MFI Timing Question

[Rslevin]

Timing on my MFI seems to be off by a 3-5 degrees (about two thicknesses of the alignment line). I have two allen head screws to lock the hub and cannot get the alignment marks any closer using two screws no matter how the hub is rotated. So I have two questions, do I need to use two allen's to lock the hub or can I use one, and how close does the timing mark need to be? Any help is appreciated. Thanks, Rich

[Porboynz]

New MFI belt? It takes 2 full rotations of the crank to get one rotation of the MFI cam drive right? Maybe cam timing is out then. Very odd, does it run OK? If you mean the toothed drive on the MFI pump I thought there were 3 retaining bolts, all essential? I must be misunderstanding your question sorry, pictures are always good.

[HawgRyder]

I remember an article about the Porsche 917 team trying different settings for the MFI.
And...I think they tried as much as 2 teeth in advance or retard and it showed almost no difference in power and function.
So...a 1/2 tooth should be fine.
My 69S was out by a little...and it was fine.
Bob

[Rslevin]

The toothed cam hub has 2 Allen head screws that hold it on and can be installed in several holes. The issue is that if I use 2 screws, the alignment can only happen in two locations and those locations are 180 degrees apart. This seems off since the other two holes will not allow 2 screws to be inserted at the same time. Hence my questions if one screw is sufficient. The hub fits very tight on the cam shaft, so the there is no backlash using just one screw. With one screw, I can get exact alignment.

The engine is out of the car, so I cannot run it to know if it runs. I suspect it will run, but the question is how well. I 2 teeth off does not make much difference, then we are well within that range. Thoughts? Thanks, Rich

[356RS]

Rich, The MFI pump timing is preformed on the MFI pump's pulley. Not the camshaft pulley. Yes the camshaft pulley has only 2 allen bolts, the MFI pump pulley has 3 allen bolts. The 3 holes on the MFI pump pulley are slotted so you can move the pulley CCW or CW a little to get the timing mark set right.