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abides.
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These cams don't look right, do they?
I took in some cams to be resurfaced and got this back.
Shouldn't the bearing journals be polished?  
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Graham 1984 Carrera Targa |
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05-12-2014, 11:58 AM
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Straight shooter
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Looks like a protective coating to prevent oxidation before install. Spray some brake cleaner on a rag and check if it wipes off. Only a problem if it doesn't come off easily.
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“Of the value traps, the most widespread and pernicious is value rigidity. This is an inability to revalue what one sees because of commitment to previous values. In motorcycle maintenance, you MUST rediscover what you do as you go. Rigid values makes this impossible.” ― Robert M. Pirsig, Zen and the Art of Motorcycle Maintenance: An Inquiry Into Values |
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05-12-2014, 12:16 PM
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Join Date: Jan 2013
Location: Grapevine, TX
Posts: 214
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Looks like they've been parkerized.
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John "Build a man a fire and he's warm for the rest of the day. Set a man on fire and he's warm for the rest of his life". -internet sage |
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05-12-2014, 12:38 PM
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abides.
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I'm just wondering if the parkerizing would be bad for the bores in the cam towers?
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Graham 1984 Carrera Targa |
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05-12-2014, 01:50 PM
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Try lubricating the bores with oil and put the cams in. If they turn freely, they should be fine. If you are worried about it you could polish the bearing surfaces with scotchbrite.
-Andy
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72 Carrera RS replica, Spec 911 racer |
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05-12-2014, 02:25 PM
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Location: NC
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Looks like it may be nitrided. Its a super thin surface hardening. Helps with wear. I would ask the guys that sent you them what they coated it with. Nothing to worry about and I wouldn't take it off. I have some cams that have that black coating on the lobes where there is no lift. We have a Masarati low mileage engine at work and it's cams are still completely black.
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92 964 RSRish project 01 996TT 95 325i 92 318i etc, etc, etc |
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05-12-2014, 02:47 PM
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Location: S. Florida
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If thats a dry molybdenum coating it's probably better to leave it on. My Webcam regrinds came back with a dark grey dry moly coating on them. A darker grey than whats on yours.
I still like to put some redline assembly lube on them because it stays put better than motor oil waiting until the motor is started and helps lubrication during the first start up. Like someone said call the place that did them and ask what it is. |
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05-12-2014, 03:21 PM
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Join Date: Jul 2013
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I just got a set of DC60's from John and only the cam lobes have the black coating...
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05-12-2014, 03:27 PM
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abides.
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Thanks for the suggestions. They were done by a local shop, but last time I used them they had polished the bearing surfaces and had coated/parkerized/whatever only the cam lobes.
Unfortunately I wasn't even planning to use these... the shop resurfaced these instead of the 964 cams I also gave them. Anyone need some 3.2 cams?
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Graham 1984 Carrera Targa |
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05-12-2014, 03:40 PM
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1984 Porsche Carrera Targa
P911
