Calderone

Wow !! So Melling Select pumps gears are bad too ????????
you know what...i will install a 70's V8 pump on my L98
maybe i will reuse the same pump that was on mine !

Eike

Is the 10555C OK for a street car?

Increase in volume of 25% over stock volume pump.
Features the addition of anticavitation grooves machined in the body and cover. The grooves reduce cavitation effects in high RPM applications. Pressure will be reduced at idle. The 10555C uses the high pressure spring only. Must use new 12550 drive shaft. For racing applications only.

Eike

nobody knows?

JLeatherman

Eike,
It really more depends on the pan you're running. If you are using the stock pan, do not use that pump. Get the stock volume/high pressure or the stock volume/stock pressure. A high volume pump will over scavenge a stock pan and run it dry, causing all kinds of problems. Also, for a stock engine, you don't need high volume.

Eike

It's for my 383 with a canton road race oil pan.

I have two HV pumps ... the 10555 and the 10555C.
The 10555C seems to have the stronger casting but pressure will be reduced at idle ... so I want to use the 10555C because of the stronger casting but am wodnering if the reduced pressure would be OK ...

Slalom4me

My vote is that a 10555C has more volume and more pressure than a
street car with a conventional 383 stroker requires. This statement is
based on the following assumptions:

• Stock clearances
• 6300 RPM limit
• No external lubrication sub-systems,
  such as:
  - Remote cooler,
  - Remote filter,
  - Turbo(s)]

Regarding Melling's statements about the 10555C

They recommend the 12550 drive shaft for all of the M-Select pumps,
not just the 10555C. The shaft is included with several, if not all of
the M-Select pumps.

The reduction in pressure at idle is due to the anti-cavitation grooves
which pass oil from the outlet/pressure chamber back towards the inlet
side. My vote is that this reduction in idle pressure is relative to the
pumps being compared to each other.

• In a given engine at idle, a 10555C will show LESS pressure
  than a 10555 (no anti-cav) because while both pumps have
  longer gears to provide 25% more volume, the 10555C is
  designed to 'leak' internally back to the inlet side through
  the grooves machined in the body and this reduces the
  pressure achieved at the outlet side.
  .
• But in the same engine at a given idle RPM a 10555C will
  show MORE pressure than an OEM pump or M-Select models like
  the 10553/10554/10552/10552C due to the greater volume
  passed per revolution of the longer gears installed in the 10555C.

"The 10555C uses the high pressure spring only." If you inspect
the springs supplied in the 10555 and the 10555C, I vote that
you may find that both have a pink high pressure spring with
dimensions described in post #12 of oil pressure relief spring.
If this is the case, then I vote that the unpainted standard pressure
spring that is described in the same post and which is available from
Melling upon request will reduce the maximum pressure of the 10555
& 10555C.

However, as stated at the beginning, I vote that the 10555/10555C have
more volume and pressure than the available information the application
(street car) suggests is required.

Since this thread is about issues reported about Melling pumps, rather
than about pump selection, perhaps consider starting a new thread
(ex: 'Oil pump selection criteria') for further discussion. Outline any
special circumstances that haven't been mentioned about your
particular engine combination & usage.

.

Midnight 85

I have the same combo in my '85 and the 10555 pump. I have no regrets,whatsoever.

Slalom4me

For those who may not have tuned in earlier, a little light reading ...

.

rodj

What do you make of post #5 + 7 dated Mar 08?

http://gonedragracing.com/forums/viewtopic.php?f=9&t=37

"Melling discontinued the lightweight oil pump casting of the M55, M55A, M155 oil pumps about 2 years ago. Any new, unused pump with the lightweight casting that was prone to failure can be returned to Melling for exchange as it is old existing stock, and not currently in production."

For real or a Mellings insider pulling the wool over?

_twisted_

Rodj - jeffmotorman is a life long motorhead, longtime former member of the defunct godragracing.com - that link is to the "new" site being used to continue in the spirit of the former site.

jeffmotorman has a speedshop/ machine shop/ raceshop in eastern pa, he isnt a melling crony. Just a guy in the know

he has a tremendous inventory that he is moving to either downsize his operation or retire.

periodically he would put up a list of items he was selling at or near cost,
so it might be worth a look occasionally especially if you are looking for shop tools or go fast goodies.

I havent bought from him, but did talk to him about heads - he didnt have what I was looking for.

hope that clears up some of the mystery.

Calderone

i did put a Melling oil pump.
i had 2 here ...M55 and the M55HV
i read on a lingenfelter book that we dont really need HV pumps
so i installed the normal one.-
i wont be racing my car,just normal driving so i guess it will be fine.-

MK 82

How much do oil pumps wear? How many miles are they good for? You read about 100K+ mile engines with the original bottom end.

MK 82

What is your primary language? Your English is better than alot of folks born in the USA!

Calderone

Spanish...
are you sure ?
my english its rusty
ME NO SPEAK ENGLISH

cv67

A stock oil pump is fine, put it in and drive it.