Mike Gigante wrote:
> Personally, I'd suspect that what we are doing is following a procedure
> in which slightly imperfect case hardening is less likely to fail.
There is actually a good reason for this procedure.
In normal operation, the lifters (like the valves) rotate slowly and
more or less randomly under use. This is because the lifter-cam
junction is slightly eccentric, and the rotation keeps wear even.
This rotation actually only occurs at higher rpms, at idle speed
the cam lobe rises too slowly to "bite" into the lifter.
When breaking in a new cam and lifters, the parts have not
meshed yet and are a little bit abrasive to each other until they
bed. If you DO NOT run the car at fast rpms, the lifters will not
spin, so all this abrasion will be on a spot, and it can wear a
groove into the lifter.
What THEN happens is with this groove, the lifter won't spin,
and wears out very quickly.
If you break them in properly, they stay symmetrical and will
always spin.
--
Trevor Boicey, Ottawa, Canada.
tboicey@brit.ca, http://www.brit.ca/~tboicey/
[ Seeking some miscellaneous MG parts, see the list on the web page... ]
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