1998 550 Maranello "sorting" thread--DIY

This is a tough question because I am not an engineer but let me give it a go.
The timing method detailed by Ferrari in the WSM is a "lift at TDC" method, which means you are measuring the amount of deflection (in mm) of the hydraulic tappet's surface from its neutral position when it is touched by the camshaft. The assumption is that the lifter that is NOT being touched by a cam lobe has fully returned to it's correct neutral (rest) position. So when a lifter's cam lobe is on the base circle, and the cam lobe is NOT touching the lifter, the lifter is sitting in a rest position. That rest position is maintained by the plunger spring inside the lifter, even if the lifter is incompletely filled with oil at that instant.
So theoretically, this should indicate that the amount of oil in a lifter should not make any difference when setting the timing, because you are not measuring valve travel to set timing, you are only measuring tappet surface travel. Of course if your lifters have incompetent check balls and leak oil under pressure, they may not transmit the proper force to the valve stem and therefore result in poor valve opening, but this is not something that impacts the actual "setting" of the timing.

Am I correct here?

 

Carl,
There are a couple of well-known Ferrari mechanics who have stated to me and in other threads that this spacer is necessary to replicate the force placed on the oil chain sprocket by the harmonic damper.
PK

 

Spent the weekend doing odds and ends, among those things pressing new cam seals (Photo 1)

Now that everything else was done it was time to reinsert the camshafts into the heads and prepare to set the timing.
The MSW insertion tool functioned perfectly. Installation of the cams using this tool was basically the reverse of removal. Remember, the cams must be reinstalled with the assembly marks perfectly lined up with the cam cap marks with the number 1 cylinder at TDC. (Photo 2)

Once the tool has fully seated the cams, replacing all cam caps and washers/nuts is tedious. All nuts must be torqued to 9 Nm. Don't get lazy, this is an important part

Apply the cam cogs, as you will need them in place to apply the belts. Note the motor still resting at TDC. (Photo 3)

It isn't too particularly important that you put the dowels in yet...leaving them out will help you to manipulate the cam cogs just a bit to make sure the belts fit on correctly. Do NOT rotate the crank without the dowels in, however. Once the belts are on you can pick a dowel hole on each cog to put the dowel in, whichever one fits, and then hand tighten the cam bolts. Once all of this is done, loosen the 19mm tensioner bolts and let the tensioner snap the belt tight. I will not be formally tensioning the belts until I have already set the timing this time.
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This is the Super Bowl for me...this is what I have wanted to get as perfect as I could, even better than last time.

Here is a detail of the Vernier gear setup. (Photo 1)

At this point, the motor is at TDC, the cams are in, cogs are in place with dowels in, cambolts finger tight, and the belts are on with spring tension only. I now will set up a dial gauge, with the pointer touching one of the two intake tappets of cylinder one. (Photo 2)

To time the intake cam of bank 1-6, rotate the engine in the driven direction only (clockwise) until the degree wheel is somewhere before TDC on the NON-FIRING stroke. Lets say 40-50 degrees before TDC (Photo 3). At this point the intake lobe is NOT exerting any pressure on the intake tappet and the tappet can rotate freely in its seat.

With the engine at 40-50 degrees before TDC on the non-firing stroke, the intake and exhaust cams of bank 1-6 look like this (Photo 4)
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Once you have put the dial gauge down on the intake tappet of cylinder one with the engine at 40-50 degrees before TDC on the non-firing stroke, zero the gauge.

Rotate the engine in the driven direction, stopping on exact TDC of the non-firing stroke. The gauge should read 0.70mm +/- .05mm. If the gauge doesn't read exactly this, the relationship of the cam to the cam cog must be altered. How you do this depends on how far off you are. If you are just a few hundredths of a millimeter off, you can just loosen the cam bolt and tap the cam lobes with a rubber mallet either advanced or retarded until your gauge reads correct. This point will be the exact timing that you want the intake cam to be set to. If you are more than a few hundredths off, you may need to remove the dowel prior to tapping the cam and moving it enough one way or the other where you would need to put the dowel in a new hole.

Don't pat yourself on the back yet, it isn't that easy. It's easy to set the timing on the cam, but you then have to TORQUE the cam bolt in place. Torquing this damn bolt almost always shifts the cam OUT of spec. You torque it, rotate the engine over again, and discover that your cam is out of spec again. Pisses you off.
I'm going to give away a secret, something that I discovered tonight. The way I managed to get my cam torqued exactly right was to tap the cam until the lift at TDC was 0.82mm. I selected a dowel hole, tightened the cam bolt until the dial gauge just started to move a little, and then fired the impact gun on the bolt. The end result with a torqued cam bolt was this (Photo 1)

No matchbooks under the caps or other wierd shizz required.

With my intake cam of 1-6 EXACTLY correct, this is what the assembly mark looks like for that cam (Photo 2)
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John,
I found TDC the "Ferrari" way; at the exact point that the piston reaches TDC.

I did not specifically measure dwell, but I would say that 1-2 degrees is about accurate.

I can provide these other measurements if you inform me how to measure when the lobe is centerline. I assume you put a dial gauge on the tappet and figure out exactly when the gauge changes direction (similar to finding TDC) as the centerline passes?

 

We must be fun to laugh at, eh?