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Join Date: May 2005
Location: Eugene Orygun
Posts: 196
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Cam, how bad is this?
This is in a motor that supposedly had a total rebuild less than 25k miles ago...#5 intake lobe. How long would it take for this to happen? Should I trust this rebuild? (1980 3.0CIS) Opinions?
 #6 intake lobe 
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09-26-2005, 11:38 AM
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Join Date: Apr 2003
Location: California
Posts: 1,592
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I have an ex-Porsche factory tech freind who told me there was a bad batch of cams in some 3.0 engines. Apparently not heat treated correctly. It will run that way for awhile but eventually when you get to the unhardened surface the lobe will ware out in very short order. It needs to be replaced or reground by someone like Web Cam. Once the thing comes apart all that finely gound metal will get everywhere in your engine and you'll need to do a rebuild after that. Do it now before it gets real expensive.
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09-26-2005, 12:22 PM
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Join Date: Jul 2001
Location: Thunder Bay, ON
Posts: 4,551
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I have a pair of 3.0 Cams in nice shape if you decide to replace.
Andrew M
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1970 911E - track / weekend car 1970 911S - under restoration 1986 930 Slant Nose - fun car |
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09-26-2005, 01:26 PM
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Location: California
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That is typical wear for a 100k plus mileage 3.0 litre engine.
I too have seen these lousy 3.0 cams, however I do not believe it was a heat treat problem. The camshafts I have seen had some manufacturing issues. The face was not parallel to the rocker. This caused the wear on one side of the lobe you see there. My guess is, the engine was rebuilt and the cams used as is. They were not repaired. If your looking to buy this engine, the cams can be repaired, or you could grind them to a "DC13" or "964" specs for a little more power.
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John Dougherty Dougherty Racing Cams |
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09-27-2005, 07:46 AM
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Join Date: May 2005
Location: Eugene Orygun
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Thanks for the advice John and all. I've already bought this motorand am just checking it out before I install it in my 914. Obviously the cam will have to be replaced. It's interesting that the other cam appears to be new....the black oxide finish is still on the heel of the cam. It appears the rebuilder replaced one cam and re-used the other.
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09-27-2005, 08:16 AM
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