dial indicator to zero for ease. At this instant, the reading on the other dial indicator should read .70mm +/- .05mm. Adjust the cam as needed (previously described), and torque down the intake cam bolt. Once the bolt is torqued, rotate the engine over several times and make sure that everything is correct. (Photo 2).

With my 7-12 intake cam timed correctly, this is what the assembly mark looks like (Photo 3)
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Now that the intake cam is perfectly set and torqued, remove the dial gauge from the intake tappet and move it to one of the exhaust tappets of cylinder 12.

Rotate the engine over 720 degrees and stop it on exact TDC at the crossing. At this point, zero the gauge on the exhaust tappet (Photo 1)

Now that the gauge is zeroed, you can continue to rotate the engine in the driven direction past the crossing and note where the dial gauge on the exhaust tappet stabilizes. The gauge should read 0.69mm +/- .05mm at this point. After adjusting the cam and torquing the bolt, rotate the engine over again and repeat the reading. After adjusting, readjusting, cursing, and retorquing for about 45 minutes this is the final fully torqued product. (Photo 2)

Correctly timed, my 7-12 exhaust cam assembly marks look like this (Photo 3)
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I knew you would notice!
I can assure you that they are not "actually" parallel, they are more divergent than they look...but there is no question that the indicator stalk is not EXACTLY in line with the axis of travel of the tappet. I am limited by my equipment. This is why I fought so hard to get it right on the money, so if I was off a bit because of this angle issue that it would still be within reference range.

If you think it would end up out of range due to this issue, maybe I should order some more "angular" dial indicator holders to make it perfect? Any suggestions?

 

Understood. Well my philosophy on something like this is do it right or don't do it all. My idea for the perfect way to do this would be bolt a steel plate to the head "sill" on which a high quality magnetic base dial indicator holder can sit; one that has many angular adjustments possible on it.

Some of these magnetic base indicator holders I have seen and used are rather chintzy....do you have a favorite brand of holder that is sturdy and durable?

 

Carl, thank you for your kind offer.
In truth I have a couple of those tip kits that have all sorts of curved pointers for this purpose. That isn't my issue. It is that the valve tappets in this car are angled "outwards" a bit relative to the spark plug holes so that in order to get the best reading the axis of my dial gauge needs to be tilted. With it bolted directly to the head, the tools I have do not allow for a rotational adjustment of the actual gauge to make the shaft's travel exactly parallel to the axis of travel of the tappet.

I think this is what Brian is referring to.

 

Is there any value to those infinitely adjustable types, like below?
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