Re: What about the 25K 105mph V8 Patrician?

Posted by BH On 2011/4/9 12:11:04

Let's consider what happened with production Packard V8s WRT engine oiling issues in a little further detail.

In January 1955, in response to complaints of squeaking rocker levers, Packard warned Zones that a horizontal oil passage in the head was not drilled deep enough to connect to an opening for the rocker pedestal screw. (Sounds like a short-lived, production-related teething problem.)

Articles and bulletins issued in the months that followed appear to deal with matters of oil consumption and flow control: educating dealer as to what is "normal"; eliminating/plugging holes in the rocker shafts that open toward pushrods, only to return them later (albeit slightly smaller in diameter); adding oil deflectors on all intake valve stems; installing new type oil rings for the pistons. Additional valve spring baffles were later introduced to keep any excess oil off the intake valve stems.

There were a couple references to sticking valves, but - except for advising of a change in valve stem finish - Packard had been through that years earlier with their inline engines. Use of inhibitor oils was strongly recommended in both cases.

While there was also a problem of premature wear at the pushrod end of rocker levers, this was due to a faulty hardening process. Parts on the shelf were recalled by the warehouse and rechecked; those that passed were reissued under a new P/N.

Now, things start to get interesting after a bulletin sent to Zones in July 1955, which advised of a redesigned tappet with greater oil reserve to alleviate complaints of noisy tappets at cold start. (Sounds simple enough, yet...)

Complaints of noise from these new design tappets, but only after the engine gets hot, were first acknowledged to dealers in January 1956. In addition to verifying oil grade and inspecting for dirt under the tappet check valve, dealers were advised to check oil gallery pressure at a specific point and install a modified camshaft thrust plate and spacer to raise it, if needed. Then, replace main bearing shells, as needed, to achieve a minimum 0.001" clearance.

However, the first mention of any problem with the oil pump itself came in March 1956. Continuing with the complaint of noisy tappets at highway speeds after oil gets hot, dealers were advised to check for a sticking oil pump pressure relief valve. The concern was for low gallery pressure at idle, AND aeration in the gallery at higher speeds, but warning that a crankcase over-full by more than one pint can also cause aeration. (Decades later, some owners have found relief by over-filling by no more than half a quart.)

In May 1956, after a confidential field trial involving plugging the relief valve bore, a new pump design was announced for production, with a sump tube kit for field service of previous models - each aimed at preventing air from being introduced into the pump. The second design camshaft thrust plate and spacer and main bearing replacement was also reiterated.

This last release was also copied by Studebaker to its own dealers WRT the 56J Golden Hawk, which used the Packard V8. What's interesting is that the 56J version of the pump did not have the piggy-backed vac pump, but a flat bottom plate. (To me, that erodes some support for the PI modification.)

Looking at all this again, it seems like the first hint of an oil pump problem came on the heels of the implementation of the new lifters with their greater reserve. Perhaps this was some sort of tipping point. If so, then no such problem with the pump could have been encountered in the endurance run.