Lusso Valve Timing
During my test drive of the Lusso at my shop, I noticed a noise from the throw out bearing in the clutch assembly. Since I needed to do some work on the engine, I would check the clutch assembly when the transmission came out.
With the transmission out of the car, I wanted to take a closer look at the flywheel in regards to the valve timing. On previous test drives, the car just didn’t seem to develop the power I was expecting from a rebuilt engine with so few miles. This engine was rebuilt about 20 years ago, but has not been driven very much. I performed compression and leak down tests and the numbers were decent, but I still felt there was more power to be found. Although my suspicions were from my gut, I also found there were signs this engine wasn’t properly set up. The first clue was the replacement flywheel installed on this car. Although it had the ignition timing marks there were no valve timing marks on the flywheel. I bolted back to back to this flywheel another flywheel I had at my shop that had the correct valve timing marks so I could transfer the valve timing marks that were missing.
The marks I needed were “AA 27” and “CS 16.” I forget the Italian translation for these letters, but AA is for the intake and CS is for the exhaust. Ferrari doesn’t use lobe centers to time the valves, but rather the moment the roller follower touches or releases the cam lobe. AA designates the moment the intake valve opens during the intake and exhaust valves overlap stroke, and CS designates the moment the exhaust valve closes.
It’s much easier to adjust valve timing with the engine on a stand, but since the transmission was out of the car, I made a tool so I could turn the engine by hand. The ratchet had to be long enough to do it from the top side of the engine and I removed the distributors so I had enough swing.
My suspicions were confirmed when I put the cams on P/M 1-6 and found both cams on the factory marks and yet the actual cam timing was off from the newly marked valve timing marks. Without cam timing marks on this replacement flywheel, the previous mechanic may have simply reinstalled the cams on the factory marks. These marks were placed on the cams when they were installed at the factory. How the cam sprockets are installed, new chains, new valve seats, valves, and adjustments all affect the orientation of a cam, so “timing” a cam to the actual position of the cam changes. Installing everything to the factory marks will get you close, but may not actually be correct.
I checked both cams and found them about 2 degrees late on valve timing. That might not seem like a lot of difference, but since Ferraris make a lot of their power above 4000 rpm, a couple degrees of valve timing can make a big difference.
The next step will be to disconnect the bolts holding the cam sprockets to re-time the cams. This process involves jumping the teeth of the timing chain on the sprocket to retard or advance the cam without losing tension on the chain, dropping the chain, or skipping a tooth on the crank sprocket. For every 7 teeth jumped, 1 degree of movement is adjusted. It’s a tricky job to do, only made harder when the engine is still in the car!
Thanks to everyone who donated already to my December Pledge Drive. I create content for this website and YouTube Channel because I love sharing what I learned and the experiences around cars with everyone on the Internet. I hope it’s entertaining to you as it is for me, but it’s information like valve timing a V-12 Ferrari that I learned from my mentor Francois Sicard that I simply don’t see on the internet. You may not take this information and adjust your valve timing on your car, but helps you understand the process so you can have these discussions with your mechanic. I get emails from several people a month with questions about where to buy certain Ferrari parts, who to send a particular part to rebuild, or how to fix something that broke. Much of this information is found by mining the data on my website and forum, but I am always happy to answer and help these queries. I try to find time in my day to answer these questions and phone calls for free, and have to admit some people abuse this access, but most people are respectful of my time and appreciate the help. This pledge drive is also the one time a year for those that I helped to consider contributing if you haven’t already. Thanks again!
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PO Box 36
Hollowville, NY 12530