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[TR] Interesting Cam Condition

Subject: [TR] Interesting Cam Condition
From: terryrs at comcast.net (terryrs at comcast.net)
Date: Sun, 13 May 2012 12:55:36 +0000 (UTC)
I have become a sudden and sound believer in ZDP.  

When I last rebuilt my engine something like 8 years ago, I bought lifters that 
Ken Gilanders at British Frame and Engine described as more hardened than 
usual.  I also sent my cam off somewhere out west to a machine shop to be 
reground.  

When I broke the engine down in April, what I found was that the lifters on the 
exhaust lobes were destroyed on the bottom, where the surface was not overly 
lapped, but rather cratered.  Same on the Camshaft.  Inlet lobes and lifters 
seemed much better.  (Why would that be?)

8 years ago, the cam came back as bare metal...no seeming special treatment.  
This time, I went to a local machine shop I trust.  The reground cam came back 
covered in black stuff that they tell me is a specially prepared designed layer 
designed to hold oil and protect the hardened surface until it "laps in."   my 
friend Barry at the machine shop also gave me a small bottle of ZDP and said to 
use that instead of assembly lube.  "Then pour the rest of the bottle into the 
30 weight non-detergent you'll use to break the engine in."

Question, though.  I would have thought that ZDP would protect from wear as 
opposed to this deep pitting.  No?

Terry Smith, '59 TR3A
New Hampshire

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