Another great weeks in the books. Take a look at the some engines in process and the final shipment!
Cummins N14 Engine History
The Cummins N-14 is a great engine; quite possibly the best Cummins engine ever produced. These engines are the stuff dreams are made of if you’re an old school guy looking for reliability. No doubt, the N14 is part of “1,000,000 mile club”. The engine features the best of engineering fundamentals mixed with one of the first electronic control system. First designed in the late 1980s it was sent into full production in 1991. The N14 engine is the follow up to the vastly popular Cummins 855 Big Cam which was produced 1976-1985. Cummins listened to it customers and designed a more powerful version of the 855 while maintaining a similar profile and bore/stroke architecture. Overall, the biggest structural difference between the 855 and N14 is the air-to-air cooling system changes but both engines are very similar.
The N-14 was produced until 2001 and saw many changes over its 10+ year run for Cummins. The most radical change over the 855 was the incorporation of the electronic control module (ECM). Detroit Diesel rolled out the first commercial electronic diesel engine in 1987 with its ground breaking Series 60 Engine and Cummins followed suit. With the advent of the first EPA Tier emissions regulations in 1994 the future of diesel engines was going to be electronic diagnostics. The N14 Celect was the first Cummins engine to feature an electronic injection system. The Celect fuel system produces systematic pressure throughout each injection cycle unlike the common rail fuel system of the 855, or older M11 or L10 models. Albeit the injectors are still cam actuated the ECM controls the metered flow of fuel to the injectors. In 1997 Cummins introduced the N14 Celect Plus which further fine-tuned the ECM to control many more custom parameters of the fuel system.
In addition of an ECM the N14 was designed for emissions purposes to consume much less oil. The N14 diesel was engineered in a way where oil flow is much more uniform thus requiring the engine to consume about 20%-30% less oil than the Cummins 855. Engineers at Cummins also came up with new pistons that positioned the top ring much closer to the uppermost part of the piston. This new design reduced a large open space between the ring and the piston liner. By utilizing this space the combustion chamber moved closer to the top ring which meant the oil got much hotter and burned off more completely. In addition to internal changes, engineers also developed an API CF-4 and API CG-4 oil for the N14 that was much more thermally stable and easier to breakdown on a molecular level.
Cummins N-14 Injector Problems
For all of the great aspects of the Cummins N14 its Achilles Heel has always been the injectors. The L10, M11 and N14 all have problems with injector failures and the surrounding electronics. The fuel system’s main components consists of the injectors, injector wiring harness and the ECM. A common occurrence will happen when, for example, when the ECM shows a 111 or 343 code in an N-14 Celect Plus model. This means the ECM isn’t grounded to the injector. Usually this starts out with only 1 injector shown to be malfunctioning but can quickly spread to others. If this happens you immediately want to shut down the engine.
These early electronic engines offered no protection against the wiring harness shortening out. There are 6 injector driver connections on the ECM which are attached to the injectors via a wiring harness. If an injector goes bad it is advised to pull out the wiring from the injector and replace immediately before the faulty wire burns up the ECM motherboard. Usually if you unplug # 1, 2, 3, or 4 injector drivers in time you can save the ECM/injectors. The wiring harnesses are known to have problems and are very expensive to replace.
Another issue with the N14 ECM is a faulty fuel solenoid. The solenoid is situated on the bottom of the ECM. If the solenoid shorts it will heat up the ECM slowly and can then destroy the entire fuel solenoid circuit, memory chip and the injector timing chip. Usually the solenoid gets so hot it melts the solder on the chips. For a 50 pin connection all it takes is one pin to loosen from the heat to destroy the ECM. It is recommended that drivers carry 1-2 extra injectors in the truck in case one goes out. Usually they go out in pairs which makes sense to carry 2 at all times.
Other common injector issues with the N-14 include:
• Injectors overfill with fuel and it overfills the crankcase
• Injector O-Rings will leak
• Misfires occurring due to a clogged filter screen on top of the injector pump
• Injector cup failures allow water in the fuel
• Over revving can cause scoring on the injector plunger barrel
• Oil Coolers are prone to clogging
• Fuel lines prone to fraying allowing debris into the injector
The type of fuel and additives used with the N-14 make a world of difference. Many fleet operators use Lucas oil additives or Automatic Transmission Fluid (ATF) Liquid Moly solutions. ATF additives prevent oil loss, helps protect and regenerate seals and rings, cleans out oil sludge, improves steering performance and helps protect the engine during shifting. Most operators will put in 1 quart of ATF per 100 gallons of fuel. However it is important to note ATF Fluid is red in nature and will show up as off-road fuel at most DOT Weight Stations. You could end up with some pretty big fines if you don’t have the proper documentation. Other preventative measures with the N-14 include using an alcohol based additive to kill off algae from newer blends of fuel. The algae in these various blends tends to eat through the older OEM fuel lines. If you use winter and summer blend diesel fuels make sure to use blends from a reputable supplier instead of some discount brand as the N-14 doesn’t do well with overly chemically blended fuels; the basic stuff will do just fine.
Even though the N14 has some injector issues make no mistake the N14 is a workhorse. This diesel engine has the power to get the job done, is easy to maintain and will last a long time. It is recommended that the oil filter, fuel filter and coolant filters all be replaced every 11,500 miles. The N-14 does not do well with cheaper filters that don’t further remove particulate matter. The early Cummins ISB series engines, (5.9 L and 6.7 L) were known to ship with cheaper less efficient filters which were also used in the early N-14 engines as well. Fleetguard or Donaldson makes a fine aftermarket filter for newer replacement purposes. Other than the fuel filters it is recommended that the valves be adjusted every 125,000 miles but a major overall should not be needed for 500,000 – 1,000,000 miles.
N-14 Engine Specs
• Displacement: 14.0 Liter
• Bore: 5.5”, 140 mm
• Stroke: 6.0”, 152 mm
• Cylinders: 6 In-Line
• Fuel System: PT
• Horsepower: 310 – 525 HP @ 2100 RPM, 360 HP @ 1800 RPM Marine
• Power Rating: 231 – 391 kW standard, 269 kW Marine
• Aspiration: Turbocharged / Waterjacket Aftercooled / Naturally Aspirated Options
• Rating Type: Continuous
• Dry Weight: 2800 lbs., 1300 kg
• Dimensions: Length 59 in, 1496 mm, Width 33 in, 854 mm, Height 51 in, 1293 mm.
• Compression Ratio: 17:1
• Injector Firing Order: 1-5-3-6-2-4
• Valve Timing: A Mark Cylinder 1-6, B Mark Cylinder 5-2, C Mark Cylinder 3-4
• Clearances: Intake Valves: 14 thousands, Exhaust Valves: 27 thousands
• Emissions Certifications: Meets NOx requirements International Maritime Organization (IMO), Maripol 73/78 Annex VI Regulation 13 and the United States Environmental Protection Agency.
We here at Capital Reman are experts at grinding and remanufacturing diesel crankshafts. Crankshaft grinding consists of removing a minute amount of finished material from the rod and main journals to rebuild the part back to OEM spec. The full 25 step crankshaft remanufacturing process is quite intensive but is critical to complete engine rebuild. This article will explain the main components of a crankshaft’s design as well as the finer points of crankshaft remanufacturing.
A crankshaft consists of rod and main journals. These journals are the end bearings at the bottom of the connecting rods opposite the pistons. The journals (also called crankpins) are connected to counterweights via plates called the webbing. These counterweights help balance the load of the crankshaft when in motion. There is also the crankshaft nose which connects to a pulley or vibration damper. The rods and mains have oil galleries embedded in them to allow oil flow throughout the crankshaft. It is important that the bearing holes are lined up properly to allow oil flow. The back end of the crankshaft is connected to the flywheel.
The main reason crankshaft grinding is done is because the crank wears over time. Over thousands miles the end play between the crankshaft and the bearings increases. When the “fit” between the bearings and the crank isn’t perfect it lowers oil pressure and decreases lubricity. The less oil to the crank the faster it can wear out. When you reduce the size of the bearings you reduce the overall surface area too. Less surface area equals less friction and better engine performance. Also, when you grind a crankshaft the journals end up having a greater radius which by reducing stress at the corners. Engine performance with a reground crankshaft can be quite noticeable when on an engine dyno. Performance crankshafts can be lightened by drilling the pins but mostly when you talk about performance parts you are referring to the camshaft. Overall, the vast majority of crankshaft issues revolve around the bearings.
During the remanufacturing process the machinist is mostly concerned with grinding the rod and main journals. Upon initial inspection of the crankshaft, with the use of the micrometer, the machinist will determine what bearings need grinding. Indicators that a journal needs grinding include if the surface has wear and make it rough to the touch. Sometimes the journal will be knocked out of center and needs to be surfaced to round and straightened. Consequently, the journal diameter could be positioned out of square at both end of the pins. Each grind is different but all crankshafts can be ground to allow for more or less stroke depending on customer needs.
When the machinist has decided to remanufacture the crankshaft he will grind the top layer of the journal away to make the surface smooth. The amount taken off is determined by looking at what OEM spec is and then seeing how badly the journal is worn. Typical amounts removed are (Standard) 0.005”, 0.010”, 0.020” and 0.030”. A crank can be ground to as much as 0.050″ as this is the biggest bearing sizes the OEM makes. The crankshaft is loaded onto the machine and then positioned using a hand-wheel which controls the manual micrometer wheel-head infeed. When the size is determined the machinist will set the indexed ring to 0 and keep the hand-wheel at 0 position. Then the machinist turns a locking knob to engage the device. Before the machinist is ready to begin grinding he then takes into account a safety allowance for any tuning errors. There are 5 different safety allowance positions: .02”- .06”. Once the safety tolerance has been recorded the machinist will engage the wheelhead back with a lever and the micrometer infeed handwheel will turn counterclockwise with the same amount of preset as the stop knobs. Ginding can now being. The machinist will manually advance the wheelhead to the ground journal until it has completed the journey around the spinning crankshaft. It is imperative that the machinist watch the speed of the handwheel and adjust it with the width of the journal. A work preset knob allows for quick stock compensation from journal to journal and allows the machinist to jump to a new journal without having to reset the specifications.
After the crankshaft is ground to the appropriate size it is then polished. The journals are polished using a piece of emery paper or polishing belts. Polishing the journals prevents any sort of rough finish for the bearings to catch on. To polish the crankshaft the crank is spun in a counterclockwise fashion and the paper is manually placed on the journals while spinning. The journals become extremely smooth which reduces resistance and improves overall engine power and torque ratings. It should be noted that polishing the crankshaft is taken into account during the grinding process. The finished polish takes off just a little bit more material on top of the grind to the exact OEM spec.
Once the grind has taken place there is going to be quite a bit of excess clearance. The clearance is simply too much and must be brought back to factory tolerances. This is accomplished by installing undersized or oversized bearings because by grinding the new journal size is smaller. The bearings used should match the proper OEM clearances for oil flow at the diameter of the journal.
Some crankshaft rebuilders will undercut the crankshaft. Undercutting the crankshaft journals and then welding them back up will strengthen the crankshaft. Some cranks are unsuitable for grinding because they are well below OEM tolerances. In this instance you can scrap the crankshaft or decide to weld. The welding buildup includes a thermal spray and a stress relief process under extreme heat. All crankshaft will also be checked for straight. If the crankshaft is not centered the machinist will heat the crank and use a Gleason Welding and Straightening machine and re-position the crankshaft. Once the crankshaft is ground, polished and straightened it is checked for hardness via the Rockwell Hardness Scale. If the crankshaft is shipping to a humid climate it is coated in Cosmoline which is a rust proofing agent.
Crankshaft grinding is a methodical yet important part of engine remanufacutring. Today, CNC machinery can grinding and polish a crankshaft in a matter of minutes however doing it the manual way provides room for performance upgrades and a keen eye for overall strength of the crank.
Technology continues to integrate itself in the diesel engine industry. The old guard is on its way out and 21st century technology is alive and well over at Cummins, Inc. The company announced the release of its new Guidanz mobile app which allows customers to access engine fault code and diagnostics within minutes.
The Guidanz app provides critical engine information about its on-highway engines as well as Tier 3 off-highway rated engine models. The information, once only found in thousands of pages of manuals is now available to customers a click of a button. The ease of use and real time data available is unreal. Every engine 2007 model year and later will featured on the app and be connected with authorized Cummins Dealers and Certified Independent Facilities.
The app works through Bluetooth connectivity with the engine. To receive real time engine data via your phone the ECM must be connected to Guidanz via the INLINE mini adapter or INLINE 7 full adapters. The ECM sends data to the adapter which pings the Guidanz app with an engine update report.
The data will be transmitted to the customer as well as operation managers, service centers or emailed directly to Cummins dealerships. Cummins calls the service “Immediate Assessment” The program will help Cummins read fault codes, diagnose the issue, assess the immediate health of the engine and schedule a repair time. The app will even create a work order and deliver the appropriate parts for the job to the service bay all without the customer having to do anything.
Even in offline mode the Guidanz system will still operate with a Smartphone or Tablet. The Bluetooth connectivity of INLINE will always ping the users phone with fault codes and engine status alerts. This means that even in remote locations such as an underground mine or an offshore oil rig operation managers can still access engine data and call or email Cummins at their leisure.
Cummins joins the list of heavy duty equipment manufacturers that are integrating diagnostic software into their products. Caterpillar and John Deere already have programs in place which are generating more service business for local dealerships. In the past many of these diagnostics issues would go unnoticed until a major problem arose. Now a small problem can be fixed before a major issue occurs. This save the customer time and money as well as generates a new stream of revenue for local service centers. The app is a free download available from the Apple App Store and Google Play Store and works with the iOS or Android Operating System.
Another week in the books! One of our most favorite engines to build here at Capital Reman is the Cummins ISX. Both the dual overhead cam and single overhead cam design were very well designed. Take a look at this a couple of pictures of this ISX Longblock that shipped.
Before anything else our number one priority here at Capital Reman is the safety of our employees. Recently we had 23 safety signs designed and erected in our machine shop and engine rebuild facility as well as re-branded the front of the building. Take a look at some our new signs and banners!