Wanted to get some help on an engine I recently acquired. New to ls stuff so don’t really know. this is the info on the build Oe rods

Mahle pistons and rings

Clevite bearings

Texas speed ls3 stage 3 cam

Btr dual valve springs

New valves

rebuilt and resurfaced heads

Melling Hp oil pump

Billet oil plunger

Mahle head gaskets

6 puck stage 3 clutch masters clutch

F body oil pan with improved racing baffle system

my question is the engine is a 5.3 is this cam going to work with this engine and be effective bc it’s meant for a ls3 ? This is all the Infor I have on the build any help is appreciated. Thanks

 

I would opt for the high volume oil pump over high pressure. That is a BIG Cam for a 5.3l and whatever cathedral heads are on it. I would get a different Cam.

 

Why the high volume pump? Not arguing, just wondering.....

 

Thanks what would you recommend as a better cam for my application?

 

I also have long tube headers and want to put a ls1 style intake to clear my hood if that changes anything.

 

LS3 is a square-port motor. Cams for those tend to have bigger exh lobes than ones for cathedral ports since their intake flows so much more. They benefit from extra help on the exh side. However, that lowers the torque from a cathedral port motor, so not necessarily a good match.

A recommendation that makes any kind of sense, would require revealing what vehicle it's going in, how much it weighs, what gears it has, what the heads are, what it's gonna be used for, etc.

 

A cam with around 220-224 duration on the intake side will be about the max you will want to go unless you want to build a high RPM screamer. You're limited on static compression ( with flat top pistons with valve reliefs, you're looking at a realistic 9.6-9.8:1 C/R ) so you don't want to go to big on duration as it will kill your dynamic compression ratio. You'll lose a lot of torque below 5000 RPM. If you have stock 706 or 862 heads, just use those. Nothing aside from aftermarket will be worth swapping on. As for an oil pump, just use a Melling stock replacement. Neither high pressure or volume is needed in an engine with factory bearing clearances. LS1 style intake is fine, long tubes are always a plus. If you want an actual cam recommendation, I'd go with this: https://briantooleyracing.com/btr-hot-rod-camshaft.html . It peaks around 6600 in a 5.3 application, according to their dyno chart.

 

Moving a higher volume of oil through the engine components is always going to be a plus when you're running a little looser bearing clearances.

 

LS Engines love oil volume. The way the galleys are designed as well as the pump itself, they are not like the SBC that will suck the pan dry if you don't have a larger capacity pan. High volume SBC oil pumps will move some oil fast and the drainback isn't that good. LS Engines drain back faster and as I mentioned above they are designed for volume. With volume comes pressure, so might as well have both.

 

A pump is a simple device that does work. Power is the time rate of doing work. Power in a hydraulic system is the product of pressure and flow. Just like electricity; power is the product of voltage (pressure) and current (flow).

Any given pump can only do just so much work at a given RPM. That is, if you spin it at some speed, there is a maximum of the product of pressure and flow, that it can generate. Since oil pumps like ours are a constant-displacement design (each gear tooth chamber moves a specific amount of oil), then if it's moving more oil through the gears than the engine will allow to pass through the bearings and lifters (which are identical to SBC ones), the bypass opens and allows the extra flow to escape back toward the sump. There's a spring that lets the valve be actuated by pressure, such that if the pump has sufficient capacity, the pressure will remain constant regardless of internal engine oil demand or RPMs. (roughly anyway... it's a bit oversimplified, oil viscosity has an effect for example, butt in basic terms, this is how it works)

A high-volume pump won't move more oil through anything unless (a) there's more pressure behind it, and/or (b) the space to move it through is larger.

All it will do, is circulate more oil through the bypass; and in the process, consume more engine horsepucker by doing more "work" except that the extra "work" is just waste (flow x pressure inside the pump).

IOW a hi-vol pump does NO GOOD WHATSOEVER on an engine with stock(ish) bearing clearances. If a std vol pump makes say 50 psi when pressurizing a given engine, and you replace it with a hi-vol pump that also makes 50 psi into that same engine, EXACTLY THE SAME amount of oil will pass through the bearings and other parts. The extra vol moved by the pump gears will simply return to the sump via the bypass.

Now, if you have an engine that a std vol pump would pump a certain amount of oil through if the bearing clearances were "standard", but they're actually larger than "standard", and the pump can't move the increased volume and also maintain pressure, then the pressure will drop, and volume will remain at the max the pump can deliver at the pressure it can sustain. Which is why the OP drops in an engine with worn bearings.

A hi-vol pump will allow the use of thinner oil, which (a) lubricates better than thicker oil to begin with, and (b) will keep the bearings cooler due to greater flow through them, if the pump can maintain the same pressure at the higher flow.

A hi-pressure pump will, by definition, move more oil through the bearings than a lower-pressure one will; IFF its volume delivery is adequate. All that a HP pump is, is an otherwise std pump, with a stiffer spring controlling the bypass valve. IOW you could put a stiffer spring into a std pump that isn't keeping up with the engine's oil demand, and the pressure won't increase at all, because the bypass is never operating anyway.

Bottom line: a HV pump accomplishes NOTHING WHATSOEVER in an engine with stock bearing clearances. It has no effect on flow ANYWHERE, bad or good. No oil will flow in greater amounts ANYWHERE - not sucking the pan dry, not through the bearings, not sitting on top of the heads, NOT ANYWHERE, NONE of the myths about them - except in the bypass. A HP pump will accomplish NOTHING WHATSOEVER if it's not moving enough oil to satisfy the engine's flow demands at the higher pressure, and thus open the bypass. Which in an engine with relatively tight (like stock) bearing clearances, even a std pump should always be doing. in an engine with looser clearances may be flowing so much through the bearings that the pressure will remain the same, if that pump can only deliver the same volume as a std one. In a loose-built (or worn) engine, to get the full benefit, a pump with both higher pressure AND volume is usually needed.

For this reason I wouldn't bother with a HV pump in a stock-built engine at all; and I wouldn't put in a HP one either (or shim the spring or do whatever else to raise a pump's pressure) without also assuring that it's also HV, or at least, delivers enough volume that the bypass pressure is reached. Which in a tight stock engine, is usually not an issue. Otherwise changing the spring doesn't do anything.

 

RB04Av, I agree with most of what you're saying. But, as you stated, this is an oversimplification. Other things do come into play. If any sort of minor cavitation occurs at high g-forces, a HV pump will recover flow/pressure quicker when the twisties straighten out. Then you have things like oil coolers, which slow/reduce flow, piston oil squirters, lifters which are .0005" smaller diameter than OEM, etc. I am personally in favor of running a HV pump, like a 10296 Melling, M365 Melling, etc. My .02.....

 

I run a melling hi volume in my stock clearance LSA supercharged 370” LQ9 motor with zero issues…cold my oil is 70/80psi at temp 45/55psi….i couldnt be happier….my cammed 4.8 which is around 225k mi completely stock other than a 220/220 cam and vortech v-3 supercharger…that old original factory oil pump is about 55psi cold and 35psi at temp…..when i turn it into a 5.3 or bigger it will get a hi volume pump as well

 

Question: Does it spend most of its time in the 6500-7000 rpm though? I have a HV pump on the LSX427 with the main bearing clearance @ .0027" and rods .0025" which is about the norm for an iron block build. Probably should have ran it a little looser for NOS and went to a heavier oil than 5W30 but it has yet to see the bottle. Oil pressure is 70-80 psi cold and 60psi hot with about 7 quarts of oil capacity. Could probably add another quart of capacity if I ran an oil cooler and I do want to because the summers here in Texas can be brutal.