Just a warning: the factory reference markings in the F engine may not always be right.... We found out after extensive search that on one camshaft the reference mark was not O.K. .... On that camshaft it resulted in a 15 and 20 degrees difference on the meters. This resuted in our case that the lower right bank camshaft will be correxted one klick. The official NL Ferrari Dealer confirmed this; they have had some other identical problems themselves. My message it just: not only use the official reference marking but have (at least once) checked exactly on your engine if all is O.K. We also found a not-O.K. valve on the side of the engine which we will repace. Has any of you also had experiences like this ? Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
What you experienced is quite normal and why Ferrari says to always use a degree wheel to time cams. The marks are really not timing marks, they are assembly marks.
Thanx Brian, (of course you are) correct ! But a lot of people and (F) shops don't seem to know that ... At Engine-Out's they only look for the markings on the 4 pulleys... and then "**** happens" ... Happy my mechanics found it out this time ! Also the secondary airvalve was made airtight with some gun-gum or so... will be replaced straight away... Stragely, one SKF belt-stretchbearing was loosing fat... maybe has been too tight... all will now be replaced... Engine will be as new again next week ! :-0)
I've experienced this exact deal on a Dino V6. Are you checking the timing at Ferrari's recommended 0.5mm (.0197")? Also, are you going by lobe center?
A good engine building shop told me to use the american standard for setting cams of .050" . The logic being twofold: the motor starts to really breath at .050" opening -and the cam ramps are too sensitive to get lobe center correct. Lobe center (LC) is the cam position that equates to max opening and center between the opening and closing ramps. Example: Take a BBi intake spec of opens 12 btdc / closes 52 abdc, the LC is 12 + 180 + 52 (=244 duration) /2 =122 (now -12) gives LC= of 110 atdc. It is fairly standard cam design nomenclature used by engine builders to describe engine setup. If you do some web searching, you'll uncover much info. Race motorcylcles, piston aircraft, on and on...... Personally I like the concept of opening and closing events specifically being considered, but lobe center covers both. ie advance LC helps lo-revs, retard LC helps hi revs etc. Anyway, my specific experience (IMHO, your mileage may vary, insert disclaimer here): I was doing this very detailed Dino rebuild and when it came time to set the cams, I checked them at .5mm (.0197") open & close AND .050" open & close to get the LC. The Ferrari marks were spot-on using .050" and one intake cam was slightly off at .5mm. Recall my first paragraph. I chose the books .5mm setting for my final choice. Being a carbureted engine, I discovered one bank breathes differently than the other during carb setup. On an injected engine this variance would be lost in the noise on setup, but the early Dino carbs do not have compensation for this. I just accept it for now and will reset that one cam later owing to the fact it's a huge chunk of work to get back in there. I have a hunch this will correct the imbalance. I'd love to hear more experienced mechanics opinions.
