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billjam billjam is offline
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Join Date: Aug 2007
Location: Perth, Western Australia
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Originally Posted by camgrinder View Post
I like your solution to the pump drive issue Bill. I wonder if drilling the holes a little bigger for a larger diameter pin is worthwhile?
I thought about doing that. Drilling out to 6mm or 8mm would be better than 5mm.
I also considered tapping the existing 5mm holes to take a short M6 round head bolt, but the end of the cams were quite hard and my HSS taps wouldn't even look at it. I didn't want to risk breaking off a tap or a drill, so I settled for 5mm.
Their strength isn't an issue, but in the very long term, there may be more likelihood of wear between the pins and the drive pin on the pump shaft because of the smaller contact area.

Considering the application, I am sure the 5mm pins will outlast me!
1988 Carrera - 3.6 engine (with ITBs, COPs, MS3X) and a whole set of turbo body panels waiting in the attic.
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Memories: '68 912, '72 911T, '80 911SC, '84 911, '85 930, '86 930, '87 911
Old 10-30-2009, 04:21 PM
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