| IMPI |
April 26th 2011 12:39 |
I also wouldnt worry about those lifters. From my own research cams are not really hardened in the sense that they get heat treated to a specific rocwell number. the lobe and follower must be the same or very very close on the hardness scale so that the one may not wear/dig into the other. as the cam an lifters break in this constant motion against each other hammers both surfaces and this hardens the cam surface. a good example is you bending a piece of wire repeatedly as this is done the wire becomes stiifer and eventually breaks. This same process happens with the cam and the lifter and cam becomes progressively harder with use antil the surface is so hard that flabes come off it and this is the pits commonly seen in worn cams and lifters. the pits in your lifters do not resemble that type of pitting as it usually has very sharp edges.
Parkerising as a method does not harden the cam but actually etches the surface uniformly this slightly rough surface is used for two reasons: it retains oil due to the microscopic pits in the metal and also aids in corrosion protection (it was developed as a low cost method of protecting weapons by the US Army)
On your lifters the fact that the photos show them to have rotated is possibly the best news as this mean that the cam and lifters are happy with each other. the moment the lifter stops rotating even the best cam and lifter will be destroyed.
The slight pits is actually good as it will retain lubricant much like the grooves in a bearing.
Armand
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