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Join Date: Dec 2000
Location: The Hague, Netherlands
Posts: 806
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damaged rocker arm, what to do?
After disassembling my engine I found that most rocker arms showed pitting. These arms were regrinds and paired with dc40 cams from camgrinder. I ran the engine with Kendall 20w50 oil. The damage is visible on most rocker arms and the odd thing is that it starts left bottom. There is no wear visible on the cams.
What might have caused this, they have probably somewhere around 20k miles on them I am also wondering how to proceed at this point, reuse as is, have them ground to spec again, or try to obtain a new set?
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Peter '13 981S '73 911T '05 996 4S cab, now gone '70 911S Targa, now gone |
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12-18-2009, 05:46 AM
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Location: The Hague, Netherlands
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forgot to add the pic from one of them
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Peter '13 981S '73 911T '05 996 4S cab, now gone '70 911S Targa, now gone |
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12-18-2009, 05:48 AM
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abit off center
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Depending on how many grinds they had it could be they were taken down thru the original surface hardness, they should be around Hardness Rockwell C scale (HRC) 60-62 and they can be heat treated back to original.
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______________________ Craig G2Performance Twinplug, head work, case savers, rockers arms, etc. Last edited by cgarr; 12-18-2009 at 06:42 AM.. |
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12-18-2009, 06:15 AM
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Join Date: Feb 2004
Location: California
Posts: 926
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Could be plugged spray bar. I sent you a PM.
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John Dougherty Dougherty Racing Cams |
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12-18-2009, 07:16 AM
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SWB Enthusiast
Join Date: Aug 2009
Posts: 77
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Rockers
Quote:
I would be interested to know how the rockers are originally hardened. 60-62RC is good but I would have thought if the basic material can harden to this level they may through harden which is risky. If they are surface hardened as you say they to have worn through. I would chuck them away. I think a DLC treatment on new parts would be a good idea. |
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12-18-2009, 08:11 AM
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Join Date: Oct 2008
Location: Nash County, NC.
Posts: 8,507
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The oil spray bar is plugged, it cost the rocker and the lobe of the cam, everytime..
Bruce |
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12-18-2009, 09:39 AM
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Join Date: Dec 2000
Location: The Hague, Netherlands
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The cams and rockers are on their way to camgrinder for further diagnosis and refurbishment. The oil spray bars were not plugged.
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Peter '13 981S '73 911T '05 996 4S cab, now gone '70 911S Targa, now gone |
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12-19-2009, 08:18 AM
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Join Date: Oct 2005
Location: Marysville, WA
Posts: 126
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The problem with the cams and rockers may have been caused by the Kendall oil. Were they not bought out by another company and now sell another type of oil? One that is no good for 911 engines. The good oil was the Green Oil which is now sold to Brad Penn.
Here is the link to what happened: Our History
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Paul Weir |
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12-21-2009, 01:45 PM
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1969 and 1986 Porsche Targa and Coupe 1720cc and 3
