Early Hemi oil pan and pumps - need some input

I think you have a replacement pump (maybe low mileage?) for several reasons:

1.) The small cover screws (four in your example) do not have the "DPCD" head markings.
2.) No Chrysler casting number on the cover. The swinging pickup pumps used 1323361, and the threaded pickup pumps used 1406255.
3.) The "USA" mark in the casting. Seems to me that would have been unnecessary in the 1950's. Additionally, the OEM castings usually had either a "DPCD" mark or a foundry designation, or both.

If you have any other pumps, compare the markings. Are there any casting numbers on the pump body? Look closely around the pressure regulator boss.

The tag and stamping font sure look like Melling to me... I googled "Melling M50" and look what I found:

http://www.streetperformance.com/part/melling-automotive-products/oil-pump/379702-m50.html

http://store.summitracing.com/partdetail.asp?part=mel-m50

http://webpages.charter.net/dhomstad/D500EngineFrame1Source1.htm

 

WOW! You appear to be correct! That makes me concerned though... this might mean I can't use it with the earlier 331 block. This pump came off of what would have been a "Dodge" 331 Truck motor (actually a 331 Chrysler installed in a Dodge truck).

As a new thought, the truck block is pretty much toast. Can the larger rear main cap/pump mount be used on an earlier block?? I could just have it line-bored (and will probably need it anyway, based on what I see).

OH! No markings on the pump anywhere. Only the USA bit and the tag with the 50 on it.

 

My 330 Desoto has a solid plug. I removed the ball and spring, but the hole was not deep enough for the HH diverter. After looking with a light there was a plug in the block and no place else for the oil to go. So the spring and ball was a back-flow valve only. Its just a straight channel to the filter.

 

It may work, but I cannot say for sure off the top of my head. I believe the two differences in pump bodies are where the suction tube attaches (either threaded into body or swinging off of cover) and I think the other is the mounting height/drive shaft height. I would have to research that more before I can say for certain. Do you have any casting numbers off the two engines rear main caps? Probably just easiest to put it up there and see how it fits... and how well the driveshaft engages into the intermediate shaft...

As you are aware, you cannot just swap main caps between engines. I would try the cap on the other engine and measure the bearing bore with a dial bore gauge. If its still round, then go ahead and check the alignment of all five main bearing bores. If it is not round, a line-bore will be required to use that cap.

I don't like the idea of line-boring unless necessary, as that moves the crank centerline up towards the cam a little bit - making the timing chain set a little looser from the very beginning.

 

I'll check out the main caps tonight. Great stuff! I have no idea where the stock oil pump is for the early 331 block. I'll have to dig that thing up and look at the two side by side.

 

I switched to the 340 oil pump and center sump pan. The 340 pump relocates the pick up tube. I made a new one using a pickup from a full sump pan. Had to bend and twist to get proper location, then cut off screen end and reweld it back on. It turned out very good, but was a lot of hassle. About half way through I thought "Why the hell didn't I just use the stock pump?" All this for 3% more flow? Was it worth it? I'll let you decide.

 

All Dodge, DeSoto & Chr high deck hemis used the same pump. Low deck Hemis have a different part # for each brand. There were 2 pumps used on 331/354 cars, of those one is listed as used on both Chr cars & Dodge truck 331, with the high deck pump used on 354 truck engines.

 

I do not know much about the Dodge or DeSoto engines, but it isn't that straightforward for the Chrysler engines.

I have several examples (at least four that I can be sure of) of 354 engines (car, truck, industrial) that use the same oil pump housing as a 392 engine. All are 1957/1958 engines and cover all three configurations of oilpans (center sump, full sump, rear sump). My 1956 331 engine is the same design as my 1955 301 and 331 engines having a floating oil pickup. I would like to hear from someone who knows for certain what oil pump parts were used in a 1956 354 car engine. I think it is more of a function of the production year than the engine displacement, because that is the only common denominator I can see.

From my examination, it appears the pumps using the 1630272 and 1734017 pump housings are interchangeable with each other. These have a threaded oil pickup tube.

A pump using the 1323360 pump housing is for use with the floating oil pickup, and will not interchange with an oil pump using either of those other two pump housings.

From what I can tell, the bolt pattern of the two mounting bolts changed slightly between the 1323360 and 1630272/1734017 housings. Therefore the rear main bearing cap must also be different. The pump sits on the bearing cap fine, but only one of the two bolt holes lines up.

Sounds like that Johnny Cash song 'one piece at a time'...

 

I just re-read all your posts...

I do not think the center sump pan will fit on your early block without some modification at the front end. I think you might be better off with the early rear sump pan and the corresponding oil pump with the floating pickup. It seems like a lot of work without much gain - unless the chassis requires it.

 

Dodgeboy, thanks for the help on the cam stuff, still haven't got the numbers I want.
I have a 56' 354 New Yorker eng all apart. It has the floating oil pickup and the # on the bottom of the pump is 1323361-52. I haven't checked the internal condition of the pump yet. In case I come across another pump, do you know any other #'s that will interchange with it?
Thanks.

Lucky667

 

Just an update. I haven't tried the pan on the block yet and won't be able to for a little bit (block going out tomorrow), but the interesting thing I found was that the mains for the my 1956 331 truck motor, my 1953 331 long bell motor and the 1955 331 short bell block ALL have the same main caps and the mounting pad for the oil pump is the same.

 

You are very welcome for the cam help. I am looking for the exact same information myself... My offer still stands if you can get your hands on any solid lifter 300 cam(s).

On the Chrysler oil pumps, the 1323361 cover corresponds with the 1323360 oil pump housing. While that cover fits one more pump housing (1327467), I don't think that pump housing will fit onto the rear main bearing cap of a 51-56 engine. If anyone has one, I would like to see a picture of it.

Fortunately, it seems the same oil pump was used on most 51-56 Chrysler engines. There is someone selling several early hemi oil pump rebuild kits on ebay, so at least parts are available. Search ebay for 350159736652. I know nothing about the quality of their parts though - does global mean they are sourced offshore? eek.

 

Assuming the pump I have is in fact the OEM replacement we discussed earlier in the thread, would I make the assumption that it would still use a standard rebuild kit (if it even needs it)?

 

The pump you posted pictures of is, in my opinion, a Melling (aftermarket)replacement - nothing OEM about it.

I say its a huge assumption to say OEM parts will fit, as Melling could have used whatever size/design gerotors they wanted (or have in production) to get the volume they designed for.

You need to measure the inner and outer rotors heights as well as diameters to know for sure.

 

There seems to be alot of mix and match when it comes to oil pumps and rear main caps. Nothing ever seems to be 100% with these.

Within the next month or so, a couple things will be easier to deal with. No matter what make early hemi, no matter what deck height, no matter what rear main cap bolt pattern, no matter what distributor.
I am in the final stages of a much simplier late model oil pump conversion, which will use an off the shelf SB Mopar oil pump (either std or hv). Need a pump? Your local parts house will have it.
The kits will also have a fool proof intermediate shaft. You will be able to order by engine size and the distributor you want to use.
Absolutely drop in. No machining necessary.
The hardest part of the whole conversion will be making your own pick up tube. Hey, I cant do it all.

 

This is why I LIKE IT WHEN YOU POST!!! Keep up posted, please!!

 

We use a stock Melling M72 low pressure 340 oil pump in most of our engines, including our Junior Fuel dragster (354 early hemi @ 409 cid) and our Engine Masters Challenge engines. In both instances, we diminish the tension on the bypass springs. The Junior Fueler makes too much pressure (@ 9000+) with the stock spring and 20-50 oil, and with the EMC engine, we want not much pressure (around 40 psi @ 7000 with 0-5W oil).

I feel that the best way to deal with the factory oil bypass on the Chrysler early hemi's is to completely eliminate it. We knock it out by inserting a rod (around .200" as I recall) through the oil pressure gauge 1/8 pipe fitting next to the distributor, and banging it out. Make sure that you get it all out. Typically the spring and ball will come out, but the shell will stay in. Often, we insert a tap into the shell, turn it as far as we dare, and bang the tap/shell out together with the rod through the oil pressure fitting.

You'll see a step where the stock bypass bottomed. We tap the hole @ 5/8 coarse, and screw in a set screw. Simple/stupid.

If you utilize a Chrysler small block pump, make sure it's aligned and free, and make sure to utilize the alignment spud included in the Hot Heads kit. Also, make darn sure that you're getting proper engagement with the drive tang or hex.

 

That would make a GREAT tech thread!! Thanks for that info. Not heard of that before. Welcome to the HAMB!

 

Thanks buddy! And good tip on that pan!

 

When I was mocking up my 301 for the small block oil pump I recall that I would be able to use the small block intermediate shaft. I didn't check the specs on the gears, but they looked pretty close.

I think the length was slightly longer but it would be easy to make the adapter slightly taller. Anyone else tried this?

 

There is some great tech here on early Hemi oiling. Thanks for every ones responses!

 

As far as % of oil going anywhere, you might want to look again @ my post #3.

 

ahhh, the ol' fractured shaft on the oil pump. it is out of alignment. thats what everyone said. little did i Know i was missing the "alignment dowel" in the block. fits half way in the block and half out where the rear main "aligns" to it. $5 part and went thru 2 pumps before figuring out about it. save yourself and more oil pump carnage. make sure the "dowel" is in your block. pull the rear main and make sure. the oil pump shaft runs right thru it. sometimes the machine shop will pull it and if you don't know to look for it, it'll mess you up.
good luck