how-to on cam timing...

Here is the degree wheel as drawn/addendumed by Steve. This is what I used to draw the markings on my flywheel... I did relabel the flywheel exhaust open/close after catching the typo above, but can't edit my first post any longer.
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Just an update...

I ended up ordering some shims to verify that the dial indicator method works... I really don't want to fudge with the valves on a good running car unless I am triple sure.

The standard exhaust shims in my car seem to be labelled "430" or 4.3mm I believe, giving a clearance of .36 or so. You need .50. So, got a 410,415,420. Thats about $40 ($13 a piece at T Rutlands). If I had know thats all it was, I would have done that first. Everyone posted about $500 shim kits...

Will see which one gets closest to the .50 gap, then use the feeler guage to get it exact...

I messaged Rob Lay to see if there was any way to correct/edit the photo in the first pic and clean up some of the data. Those posts are now "locked." He hasn't replied...

Plan to repost all new pics, with the correct indicator angles etc, as soon as I get the shims... Will see how the to methods compare... they should be about the same...

Bo

 

Thought about grinding one down... but would be hard to do it perfectly symmetrically...

I believe the 4v and 2v are different sizes? Either way, T Rutlands had the valve shims pretty reasonably at $13. Other places were $28.

 

Alright... Updates...

I decided to do the shim method, as described in the wsm... It was a helluva lot easier. My hesitancy to do it was my lack of desire to but dozens of shims to set the intake and exhaiust valves to the prescribed .5 mm...

Well, you only have to but 2 shims... Not sure if anyone mentioned that before...

I bought several, a 370, 380, 400, 410, and 415...

 

The shims only come in .05 mm variations. A 430 for example is 4.3 mm on my caliper, a 425 is 4.25, and so on.. And you will need a caliper...

The standard allowance for movement for the intake is .2 to .25, .35 to .40 for the exhaust...

So, you need to put in slightly undersized shims to get a spacing of 0.5 or greater...

For example, for my exhaust a 410 shim worked great. I was able to put in a feeler gauge of about .55... With a tight fit....

But you need 0.5 you are thinking... Yep... So I had to use a feeler that was .05 to make if the difference... Make sense?

 

So, in my case I had a .05 feeler gauge between the cam and the shim giving an effective spacing of 0.5 as required by the wsm...

I then rotate the crank until the cam hits the feeler/spacer. Not sure who posted this before, perhaps Brian or Steve... But you apply pressure until you can't spin the shim with your finger... That is the opening you note on the degree wheel... Heck of a lot easier than using an dial indicator...

Brian crall mentioned that he doesn't require a dial indicator... I assume this is what he was referring to...

The degree difference in between being able to move the feeler gauge with significant resistance, and not being able to move it at all... Is 1/3 of a degree or so...

It would make sense, that once you can barely pull out the feeler or not move it at all,that's about where the valve starts to open...

Works the same for closing measurements...

 

This is about 5x faster than using a dial indicator, and is super reproducible... If you can spin the shim or pull out the feeler, there is obviously pressure being applied to open the valve...

Couple interesting comments...

You have to use a piston stop to set tdc... Eyeballing the crankshaft gets you to +\- 2 degrees. I don't see how you can get closer... The viewing angle has a huge impact on the reading...

If you just buy 2 shims to do this, a 370 and a 410 put you in the ball park for the intake.exhaust. Total cost $15.

Shims only come in certain sizes spaced at .5 mm. So, you can't get an exact degree setting, the closest you can get is a .5 variance... That's why the range is spec'd at .20-.25 and so on. That 0.5 translates to about 2 degrees on the degree wheel...

My final measurements were within a degree all the way around.

That was a lot of work, for something that was spot on... Next time, if I do it, it will be 10x faster to do as I now have the tools and shims..

Hope this helps folks...

Final questions...

What's the torque for the tensioner bearing bolt? Couldn't find it in the wsm...

Cam bolts are 100 newtons... Or 75 ft/lbs... But need to verify... Anyone apply any blue thread locker to either?

Bo

 

I was referring to the timing mark for tdc when I inadvertently said crank shaft... Seems there is some variation depending on what angle you view it at, perhaps not 2 degrees .

I thought many had said in most of the prior threads that the best way to tell tdc was with a piston stop... That's why I went out and got one... sigh. will recheck with dial indicator and verify tdc (which is how I first did it) marks and adjust as needed... Thanks for the info.

So now we are saying that's not how Ferrari defines tdc??? I thought that definition was pretty universal... always interesting...

Will review wsm again...

 

For the sake of being scientific... I went back and redid tdc based on tdc mark, using piston stops, and using a dial indicator...

If you eyeball the tic mark on the flywheel, you can get it to within 0.5 degrees or so (perhaps slightly less)- (I originally said 2 degrees - you can get closer than that). I did this several times, to see how close I can get each time. With a 16 inch degree wheel, this is about as good as you can get. Perhaps with a large degree wheel, you can fine tune this further. There will always be some degree of error as you are aligning the marks visually...

I then went and set TDC using a piston stop. I set this as ZERO on the flywheel. This mark was very reproducible regardless of how many times I did it.

I also went back and then set it via the visual method on the flywheel... The difference was about 0.75 degrees... so, clearly and as expected, a difference... Brian mentioned that ferrari defines TDC not in the middle of the dwell, but at the moment when the piston first hits top dead center (beginning of the dwell?)... So there should be a difference in this measure...

One of the pics below is using the visual tdc markings, one is using the piston stop (don't recall which pic I took first). Either way , the difference between the 2 methods of measuring was about 3/4 of a degree...

I hope I am explaining this in a way that makes sense... doing the best I can here...
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I then went back and set it using a dial indicator... I called it top dead center when the indicator first peaked or plateaued...

Did this multiple times...

The best I could get with comparing doing it by indicator and visually, was 0.5 degrees... (IE. Due to variation in visually aligning it)... Meaning, when I set it visually that was "zero." But the dial indicator method was a 1/2 degree off from that and vice versa. IE. The delta was 0.5 degrees, if you assume the dial indicator gets it "perfectly." Using the visual method of picking tic will never hit on exactly the same spot, but within 0.5 degrees.

The dial indicator measurement also allows some error... When you are spinning the crankshaft, you can't exactly rotate it in 100ths of a degree due to valve springs/etc.
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I am sure proffesional mechanics, with large degree wheels and prograde tools can get more accurate... Thats why they are the pro's... I really wonder how close the home diy guys are getting. I also wonder how close the dealer is getting. I somehow highly doubt that if the measurement is 1 3/4 dgrees (allowed is +/- 1) off they re-time the cam (I say this based on all the other shortcuts I see elsewhere from prior majors)...

But best as seems reasonable, if you are simply using the visual tdc marks you can probably, at best, with a 16 inch degree wheel, hope to get within 0.5 degrees (assuming that the dial indicator is the gold standard)...

With the use of the piston stop, within .75 degrees or so... So, no piston stop needed...

Thought that was interesting...

At what difference do you actual appreciate a measurable difference in performance/emmissions? 1 degree off? 2 degrees off? 3 degrees of?

 

Dial indicator is providing the same results each time... I was trying to compare the reading from the dial indicator, to the visual alignment on the flywheel tdc marks...

Trying to say that folks visually using the tdc marks, can probably get to 0.5 degree accuracy...

I would think that what this shows is the tdc marks are "good enough," though you aren't going to get it perfect...

I see folks on here using degree wheels that are 12 inches in size... whats the accuracy of that?! In comparison, I think Brian said he uses a very large degree wheel with lots of spacing between degrees...

But, at what point does it make a difference???

Even if you set the marks perfectly, the moment you start driving the belt stretches... Also, as I mentioned, the difference between available shims is 0.05mm... The difference between being able to fit a 0.2 feeler gauge and a 0.25 feeler gauge is probably a degree (or more)?

At what point does the performace get degraded? Also, the timing marks are different in the US vs Europe...

Either way, I wanted to do it right... Plan to check the valve timing one more time this weekend, just using the TDC marks...


In summary, if you have the means and resources just take it to Brian Crall, as that is much easier and probably way more sensible If there are any errors above or confusion, I apologize. And of course I recommend everyone do their own due diligence, read the WSM, and only read internet posting for their entertainment value. If you live in Wisconsin and have a lot of time on cold weekends, doing this can be misconstrued as "fun."