High Flow / High Pressure Oil Pump

[Bolisk]

Hello all!

Quick question. The previous owner of my 1970 Vette, installed a high flow / high pressure oil pump in the 350 / 350 engine. Currently the engine appears to operate on a PSI of ~75.

Should I be concerned about this? Can it blow out the main seal, or any other seals in the engine?

I have an alternate releif valvue spring that I could install that, according to the prevoius owner, is a lower pressure spring. Should I do this? How hard is this spring to replace?

Thanks for the help!
-Bolisk

 

[Hib Halverson]

Take the high volume pump out.

No SBV8 needs such a pump unless the engine is a very high power race engine with certain modifications that significantly increase oil flow and, these days, that is rare.

In this instance, all the high volume pump is doing is taking too much of the engine's power to drive the pump and creating problems with excessive oil pressure.

You could put in a lower-rated relief valve spring but that would not solve the problem with excessive power loss to drive the pump and it would probably reduce pressure too much. What you need is 10 psi per 1000 rpm with the oil at operating temp. For example, if the engine turns 5500 rpm, you need 55 psi. If it goes to 6500 you need 65 psi.

The spring is replaced by removing the pump, driving the roll pin out of the pressure relief valve bore, replacing the spring and replacing the roll pin. A DIY with intermediate mechanical skills can do this is he/she can also remove the oil pan.

Remove the high-volume pump and sell it on eBay.

Replace it with a stock oil pump fitted with the high-pressure relief valve spring, PN 3848911. Then use a high-quality, 10W30 engine oil. If you have an aftermarket camshaft with high intensity ramps and higher-tension aftermarket valve springs, you need to use a "racing oil" such as Valvoline, a premium synthetic, such as Red Line, or use a mass marketed 10W30 with an oil additive having extra EP lubricants.

 

[Bolisk]

Thanks for the reply.

I'm currently running Rotella 15w40 because of the mechanical lifters. Is that ok?

 

[Bolisk]

And yes, I do have the only Rotella with the Zinc in it.

The 350/350 only has about 100 miles since the rebuild.

 

[JohnZ]

Thanks for the reply.

I'm currently running Rotella 15w40 because of the mechanical lifters. Is that ok?

Yes, it is - good choice.