Anyone making a reliable oil pump anymore?

[K201979]

Im gearing up for a manual trans swap and while I've got it apart I'm going to do the rear main seal. While I'm in there i feel like i might as well replace the oil pump(cheap insurance). Of course the first place i looked was Melling, and specifically the M55. Im reading that in 2006ish they thinned the castings on their lower end pumps and now they are prone to breakage. Ok, maybe a Milodon pump. I found that in about 2009 they had a bunch of ill fitting, poorly cast/machined pumps hit the market. The crank counterweights were apparently hitting the pump. I cant find any info on weather or not these problems have been remedied. I know that i can buy the Melling select pumps and they have the original casting but I'm having a problem supporting a company that will farm out work and not have better quality control on a part as vital as an oil pump. Im at a loss. The only pump i can find that says its American made is a Summit brand and i don't know if i believe that either. Im about to do some research on Moroso pumps, but i suspect i will find the same nightmare(at a higher cost). Any current engine builders out there that can recommend a reliable standard volume, standard pressure oil pump for a mild 350 with a stock style pan? Thanks.

 

[bucket]

I wasn't aware that Melling cheapened the pumps. So the M55 is a "Select" or is that a different number?

For whatever it may be worth, I'd leave the current pump in place. If it ain't broke, don't fix it I guess.

 

[legopnuematic]

Thats what my thoughts are. leave it alone but I would put a new collar on the drive shaft for the pump or get the one that uses a steel sleeve instead of the plastic one.

 

[RecklessWOT]

Im gearing up for a manual trans swap and while I've got it apart I'm going to do the rear main seal. While I'm in there i feel like i might as well replace the oil pump(cheap insurance). Of course the first place i looked was Melling, and specifically the M55. Im reading that in 2006ish they thinned the castings on their lower end pumps and now they are prone to breakage. Ok, maybe a Milodon pump. I found that in about 2009 they had a bunch of ill fitting, poorly cast/machined pumps hit the market. The crank counterweights were apparently hitting the pump. I cant find any info on weather or not these problems have been remedied. I know that i can buy the Melling select pumps and they have the original casting but I'm having a problem supporting a company that will farm out work and not have better quality control on a part as vital as an oil pump. Im at a loss. The only pump i can find that says its American made is a Summit brand and i don't know if i believe that either. Im about to do some research on Moroso pumps, but i suspect i will find the same nightmare(at a higher cost). Any current engine builders out there that can recommend a reliable standard volume, standard pressure oil pump for a mild 350 with a stock style pan? Thanks.

Moroso is still very much an American made pump (unless something just changed). I know a guy that does piecework welding for Moroso at home, I remember one time 3 or 4 years ago I stopped by his house and he was welding a few hundred pickup tubes in his basement lol.

 

[K201979]

The M55 is the lower end. Used to be the old standby, now a farmed out, thinner casting, from what i can gather. The select(or performance i think they call it) line have a 5 digit number like 10553. The 5 digit number ends with a “st” for their “sharks tooth” pumps(helical cut gears). From what i understand, the performance pumps are still made with the older, thicker casting. Ive thought about leaving the old pump. With parts the way they are these days, thats probably the best logic. It aint broke. i was just trying to prevent a future failure but sounds like running what i got might be the best way to do so. The collar is probably a good idea, and the inside info on Moroso stuff is good too. Thanks for the comments.

 

[K201979]

Apparently, the thin castings are everywhere unless you go for a performance pump. My research is done. Ill run what i got till it wont run no more and figure it out then.

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[Shorty81]

I have a Melling high flow pump on my bbc, don't remember the part # though, happy with it so far. Installed 2016.

 

[K201979]

Im sure even the thin casting would be fine in my application(under 5k rpm, stock engine mounts) but i was being overly cautious because my truck sees some ruff terrain. Might even be what is in there because it was rebuilt in about 2014, before i got it, but im gonna run it for now and worry about it later.

 

[Craig Nedrow]

GO HERE: http://performanceunlimited.com/oilpumpmods/index.html
I do this to every pump (Melling) I use. My 355 chevy runs 47 lbs oil pressure at 2500 RPM, engine has 3500 miles on it so pretty tight. You would be surprised when you pull one apart. Scored housings, gears, top plate clearance to much. It's a casting and the oil passages are rough, just like on the engine. This article is really good, but if you don't have all the measuring tools, (I am a machinist) at least smooth the oil passage, clean the screen, weld the pickup tube to the body, make sure the gears are all the same height, and CLEARANCE THE HOUSING AND POLISH THE COVER PLATE!! The pump in the 355 has .0025 clearance between the gears and the top of the housing measured with a depth mic. I DO NOT use a file. I have a piece of plate glass and use different grits of wet or dry sand paper with motor oil. You will often notice marks on the top plate of a used pump like the one in the picture. Mine was that way and was caused by the pump housing not being perpendicular to the gears. Mine was off .001. I fixed it by the sandpaper method applying more pressure on the high side to bring it down. Without a depth mic, just measure with feeler gauge in four different spots, until you get the same feel on the gauge at all spots. Using the polished top cover to set the .0025 gear to housing clearance. Use a figure 8 motion to polish and final clearance as this will keep things flat and parallel. Sorry for the long post, but I have NEVER HAD A PUMP FAILURE in thirty years of doing it this way.