John C. Slade wrote:
>
> My two bits worth.
>
> Being in the middle of an engine rebuild job with three Alpine engines
> in pieces, I have some interesting observations. One of the cams has a
> fuel pump eccentric with heavy scoring, double grooves which move
> forward and back on the cam as they go around it. The second cam has
> the same phenomenon but relatively mild, while the third has no
> surface damage at all.
>
> Fuel pumps apparently come with two different versions of the
> activating lever. One has a solid bronze coloured lever, the other
> (7950175 stamped on the arm) has a lever of the same size and shape,
> but laminated from three pieces of steel held together at the cam end
> by a substantial rivet directly above the cam contact point. The cams
> with the scoring damage both had the latter type of fuel pump arms,
> the cam with no damage had the first type.
>
> If a cam is sent for reconditioning, mild scoring can be ground out,
> but more serious scoring will probably need to be welded and ground.
> The fuel pump appears to have some tolerance regarding the exact
> position of contact, and with mild cam grinding will still contact the
> cam in a functioning position.
>
> John S.
Just to add to the above, it should be remembered that cams, including
the fuel pump eccentric, are case-hardened, and a "mild grinding"
at some previous time might have broken through the case, allowing the
soft metal underneath to score easily.
Ron Tebo
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