'55-'56 oil pump

[RO]

Anyone seen this before? Seems to be a Service Bulletin associated with it. "It stops the areation of the bypassed oil from the relief valve."

http://cgi.ebay.com/ebaymotors/ws/eBayIS...item=2453344126

This is an original new old stock oil pump tube kit for all 1955-56 Packard automobiles & possibly Nash & Hudson with the Packard 352 engine. The Packard part number is 6484613. Also included is a four page copy of the Packard technical bulletin that shows how to install the kit. If you have lifter noise in your V-8 or plan on rebuilding the engine you should install this kit. It stops the areation of the bypassed oil from the relief valve

[RO]

OK, I found the Service Bulletin 56-20 dated May 3, 1956 and I guess this is the infamous "threaded plug" kit for the oil pump.

[Guest imported_PackardV8]

The open port pump has a rather large cavity on the suction side of the pump, HIGH in the pump that the pressure relief valve opens into. The PLUGGED pump has NO such cavity. I believe this is why the open port pump is so prone to accumulating air. Air accumulates in the cavity gradually and then is suddenly pushed on thru to the pressure side once the valve begins to dump. Even if the plugged pump were modified to operate with a cotter pic instead of the plug i believe the air accumulation would be diminished because it would be passed on in smaller amounts over a longer cycle.

[Guest]

I am wondering if anyone has used the oil pump sump tube kit and what they felt the results were. Is this a worth while item or not?

[RO]

Curious as well; these have showed up on ebay two or three times recently.

[Guest Randy Berger]

It was a hit-or-miss method of trying to resolve the oil pump problem. It

did not. The solution is to have the pump rebuilt when needed and add a bushing at top of pump. My personal druthers would be to add a bushing at bottom also and extend the pump shaft down into it so that the shaft would be supported at both ends. There is not enough room to do that without eliminating the vacuum pump which I am reluctant to do.

In short, don't waste your money.

YFAM, Randy Berger

[Guest]

Agree to all of the above. I am at work building them the way Packard should have done:

1. NEW gears

2. Bypass dump tube

3. Thicker bottom plate with bearings

4. Longer drive and idler shafts

5. Long bronze drive shaft bushing in the pump body

6. Second design cam retainer plate and cam spacer.

This should cure any and all oil supply problems on an engine with decent bearing clearances.

thnx, jv.

[55PackardGuy]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">"A considerable amount of oil pressure (and volume) can be lost between the ends of the oil pump gears and the pump cover."</div></div>

Brian,

Just a note to concur and emphasize this point about the pump cover. I had a dramatic personal experience with this on an Opel 1900 engine. It had low oil pressure and obvious upper end oiling problems (lifter noise, cam was shot). My dad did a compete rebuild and, to my chagrine, the oil pressure was not much improved. By pure chance, the oil pump "face plate" (it had an external pump) started to leak shortly afterward through a hole in the faulty aluminum casting. I replaced the face plate and... INSTANT OIL PRESSURE! It was a 5-minute job and a cheap part, and saved the engine from further damage. (It had again developed some lifter noise in the miles I had put on since the rebuild.)

Moral: ALWAYS check the gear cover for scoring or any sign of excessive clearance. It's an easy first step that might solve the whole oil pressure problem!

(Of course, I know there are many more nuances and complexities to the Packard pump system, this is just presented as a "case history" of a generic oil pump issue. But I think it's an essential one.)

[Guest imported_PackardV8]

Any bronze bushing that is used in any application should be provided with an oil GROOVE of some sort.

[55PackardGuy]

Brian,

Soooo if I'm reading you right, this may be a "hard fix" for the Packard pump and might therefore go unexplored in attempts to gain oil pressure. Isn't "cross-pollination" of experiences with different cars interesting?<img src="http://www.aaca.org/ubbthreads/images/graemlins/cool.gif" alt="" /> Of course, it can also contribute to some "wild goose chases." <img src="http://www.aaca.org/ubbthreads/images/graemlins/tongue.gif" alt="" />

[55PackardGuy]

Brian,

Not being anywhere near an "expert" on the Packard oil pump, I don't mean to give any input into the specific causes of the many types of problems that could occur. However, I do think I can give some fresh insights into possibilities that might become obscured over time because of the inherent difficulty of concentrating on a particular problem very intently: you can lose perspective.

I brought up the face-plate wear issue because, after reading a lot of the posts (probably all of 'em) on the Packard pump, I noticed that the issue of possible face-plate wear seemed not to have been addressed.In fact, I came to think that it was a non-issue because it was not mentioned--at least not that I found. I know it WAS an issue on Opels of the vintage I owned, because the face plate on the pump was aluminum (or some kind of non-ferrous junk) and the steel gears just wore it out. After this incident, I began to wonder how many of these cars found their way to the junkyard early because this 5-minute fix wasn't applied.

Now, I'm beginning to wonder how many other cars with low oil pressure that is blamed on bad bearings actually started out with the low oil pressure due to a bad pump which led to the bearing failure in the first place. Then, the engines were rebuilt and the owners said "WTH this thing still doesn't have enough pressure!?"

Given the general similarities in gear pump configuration, this could have some very broad implications for vehicle longevity. Maybe something as simple as a good oil pump is what makes some engines survive so long. And think of how regular oil changes would improve the life and functioning of the pump. Is the pump the first thing to "go" on a neglected engine sometimes? Often?

[Guest]

As one who know little on this matter let me as a question that I have not seen discussed yet. Is there any chance the Packard sump pickup was part of the problem. Looking over this part of the pumps makes me wonder if it is always fully submersed, especially on acelaration? Just a thought.

[Guest Randy Berger]

To ALL, since no one has defined the exact cause of the oiling problems, all questions are valid. Not having expertise does not disqualify you from posing your question(s). The questions themselves may jog someone into thinking of an area not yet fully covered. Some ideas are so simple (like having a valve to shut off oil to the filter) that you knock your head into the wall for not thinking of it yourself. My pump rebuild has held up fine, but I have not put 60,000+ miles on it yet.

YFAM, Randy Berger

[55PackardGuy]

Hey, Brian,

Thanks for getting up so early in the morning and posting so many words of wisdom. How do you think that clearly? Coffee?

Much appreciation for the food for thought. It's incredible how interesting this subject is to me in spite of the fact that I don't even presently own a Packard. I think this may be partly because I've always had such affection for these cars (and defended them as incredible works of art and engineering) and I like to see anything that contributes to their longevity and survival as an example of the marque at one of its finest, and sadly last, moments.