Oil Pump Update?

[AmericanPie]

I'm rebuilding a street 327 SBC and one commonly-available oil pump that was often recommended for this application was a Melling "Select" #10553. However Melling says this unit has been discontinued and has been replaced with "10553ST" Shark Tooth pump, which uses helical gears instead of the straight-cut spur gears previously used. This new pump is also on back order.

I was also searching some older (circa 2007-2010) posts about oil pumps and there was a lot of concern when the manufacturers started making gears out of powder metal instead of billets. Is this still an issue or have the powder metal gears proven their worth?

As an alternative to the new Shark Tooth 10553ST pump, there are still a few leftover Melling #10552 and #10553 pumps around, as well as some NOS GM #3764547 pumps. Which one of these would be the best choice? Or is there something else in the aftermarket that's better?

[BOOT]

Just a quick google of the part number 10553ST brings up Summit & Jegs. Both have plenty in stock but Summit ships free and Jegs you'd have to spend a bit more for free shipping.

Sharktooth is a nice pump but idk if you really wanna spend that much vs a M55 or M155, with a high pressure spring if that's really what you need/want.

If your diy type I modded a Melling & Milodon in my vids and their are other mods that can be done.

[tenxal]

If you don't have a good used one to rework, the Moroso 22101 is what I'd recommend.

If you go with a Melling, remove the bypass valve and make sure it's free. They have a history of the bypass sticking when new.

[Walter R. Malik]

I'm rebuilding a street 327 SBC and one commonly-available oil pump that was often recommended for this application was a Melling "Select" #10553. However Melling says this unit has been discontinued and has been replaced with "10553ST" Shark Tooth pump, which uses helical gears instead of the straight-cut spur gears previously used. This new pump is also on back order.

I was also searching some older (circa 2007-2010) posts about oil pumps and there was a lot of concern when the manufacturers started making gears out of powder metal instead of billets. Is this still an issue or have the powder metal gears proven their worth?

As an alternative to the new Shark Tooth 10553ST pump, there are still a few leftover Melling #10552 and #10553 pumps around, as well as some NOS GM #3764547 pumps. Which one of these would be the best choice? Or is there something else in the aftermarket that's better?

For your application, I personally would use an M155 pump and install the higher pressure spring. That pump uses the larger inlet tube.

[AmericanPie]

So do all these pumps now use powder metal gears? Has PM proven to be a good substitute (or even an upgrade?) for billet gears?

Also, if rebuilding my 327's original oil pump is a practical option, where can I have this service done? The engine has about 115K miles and I have no reason to think the pump is worn.

Thanks guys for all the great advice!

[racear2865]

all pumps can have a problem with unloader sticking. I remove and brush the hole with a valve guide brush hone. The sharp edges from the drilled holes will be broken with the brush hone. Then lubricate with assembly lube.

[rustbucket79]

So do all these pumps now use powder metal gears? Has PM proven to be a good substitute (or even an upgrade?) for billet gears?

Also, if rebuilding my 327's original oil pump is a practical option, where can I have this service done? The engine has about 115K miles and I have no reason to think the pump is worn.

Thanks guys for all the great advice!

Bust it apart, if the housing, end plate and gears all look decent there is no reason not to reuse. Tap out the bypass spring retainer and do a good cleaning. A little loctite on the bolts doesn’t hurt during reassembly.

FWIW there are thousands of M55 pumps with the PM gears installed in engines every year without issue.

[BillK]

I'm rebuilding a street 327 SBC .............

I have never used anything other than an M55 or 55A on a street small block Chevy. Just dont see any reason to. The 355 I had in my race car shifted at 7500 and went through the 1/4 mile at 7800 rpm and all it had was an M55A. No reason to reinvent the wheel. The SBC oiling system is pretty bulletproof like it came from GM.

[cad]

If you're going to race only, I would never run a M55. We have had 2 break within 2 years.... I called Melling and they said the 10553ST is highly recommended for high RPMs to withstand any vibration. My mistake, but I caught it quick enough and only had to do rod bearings earlier this year.

[novafornow]

I am a big fan of the ST pump. EXTREMELY SMOOTH. I don't believe that you will find many that would go back to a standard pump once they have used one.

[Schurkey]

Any respect for the Melling M-99HV-S "big block" pump kit? (Kit comes packaged with a #305S pickup for an ~8" pan, and a steel-collar drive shaft.) Melling lists it only for the 302 Chevy, but it'll fit any of 'em depending on pan depth and windage tray clearance.
https://www.summitracing.com/parts/mel-m99hvs

I have heard good things about it in a small-block application, particularly when using the lower-pressure relief spring and thin (5W-30 or thinner) oil. Lots of oil flow, but not a huge drag on the distributor gear.
https://www.hotrod.com/articles/ccrp-09 ... oil-pumps/

Bought an M77 pump and 305S pickup, haven't used it yet. Pickup interferes a little with the OEM windage tray of a TBI/Vortec 5.7L. Tray needs minor trimming and reinforcement. I have heard (but not confirmed) that the M99 pump has the pickup hole in the correct place for a small-block, while the M-77 doesn't. On-line photos don't seem to support the idea of a relocated pickup hole.

I sent Melling an e-mail through their web page contact system, asking about the volume of the "big block" M77 pump compared to the small-block pumps, but I never got a response.

[Lizardracing]

If you go with a Melling, remove the bypass valve and make sure it's free. They have a history of the bypass sticking when new.

This literally blew up the can on the oil filter a few months ago. What a HUGE mess.

[rustbucket79]

So do all these pumps now use powder metal gears? Has PM proven to be a good substitute (or even an upgrade?) for billet gears?

Also, if rebuilding my 327's original oil pump is a practical option, where can I have this service done? The engine has about 115K miles and I have no reason to think the pump is worn.

Thanks guys for all the great advice!

If your pump gears, body, and bottom look decent, and the engine previously had no issues, break it down completely as already mentioned and clean thoroughly. You could upgrade the spring to a higher pressure one. I have the same old style heavy housing M55 with the steel gears in my drag race small block since the early 2000’s, no need to replace what isn’t broken.