Quote:
Craig wrote:
Packard8 Quote:I cleaned up the Hash pump (sludgy and the relief piston was stuck).
Good catch! I believe this is the "fatal flaw" in the Packard V-8 oil pump design which causes lifter clatter and later engine failure if it continues.
I'll start a new thread on this when I have all my info and pix together.
Craig
A sticking relief valve was first noted, as a cause of oil aeration/starvation, in an article on "Noisy Hydraulic Tappets" in
SC Vol. 30, No. 3.
This was also addressed in a confidential memo to Zones, regarding a field trial that involved a slight modification to the relief valve and plugging of its bore. That approach, however, was dropped for field service, in favor of the sump tube kit announced in
STB 56T-20, regarding hydraulic tappet letdown. Step 3 in that bulletin specifically addresses inspection and repair of the relief valve for sticking.
Meanwhile, plugging of the relief valve bore was only iincorporatedinto the second design pump that was introduced in production - noted in BOTH
STB 56T-20 AND
SSL No. 936.
While I still think the sump tube kit should be installed on the first design Packard V8 oil pump in case of a sticking relief valve, a greater concern for that condition would certainly be low oil pressure.
As seen with the Hash pump, which is of a completely different design, the condition of a sticking relief valve is not exclusive to the Packard V8 oil pump.
Things like poor maintenance and lack of use further contribute to the problem.
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