Melling Sweats The Details On Wet Sump Oil Pump Technology Part 3

Melling managed to shave approximately 1.75-pounds off the weight of the small block pump. As mentioned previously, pump bodies and pickups for all of the billet pumps are CNC-machined from 6061 T-6 aluminum and then they’re hard-coat anodized.

Melling Sweats The Details On Wet Sump Oil Pump Technology Part III

When we left you in the last issue, we had covered the needs for increased oil pump performance. Typically, with a race or high performance engine you’ll need more pressure and, in some cases more volume. We also addressed the role bearing clearances play when it comes to oil pump performance. Additionally, we briefly touched upon OE-style pumps (and variants of them). With this issue, we’ll look at several modern, high tech solutions. Check it out:

Today, you don’t have to concern yourself with the issues that come with OEM pumps. The folks from Melling have a comprehensive lineup of billet oil pumps designed specifically for high performance applications. When you examine the Melling billet pumps, you’ll discover the body along with the pickup housing is nicely CNC-machined from billet 6061-T6 aluminum. CNC machining obviously provides for exact tolerances and surface finishes. These pieces are hard-coat anodized. This dramatically increases the surface hardness providing a durable wear surface for the internal components. You’ll also note the respective pumps are actually very compact. In fact, both examples shown fit within the same space taken up by the original cast iron pump.

Let’s stop right here, because this is important: Today, there are a couple of other options out there when it comes to internal wet sump oil pumps. Included are gerotor configurations. These pumps work in a different way than gear style pumps. They function well, and some folks like them, but the nature of them is this: They take up a lot of real estate inside the oil pan. In many (if not all), cases you’ll need to use an oil pan designed specifically for the gerotor pump. That all adds up to the cost of the swap. Back to the Melling pumps:

When you disassemble a Melling billet pump, you’ll find they do not make use of thrust bearings for the gears. Instead, the gears operate directly against the hard coated pump (and pickup) bodies. Melling tells us their billet pumps consume less power when compared to other pumps built with thrust bearings. Omitting the bearing(s) wasn’t a cost saving measure. Instead Melling’s engineers saw it as a way to eliminate a potential catastrophic failure point. The last thing you need is a piece of a bearing rattling around the inside the pump body and pump gears. Makes sense to us. The old design principle of KISS (Keep It Simple and Straightforward) was applied and a robust yet simplistic design proved to be the best during development testing conducted at Melling.

The billet pumps from Melling are engineered with an integral bottom oil pickup. This means there is no (likely) fragile tubular pickup to break or fracture. Let’s examine this a bit deeper: In the old days, it was common practice to press an extended pickup into the pump. Then you’d braze the pickup tube to the pump body. The thought was it would keep the pickup from falling out. More often than not, the weld would seem fine, but it probably wasn’t (keep in mind we were brazing dissimilar materials). The result would be a broken weld or worse. That’s why aluminum bottom pickup assemblies became popular. There was nothing to break. Or fall off.

Melling takes the bottom pickup arrangement one step further. Here, the pickup screen has been integrated into the pump body and features a stainless steel wire mesh. This provides for superior filtration (basically, it keeps bigger chunks out) along with improved pump efficiency. The pickup screen is held in place by way of a large, heavy-duty c-clip. This allows you to remove the screen and clean it along with the pickup inlet. By incorporating optimized pickup and inlet points, Melling Engineers effectively minimized the effects of pump cavitation. This was something that wasn’t accomplished with the old add-on bottom pickups of old. The result of the Melling R&D is that the oil entering the pump is essentially super-charged to provide improved pump performance at high operating speeds. This is a patented feature only found in the Melling pumps.

Another patented feature of the Melling pumps is that the length of the pump’s drive shaft has been increased to allow for longer pump depths, as well was additional support in the cover. Increasing the support eliminates shaft deflection which in turn, allows the gears to run true at high RPM levels. When you install the intermediate shaft on a Melling billet pump, you’ll note there is a rib inside the collar. There is a corresponding groove machined into the oil pump shaft. The idea here is to provide a secure connection between the intermediate shaft and the pump. According to Melling the proper way to install the intermediate shaft is as follows: “Firmly tap the collar onto the pump shaft, taking care not to damage the oil pump or the intermediate shaft. When properly installed, the intermediate shaft will have axial movement relative to the pump drive shaft.”

Fair enough, but another big breakthrough is the design of the gears, particularly in certain Melling small block oil pumps. When you look at a conventional spur gear pump setup, it’s easy to see the profile of both gears proves identical. With the Shark Tooth asymmetrical layout, the gears appear to have a helical twist in the profile. The helix profile has allowed Melling to reduce the clearance between the pump body and the gears. This results in improved pumping due to a reduction in internal leakage and according to Melling, this also has an effect upon oil temperature: It lowers it.

According to the folks from Melling: “The helix of the gear teeth allows the oil chambers in the pump to fill and discharge gradually allowing for smoother operation. This provides a significant reduction in the flow ripple and its resulting pressure ripple experienced in the engine’s lubrication system. This is accomplished by the overlapping pump chambers in the helical gears. One effect is the reduction in cyclic loading created by the torsional forces on the oil pump drive shaft. It has also been reported to us that spark scatter is reduced. The difference in performance can be felt by just turning the new pumps by hand.”

We’re just about done, but thanks to the folks from Melling, we have a series of oil pump installation tech tips to offer. We’ll share those with you in the next issue along with several more photos of the Melling billet oil pumps. Watch for it!




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Melling Oil Pumps

When it comes to overall size, the Melling small block Shark Tooth pump isn’t any larger than a conventional iron body small block Chevy spur gear pump. Keep in mind this pump is engineered with an integral bottom pickup assembly.

Melling Oil Pumps

Melling’s billet big block oil pump is very similar to the small block setup when it comes to overall size. This particular pump is designed for use with an 8-inch deep pan.

Melling Oil Pumps

Melling managed to shave approximately 1.75-pounds off the weight of the small block pump. As mentioned previously, pump bodies and pickups for all of the billet pumps are CNC-machined from 6061 T-6 aluminum and then they’re hard-coat anodized.

Melling Oil Pumps

A major advantage of the Melling billet pumps (big and small block) is the fact they eliminate the need for a press-on pickup and tube assembly. The bottom pickup ensures there is no potential fragile tubular pickup to break or fracture.

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