Degreeing Cams

When I degreed my cams I used .050" valve lift (QV).

 

+1 on my ‘82 308GTSi

 

FORGET THE DAMN ASSEMBLY MARKS.

They are near USELESS after you put the cams back in, using them to do it, so no valves hit pistons upon a full 720 degree crank rotation.

After that, those ASSEMBLY, NOT 'TIMING' Marks are 99% USELESS in the Valve Timing procedure.

Use the Shop Manual data for timing your valves correctly.

NOT THOSE €%:&&@=; £ Marks.

From your pics, with that gauge, you are on the Very Correct Track.

March ON !!!

 

Ferrari never made a 1980 308GT/4. The last year of of production was 1979. Your car has the same cam timing as a 78/79 US Spec 308GTB (above)
If you look at your engine block, the engine number prefix should be F106AE, which is a 308 carburated motor with catalytic converters.

The cam timing data that you have in your last post is correct for your car. One sure fire way to check this is to look at the part numbers on the cams themselves.
In you photo above, I can see the number A111694 (which is the same cam as 78/79 US spec 308GTB). The other cams should have the numbers: S111696, S113258, A111695 on them. A stands for aspirazione (Intake) and S stands for scarico (exhaust). The later 2 valve injected 308 motors 80-82 used the same cam timing.

While I agree that the cam assembly marks are not super accurate for setting cam timing, they should be closer than the marks depicted in your photo.
I use the factory method, which is to set the valve clearances at .5mm/.020" on cylinders 1 and 5 valves, and then use the factory cam timing marks that are on the flywheel. These marks will also confirm the cam timing. There should be intake opening marks (AA16, Aperta Aspirazione) and exhaust closing marks (CS14, Chiuso Scarico) on the flywheel for each cylinder bank 1/4, 5/8.

Brian Brown
San Francisco Motorsports

 

I would add that if your going to degree your cams, you may want to find TDC with you dial indicator and use that as opposed to the flywheel marks (although they may be correct). You will need to find TDC for # 1 for one bank and #5 for the other bank.

 

That pic does appear to be about 1 belt tooth 'Out' which is 12 Degrees.


HOWEVER ...

RifleDriver posted a few pics a few years back(the pics are still here) where indeed the Assembly Marks were that far 'OFF' when the cam was 'Perfectly' timed.

And at least one pic was of a cam from a Testarossa.

How the cam Assembly Mark could be struck THAT FAR OFF is anyone's guess.


Maybe a 3-Bottle as opposed to a 2-Bottle (vino) lunch?

 

Interesting.

My 81's flywheel has no such valve timing marks.

Only marks for TDC 1-4 and TDC 5-8.


I DID Create those valve timing marks on my flywheel; however, using a darn accurate maritime compass, large magnifying glass, a sharpie and a boat-load, near poop-load, of patience.

 

TDC is not at the center of the dwell, as you define it. It is at the piston's highest point. If you find the highest point you can rotate from there in either direction by the amount you are calling the dwell. That is, there is a "dwell" to each "side" (CW or CCW rotation) of TDC.

 

Ferraris method is pretty simple, requires no dial indicators except to confirm TDC marks or indicator mount tooling or degree wheels. Its quite accurate and repeatable and is hard to screw up.

 

For me it seems easier to put a dial gauge on a tappet and a timing wheel on the front and then measure the peak lift degrees (instead of changing shims, measuring, changing shims back again.) If I had a shim removal tool it might make the factory method a bit easier.

 

The Ferrari method?

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Easy to understand the confusion.

Really though they developed a very easy way to do it quite accurately with minimal tools and special equipment. They felt it important enough that people not extensively equipped should be able to do it.

 

Good to see you back, Brian.

 

That IS Funny !!!!!!

 

Lucky you— looks like you got a mid-week engine assembled before lunch!