348 Offset Factory Camshaft Markings?

Ricardo - I'm sure your mechanic did a proper job of degreeing the cams, so I'm sure everything's fine. There are various threads here on Fchat that discuss that factory marks were just to get cams approximately lined up. Degreeing the cams can result in final marks being off a little.

I started a major on my 348 about 2 yrs. ago, and I noticed that marks on 3 of the 4 cams lined up nearly spot on, but the 1-4 intake cam was off over 1 line width. I thought perhaps this cam was off, but when I reassembled the engine and took lots of time to degree the cams, the 1-4 intake cam was exactly where it had been when I first started the overhaul.

I"d rest assured that your mechanic did a good job on your cams. Enjoy your car!

Edit: See pic.
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It is nice to see this is Finally becoming the norm....

 

The password for today is "reference" mark --- funny word, "reference", when you read Webster's definition, it actually has a specific meaning.....

 

Where are all those guys that scoffed at this and said they degreed theirs and the marks all lined up perfectly?


Nothing new. Here is a C4 and a TR.
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indeed.........nice portrait of "Tuco", BTW

 

You really ought to see the LM002 cams after I degreed it. You would think they hired Ray Charles to mark the cams.

 

Just a question, and not meant to stir any trouble or look for a shortcut, but if you lock the cams in place before removing the belt will you still have to degree the cams after the new belt is on? Reason I ask is because I thought I saw a thread somewhere about a 348 or 355 and the owner made a homemade locking device for the cams....this question is purely out of curiosity.

 

I'm NOT shocked seeing the positions of the "reference" marks after using a degree wheel. From what I understand the tolerances in these engines are very precise and the marks are "starting reference marks" NOT "THE" timing marks. If valve clearance isn't right or the timing isn't dead on...you run 2 risks on these engines. Being so far out you cause damage OR you are not making full power. Your car may run, but not at it's full potential.

I have done timing chains and belts on cars for years but only trusted MY 348 engine to an expert. I know after seeing this post I did the right thing sending my car to enginefixer. I could have tried doing it all myself but you have to be smart enough to know when a task is outside your scope of understanding. Locking the cams or just slipping on a new belt is false security IMO. Hope I don't get flamed...probably will LOL but I know I did the right thing sending my car to the shop for it's belt service. Guessing or "thinking" you know what your doing can have VERY bad/expensive results when setting up cam timing and clearances.

Anybody that has done work of any kind will tell you they are better at it after doing for years. I don't know why anyone would trust the heart of their Ferrari to an inexperienced technician...nothing against shop newbees or DIYers as we all have to start some where but I want someone that's done it a few times when working on the stuff that's critical.

Timing is absolutely critical on these cars...period. If you are not experienced or looking to "learn" this isn't the engine to do it on. I can swap parts as good as any monkey...this task isn't a parts swap.

 

I have never understood the "locking" concept so I am no help there. The timing resulting from locking the cams is no better than what the last one doing it did. Lets just say there is a row of engines outside the factory dyno cells that didnt pass their runs, a good many of them due to cam timing being off. It is not quick and easy and why many dont bother with it. Not "Bothering with it" amounts to doing a Partial job", simple as that. Think any Race Engine builders just line up a few marks? What is a Ferrari if not a race car with a license plate! I said it once and its worth repeating... I am glad to see it being done on a more regular basis these days. If you are told the cam timing was done, ask for the results. If they match the manual there is a high likely hood it was never done. Fighting for that last degree can be a time consuming endeavor.

R,

All the cams are the same on the 348, you are seeing a Cat V. Non Cat set up spec's.

 

Excellent post Mark.

 

Thanks Dave.

 

It's also worth noting that as an engine accumulates mileage, wear and dimensional changes (from repeated contact stress) of all the associated components are going to affect the relative position of where the cams need to be to remain in accurate timing.

Therefore, if you set the timing (by correctly "degreeing" the cams / valves) on a car, say every 15K or so, where the reference marks end up could easily be different each time. And, subsequent "alignment marks" will likely migrate away from their previous relative positions --- even though the timing is accurate each time it has been set.

This is why simply maintaining the previous alignment positions when doing a later adjustment is not the way to go, IMHO. Even, if they were spot on last time, they may not be spot on anymore.

 

I'm right here RD. I must have had the two best ferraris ever. My 348 lined up perfectly and my current 550 does too. Is that totally impossible? I think not. We do have modern manufacture that years ago help to give us the tolerences and predictable wear to give us the 100k mile tune up Northstar V8 about 20 years ago. The OP himself has 3 out of 4 cams perfect on line up and one cam off by a line width. Was that correct degreeing? Probably. Is his an unreasonable result? nope. Are there other factors that may lead to a cam being off? yup even past head job, cam shaft change etc... I never promoted the idea that the assembly marks were perfect and I have beaten the drum for a long time against camlock tools for belt changes. I have posted here that you should check timing with a dial guage/degree wheel but not to be surprised by what one finds.

 

Ace,

There are 2 kinds of cam locking. One is locking camshaft when cogs are off so that you can torque cam cog bolt on or during initial reassembly of the cogs to cams. Second is locking camshaft when swapping belts. The problems with the second reason is why there is a first reason. If someone locks camshaft with a "camlock" and then just swaps a belt you commit several errors. First you duplicate the error of just copying the first mechanic maybe right or wrong in timing. Second, engine wear changes absolute timing because parts are not in the same position but this is very small level of change. Third belt stretch while only a couple % is another introduced error. Third as the belt is swapped 3 cogs are not moving and there will be some slack between and the tensioner will not take up all the slack which introduces more error and maybe the most error. So the easiest way to remove that error is to unpin the cam cog and pin or lock each camshaft in position at your initial assembly marks before you time with a degree wheel. Some people have 3 hands and don't pin cams but I don't like the spring pressure rotating my camshaft and dinking pistons on valves then I have to hold the shaft and slide the cog on then the belt and manage all 4 at the same time and .... so I'm just lazy and I lock the cam with matchbook covers under the caps. Yes there is a group of people who think that is a bad idea but I have seen no better ways shown by those who hate my method. So I'll be glad to stop promoting that when I see something better you can do without another person to help. Then after timing there is torqueing of the cam bolt to the shaft and cog. There is a thread here on how important that is...the guy lost his engine. Some shafts have detents to put a wrench on the shaft so you can torque the bolt at the cog. Some shafts have witness marks of people who have used visegrips. Some guys use a rag on a lobe then a wrench or vise grips on the rag. That just makes me nervous. Some will try to torque and hope the belt will not rip. I've never seen that done but heard about it. That makes me nervous too. Me I use matchbook covers under multiple cam caps and that makes other people nervous. But I have found over many motors and 30 years that judicious use of force (less than the rated torque for the installed cap) is all that is needed and you can torque the cambolt to spec with no issues. I also have about 20 hammers and each has a different purpose. I'll also be glad to stop promoting my cam bolt torquing technique if someone shows me a better way. So far 30 years I've not seen it yet.

 

Thanks FBB

 

...this (locking with paper "things") is going to ignite a s***-storm, fellas (at least it has in the past).... I'm gonna stay far, far, far away from it But, you may want to put your rain gear on.......have fun, and enjoy....

 

I'm not a qualified mechanic, although I play one here and on my 348. My background is Mech. Engr, though. My take on using cam locks and changing belts is as follows.

Tension on installed belts varies around the circumference of the belt, both static and dynamic. The static tension changes before/after the cam cogs, and since F=MA, dynamic operating forces are induced in the belt as it changes direction (accelerates in engr. terms), around the tensioners, pulleys, and cogs.

Obviously, varying force in the belt also means varying deflection in the belt; after all, it is elastic to some extent. And after new belts are run in, they also stretch and perhaps the stress/strain curve for the belt may change, since they are not perfectly elastic and do stretch.

So even if you lock cams, and then R&R a belt, I don't see any way you can duplicate the original variance in force around the belt, before the old belt was removed. So it seems to me cams will HAVE to move, a bit at least, once you remove the locks, until static differences in belt force are reached.

If anyone has done this, and says their marks still line up before and after, good on you. But with the engine out, I'd rather be sure, and do it the long way!