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[Jim K]

I finally had my 3liter 12v cams made and I couldn't wait to put them in. Well, found some time, took the Motronic cams out and in went the 11.8mm jobs. I had specified 110* lobe centers and I installed them lining up the marks with the corresponding marks on the bearing caps like any Alfa mechanic or DIY would do. Good thing I wanted to be thorough...I decided to do it properly and mounted a dial indicator with a special long tip resting on the follower, a protractor attached to the cam hub and a pointer (see pic below). After adjusting and zeroing the pointer on the protractor (lobe full lift) I checked the lobe centers...98* instead of 110! Both cams were off by 12*!!! Since I have slotted the hubs to make them adjustable, I easily set the cams where they should be. Most definitely, setting at the actual marks and starting the car would result in many bent valves with these high performance profiles having pronounced lift at around TDC.
Its not the first time I find cams with wrong timing marks. The moral of the story is: whatever performance cams you buy, doublecheck the actual timing; do not rely on what you see and trust no-one! In any case, do the make or break test (literally!): when you're finished with everything, bring the engine to TDC overlap and check valve/piston clearance by jamming a screwdriver under the cam, pushing down on the follower until you feel it stop (piston/valve contact). Do this for cylinders 1 and 5 as you can see the TDC mark on the crank pulley. You must have at least 1.5mm intake and 2mm exhaust travel. Its your money you're playing with so take care, these can be very expensive oversights!
Jim K.

[AlfaTipo]

Jim, this may be a very timely caution.

I checked timing marks yesterday after changing the water pump (note to self; ALWAYS change the pump when changing the timining belt), I noticed the belt could only be fitted if the crank pointer was aligned with the F (2 degrees?) mark not the P. The cam marks aligned with the cap marks.

I am pretty confident the alignment was like this before and after I changed the belt 500 miles ago (see note to self above). The previous owner (I'm the second) had Shankle cams installed. I suspect the problem occured at that point.

I was going to reset the cams so all the marks lined up and the belt could be fitted. However, I will now check TDC accurately and rotate the cams so the marks align. Am I making sense here?

I do, however, have a question. As I have not realigned the cams before, what can I expect? Is the cam/pulley alignment set by notches or a smooth movement of infinite precision?

Little bit of knowledge etc....

Looking forward to the book. Have my Amazon pre-order in.

Thanks for any input on this.

[Jim K]

With the std setup, by following the marks you can do a reasonable job of setting timing. Assuming the bearing marks are correct (??), you can try to align the cams with the crank on the TDC mark. If you are not perfectly aligned, with std cams I wouldn't worry about a difference of .010"-.020" between the cam/cap marks, at the most you'll be 4* off. If you want to do better, you must slot the hubs a little, just enough to allow 'perfect' alignment. If the head has been milled by any significant amount you will have to go this way as timing will be retarded after you adjust the tensioner.
Jim K.

[AlfaTipo]

Thanks Jim. I take it any puller work to get the hubs off? I have a 3-way and I can get bolts to fit.

[Jim K]

As long as you can fit 3 bolts it'll work fine, thread is M7x1.
Jim K.