Anyone who has replaced a MG camshaft in the past 20 years is using
an aftermarket replica part. I'm not sure anyone knows the objective
quality of original equipment parts that are long gone. I can only
say that I believe the Crane Cams cam is a good quality part, made
from an original forging. There is a good chance the some other
recent replacement cams are not such good quality, but I don't have
any personal experiance with those, as I have been using the Crane
Cams cams exclusively since turn of the century.
One interesting point is that the 18V type tappets were off the shelf
parts forn Moss Motors, way back then, and they have not failed or
eaten the cam. Maybe they don't make them like they used to. There
has been more recent reports of tappets not being hard enough,
resulting in failure of the tappets and damage to a cam shaft.
The point is that many of us use standard motor oil and drive engines
long and hard with no cam or tappet problem. Then there are a few
who experience cam failure in as little as a few thousand miles after
assembly with new parts. This is not everyone mind you, but the few
who have failures like this make a lot of news (or noise). To me
this must point to a parts problem (or installation issues), not an
oil problem. If it was an oil problem all of the engine would be
failing (including mine).
I just checked my records, and the last tappets I bougnt were the 18V
type from Moss (460-605) in August 2000. It was 8 pieces for $30.60
total (possibly includug pro-rata shipping cost). Less the $4
each. This part number has been listed as N/A for quite some
time. Today an 18V type tappet set from the same source (460-604) is
$199.95, or $25 each. As I recall, some time after I bought mine
there were qualith problems, and Moss discontinued sales of their
part, referring customers to some much more expensive parts supplied
my a well know "speed shop" type source. That may be what they are
selling now for the much higher price. Moss now also offers an
"Uprated Tappet Set" (18V type) for $79.95 ($10 each). Go
figure. Uprated from what I don't know, and none of these tappets
have ever had any functional specs attached (like hardness figures).
I'm pretty hep on such things, but I have no idea what the quality
level is on any of the parts sold in the past 10 years. There have
been some recent comments on various BBS about actual measured
hardness of some tappets, some being better than others. I don't
know how to judge the quality of any tappet without hardness
testing. Considering the current state of affairs, I think any
vendor selling flat tappets should include a certified test results
sheet with every tappet shipped. And if somone does a QA test and
finds the parts don't measure up to the spec, the vendor should be
severely chastised in public (or worse).
$.03,
Barney
At 01:47 PM 1/30/2013 -0500, Eugene Balinski wrote:
>Barney,
>
> Is there a possibility that the Crane cam that you use along
> with the tappets are of better quality or different materials than
> the stock components in an 18V motor ?
>
>Maybe that is the difference in the ZDDP requuirements ?
>....
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