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Melling SharkTooth Oil Pumps and High Pressures: Is this a problem?

General engine tech -- Drag Racing to Circle Track

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NewbVetteGuy
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Melling SharkTooth Oil Pumps and High Pressures: Is this a problem?

Post by NewbVetteGuy »

Carl Hinkson has posted some information about two engines running Melling SharkTooth 10552 oil pumps and experiencing very high oil pressure.

Picture of a 383 with a 10552 making 70 PSI @ 4,000 RPM and 98 PSI @ 5,900 RPM here: https://www.facebook.com/photo/?fbid=10 ... 7988870326

He says the bypass valve is too long and not exposing enough of the bypass hole.


Another guy took apart his 10555 pump and found that half the bypass hole is blocked internally. (Photo Attached)
10555ST.jpg

I've heard a few folks complain about high pressure on these for a while online; some of these pumps were purchased 2-3 years ago. Looking for additional opinions on whether this is normal and what the right "fix" is.

I've got a 10553ST sitting on my engine on the stand and I was HOPING to get it back in the car next weekend, but now I'm worried about the stupid oil pump... NOT easy to pull the pan on a C3 with a modern rack and pinion steering conversion, so I want to make sure this is good-to-go first...



Adam
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Re: Melling SharkTooth Oil Pumps and High Pressures: Is this a problem?

Post by NewbVetteGuy »

Some folks are removing the bypass valves and shortening them to work-around this problem.

Carl says he contacted Brian @ Mellings and they're looking into it as of 2 days ago but no "official" reply from Melling yet...

Problem confirmed on some 10552 ST, 10553 ST, and 10555 ST pumps so far.

I've never taken apart an oil pump and I don't actually understand the root of the problem here, so if anyone can explain what might be the problem for an oil pump bypass newbie...


Adam
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Re: Melling SharkTooth Oil Pumps and High Pressures: Is this a problem?

Post by mag2555 »

Does the bypass assy from a non Shark tooth pump fit in these problem pumps?
You can cut a man's tongue from his mouth, but that does not mean he’s a liar, it just shows that you fear the truth he might speak about you!
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Re: Melling SharkTooth Oil Pumps and High Pressures: Is this a problem?

Post by NewbVetteGuy »

And how would you even check the oil pump bypass with the pump not on the engine? (How to spin the thing to 3,000 RPMs?)

I asked my local machine shop, who's been fantastic so far today if they'd take a look at my pump if I dropped it off tomorrow and they said that they don't have a 3,500 RPM trill and to just call Melling in the morning...



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Re: Melling SharkTooth Oil Pumps and High Pressures: Is this a problem?

Post by bthomas »

unscrew the pressure relief spring port, remove spring, reinstall plug. valve will now freely slide in/out.

remove relief hole plug, you can now see the inner relief hole, and how its partially blocked as the valve won't slide far enough. (too long)
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Re: Melling SharkTooth Oil Pumps and High Pressures: Is this a problem?

Post by Tom68 »

NewbVetteGuy wrote: Thu Jun 23, 2022 6:52 pm And how would you even check the oil pump bypass with the pump not on the engine? (How to spin the thing to 3,000 RPMs?)

I asked my local machine shop, who's been fantastic so far today if they'd take a look at my pump if I dropped it off tomorrow and they said that they don't have a 3,500 RPM trill and to just call Melling in the morning...



Adam
It's measurable and calculable if you can be bothered.
It's a measurable spring and travel distance.
Whether the relief port is big enough is another issue, and a perpendicular intersecting round hole gives variable relief depending on excess flow.
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Re: Melling SharkTooth Oil Pumps and High Pressures: Is this a problem?

Post by leahymtsps »

Carl is just being Carl. If they weren't running a pump with too much volume
they wouldn't have this problem.

Tom
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Re: Melling SharkTooth Oil Pumps and High Pressures: Is this a problem?

Post by rgalajda »

You have 10553ST melling ------ High pressure standard volume pump (+10 psi) spring installed
•Includes optional yellow standard pressure spring (not installed)

10552ST melling ------ is 10% higher volume high pressure pump ( with two optional pressure springs -10 psi and +10 psi )

10555 melling ---- 25% increase in volume over stock oil pump. The lower pressure spring is included to reduce pressure if desired.

10555C (Anti-Cavitation) 25% increase in volume over stock oil pump. The 10555C uses the high pressure spring only. Racing Applications Only.

None of these pumps are the same and all have specific applications.
It comes down to details. ( such as which spring is installed? ) and engine build details

Knowing when to use a higher pressure pump or higher volume pump is the key when engine building. You can not apply these to a stockish street engine build

The QUESTION is why did you choose High pressure standard volume pump (+10 psi) spring installed
More detail of your application would help
If this is a small block chevy with standard crank and rod clearances , than install the yellow standard pressure spring.
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Re: Melling SharkTooth Oil Pumps and High Pressures: Is this a problem?

Post by NewbVetteGuy »

leahymtsps wrote: Fri Jun 24, 2022 6:20 am Carl is just being Carl. If they weren't running a pump with too much volume
they wouldn't have this problem.

Tom
The problem exists with the 10553 standard volume and standard pressure version of the pump, though.

If the bypass doesn't bypass enough oil, isn't the pressure going to continue to rise regardless of which spring is in it?


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Re: Melling SharkTooth Oil Pumps and High Pressures: Is this a problem?

Post by NewbVetteGuy »

rgalajda wrote: Fri Jun 24, 2022 6:57 am You have 10553ST melling ------ High pressure standard volume pump (+10 psi) spring installed

Knowing when to use a higher pressure pump or higher volume pump is the key when engine building. You can not apply these to a stockish street engine build

The QUESTION is why did you choose High pressure standard volume pump (+10 psi) spring installed
More detail of your application would help
If this is a small block chevy with standard crank and rod clearances , than install the yellow standard pressure spring.
There's no such thing as a standard volume and pressure SharkTooth pump from Melling, AFAIK.
Their "standard volume, standard pressure" SharkTooth pump is +10% pressure and volume vs. a regular lobed pump (not +10 PSI).

My understanding was that the additional flow and volume just comes from the shark tooth design itself, even when used with a standard pressure spring.

This problem has been reported by multiple people running the supposedly +10% pressure and flow 10553ST pump. 60 PSI + 10% should still be only 66PSI, not 100 PSI, right?


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Re: Melling SharkTooth Oil Pumps and High Pressures: Is this a problem?

Post by cgarb »

I have the shark tooth pump in my 355, it's the one they claim as standard volume. It did have high oil pressure the first time I started it. It was over 90lbs when you would rev it. The pump came with 2 springs. I swapped out the spring for the lower pressure one and it helped. The spring that I put in by feel felt very similar to the spring in my old z28 pump. The one that was in it out of the box was noticably more stiff. Once I get heat in the motor and the oil gets up to temp it idles around 40lbs and it goes down the track a little over 65lbs. That's with SAE30 oil and a vacuum pump pulling 9 inches of vacuum. I'm not concerned with anything. Bronze distributor gear looks great after some use, so I'm just gonna keep on keeping on with it.
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Re: Melling SharkTooth Oil Pumps and High Pressures: Is this a problem?

Post by rgalajda »

From Melling Website


(262 - 400 S.B.) OHV - 1957-04 - 8 Cyl. Standard Volume, High Pressure Performance Oil Pump
MADE IN MICHIGAN
Melling Part Number 10553ST
Features
Description
Standard Volume, High Pressure Oil Pump
Performance upgrade of M-55. Street and Strip Applications.
U
•Cast iron housing & cover with phosphate coating
•Exclusive billet steel Shark Tooth helical gears reduce pressure
ripple, reduce torque ripple, improve distributor operation and
improve shaft and gear wear
•Includes 12550 chrome-moly steel intermediate drive shaft w/steel guide •High pressure (+10 psi) spring installed
•Includes optional yellow standard pressure spring (not installed)
•Uses 5/8” diameter press t oil pump screen (not included)
(262 - 400 S.B.) OHV - 1957-04 - 8 Cyl. Standard Volume, High Pressure Performance Oil Pump
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Re: Melling SharkTooth Oil Pumps and High Pressures: Is this a problem?

Post by leahymtsps »

NewbVetteGuy wrote: Fri Jun 24, 2022 1:48 pm
leahymtsps wrote: Fri Jun 24, 2022 6:20 am Carl is just being Carl. If they weren't running a pump with too much volume
they wouldn't have this problem.

Tom
The problem exists with the 10553 standard volume and standard pressure version of the pump, though.

If the bypass doesn't bypass enough oil, isn't the pressure going to continue to rise regardless of which spring is in it?


Adam
You know this for a fact or are you just repeating what Carl posted?
FWIW a 10553 is a high pressure pump.

Tom
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Re: Melling SharkTooth Oil Pumps and High Pressures: Is this a problem?

Post by dfarr67 »

cgarb wrote: Fri Jun 24, 2022 2:51 pm I have the shark tooth pump in my 355, it's the one they claim as standard volume. It did have high oil pressure the first time I started it. It was over 90lbs when you would rev it. The pump came with 2 springs. I swapped out the spring for the lower pressure one and it helped. The spring that I put in by feel felt very similar to the spring in my old z28 pump. The one that was in it out of the box was noticably more stiff. Once I get heat in the motor and the oil gets up to temp it idles around 40lbs and it goes down the track a little over 65lbs. That's with SAE30 oil and a vacuum pump pulling 9 inches of vacuum. I'm not concerned with anything. Bronze distributor gear looks great after some use, so I'm just gonna keep on keeping on with it.
For street duty in a 383- I have a ported Z28 Melling/rear gap, in your opinion is it worth changing out to a ST- are they that good?
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Re: Melling SharkTooth Oil Pumps and High Pressures: Is this a problem?

Post by rgalajda »

10553 and 10553ST are different pumps


What is a " ported Z28 Melling/rear gap"
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