CPPerformance

In recent months there have been a barrage of claims by some sea pump manufacturers and/or their distributors regarding quality, construction, durability, fit, finish, and lastly something called "Run-Dry Technology". Although we have yet to find an engine that will run without water or any type of cooling, this gave rise to some amazing questions in our minds.

For quite some time now we have had this same type of run-dry technology available. This technology basically comes from loosening the load and tolerances of the impeller to the point that the contact pattern of the impeller really does not generate enough heat to damage the impeller. The problem with this is that the performance of the pump is greatly compromised . Yes, on a test bench with three feet of hose, in a staged environment, it still works. In the "real world environment such as a boat traveling at high speeds loading and unloading the pumps pick-up it does not. But rather than make unwarranted claims, why is it that all of America's propulsion leaders still "DEMAND" our pumps for there high performance needs? While many of us even had hopes and aspirations of the "Dream" of run-dry technology, what soon followed was the "Nightmare" of poor performance. Remember pumping water is only a portion of the pumps job it needs to be able to pull water through the pick ups and strainers to the pump and hold the prime. Do you have any idea how long rubber impeller pumps have been manufactured - literally for decades in this country. How do you think everyone came to the design tolerances that they use? There's a reason that your stock pump has tight tolerances, as well as both the Keith Eickert and Hardin Marine brand pumps. When you are the "Giant Marine propulsion leader", and you have a lake of your own that you do thousands of hours of testing on, you cannot risk the millions of dollars invested in your propulsion system, to a design that has proven to be inefficient. If your $20.00 sea pump impeller could work as good as it does now and also last forever, why is it that everyone is not doing it? I can assure you it's not a conspiracy, it's about reliability and longevity, and that is truly our claim. Our product design and materials are superior, and our record shows it. Nearly every world championship racing team uses our products as well as nearly every professional aftermarket offshore engine builder.

What better way to let you the discerning customer, evaluate the markets pumps for your own review, than to do a side-by-side comparison. We thought we would bring you the opportunity to disassemble both pumps and share our findings. For this comparison, we disassembled one of the dual impeller pumps that are made in the "USA". Yes we are proud that all of our pumps are assembled manufactured here in Palm Coast Florida and not a distant country. We also disassembled one of the overseas pumps (made in Great Britain) with dual impellers.

For reference sake, Hardin Marine is the proud supplier of many of the worlds leading OEM manufacturers. At Hardin Marine, we are proud to be the preferred supplier of pumps to Mercury Marine as standard equipment on both their 850HP and 1075HP models. We are also proud to provide Ilmore Marine engines with there exclusive Hardin Marine sea pump designed to meet their needs on the extraordinary Viper engine packages. These pumps are also the choice of the industries best aftermarket marine engine manufactures including Keith Eickert, Chief Engines, NOR-TECH Engines, Teague Custom Marine, Total Marine, Sterling Engines and Paul Pfaff Racing Engines to name just a few.

CPPerformance

Mandrel Comparison:


Keith Eickert/Hardin Marine - This is a view of both company's pulley drive mandrels. Note the mandrel on the right is manufactured from premium quality steel and is CAD plated for premium corrosion resistance. The purpose of a "Steel" mandrel is that it is not subject to expansion and contraction caused by temperature transmitted through the pump shaft. This is the entire reason it is never recommended to install an aluminum pulley without a mandrel onto a pump shaft. As the pulley becomes warmer it will expand and eventually separate from the pump shaft during use, causing catastrophic damage. This mandrel then incorporates a stainless key pin to position and retain the drive mandrel on the stainless steel shaft. The 5/16" SAE Allen bolts are provided to retain the drive pulley. The common metal types are resistant to wearing from contact with each other. The Hardin Mandrel is then retained by a stainless steel 5/8" locking jam nut.

KPM - The left hand side of the picture shows a view of the aluminum KPM drive mandrel. Upon close examination you will notice that this anodized aluminum mandrel "Does Not" use the preferred method of keyway style retention. Instead this unit uses two horizontally opposed small stainless set screws that are designed to load against the flat ground sections of the aluminum pump shaft. The stainless steel set screws provide a very small contact area that is less than 1/2 of the mandrel to shaft contact retention space used in the key stock design. The use of dissimilar metals could also be a source of galvanic corrosion creating premature failure. This mandrel is retained by a small 1/4" retention screw which is all that retains the entire water pump pulley assembly. Lastly, get out your "Metric" tools as you will need them to tighten your pulley on this mandrel.

CPPerformance

Pump Shaft Comparison:

This picture shows the front end of both pump shafts with the bearings installed.

Keith Eickert/Hardin Marine - On the right hand side is the Hardin Marine Shaft and bearings which is also used in the Keith Eickert pump. This shaft is manufactured from premium 17-4 PH (Pre-Hardened) marine grade stainless steel. The bearings are high speed, oversized, sealed units. These are a press fit installation. Each bearing is retained on the shaft in its exact location to provide added support to the pumps snout assembly. Also, the Hardin Marine shaft shows the large 5/8" threaded end for retention of the drive pulley.

KPM - On the left hand side you will see the anodized Aluminum KPM pump shaft. Keep in mind an aluminum pump shaft has a fraction of the structural and torsional strength of a 17-4 PH stainless shaft. In addition, the anodized shaft offers little corrosion resistance in the saltwater environment. The shaft is the main backbone of any sea pump. Virtually all other leading sea pump manufacturers in the market today use stainless steel pump shafts including Mercury Marine, this is not a coincidence when quality and dependability are your first priorities . Next, the smaller than standard size bearings (.020 smaller and .110 narrower) than even OEM bearings are installed as a slip fit. There is no method of retention used to hold these bearings in place, which allows them to slide and float forward and backwards in the pumps snout housing. Also depicted here is the small 1/4" retention screw that is the only method of pulley retention. As you can see, what would be considered a key slot extends all the way to the end of the shaft assembly.

CPPerformance

Impeller Comparison:

Here is a picture of both brands impellers the Hardin Marine/Keith Eickert/Mercury impeller shown on the right and the exact replica of it from the KPM pump on the left. The rubber content is the same durometer, same number of blades, same bronze sleeve.

CPPerformance

Pump Body Comparison:

And here in this picture you will find all three of the pump bodies.

Keith Eickert - At the top left is a view of the Keith Eickert hard anodized aluminum pump body. These bodies use an o-ring style seal to mate multiple bodies and the brackets together. Points of interest to note would be a stainless steel impeller sleeve that is designed to eliminate corrosion caused by the impeller scrubbing of the bodies anodized surface during operation. Another key feature is that the stainless steel insert eliminates "Erosion" caused by salt, sand, and/or debris that acts like a sand blaster against the aluminum housing. The sleeve also allows simple overhaul of the pump body due to the ability to remove and replace the sleeve for service. Note the compact design as well as the fact that there are no unprotected or non-anodized holes from secondary machining operations. These parts are machined first and then Hard Coat Anodized to Military Marine Spec for the ultimate in corrosion resistance of an aluminum component.

Hardin Marine - Top right of this picture is the view of the undisputed durability and functionality champion. These bodies use the same O-ring seal design as the KE bodies but are manufactured from marine grade 316L stainless steel. These bodies use design cues from the famed Keith Eickert pump body while adding the corrosion resistance advantages of 316L stainless steel. In a saltwater environment this is the very best money can buy. These bodies are nearly indestructible. Independent continuous duty testing of 4,000 hours showed virtually no wear. These bodies also undergo a secondary machining operation to remove any excess weight making them the ultimate choice for any application.

KPM - The bottom center image reveals the main impeller body of a KPM pump. Closer examination shows multiple points of interest starting with the sealing of the components. This entire pump is "Siliconed" together, the bodies do not use the superior O-ring design sealing method. At quick glance, you will see that the silicone is not used to separate the inlets/outlets from the impeller cavity. This is a sure sign of internal bypassing. A positive seal is required to maintain consistent suction and pressure. There is no protective sleeve or stainless corrosion resistant components on the inside of this housing design. The design is also not serviceable, as water, silt and sand corrodes and erodes the surface of the merely anodized body there is no means of repair, your only choice is that of costly replacement. Another subject to note is that these units are machined after they are anodized, leaving the machined surfaces and tapped holes unprotected from corrosion or galling.

CPPerformance

Wear Plate Comparison:

Keith Eickert - This picture shows both bodies. On the right is the Keith Eickert body with a stainless steel wear plate. As in OEM pump designs, the use of stainless steel wear plates is crucial to impeller crush. The reason these pumps incorporate the wear plates are based around its given name "Wear Plate". The impeller is designed to have a precise amount of crush which is determined by wearing the impeller into the plate. A variance of .020 can make the difference in the entire pumps performance. This stainless steel wear plate is also used in both the Hardin Marine and stock OEM Mercury Marine Sea Pumps.

KPM - On the left the image shows the KPM aluminum pump body which attempts to incorporate the wear plate into the body. Once again the aluminum construction is not conducive to this type of wear. As the body wears it requires complete replacement. Without the use of a stainless steel wear plate there is no way to do a simple replacement and service in the field.

CPPerformance

Mounting Bracket Comparison:

Hardin Marine - In this view you can clearly compare both manufacturers brackets. There have been some comments as to clearance problems with our pumps, this is a fallacy as we make multiple bracket styles in order to accommodate tight clearance situations, even our standard bracket fits in OEM locations. On the right is the Hardin Marine pump bracket, this same design is also used on the Keith Eickert pumps. This unit was designed to be very tight and compact in order to cure mounting problems, especially in tunnel or cat boat designs. The very short drop distance keeps the pump compact and tight to the engine allowing added stringer clearance along with shorter belt run lengths. The bracket is completely hard coat anodized for corrosion resistance. Also you will be able to once again view the o-ring seal used. Belt tension and pump positioning is doubled through the use of the floating pump lock down washer. This eliminates the age old problem of attempting to tighten the pump and the threads of the bolt causing the pump to walk or shift during tightening.

KPM - On the left you will find the KPM mounting bracket. Issues to make note of are what looks to be an unprotected finish of the bracket. Next since this pump does not use an o-ring seal you can see what appears to be a whole tube of RTV silicone used in an attempt to seal the bodies from the bracket. Note that all of the pumps sea water is passed through the bracket presenting the possibility of excessive corrosion issues that could lead to premature pump failure. Pump lock down or tightening into position is fashioned in a non-positive locking format. Lastly, the very long drop of the pump will surely wreak havoc when attempting to mount the pump in many applications.

CPPerformance

Pump Snout Comparison:

This image shows both the Keith Eickert/Hardin Marine pump snout on the right of this image and the KPM pump snout on the left. The Hardin Marine unit on the right houses the substantially larger high speed bearing pack and is hard coat anodized once again for corrosion resistance. The KPM unit on the right uses a 30% smaller bearing pack.

CPPerformance

This is the back side view of both pump snout assemblies. While we are definitely being a little picky, we noted that the O-ring grooves of the KPM pump are only partially machined. This will allow the rough edges to damage one of the very few o-rings found in the KPM pump assembly. The seal was also installed crooked on this particular pump. This pump was a brand new unit purchased specifically for this evaluation.

CPPerformance

Installed Impeller Body Comparison:

This image shows both impeller bodies with the impeller installed. Note our aluminum impeller body uses an exclusive stainless steel liner which provides an OEM crush impeller load. Extended duration use on all aluminum housings 15 years ago showed deterioration to the body from foreign particles, sand, etc causing a result similar to sand blasting of the housing. Extensive research and development showed that the pump housing life could be extended greatly by protecting all vulnerable surfaces from this effect. Obviously we could remove the liner and end up with a loose impeller in the housing and offer this type of run-dry technology. unfortunately the performance of the pumps ability to pull water under extreme loads becomes inefficient and can result in engine damage. While addressed earlier the question isn't about the pump running dry the concern is the damage to the engine as it runs dry. Also note the similarity of the impellers in relation to their installed environment.