Any danger with this setup?

[Bill I.]

1967 L 79, PO put in a high pressure oil pump or spring AND the 80# gauge. Pressure is 70, 75 cold, drops to 50,60 when warm, and idles around 40 or so. Using 10/40 oil.

Anyone foresee any problems? Thanks, Bill

[Joe C.]

Re: Any danger with this setup?

1967 L 79, PO put in a high pressure oil pump or spring AND the 80# gauge. Pressure is 70, 75 cold, drops to 50,60 when warm, and idles around 40 or so. Using 10/40 oil.

Anyone foresee any problems? Thanks, Bill

Nothing major.
More oil will bypass the oil filter until the engine warms up, than if the engine used a standard pressure pump.
Less horsepower and torque across the entire rev range because it takes more power to drive the HP pump.
Lower fuel economy. Yeah....like you CARE about that, right?
More spark scatter, since the pump pulsates more than the standard pump.
Nothing to be gained, only minor losses.

Yes pilgrim. You now have bragging rights alright.................and that nice, impressive oil pressure to keep you feeling warm and fuzzy. Lose the 10W-40 and use 5W-30 or 10W-30 oil. If you are using SM rated oil, you should add some ZDDP to it. If you don't feel like adding any ZDDP, then use API CJ-4 rated (diesel) oil.

[Bill I.]

Re: Any danger with this setup?

Thanks Joe, appreciate the answer, Bill

[Jack P.]

Re: Any danger with this setup?

1967 L 79, PO put in a high pressure oil pump or spring AND the 80# gauge. Pressure is 70, 75 cold, drops to 50,60 when warm, and idles around 40 or so. Using 10/40 oil.

Anyone foresee any problems? Thanks, Bill

Bill , your numbers are just the same as mine. L79 blueprinted and balanced.
I have a new 10552 HV Melling pump. I always suffered from low pressure. "Oil Saga" post a while back. On my first rebuild, the builder left out the oil plugs in the front of engine. Next rebuild, this summer, new pistons, lifters, etc. and oil galleys cleaned etc, and pressure is close to 75 at start, 60 running warm and 40 + at idle. Bypass is blocked so all oil goes through filter.

Jack

[Jim H.]

Re: Any danger with this setup?

Bill,
Did the exact set-up as yours when I rebuilt my 427/390 (we kind of modified it with a hotter cam; bigger pistons so it was pushing 425hp) worked fine and sounded cool. Your set-up is great. As Joe mentions ZDDP oil API CJ-4 rated is a must.
Good luck,
Jim
Denver CO

[Ronald L.]

Re: Any danger with this setup?

Jim,

What pump did you use for you 427?

I pulled my pan to change gasket & clean, found an o-ring, old gasket material in the oil pickup screen, it is doing its job.

But thinking to just change it out.

Any one know who made the pump originally for GM?

Then the question of going with a Hi Volume pump requires a different shaft off the distributor, any other issues?

[Timothy B.]

Re: Any danger with this setup?

Why not use a stock pressure standard volume pump and blueprint it by making sure end clearance is .002+-.001. Use 220 wet on a flat table and feeler guages.

Also, check the mating surface of the pump where it bolts to the rear main cap to make sure it's broached flat. Some offer a gasket here but GM never used one so it's a source for pressure loss if not flat.

All this extra pressure will bypass inside the pump and volume in excess of what the filter can handle will bypass at the filter so where is the gain...