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JFairman JFairman is offline
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Join Date: Jul 2006
Location: S. Florida
Posts: 7,274
If the motor has never been apart in 133,000 miles the exhaust guides are definately worn out and probably the exhaust valve stems too so they will likely needd to be repalced.
The intake valves run much cooler and may be OK, but the intake guides will be somewhat worn at that milage so they should be replaced along with the exhaust guides.
Stock valve springs are usually replaced while your at it, with that much milage but if it's driven on the street only without redlining it daily they may be ok to reuse if money restricts that.

Even if the ring gap is within spec the ring lands in the pistons wear getting bigger and oil and combustion pressure gets by.
The cylinders wear from round into a very slight oval shape at the scuff areas 90 degrees to the wristpin and taper from top to bottom gradually as they are used.

A good machine shop experienced with 911 motors can check all that stuff out.
Old 12-29-2009, 11:47 AM
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