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Join Date: Dec 2005
Location: Mount Airy, MD
Posts: 4,299
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cam journal sleeving
I picked up a set of four bearing, center lube cams. One of them has sleeves to make a 47 mm journal to a 49. Given the tack welds to hold the sleeves I'm pretty sure that the other was done as well (the journal feed holes are plugged) since it has 'defects' like from spot welds. Anybody seen this before? Do I need to have the journals welded and ground? General thoughts??
t 
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1967 912 with centerlocks… 10 years and still in pieces! |
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02-16-2010, 01:47 PM
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Location: California
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Interesting. I have seen this done before, but never on a 911 camshaft. Makes me wonder if they are both matching profiles.
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John Dougherty Dougherty Racing Cams |
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02-18-2010, 07:08 AM
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John:
Well, I got them in a box with your address, just need to chase up some tape to seal it up and it shall be on the way for your expert laying of hands! I think they are the same as the other shows scars that I would expect from having been sleeved. What cannot seem to determine is if they are 906 or sprints. I know they were 'tested' by webcam (previous owner) to be 906 profile, but given that they didnt tell the PO about the sleeving and that the lobes are pretty equal height (simple base circle to lobe peek). I know this doesnt account for rocker ratio and the like, but given the big difference in exhaust lift between the sprint and the 906 I should think the difference would be noticeable. t
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1967 912 with centerlocks… 10 years and still in pieces! |
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02-18-2010, 07:34 AM
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3 restos WIP = psycho
Join Date: Feb 2005
Location: North of Exit 17
Posts: 7,665
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This does make me curious - what kind of regrind can be done on 906 cams to improve mid-range:
Can you alter lobe spacing and profile (faster ramp speed)? Can you undergrind the circle for more lift? John, are there any benefits to be had and if so, have you ever done a "mod-906". If you have, how close to the Sprint cam is it? From personal experience, the Sprint cam is amazing in a 2.8L. BTW, I just picked up a set of your mod-Solex cams from a guy whose project changed. I already have a set in my '66 that you reground from my original, pitted center lube Solex cams and LOVE them! On that note, I sent you an email.
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- 1965 911 - 1969 911S - 1980 911SC Targa - 1979 930 |
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02-18-2010, 08:01 AM
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3 restos WIP = psycho
Join Date: Feb 2005
Location: North of Exit 17
Posts: 7,665
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Just for fun:
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- 1965 911 - 1969 911S - 1980 911SC Targa - 1979 930 |
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02-18-2010, 08:16 AM
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Location: California
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Tadd, I have measured a few "906" cams with different profiles. it will be interesting to see what you have.
Kenik, I have ground the 906 cams to DC60 specs on 98 lobe centers. I find they have between 95 to 96 degree centers stock. I also wonder if I need something between the DC30 and the DC40. Maybe 250 / 234 @ .050" with .460/.420" lift. Or maybe grind a set of 102 lobe center S cams. btw, your spreadsheet has the DC30 specs at 1mm, not .050". 
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John Dougherty Dougherty Racing Cams |
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02-18-2010, 08:18 PM
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