The manual does say to check the timing AS WELL, which to me means in addition, and it also means what I said was a full on cam timing to factory specs. So just how is it that I'm "wrong"? Image Unavailable, Please Login
My understanding of the workshop manual procedures referenced. The 1st procedure referenced is an assembly procedure using the timing marks as a rough reference when positioning the cams. The 2nd procedure is the factory timing procedure to be carried out after assembly. Not an optional operation. Just my understanding. I could be completely wrong!
I just want to clarify: a DIY major is not a "shortcut". You can say it's cheaper, but it's not the quick way to get it done. Opening your checkbook is the quickest way to get it done. The quality of the work done is a completely different discussion. A careful, experienced mechanic who has been properly trained, and more importantly has learned from past mistakes (own and otherwise) will always be a pretty safe bet. But everyone makes mistakes. In my experience, DIY means that the job is going to take 10 times longer than an experienced tech; but I can double, triple, quadruple check my work, asking all the stupid questions and assuming nothing. No one who does this for a living could possibly make ends meet at that pace. The times I screw up are when I have done something before, and I get complacent or hurried. Thus far, I have not screwed up any project that I approached with a healthy dose of fear. Several of those owe many thanks to folks on this board. That being said, a GOOD mechanic will be looking over the entire drivetrain for issues with a trained eye that has seen things go bad. That is arguably where paying someone else makes good sense. They may notice something significant completely unrelated to the cambelts, but discovered on the way. But you have to know who you are dealing with, and a piece of paper that says they are certified doesn't mean anything to me.
These cams were all degreed and are correctly timed. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
These cams are from a TR and are off 5 and 6 degrees. That is more than enough to severly overheat a cat and cause a loss of power and throttle response and power. Image Unavailable, Please Login Image Unavailable, Please Login
And there you have it kids as illustrated by Professor Rilfedriver. So... If you just line up the cams to marks on the caps, and be a lazy butt as I was, your timing won't be perfect. If you want the timing perfect slap a wheel on the crank and time those cams. Thanks for posting the pictures Brian the lesson was a pleasant and welcomed surprise.
Yo, Mr. Kotter. So like .......uh..... what cam timing are we supposed to follow? Image Unavailable, Please Login
While another set of 348 specs say this. Image Unavailable, Please Login Image Unavailable, Please Login
What are the correct specs to set 348 cams to? Because if you set them to one, they will be off the other, and if you set them to the other they will be off another, and if you just set the cams to the marks on the caps will they be on one set of specs and off the other, or off them all??? All of the specs are for a 348. Is it this, or is it that, this, or that???? One has no over lap at BDC and 4° at TDC, while another has 2° over lap at BDC and 2° at TDC, and yet another has 4° at TDC and 8° at BDC? Oh these text books can be so confusing. LOL! What say you Mr.Kotter?
I am in total agreement that the factory marks are not to be followed, but my marks must have been the bearded lady of the group on one bank of cylinders because they line up very well. The other bank not so much though......
When I completed my engine out on my 355 a couple of months ago I also degreed the motor and my marks all lined up. I don't know if the newer cars are degreed more accurately than the older cars....but this is my experience.
In answer to Ernie's earlier comment, the first set of cam timing figures he quoted (14-53-53-10) are for a non-catalyst engine, the second set of figures (12-56-54-10) are for a catalyst equipped engine, and I assume that the third set of figures (10-58-50-14) are for the later F119H engine. I wonder - who's to say the cam timing notches that APPEAR to be incorrectly placed, and do NOT line up after using a degree wheel, were not 100% accurate when the engine was originally assembled at the factory? There has to be a wear factor involved, even if it's only slight. The valve stem has been bouncing off the bucket, the valve head has been hammering on the seat - that's why the clearance changes and the shims have to be replaced to return to the original specs. And there are tolerances to factor in. An intake valve that is adjusted to 0.20mm isn't going to open at the same point as an intake valve adjusted to 0.25mm, but both are going to be set within factory specs. The marks won't line up unless everything is EXACTLY the same as when the marks were originally made, and the engine was totally fresh with no wear on it. I'm also curious as to difference in the notches on the caps as seen in Rifledriver's pictures. Some of the notches appear to be cast into the caps, and some of them appear to have been made with a hammer and chisel. The notches in the caps must have been part of the manufacturing process, but the notches in the cams themselves couldn't have been made until the cams themselves had been timed, as far as I can see. In other words, a new front cap WOULD have a notch, but a new camshaft COULDN'T have a notch. That wouldn't make any allowance for the different cam timing used on catalyst/non-catalyst engines, and the parts books show that the same cams are used on all the 348 engines.
Cams come out of the box with a notch. It is put there during the manufacturing process long before it is even known what motor it is going into. As you say, no provision for different cam timing on all those different motors that use the same cams. In the engine room the guy doing the timing sometimes put his own marks on the back of the cam, all the others are made in manufacturing. When the cams are degreed those marks line up. Part of the reason for showing the TR cams is those are timed differently for cat equipped cars. It is well known that running the non cat timing will make the cats overheat. The part numbers are the same. Timing to insure no cat overheat is only possible by degreeing. Your comment about wear really isn't very valid. Wear that is measureable timing wise would also be visable and the only wear that would matter would be within a couple of degrees of the open event on the intake and the close event on the exhaust. Cams wear the most on the tip of the lobe. By the time it effected the open and close points it would be worn to the point of being unusable. Wear on any other component wouldn't matter with the methods used. And on the wear issue, on 355, .005 inch of valve lift at TDC equals 1 degree. I really think we would notice 5 thousandths cam wear because that is a lot and it would not effect timing enough to prevent it from still being in spec. Ferrari has always advocated degreeing cams and it was not until the 348 where the flywheel is mounted remotely that they didn't put valve opening and closing marks on the flywheel to facilitate that. They have also always provided a method in the drive system to make very small adjustments to achieve correct timing. I have stood over the guys doing it at the factory and have opened many untouched Ferrari motors. Timing marks are not lined up with any consistancy on new motors. Ferraris position is and always has been the marks are assembly marks, not timing marks. All that having been said, the 2 valve motors just dont breathe enough at low lift to be a large issue. When Ferrari went to 4 and 5 valve heads the low lift breathing was so much greater that the cars became far more sensitive. Add cats to the mix and it becomes imperative to time them correctly. Add to that the helter skelter marks that are sometimes seen and doing it any other way becomes real folly.
That would make sence, I guess the marks being assembly marks are just to get the cam "in the ball park" so when winding over you don't smash a valve. The actual timing is done with a degree wheel and dial guage. Once YOU have it set, YOU can put paint marks on the gears to make belt replacement next time quicker, but until **** YOU!!!!!**** have checked it, all the marks arn't worth ****...... Just my 2 cents....
I noticed this thread went towards what should/shouldn't be done and whatnot. But did we ever get an answer to the original question? Basically replacing the belt in place, on a car that is, and has been working fine for the past "x" amount of years? I noticed there was talk about how there may or may not be symptoms yet, and all the things that could possibly happen, how you shouldn't line up using factory marks, etc. But if you were to purchase the car and continue driving it for the next 3-5-7 years (a different discussion on it's own), when time came to replace the belt, would it not be possible to replace the belt without degreeing the cams? IF you purchased the car and decided to do the 30k a month later, that is a different story. But if you have had it for "x" years, let's say 5 years, and have not had any problems, is it not possible to just change the belts without any further negative consequences?
Reading into Miltonian's and Rifledrivers posts, I find it really interesting that there is a separate timing for catalyst equipped and non-catalyzed cars. Given that all 348s imported into US had catalysts (correct me if wrong) and were timed accordingly, then putting on a set of test-pipes (in lieu of cats) will result in an imperfect timing. Would this this cause a problem problem upstream (header or earlier in the combustion chain) or am I reading too much into this? Would a higher flow cats matter as well?
I don't believe so. The O2's are pre-cat and read before the cat so there is no adjustment needed. I do not beleive the cat ECU's effect air/fuel and timing, but I may be wrong. --Mike
For me, when I did my cams I was a lazy butt just lined things up to the marks on the cams and the caps and called it a day. Did it work? YES! Is that the best way? No! I think that the marks on the cams and caps are in between the range of specs given, a generic setting. Now I haven't done this yet but, it would not surprise me one bit if you measured the cam lobes out of different year 348's and find that they have the same lift. With maybe the exception of the "H" block engines, maybe. So why all the different specs? Like has been pointed out, the cars equipped with cats. See the first set of specs I gave (post#34 of this thread) was for a NO CAT 348. The cam over lap for that particular spec is in pic #1 below. The second set of specs I gave (post #35 of this thread) is the next pic (#2 below) is for the same model year 348 but one that is equipped with cats. If you look at pic #1 (no cat) you will see that the intake opens 14° Before top dead center. You will also see that the exhaust closes 10° After top dead center. So the total time both cams are open, or the over lap, is 24°. If you think about it that is one full dowel hole on the cam Pulley (bottom pic #3) that both cams are open at the same time. Then if we look at pic #2 (cat equipped) you will see that the intake opens at 12° btdc. But the exhaust closes at the same 10° atdc that that the non-cat cars do. For a total of 22° of valve overlap. That is a difference of only 2°, or basically 1/5 of the gap of a single tooth on the timing belt. Heck you can start out with the cams times timed dead nuts on. But then as the belts age and get stretched from usage you can have your cat equipped car end up with non-cat timing. Here is another monkey wrench in the system, the valve shimming. I have one set of specs that gives the exhaust gap as .30mm - .35mm, while another has the exhaust as .35mm - .40mm, and this is for the SAME year 348, AND both cars are equipped WITH cats. Now any of you that have done a valve adjustment on a 348 know it is WAAAAAAAAY hard to get the spacing dead nuts on the money. You pretty much have to have an unlimited supply of valve shims at your disposal to be able to get the exact gapping. What I'm getting at is that if you adjust your valve gapping to the tight end of one set of specs (.30mm) the lobe will be coming in contact with the shim sooner, and loosing contact sooner, than if you made your valve adjustment to the loose end of the other set of specs (40.mm). So how much of an effect will a difference of .10mm have on the cam opening and closing even though you have the cams timed to open at the correct degree? Just because you time the #1 and #5 cylinders to spec does not mean that #'s 2,3,4,6,7 & 8 are timed properly, nor will they all have the exact same valve gapping. So your timing for #1 could be dead nuts on but #6 & #2 could be off a hair because the gapping is either loose or tight +/-.05 -.10mm. As for the valve overlap. Those that are wondering what the difference is, why one can open sooner and the other open later, it's the back pressure in the exhaust pulse. In simple terms the cars that don't have cats have less restriction in the exhaust because they don't have the matrix of the cat guts slowing the exhaust air down. So you can start opening the intake sooner to take advantage of the scavenging effect the exhaust has as it leaves the cylinder. Have you ever had an aquarium, and did you ever syphon the water out of it? Well it sort of works the same way with the valve over lap. You can use the exhaust leaving the cylinder to help suck in the fresh mix of air and fuel. But if you leave it open too long you can suck some of that mix out with the exhaust and you can loose power. (This is what Brain was talking about when he said that it can cause the engine to run rich if the cam timing is off. See Mr.Kotter I get it. ) You can also open the valves too soon and as a result, instead of the exhaust going into the headers and then helping suck in the fresh mix, the intake can get contaminated with the burnt gases of the exhaust getting pushed up the intake charge because the cam was opened too soon = a car that isn't making good power, and or runs like crap. (How'm I do'n Mr.Kotter?) So because the cars with cats have the back pressure to deal with the intake cam is opened later so that the exhaust doesn't goof up the intake mix all that much. (I sound like I know what I'm talking about. LOL!) But here is where it gets goofy. Why is it that the "H" block motors (GTB/S) have their intakes opening even later that the cat equipped cars? The GTB/S 348's have their cams opening at 10° btdc, and closes 58° abdc. It is open the same duration at the cars WITH cats but it opens and closes 2° later. Then the exhaust cam is opening later at 50° bbdc and closing at 14° atdc. Again the duration the cams are open is the same amount as the cat equipped cars, just opening and closing later. What it looks like to me is, they just moved where the engine makes power higher up in the rpm band. Which is why I think the cams on the various year have to have the same lift on them. It's also why I think the cam marks are in the middle off all the specs. Because if the timing can vary so greatly between the different models the cams have got to be the same, and the marks have got to sit in the middle. So that is why I, gapped my shims within the specs, set the cam marks to the cap marks, and called it a day. But hey, what do I know, I'm just a Stooge. The next time I do my belt change I'm gonna put #1 on tdc, set the cams to the marks, and THEN have a look to see when things are opening, when things are closing, how much over lap there is, and where in specs the plain old cam marks sit. It won't surprise me if they are just fine. 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This is interesting, thanks to Rifledriver for the explanation. If the cams do indeed come "in the box" with the notch already on them, then it seems pretty clear that the notch is there for assembly purposes only, NOT for indicating exactly correct cam timing. In other words, if you assemble a cylinder head on the bench, you can use those notches to insure that the open valves will not hit on the top of the pistons at TDC on the ignition stroke when you put the head onto the block. But when you check the notches later, and they don't line up exactly, that does not mean that the cam timing is incorrect. And if you expect the cam timing to be exactly correct because the notches line up exactly, you could very well be wrong.
I agree with what you post here because the WSM clearly says those are assembly marks and to check timing by degreeing. It was like that for all 4 ferraris I owned since the 70's and RD says way back even further. The interesting thing I find is that if everything is premarked then nothing should ever line up unless ferrari is at the level of manufacture where is can nail everything dead nuts. I have no idea what it would take to do that. My guess would be ferrari scribing cam caps at the cast in cam mark after degreeing because if it was all predone I would expect never to have cam marks line up. This would explain why some times the marks = the degree setting and sometimes not i.e. hand scribed marks. In fact cars can have all 4 cams line up and have perfect timing I proved it on my engine in one of the early cam timing threads when there was a big stink about it marks vs. degreeing. IIRC I even used two different methods to check the timing "opening and lobe centerline". http://ferrarichat.com/forum/showthread.php?t=148917
To continue this thread, i took these pictures while doing a routine inspection the other week. I noticed the red/pink painted marks on the cam sprockets. They are consistent on both sides. Do these mean anything? Last major was by Ferrari of Denver in 2005. Also, do you think FoD would have timed it properly? Pic 1: 1-4 Pic 2: 5-8 Image Unavailable, Please Login Image Unavailable, Please Login
