1956 Packard Panther Project

Project Topics

Engine Oiling System

The oiling system is probably the ONLY significant weak point of the Packard V-8 engine compared to its contemporaries. In any engine, IF oil is NOT delivered without interruption or aeration, then BAD THINGS HAPPEN and this is the case with the Packard V-8. Opinions vary as to why there is a problem under certain conditions. For instance, the Packard factory issued a field fix for the pressure relief valve (see below) and then re-engineered the pressure relief design for 1956 (basically the same as GM). Other opinions blame the attached vacuum pump on the bottom of the oil pump. My (and others) personal opinion is that because the vacuum pump causes the pumping body to be raised above the bottom of the oil pan by the thickness of the vacuum pump AND WHEN the upper driveshaft bearing becomes worn, this bearing is ABOVE the sump oil level and then AIR can enter the input side of the oil pump through this worn bearing under certain conditions.


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The Packard V-8 oil pump has an auxilliary vacuum pump attached to the bottom. The vacuum pump is driven by an extension shaft from the drive gear. This was added to alleviate the common problem with vacuum windshield wipers, to wit: when accelerating or under load (e.g., going up a long hill), engine vacuum is relatively low and the wipers do not work very well, if at all. With the auxilliary vacuum pump driven by the engine (oil pump), vacuum is always available, hence, problem solved, sort of (see above).

When I examined the oil pump from the engine in my 1956 Clipper (to be Panther), the oil pump's drive gear lower pin driving the vacuum pump was sheared! So that vacuum pump didn't work. Also, there is NO vacuum coming from that pump in my 1955 Patrician, but I do not know why because I have (thankfully) never had the pan off. The generally accepted procedure today is to remove the vacuum pump and replace it with a 1/4" solid plate, as shown below (this pump also has the late-1955 pressure relief Field Fix):

(Picture thanks to Keith Lummas)

Another modification to the oil pump is to increase the oil passage diameter, as shown:

(Picture thanks to Keith Lummas)

A few other things have been recommended to me over the years:

  1. Use 1956 camshaft thrust plate because it restricts oil to timing gear. (have that)
  2. Increase the size of the internal oil passages where feasible. (did that)
  3. Use 1955 Field Fix oil deflection baffles above rocker arms. (can do)
  4. Use STP, Marvel Mystery Oil, Wynn's Friction Proofing, etc. (could do)

However, what I believe might really "band-aid" the problem is an external oil pressure saver, such as the one made by Canton Racing Products. I intend to try it and we'll see!

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