Replacement Oil Pump

[Driftwood]

While I'm installing a new oil pan gasket on my 69 350/350 SB, I'm considering also replacing the oil pump. Any suggestions-- stick with GM or are there better high performance parts to use? Thanks for any info.

 

[Jack]

Melling, Dynagear, Clevite, TRW/SpeedPro/Sealed Power brands are all very good.
JACK:gap

 

[vette-dude]

While you have the pan off--I suggest you replace the oil pump dive shaft with a metal sleeved one. The plastic sleeves on the stock pumps are known to fail. Cost is about $8 to $10.

Randy

 

[Driftwood]

melling pumps

I see Melling offers 3 types-- standard volume, standard volume with high pressure, and high volume. Any recommendations?

 

[vette-dude]

I like and use high volume pumps. High pressure pumps usually create more problems with seal and gaskets then they are worth.

Randy

 

[MaineShark]

I've heard some people say that the high volume pumps can wash out bearings in cars that don't actually need them. I'm not enough of an expert to know if it's true or not, but I have heard that. Other people swear by them.

Joe

 

[JohnZ]

You don't need either high-pressure OR high-volume; the SB Chevy oiling system is extremely well-developed (only 65 million of them out there) and the stock oil pump will work just fine.

 

[mvftw]

What about the rear main seal?

 

[Driftwood]

Rear seal also

Yes-- I'm planning on changing the upper rear seal also. I'm going to try a one-piece oil pan gasket. Oil pan gasket, rear seal, and oil pump. Anything else I should do while I'm in there?

 

[cruisin-davey-g]

Re: Rear seal also

Yes-- I'm planning on changing the upper rear seal also. I'm going to try a one-piece oil pan gasket. Oil pan gasket, rear seal, and oil pump. Anything else I should do while I'm in there?

I used a stock pump out of an LT-1, works great. Here's a suggestion, if you change the pump & pick-up, it would be a good idea to spot weld the pick-up tube to the pump body. it has been known that the tube may dislodge from the pump & become disconnected.

 

[Driftwood]

Meling Oil Pump M-55 or M-55A

I'm ready to finally change the oil pan gasket, upper rear seal, oil pump, and oil pump dive shaft. Melling offers 2 pumps for Chevy 350 SB-- M-55 and M-55A. 55A is for standard 350, the 55A is for 350 performance engines. Anyone know which one I need for a '69 350/350? Thanks.

 

[Jack]

M55 is std press & std vol (*probably best for yours).
M55A is Hi-pres & std vol.
M55HV is Hi-pres & Hi-vol (comes w/ 2 springs ... Hi-pres is installed ... you can switch to std pres & still retain Hi-vol).

There are several others also ... those are the routine three.

To echo JohnZ ... unless your motor has been modified/clearanced accordingly you neither need nor want Hi-pres nor Hi-vol. Chances are the M55 is the pump for you. Always get a new pu tube-screen to match your pump ... some pumps have 5/8" inlets & others have 3/4". Pretty sure M55 is 5/8". BTW ... we run std pres & std vol in our circle trackers ... we do so intentionally ... we have plenty of pressure & volume w/ a std-std Clevite pump that's equivalent to M55. To echo CDG ... tack weld the tube to the inlet. Chances are your new pump will come w/ a new op drive shaft sleeve (guide) ... a metal one ... use it instead of OE-type plastic ... if it don't come w/ a metal sleeve, get one. Maybe your new shaft will come w/ a metal sleeve.
JACK:gap

 

[cruisin-davey-g]

Right you are, Jack! No other explaination needed!

Dave:

 

[MaineShark]

I'm still not sure whether I might want high-pressure, to compensate for the pressure drop that will occur when I add my oil cooler.

Does anyone know how much higher the pressure will be, with the high pressure pump? That way, I can just see how much my pressure drops, and decide hwether the pressure drop is similar to the pressure increase of the new pump.

Joe

 

[JohnZ]

I ran external filters and coolers with #10-AN lines running all over the place on all my Cobras and my Grand Sport with stock oil pumps, never had any oil pressure issues.

 

[JonM]

Note the weld...it only has to be tacked...this welder went nuts...

 

[Driftwood]

Thanks for successful weekend!

Thanks to everyone for the oil pan/ rear seal/ oi pump info. Last weekend I successfully replaced the oil pan gasket, oil pump, oil pan drive shaft (steel sleeve), and rear main seal. I was really impressed with that Felpro 1 piece gasket. The original oil pump nylon sleeve was cracked in half, so going to the steel sleeve was probably a good suggestion. I also took the time to repaint the oil pan. With the Melling M55 replacement pump my pressure jumped from 35 to 55 psi. Does that sound about right for a 350/350 with 10W30 oil?

Things went so well I had time to change the water pump, which was also leaking. At least three more fluid leaks to go-- lower radiator neck, intake manifold, and power steering ram. One weekend at a time...

 

[Jack]

Re: Thanks for successful weekend!

With the Melling M55 replacement pump my pressure jumped from 35 to 55 psi. Does that sound about right for a 350/350 with 10W30 oil?

Assume that's at hot cruise ... 55psi sounds good.
JACK:gap