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Robert, sorry I missed you at Hershey - hope you found any needed parts. I bought the display license plate frame from Mid-Atlantic Packards. They had sold out to a bunch of Ford folks. They probably just wanted to buy a part that wasn't pre-rusted.
While I was enjoying the train meet, my friend removed the core plugs and scraped the block. As suspected a lot of crap in there. As I was cleaning up the block today to paint it, I looked for the Utica engine plant number on the right rear boss where it is supposed to be - nothing. On a hunch I chemically stripped the paint off the area where all other V8 Packards have their serial number just to the right of the oil filler tube. The number "C1339" was stamped there. I am waiting for Owen Dyneto to state what his Utica number is. He said he thought he had written it down. My engine was cast on 9/21/55. Owen thought his was cast in November of 1955. None of this is must-have info, but it adds some provenance to the vehicle and satisfies my own curiosity.
Robert, if you look up this info on your engine would you post it for those of us who are curious??
I forgot to pick up core plugs to block the exhaust from the intake manifold - get them tomorrow.

When I dropped the pan today I discovered I had the latest version of the oil pump?? That means it was replaced at some point in time since it was cast 09/21/55?? Will plastigage mains and rods tomorrow.

Randy,

Sorry I missed you as well. I had a great time at Hershey. I found a few parts, saw some nice cars, but most of all met some great people. I look forward to meeting you another time as you have been a tremendous help to me from the very beginning.

My block casting date is 7-30-56. The boss pad just to the right of my oil filler tube is blank. I also chemically stripped mine when I prepped the block but best I can tell it was never stamped. I do not remember seeing anything stamped on the rear boss pad as well.

According to the previous owner, my Carib received a factory surplus replacement block very early in its life and all the bolt-ons were reused. He told me this the day I purchased it and that seems to match up with the few date codes I found on mine.

Everytime I found a date code on my engine I felt like one of the Hardey Boys! I can appreciate the curiousity.

Best Regards,
Robert.

Upon closer inspection I find I have a modified oil pump and I think Packard did it. That means there are three different oil pumps.
1.The pump used in 1955 and part of 56 which has the relief valve spring contained by a small cup and a cotter pin.
2. A pump which still bears the same casting number 440662, but was never drilled for a cotter pin. The casting is threaded for a bolt with a gasket on it. Packard must have been using up the earlier castings but modifying them for a sealed fit at the pressure relief port. I can't blame Packard for not wanting to scrap a bunch of castings.
3. The modified pump mentioned in TSB 56T-20 which has the casting number 64xxxxx. Actually they could be referring to pump number 2 because it has the threaded plug.

In any case I called on Packard Parts Extraordinaire and he is sending down the latest oil pump which I intend to have Bob Aller rebuild.

Misprint in parts manual. 5.1202 states that 6492431 is the part number for all 55th pump bodies. 6492430 is the casting number on the very late oil pump body. 6492431 (one number greater, according to Packard practice) is for all 56th oil pumps. I have 6480508 as the latest oil pump assembly written in my parts book but cannot remember where I got that number. It has to be SC or TSB.

Randy -

I have a copy of a factory letter to Zones (never released to dealers) that predates STB 56T-20 and talks about a field trial of plugging the relief valve bore on the original pump body (as installed on cars). Yet, a follow-up letter to Zones warns not to install a plug in the field, but advises of a forthcoming sump tube kit.

Have you dissassembled your pump (that is #2, as you cited) and found it to have the 1" long relief valve piston?

I believe PackardV8 noted (in another forum past) that there are also internal differences WRT the internal passage for the relief valve on later design pump body.

Randy -

Good catch! That error appears in both the reprint as well as the original 1956 printing that I have.

The application listing for P/N 6492431 also references a 1" long relief valve piston, and when you look down the page, the related parts:

6492432 Piston - pressure relief valve
6492434 Spring - pressure relief valve piston
6492433 Plug - pressure relief valve psiton spring

...are all noted for 56th Series only (the late design pump).

Meanwhile, perhaps the one number higher P/N for the pump body represents the finished/machined part.

I see that there is no listing for a complete oil pump of the later design - that is, the one having the revised pump body with the plugged relief valve port and 1" piston.

As I have found some handwritten notes for newer P/Ns for other parts in the original parts book I have (though not this one), P/N 6480508 may very well be the number for a complete pump assembly of the later design, but I have never found any evidenece of it in any bulletin. Unless someone else has any hard evidence, I suspect the factory didn't want pumps being replaced carte blanche, but wanted the sump tube kit tried first (as a matter of warranty cost control) and withheld that P/N from publication.

Brian, I unscrewed the threaded plug on #2 pump (original to my Caribbean) and the relief valve measures 1 3/4" long, which is the normal 55 valve length. This pump is obviously from the factory as it was never drilled for cotter pins. A call to Mike D. got me the proper late oil pump for rebuild purposes. Still waiting for a callback from Aller.
Mike D's price was reasonable and he shipped it promptly.
I'm wondering where/when I read about the late oil pump? My first notice of the late pump was its removal from my parts car. I noted the two different casting numbers and started looking at the parts book for answers. I just reviewed the SCs and it is not mentioned there.

Randy -

Your #2 pump appears to be a modified version of the early/original 55th-56th Series design.

I had discussed the early and late pump designs with PackardV8 (Keith) years ago at the old CC Live Chat, which fell victim to the bursting dot-com bubble, and again with him and Turbopackman (Eric) at the AACA site, though many of the latter posts are no doubt lost now. While Keith may have mentioned a possible third design, I don't recall any evidence supporting that, but there may have been some confusion with the Hash version.

STB 56T-20 (dated May 20, 195) merely advised that "oil pumps for production have been revised to include threaded plug" and not much else - except the introduction date of April 10 (and starting engine numbers). However, the parts book further indicates a 1" valve in that later design, and I believe it was PackardV8 who tipped me off about that additional change, years ago.

Prior to that introduction, the field trial outlined in the confidential letter to Zones (dated March 20, 1956) recommended brazing the cotter pin holes shut, tapping the hole with a 9/16-24 thread, and fabricating a plug that would place the (original) valve spring retaining cup in the same position as before. However, the valve piston was also scored to permit trapped oil to shuttle back and forth.

BTW, PackardV8 tried something quite similar with an early pump on his Exec, in addition to replacing the vac pump and separator with a thicker bottom plate and upper and lower bushings for the driving shaft.

The follow-up letter to Zones (dated April 24, 1956) advised that an initial supply of sump tube kits was being shipped to the Zone parts warehouses - in advance of the release of STB 56T-20.

If you had found evidence of cotter pin holes closed up, I'd conclude your car was involved in the field trial. If the holes were never drilled, then you might have an intermediate attempt to introduce something into production prior to the release of the later design (and sump tube kit).

Pressure relief piston in #2 pump should have at least one hole drilled thru the side of it OR a flat ground along one side of it. If not then it would not be a professional nor factory modified pump unless someone changed the piston at a later date.

The 1" long later piston from the factory either had a hole in the side AND/OR a recess turned around the diameter. At that time some 6 or 7 years ago i inquired with Kanter about a replacement piston and spring for the late pump. Kanter denied any such knowledge nor documentation extant of the late piston or spring.

Look #2 pump over very closely to see if there is evidence of the cotter pin holes having been plugged.