Lowered oil pressure with roller lifters..?

[Matt Driskell]

We just dynoed a 582 BBC this week that had crower lifters in it last year. This time we went with the Ultra Pro lifters made by Morel and they are pressure fed. When the engine came in the shop a month ago we put it on the dyno befor the freshen up and it had 85# of oil pressure at 7800. After the freshen and the new lifters, which did mic. bigger than the Crowers by .0005, the oil pressure was down to 71# at 7800. The 85 pounds of oil pressure was a little high for my liking and the 70 was about perfect so things were ok, but I did see a drop in pressure.

[BlackoutSteve]

Thanks guys.
Running a heavier oil may only mask the low oil pressure. Even though I use a synthetic, it's still a 50 weight when hot.
At temp, shouldn't this behave even like a regular 50 single weight mineral for example?
If I put in a heavier weight oil, I'd expect the gauge to look worse (measuring it after the mains like I do), or better if I measure it at the OE location, between the pump and the mains. (Which to me, is not a true reading of the engine's oil pressure.)

Also, I only just got off the phone from Isky, and they confirmed that a drop of 10-12lbs is typical with these lifters.
I guess I'll just have to wait and see on the dyno how it behaves under load and hope it will make 60-65lbs like 70MC's does.

[BlackoutSteve]

Just looking for some feedback please..

If this were a supercharged engine and I was struggling to make boost, and like a wet sump oil pump, not being able to change the drive ratio, a bigger supercharger/pump would be the simple and obvious solution, right?

I have no idea whether the Moroso or Titan billet oil pumps deliver more (enough) oil than the Melling HV77 that I have installed, but regardless, I'm not paying the AU$ on either one of them. ..
and I refuse to live with 5-10psi idle and 45psi peak simply because I have a roller cam and bought the best lifters that I could afford.
(BTW, those pumps are US$450 and US$775 respectively!)

The HV77 has 0.250" longer gears (1.390") than the standard volume GM-BBC pump (1.14"), and is said to flow 25% more. (GM's HV has 1.30" gears incase you're wondering.)
If I were to increase the gear height by another 0.250" (+1/4" to 1.640"), would this additional 18% volume over the HV77 be enough to raise my idle pressure back to where it was, around 25psi I wonder..?
Or, should I increase volume by 25% over the HV77 by 0.3125" (+5/16") and then mill back if it's too much?

That's that plan and it's suprisingly quite simple to do to one of these pumps with a few doner parts.

Am I nuts to be even attempting to do this?
I have never wanted to ever fool with the stock oiling system, but the rolller lifters are not stock and have now increased oil demands over the oil pump designer's expectations.

If I don't do this, what do I do?

[Matt Driskell]

I would look at the clearance's in the engine, main and rod bearings, lifter bores, cam bearings. You have a pressure loss somewhere. The 582 that I dynoed had a M77HV oil pump with anti-cavitation slots milled in it and hot on the dyno idled at 53psi and had 70-71 psi through the entire dyno sweep, 5600-7800. My thoughts are you have the correct pump but excess oil pressure loss somewhere. The Moroso billet spur gear will be no better, probably less psi. The Titan or the Gerotor Moroso might help but I would try to fix the problem. Good luck.

[Wolfplace]

Steve,
As I stated in this or your other post,,, possibly both,,
I could care less about the 10lbs at idle as long as pressure goes up to relief value at RPM

But I completely agree with the above post, if you are not making pressure with an M77HV pump something is not right.
Just throwing more pump at it is not the answer.

The first thing though do you have any off idle numbers yet?
If your 45 is what you are seeing & the gauge is correct if it were me I would be taking the thing apart, checking & measuring things.
You have way too much leakage somewhere, that pump puts out enough oil for two Rats,,,,

[F1Fever]

saw something like this on a 496 once, the filter had collapsed. Steve, have you checked or replaced the filter? so simple, but sometimes simple is the answer...

[74RAT]

just an idea here,, but,, would oil restrictors still provide enough oil to the rollers,, while keeping more priority main oiling in this situation??

[Wolfplace]

just an idea here,, but,, would oil restrictors still provide enough oil to the rollers,, while keeping more priority main oiling in this situation??

=
No sir,, not in my opinion.
I do not put oil restrictors in any Chevrolet engine I build.
Haven't for as long as I can remember.
Rollers need a lot of oil to survive.
So do springs, to the point of adding oil in an endurance application.

[TheEngineWorks.com]

Steve, I believe some of this has to do with where your picking up your reading from.. Most don't pick it up in the front, so you are comparing apples to oranges.. I know most of the BB I do are read from one of the back galleys, a SB is picked up right on top above the oil pump. I have taken readings from the front and back on a SB and seen a big difference in pressures.

I would bet your concerns are over nothing, if all else is right, you are gonna bleed a good bit more oil off with those lifters, although I don't think its gonna effect what the bearings see in pressure much at all.

Also, I would dump that high dollar oil and just run Rotella T, its a lot cheaper and will help out on cylinder wear and other high pressure components. Even the reformulated stuff has 1500ppm of zinc..

[F1Fever]

How's Eddie been? also doesn't to Rotella seem to dirty up real quick? every time I've used it's lifespan seems to be over real quick, at least on the street.

[BlackoutSteve]

Oh Hey Eddie! How are ya? Good to see you on my copy of Drag Week. Well done! That smokey back drop was just perfect, I love it.

I thought it may have been an issue also, so I swapped the gauge's pick up to the pump end of the main gallery expecting to see a huge difference. There wasn't. It was maybe 3-4psi while the oil was cool enough to be idling at 20-ish.
That was a pretty good indication to me that I wasn't bleeding a heap through the bottom-end. I'd even go to say that a 3-4psi drop is damn acceptable for all main, rod and cam journals combined.

If I could have, I would have swapped the gauge's pick up to the front if the lifter gallery, but not possible. I bet that would have revealed some low numbers. (I'm assuming, of course I'm assuming, I'm always assuming!)