Help w/install of cam drive gears and oil pump

I am a confused by the shop manual regarding the installation of the cam drive gears and oil pump. Shop manual says to "paint the groove (so to make evident) corresponding to the reference notch on the rear surface" - I am not sure what they mean or why it would be important to "reference" the cam drive gears as my understanding is the timing is done up top by aligning the marks on the cams while engine is at #1 TDC...I don't see a reference notch on the rear surface - I've searched past forum posts but still don't get it - is there a step by step procedure? Any help appreciated - Thank you

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I believe this to mean that you make a paint mark on the front surface of Pulley 1 (Fig 30 page B37) corresponding to the "TACCA RIFERIMENTO" groove on the backside of Pulley 1 just to make it easier to see from the front when things are assembled.

Your photo shows the Pulleys 1 already installed, but my guess is that there should be some sort of marks/grooves/cast features (like little arrow heads or dimples) on the front of the timing case that would be aligned with the TACCA RIFERIMENTO groove on the back of each Pulley 1. Do you have any photos of the front of the timing case with Pulleys 1 not installed? (Unfortunately, Maranello Classic Parts does not have a photo of the QV front timing case).

Interestingly, this procedure is not called out for the 2-valve engines in the 308GT4 WSM (which are identical in this respect), and (again), my guess is that it is just to have a repeatable procedure for assembly so that if the system is ever disassembled it can be put back together in the exact same way. The reason that this is (a little bit) important is the the number of teeth on the crankshaft driving gear (24T) and the number of teeth on the driven gear (32T) share common numerical factors -- so not every tooth touches every other tooth and you get a certain wear pattern on each gear. If just randomly reassembled a second time, you would get another (new) wear pattern superimposed on the old wear pattern -- which is best avoided for gears. IMO, it's just a good-gear-practices refinement that they added (to the initial assembly process) for any future disassembly/reassembly.

 

Steve - thank you for weighing in - below is a photo of the front of the timing case with no pulleys - I don't see any marks and don't remember seeing any reference marks when I disassembled this. I get what you are saying about the gear mesh and trying to "replicate" the original gear mesh upon re-installation. However, if I have no reference marks, I am going to have to re-install this and take my chances, right? As always, appreciate your help and value your input - Joe

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Steve - I will check...The lower arrows in the picture above point to what I would consider "weep holes" - you can put a paper clip in there and it will go through...My last question is, if I do not figure out the TACCA RIFERIMENTO notches mystery, is the worst consequence that my gears will not be in the "original mesh" or is there any impact on the cam timing (I think not which is why I was surprised by what the shop manual was saying). Thank you again - Joe

 

If those holes go into the space between the lip seal and the outer bearing = agree (i.e., they would let someone know that the lip seal has failed before all of the grease gets washed out of the outer bearing by the engine oil).

Yes, I believe that's the only downside, and the cam timing can still be set correctly even if the gear mesh is not "original". If you get no more information, I'd go with using the center of those upper pads as the reference for the TACCA RIFERIMENTO marks (as that agrees with the Fig 30 drawing).

 

Steve - thanks for following up on this - Here's a photo of the cam drive that faces the back of the timing case cover and I don't see marks here either...I'll do some more research or wait for other replies (someone here must know definitively?) - Joe

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I checked the back of the cam drive pulleys and there are no marks on them either. Could the shop manual be suggesting that the keyway in the cam drive pulley shafts be installed pointed up and to keep them in that orientation as the cover is installed? Even then, since the crank will not be in the same location as when these were removed, you will still not achieve the same wear pattern on the gears.

Maybe Rifledriver (Brian) or anyone else who knows can weigh in ?

Should I be posting this question in another forum? Thanks

 

All,

I wish I could be of more help. I did this and marked all the pulleys before removal just so they would line up exactly as I took them off. I did put a new drive gear on one side as the bearing failed and I think it may have tweaked that gear. I am certainly not an expert but it would seem if your flywheel is a PM 1-4 and all your cams line up that you did it correctly but dont quote me on this! Let us know if you learn anything new.

Here are two pics of my front case which is different from yours and the marks I made before disassembly. I do this as I am not that smart! ha What is amazing it is still running!!!

Rob

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