That is correct: not to the sump itself, but rather, the sump (intake) side of the pump.

The VVT/AFM/DOD/whatever other TLA engines have other relief valves that DO return to the sump proper.

 

Thanks got parts coming, BTW guess what that is under the front fog light ??

 

A/C dryer.

 

Not a good place for anything that services the automobile but is it a power steering pump?

 

I agree. According to Dart, theres already WAY too much oil circulating thru the stock engine. I also think more volume is needed for piston oil squirters.....

 

Piston squirters add 8 extra holes to the system. Axle oiling lifters add 16 extra holes to the system. VVT, DOD…same thing. You can’t have enough pressure without there first being enough volume, since pressure is a byproduct of metered volume. So extra volume is required for the above mentioned “extra holes” in the system. Yes, the holes are metered, but require extra volume all the same. Same thing with add-on oil coolers, etc. They add length to the system, so extra volume is required to maintain the same pressure, and often times if in a case like my 434 where I’m running a really big oil cooler and axle oiled lifters, I need extra volume and pressure to achieve a tolerable oil pressure at hot idle. There really is no “one size fits all” oil pump for a performance build. The pump needs to be sized according to what the needs are for the engine, in which case clearances, rpm, oil viscosity, expected oil temp, size of coolers, squirters, axle oiled lifters, VVT, DOD, ring package, even type of rockers, etc all have to be taken into consideration. If your doing a simple stock rebuild, going right back into the same vehicle, then an OEM style pump can be utilized. I’ll say it again here…oil pressure is a byproduct of metered oil volume.

 

Don’t take my word for it if you don’t want to guys. Spend some time on the phone with Melling asking questions. I spent many hours 30 years ago doing test analysis with oiling systems for race teams trying to find hp. Most guys have never heard of oil windage under the valve covers, costing power, but it’s a real thing. Dry sump systems were fairly new back in those days and we spent a lot of late nights gathering data and trying different clearances and pump settings vs. pump stages. Line sizing and line length was a big deal and still is, although it’s fairly standard today. I know this isn’t a dry sump thread, but the testing we did crosses over from dry to wet sump. just trying to say I understand the principles fairly well. Improved Racing would be another great contact if you guys want to learn more about the importance of setting up your oil pump properly.

 

Scott, thanks for clarifying your oil pump reasoning.
Yes, if you have piston squirters, lifter axle oiling, extra bearing clearances, or have DOD/AFM &/or VVT, more volume IS needed. This is a good thread....
My point in the past was, if an engine had NONE of the above extras, extra volume was not needed nor desired. Do you agree with this?
This is a good thread....

 

Completely agree 100%

 

Does anyone measure oil pump relief valve installed spring height pressure to know what expected engine oil pressure should be? i.e. if relief piston OD is .571" or area of.256sqin then spring installed height pressure of 19.2 lbs equals 75psi max oil pressure. If expected pressure isn't achieved then insufficient volume is the problem for oil weight used.

 

Stick with a stock standard volume and pressure pump. All a high volume pump does, in most applications, is just rob a little bit of power and aerate the oil more with no benefit. The same for high pressure. Oil pressure is a lot like blood pressure in that too low and too high are both a bad thing. Too little pressure is self-explanatory but too high of pressure can also be a problem. Above ~65 psi, aeration starts to increase exponentially because the high pressure increases the capacity for entrained air. That's why most OEM pumps have a bypass setting of 65-70 psi. Note that there's no benefit whatsoever to having oil pressure >65 psi. Even Pro Stock engines turning 10,500 rpm and Sprint engines turning 9,500 rpm see no benefit.

I see no issue with 2700 rpm at 70 mph. That's about where my 5.3L runs in 3rd gear while towing.

As for the oil cooler, have you measured oil temps to determine the need for it? The ideal operating oil temperature is 210-230*F as this is hot enough to boil out any moisture from combustion or condensation and promote good additive reactivity while not being so hot as to cause thermal breakdown. If your oil temps are creeping up to >240*F, then I'd say you have a need for a cooler to bring it back down to the optimal range. If the oil temp is currently in the optimal range and the cooler brings the temp down to <200*F, then you could end up dealing with excessive water dilution, nitration, and reduced additive reactivity that could lead to more wear. Just keep that in mind. Even when towing a 6,000 lbs load, my 5.3L never gets over 230*F oil temp even when pulling up a long incline. I don't have an oil cooler.

 

The oil "cooler" in most stock vehicles (trucks for example) are actually oil WARMERS. In the trucks, such as the 6.0 HD ones, they are located in the HOT tank of the radiator, as opposed to where trans fluid coolers are, in the COLD side. In such a truck the LOWEST temp that the oil could EVER POSSIBLY be at long-term, is thermostat temp; and most of the time it will be somewhat above that. Which is fine.

Oil does indeed need to be at least close to, if not above, the boiling point of PURE water AT SEA LEVEL PRESSURE which is 212°F, specifically for the purpose of keeping impurities boiled out of it, as mentioned. Of course COOLANT, which is NOT pure water, and which is at pressures FAR ABOVE sea level, boils at a MUCH higher temp, under normal engine operating conditions; 265 - 270° or the like.

High oil pressure DOES NOT "aerate" the oil. The only common thing that does that, is if the pump sucks air; e.g. the wrong pickup tube O-ring. As long as the pump gets un-air-bubbled oil, the oil will not be "aerated", at ANY pressure. The problems directly traceable to excessive pressure (exploded oil filters and pressure sending units, and blown-out can retainer plate gaskets, for example) do not include "aeration".

All of this of course, is in application to a STREET DRIVEN vehicle fueled with pump gasoline. It DOES NOT strictly apply to one used for pure racing, and particularly one with some other fuel such as methanol. For such engines the oil pressure requirements can be quite different.

Most OEM pumps for these motors have a bypass spring designed to limit pressure to 50 - 55 psi, NOT 70.

That said, 70 psi is plenty. Stock-ish 50 - 55 is usually just fine too. Gen 1 small blocks would go a quarter-million miles or more on a 35 psi regulator spring and there's nothing about LS motors that's substantially different in that area. The only reason for a HV pump is for engines that, AT THE OIL FLOW that their bearing clearances, lifter feeds, and whatever all else, might result in, it MIGHT require a HV pump to keep the pressure at a satisfactory level, PARTICULARLY if there are parasitic "pressure drops", like oil coolers, in the system. The pump can only do just so much "work", with "work" being some kind of a function of pressure × volume; if, at whatever volume the engine requires, the pump can't move enough oil to keep the pressure at the desired level, then it's inadequate. I don't see how a 10296 is excessive for any street application in that way. In fact, unless you're in one of those Pure Stock kind of classes where every tenth of a horsepucker matters, the tiny extra loss from such a pump, is going to be lost in the noise as far as whether it "uses" extra HP. Just really not a factor.

10296 FTW. Next-best is a ported stock pump with a higher-pressure regulator spring.

 

High oil pressure doesn't cause aeration, it simply facilitates it. The higher pressure increases the capacity for entrained air which can then escape at a low pressure point (ie: the bearings). This was seen with a Sprint team a few years ago who kept having bearing issues which turned out to be excessive aeration at high pressure causing bearing cavitation. They were running 80+ psi. Simply restricting the pump to 60 psi solved the issue, and they also switched to a better oil shortly afterward. This has also been seen on the dyno with mild engines on pump gas. Ideally you want to prevent aeration to begin with, which using a good quality oil will help with, but sometimes it's inevitable.

Of course, this doesn't matter much for a street driven car. A HV / HP pump would just be overkill. It would be like going to a 12" wide tire when your car can dead hook on a 8.5" tire all day. There's just no point.

Oil flow is the main parameter we're after. Pressure gives an idea of the flow, but not directly correlative because of other factors. I don't hardly look at oil pressure much except to ensure limits. So long as there's 5-6 gpm flow at WOT, I send it.

Methanol engines are different breed because you have to deal with so much water dilution. Dealing with Pro Mods, it's not uncommon for the oil to be 4-5% water after 7-8 hits. Some change it, some will simply boil the water out and put it back in the engine. A hefty amount of dispersants is necessary to ensure the water stays blended / suspended in the oil. These in particular (can't speak for others) also cap around 60 psi as no benefit has been shown beyond that point. I had a look inside one after testing a new oil development earlier this year and bearings were immaculate after ~20 runs.

I've been in touch with a certain Pro Stock team (currently in the championship chase) seeking every last hp they can get. With a 0W-2 oil, the oil pressure is barely bumping the needle at idle.

 

Chevelle,
what’s the idle oil PSI of your 434?

 

75 at cold startup. 40ish hot idle. Gibbs LS30 full synthetic and I like Wix filters. I know, I know, but I still run them.

 

I agree with most, if not all, of your post. I do think that the piston oil squirters, and the oil lines to the oil cooler do require a bit more volume than a stock pump delivers, due to the 'bleed off' effect of the piston oil squirters. But not any increase in pressure. Also, Im sure you know valve springs rely on oil cooling as pretty much the only cooling they get. Perhaps having oil between 195°-210° will help extend spring life. Since I have an LS7, with LS7 heads (), any help for the valvetrain in this engine, and its 1.8 rockers, can't hurt a thing. I can't speak for anyone but myself, but my oil temps during normal freeway cruising are usually 190°-195°, and I've never found moisture in the oil. I suspect the actual oil temperature deep inside the engines guts is actually 15°-20° higher in my C5. Probably depends on where in the oil system the oil temp sensor is mounted, which, in the C5s case, is in the oil pan. Good thread......

 

This is a good post.
I used the 10296 on my alum 5.3. L33.
Mains are .0027-.0029” Rods .0025”.
I modified the thrust bearing to feed some oil to the thrust surface. Orig cam bearings.
So it’s a bit “leaky”. 😊

Also ditched the 5qt Mast pan for a Moroso 7.5 qt race pan.

So two spring choices for pressure. I left the high pressure spring in. No clue what’s correct there until you run the engine up to temp. Right?

10W-30 Shaffer oil.

75psi cold start, 42psi hot idle. Sadly I’m not logging pressure with HPT, and a bit difficult to glance at the gauge at 150+. But I believe it’s in excess of 80. Adding that to the data log will happen this winter.

I may install the lower pressure spring when I have it apart this winter.

FWIW, I drive this car to the track, so the oil is hot. If we sit too long, I warm it back up before a pass.

I use Wix XP filters. The longer one that fits the pan. So what’s the beef with Wix filters?

Ron

 

Interested in knowing about this myself.

 

Wix was acquired by Mann+Hummel a couple years ago, the same company that ran Purolator into the ground. Production is being shifted to Mexico and South Korea, and quality control is lacking. In ISO 4548-12 filtration testing, they're coming out well below their advertised filtration rating. One of them also exhibited a bypass failure in a recent bubble point test.

I posted some data on a bunch of filters on here earlier this year.

https://ls1tech.com/forums/advanced-...ency-data.html

More heat is generated from the bearings than is transferred from anywhere else, even the piston/ring area. Piston squirters may take exception to that, hard to really say. As a note, only ~3% of combustion heat makes it to the oil. Typical temp rise through the bearings is 30-50*F over sump temp depending on rpm and load so I'd expect ~220*F bearing temps on the highway. Some racing engines can see up to 75*F temp rise such as NASCAR cup engines with ~280*F sump temps and ~355*F bearing temps. (...and a 0W-16 oil)

Common steel valve springs can run as high as 450*F before they begin to fatigue. Of course, you don't want them to get that hot, and a street engine with a hydraulic cam and even spirited driving won't get them anywhere remotely close to that temperature. It's not really an issue to be concerned about other than just ensuring they're getting oil flow to them. Valve spring temp is more of a concern with solid roller applications with high spring rates and high lift running at high rpm such as NASCAR, F1, Pro Stock, etc... It's common for them to use oil squirters in the heads just for cooling the valve springs.

Small amounts (<2%) of water can be present without making the oil appear milky. If there is some trace amounts there, it's obviously not causing any harm. I don't think I saw it posted (if it was, forgive me) but what oil are you using?

 

truth, unfortunately folks.