As expected, the 7-12 Bank's cam timing was off. RIFLEDRIVER and FoS were both correct in their conclusions based on the gas analysis. THANKS to RIFLEDRIVER (Brian Crall) for his input and experience! That said however, don't get me started on FoS :-( NOW, I know why the tech (not RIFLEDRIVER or FoS) had to "punch out the catalyst" from the driver's side pre-cat during the 1997 Major Service. :-( Don't get me started on that shop either! This serves as a lesson learned - NEVER trust that the cam timing is correct and merely change out the belts! At least ONCE, the first time you are in a particular engine, you MUST check the timing! One 'may' avoid it the second time around - but for me, I'll do it each time. In my mind, it is like a hydrotest - it CONFIRMS everything before you waste the R&R labor. Still need to check the Bank 7-12 exhaust valve...... Life Is Good! Vincenzo
on my cams I have three holes and a dowel pin goes in one of the holes. Was your bad cam's dowel in the center hole?
Have not yet opened up the system - all the work to-date is baseline on the current system. Will advise soonest. Life Is Good, vincenzo
Here is the data collected on the last cam (Exhaust 7-12). The raw data was so good, only four runs were needed to convince me that the data was sound. The outcome is amazing: Both the OPENING and CLOSING events were determined within four digits of accuracy! BOTH events calc out to 2.524 degrees LATE!!! Without "doing the math" it would appear that the opening was 3 degrees late... and the closing was 2.047 degrees late. These numbers are impossible for a symmetric cam. BOTTOM LINE: DO THE MATH! Life Is Oh, Sooo Good! vincenzo Image Unavailable, Please Login
Here are the final results now that the technique and math have been fully developed. Bank 1-6 IN SPEC (within 1 Deg or less) Cyl No.1 IN: 0.50 Deg Late Cyl No.1 EX: 0.09 Deg Late Bank 7-12 OUT of SPEC Cyl No.7 IN: 3.96 Deg Early Cyl No.7 EX: 2.52 Deg Late As a reminder, the pic shows the gas analysis values that the engine mustered with the above shown cam timing (fall 2008). HC on Bank 7-12 was way off. Here is the discussion that we shared back then: https://www.ferrarichat.com/forum/boxers-tr-m/212871-tr-major-fcar-dealer-assessment.html RIFLEDRIVER's 2008 input was spot-on. Thanks again! Life Is Good, vincenzo Image Unavailable, Please Login
thank you for this real good information but why you nopt meassured also each single cylinder also? would be interesting to see the HC how it will be different, may be also 1 or more injectors have not working right? I think the reading have been at idle? what was changing when accelerate?
The gas analysis was done in '08 by the Ferrari Dealer. The analysis was only thourogh enough for diagnosis. In theory, all cylinders on each bank would be approximately the same. The car was stationary during the testing - presumably at idle. I have little detail from them on their procedure. At the time ('08), the injectors were new. After the long storage, they are now with CIS for cleaning and analysis. Sorry - but I have no more detail - just the Dealer's conclusions. Life Is Good, vincenzo
The sprocket to cam is a pinned connection held in place with a bolt. With the pin in place and the bolt not yet torqued - Look At The Lash! [ame]http://www.youtube.com/watch?v=qYpq0jBwoL4[/ame] This lash MUST be eliminated in a consistent way. There is NO way to change the cam seals and return to the previous cam timing unless this lash was, and is consistently removed. How did the last tech handle this when the car was last serviced!?!
At the last service, I did not consistently remove the lash :-( Check here for detail: http://www.ferrarichat.com/forum/boxers-tr-m/513210-83958-major-2016-tear-down.html Life Is Good - but not consistently! vincenzo
That would certainly help, but with the right technique and a full awareness of the need to consistently take up the lash during assembly, it won't be an issue. The real Lesson Learned is that there is no way to 'just change the belts' and expect the cam timing to remain unchanged..... unless of course, you do not remove the pully to change seals. You never know if the previous tech properly and consistently took up the lash during assembly. Life Is Good, vincenzo
...but before getting too far, these pics capture the current state of affairs. These marks were captured as the system was going back together and may be a bit off due to the lash issues previously described. Image Unavailable, Please Login
final pic of how it "was"... KEEP IN MIND: the degrees shown here are crank degrees... divide these numbers by 2 to get camshaft degrees. Image Unavailable, Please Login
...tells me what is needed to get the cam timing correct. Lash issues may have distorted the original timing results and as such, this timing correction may require an additional iteration. We'll see..... Having just set the bank 7-12, it is pretty easy. Just realign the pin and holes per the calculations and then set the belt in place while rotating the cam (as indicated) to get the nearest tooth to line up. One tooth is over 7 degrees of rotation, so with a correction of 4 degrees or less, it is just a matter of jumping into the nearest belt slot. Image Unavailable, Please Login
The spreadsheet shows where the dowels were. Each cam has 3 holes and each sprocket has 13. Note: Moving the pin in the cam counterclockwise (negative number per my convention), ADVANCES the cam Moving the pin counterclockwise in the sprocket, RETARDS the cam. Easy to get confused if you don't think it through!
This pic shows the intake cam on bank 1-6 as the belt was being fitted. Refer to the spreadsheet in post No.42 and you will see that the sprocket's pin was moved clockwise in the cam by one position. The pin remained in the same sprocket hole. As a result, the belt moved by 3 teeth in a clockwise rotation. The spreadsheet directed that the cam be rotated in a clockwise direction until the belt slides into place. Image Unavailable, Please Login
When a hard steel surface slides over a softer steel with high compressive loading, galling is a typical result. The crystal structure actually tears and then friction welds itself into lumps. Ferrari quotes torque on clean and dry threads. At my last service, this resulted in galling on the soft washers under both the cam bolts and tensioner bolts. The pic shows a typical example (cam bolt's washer). For this service, the minimal galling lumps were removed with a bit of scotch-brite. The area under the bolts heads was then coated with a very thin layer of anti-seize. The threads were left clean and dry. Image Unavailable, Please Login
...the engine was rotated several times with the cam bolts lightly, finger tight. This rotation ensures that the lash issues (as shown in post No.34) are eliminated. The tensioners were then tightened at their greatest inflection depth to ensure that they are exerting full pressure on the belts. The tensioner depth is easy to judge with this setup. Tomorrow... the cam timing will be double checked! Image Unavailable, Please Login
Here is a before and after pic of the cam timing marks. The Intake Cam for Bank 1-6 went from 0.5 Deg retarded to 0.25 Deg advanced. I was aiming for 0.1 Deg advanced. :-( but getting precision down to less than 0.15 Deg seems impractical. Regardless, the factory spec calls for a tolerance of +/-1 Degree, so the 0.25 (+/-0.15) should be just fine The measurement system and methodology was the same as before. The total measured duration (242 Deg) was the exact same value as the first measurements. Everything looks great so far. Life is getting precise! Vincenzo Image Unavailable, Please Login
Here is a before and after pic of the cam timing marks. The Exhaust Cam for Bank 1-6 went from 0.09 Deg retarded to 0.19 Deg retarded. The cam settings were unchanged from their original positions. The precison of the 'new' measurements are 0.1 Deg off from the original readings. On the intake cam, the precision was seen to be 0.15 Deg.... so this result of 0.1 Deg is even better. Regardless, the factory spec calls for a tolerance of +/-1 Degree, so the 0.19 Deg +/-0.1 is an excellent result. The measurement system and methodology was the same as before. The total measured duration (242.7) was 0.57 Deg greater than the original readings. Everything looks great so far. Life oh, so precise! Vincenzo Image Unavailable, Please Login
Hi Vincenzo, I remember seeing your "after" 7-12 cam pictures on someone else's thread. I just can't find them. Do you still have them? Thanks, Jeff
Sorry Jeff, I didn’t bother saving or documenting (?) the relative positions on the 7-12 bank. The overall story is the same.... these cam marks can only be relied upon for the initial mounting of the cams. Without a large degree wheel, top line instrumentation and a lot of care... the timing will be impossible to get well within spec. Close counts in hand grenades... but not timing. One other point to reiterate... this setup (ipad mirrored to an apple tv with front mounted display) appears to be rather silly, but it really worked well. I highly recommend it. If you can’t see precisely what is happening.... you will never achieve precision. Seeing an awkwardly oriented gauge on cyl 12 (far back, right side of engine) is nearly impossible. Image Unavailable, Please Login
