Making the 6.0L Right – Part 1

•April 26, 2010 • Leave a Comment

The 6.0L motor can be made right, however, it takes an owner with some determination to improve and understand their vehicle.  Two of the most important systems to understand are the exhaust gas recirculation(EGR) and oil cooling systems.  Both of these systems must dissipate heat from the motor in order to keep the horsepower harmony moving forward.  In this article we will examine the EGR cooler.

EGR Cooler Diagram from bulletproofdiesel.com

The EGR cooler takes in hot exhaust gas and passes it through a heat exchanger.  Engine coolant is used to extract heat from the hot mixture.  The primary goal of the cooler is to prepare some of the exhaust gas mixture for reintroduction into the air intake.  This system reduces the emissions at the tail pipe by diverting some unspent fuel back into the motor for combustion.  The cooled exhaust gas is mixed with fresh air for the next cycle.  Click here to see an animation of this process. The cooler is designed at the factory to withstand a certain number of heating and cooling cycles.  As the parts fluctuate between hot and cold they also change dimensionally in size.  This constant straining of the material as it changes size will eventually lead to failure over many cycles.  The stock cooler shows a consistent pattern of failure at the seams of the internal cooling system.  This problem is easily fixed with an aftermarket EGR cooler from Bullet Proof Diesel.  They start with the body of a stock EGR cooler and remove the internals.  From there the cooler design is greatly simplified.  The factory unit is a complex radiator fin style system.  Bullet Proof Diesel reworks the original cooler as a shell and tube style exchanger.

EGR Cooler Fix from bulletproofdiesel.com

The stock cooler passes hot exhaust gas between the horizontal rows of fins.  Engine coolant runs down the vertical columns between cooling fins.  The point where the fin connects to the vertical column is also a thermal stress riser and a primary point for fatigue failure.  When the cooler fails it opens a passageway between the intake of the motor and the engine coolant.  Coolant inside of the cylinder can lead to blown head gaskets and white steamy smoke from the tail pipe.  The shell and tube design is elegant and durable.  Hot exhaust gas passes down the center of long tubes which run the length of the exchanger.  Coolant runs around the outside of the tubes and cools the exhaust gas.  It reduces the thermal stress risers and provides a radially uniform expansion.  When the tube gets hot it expands equally about it’s cross section.  This is the EGR cooler going on the resident test mule as a preventative maintenance measure.  This will eliminate a point of failure and give the owner a boost of confidence when putting the truck to work.

EGR Cooler Thermal Fatigue Failure

Fixing a Lemon

•April 22, 2010 • Leave a Comment

The goal of this blog is to determine if a real 6.0L lemon can be turned into lemon aid. I believe it can. I started driving the truck somewhere a bit after 85,000 miles. It has a real deal CA lemon title and it was correspondingly inexpensive. Its been nothing but problems and scared off most of the previous owners for a variety of reasons. Next thing I know I’m driving it and impressed. However, as an engineer I’m also concerned with its previous history. The problems are systemic and there are answers.

Here is a look at the problems from the Ford RAV Document that the dealer makes people sign when they purchase a lemon. All of the problems are reported with mileage at failure.  Some of the noted information occurs at the same mileage.

#1 – 223 Miles
– Customer states temperature light on.  Service tech determines the Engine Oil Temperature sensor has failed.  EOT sensor is replaced and tested.

#2 – 995 Miles – Customer states that the check engine light is on.  Dealer clear the code and test the system.

#3 – 9213 Miles – Customer states that the 12V power point in cab has failed.  Dealer orders a replacement part.

#4 – 9213 Miles – Dealer responds to a PCM recall and reflashes all three of the computer modules.

#5 – 10840 Miles – Special order parts for the 12V power point arrive at the dealership and installed in the customers vehicle.

#6 – 45157 Miles – Customer complains that the engine runs rough on cold start and the check engine light is on.  Dealer determines cause of failure to be the number 7 injector and erratic ICP operation.

#7 – 47427 Miles – Dealer responds to PCM changes and reflashes computer.

#8 – 47427 Miles – Customer is eligible for one time customer assurance test drive with a dealer representative.  Dealer test drives truck with owner.

#9 – 47643 Miles – Customer complains that the engine runs rough and the check engine light is on.  Dealer observes massive systemic failure.  The following components failed and were replaced by the dealer, turbocharger, #6 fuel injector, EGR sensor, MAP sensor and a leaking turbo tube.

#10 – 48940 Miles – Customer is back with more problems.  The motor continues to run rough and surge.  Dealer determines #7 and #6 injector failure and replaces the components.  The second #6 injector lasted just over 1000 miles.

#11 – 55668 Miles – Customer complains that the check engine light is on and motor runs rough.  Dealer observed continuing systemic failure.  The EGR valve has failed and the turbo is experiencing issues with the variable vane geometry sticking.  The turbo is cleaned internally and the EGR valve is replaced.

#12 – 55668 Miles – Customer complains of excessive exhaust noise.  Dealer observes blown exhaust gas manifold and replaces the gasket.

#13 – 57001 Miles – Customer notes the check engine light is on.  Dealer inspects and observes the turbo variable vanes are sticking.  The turbo is replaced again.

#14 – 59585 Miles – Customer states the check engine light is on again and the motor lacks power.  Dealer determines that the fan clutch and MAP sensor have both failed.  Both components are replaced and tested.

#15 – 64820 Miles – Customer complains that the check engine light has come on once more.  The motor runs rough and lacks power.  Dealer determines #7 injector has failed along with the EGR valve.

#16 – 68385 Miles – Customer reports engine surging and the check engine light is on.  Dealer determines that the oil cooler has failed.  The cooler is replaced and tested.

#17 – 68390 Miles – Customer reports exhaust noise.  Dealer checks and replaces leaking turbo exhaust pipe.

#18 – 69585 Miles – Vehicle is reacquired as a buyback.  Dealer finds oil leaking at the CMP sensor along with the left and right bed plate gaskets and rear cover gasket.  It has a broken dipstick and a leaking EGR cooler hose.  A hot side duct at the turbo has slipped out of the clamp and torn.  The EGR cooler was replaced along with the hot turbo duct, dipstick, CMP sensor, bed plate gaskets and rear cover gasket.  It was road tested 16 miles and determined to be acceptable.  At this point all of the additional aftermarket parts installed by the customer are removed including the fuel tank and air bags.  The truck is then inspected and accepted into the Ford RAV program, short for Reacquired Vehicle.

Testing a Built 6.0L Motor

•April 21, 2010 • Leave a Comment

Admittedly, this video link isn’t advertising the Ford 6.0L motor. However, if you take a look at the stickers on the truck it is one of the shop trucks owned by Diesel Tech 1. They helped write the book on building power with the 6.0L motor of which the red truck has plenty. The advertised product in the video is actually parts for axles but they are using the 6.0L to show how much power you can put to the ground. The red truck is chained up to the tractor trailer and loaded with several thousand pounds of steel in the bed. Then it is put to the test with some throttle!

Chip on the Power Stroke Shoulder

•April 9, 2010 • Leave a Comment

The Ford 6.0 liter diesel motors are legendary for all the wrong reasons.  They suffer from a smattering of problems.  Fortunately, most of these problems have been well documented by the diesel performance shops.  An excellent guide to get you up to speed with the problems is available at this link and published by Diesel Power Magazine in July of 2009.  After reviewing the list in the article, it is clear to see the majority of problems are in the top end.  If you’re a 6.0L owner its an encouraging sign.  At least the bottom end is structurally sound.

The real problems creep up when you examine the parts bolted to the top of the engine block.  Fundamentally speaking a motor is a thermodynamic heat engine.  It extracts chemical energy from a fuel through a series of temperature and pressure cycles.  The top end of the motor is the director for this symphony of horsepower in motion.  It consists of the intake, exhaust, turbo charger, cylinder heads, fuel injectors, and the cooling systems.  The systemic failure of the Ford 6.0L motor is primarily due to component failures in these systems.

The story of the Ford 6.0L lemon starts with a motor manufactured by International Harvester named the VT-365.  Then along came the Ford Motor Company badly in need of a competitive motor for the lucrative consumer level diesel truck market.  Ford had historically used the trusty 7.3 Liter motor which had strongly contributed to the excellent Superduty truck reputation.  New regulations and market pressures forced the 7.3 into retirement.  The 6.0 needed to comply with emissions regulations and to provide the necessary improvement in horsepower and noise levels to be competitive.

In order to get the necessary power from the motor Ford would need to improve the performance of the industrial version for the consumer truck market where horsepower is king.  International is still selling the VT-365 motors into the world’s industrial markets.  The key point to understand is that the parent company, Navistar, is a huge global corporation which supplies engine platforms to three major truck markets, industrial, RVs, and consumers.  In this role they can offer a tailored solution to meet the customers needs with a common engine platform.

There is quite a bit to be learned about these 6.0L diesel motors once a comparison is made between the three market segments.  The VT-365 horsepower rating for the industrial motor is reduced from the power levels marketed by Ford to consumers.    Take a look at this link and scroll down to the very bottom where the Performance Data table is located.  The engine data indicates the industrial motors are available in four configurations starting at 175 HP and topping out at 230 HP.  All of the configurations are governed to a top speed of 2800 RPM.  Upon further examination you will notice that there is a Q&A section.  The second question in the list explains some of the differences between the Power Stroke 6.0L and the RV-market VT-365 which is once more slightly different than the industrial configuration.  The RV motor is equipped with 300 HP rating and a top speed of 3000 RPM.

The configuration marketed by Ford was offered at 325 HP with a top speed of 4200 RPM.  On top of that programmers for consumer diesel trucks unlock additional horsepower at the touch of a button.  Take a look at this link for the Edge Platinum programmer.  At the bottom they advertise 100 HP over stock improvement on full race mode, level 5.  I’m confident there are plenty of people driving around on level 2 making an additional 40 HP.  When an engine makes more power it must also make more heat and pressure as the pistons cycle.  In order to run reliably the motor must be supplied with adequate lubrication and cooling for the moving parts.  That means the motor needs the proper engineering to dissipate all of that heat which creates the wonderful HP we love.

Lets look at an example.  The Exhaust Gas Recirculation system, EGR for short, redirects part of exhaust gas back into the intake of the motor.  This system is necessary to meet emissions regulations.  It directs some of the hot exhaust gas back into the intake in order to burn any unspent fuel still in the air mixture.   Before this can happen the EGR cooler uses engine coolant to cool the incoming air and fuel charge.  When the motor makes more power the exhaust gas temperature will increase.  When this hot exhaust gas is dumped into the cooler it places an increasing demand on the engineering of the cooler.  As the cooler experiences thermal heat cycles it is subjected to fatigue.  This leads to ultimate failure of the part in the long run.   When a company decides to take on the risk of manufacturing in the millions there is a certain necessary balance between economical and durable.  At the design stage worst case parameters will be established by which the product will be tested.  Its not uncommon to find parts which may fail at 15% above the worst case scenario.  Even a single dollar taken out of the per unit cost can save millions over a product life cycle.  Product engineering is a delicate art.

This all leads us back to the ultimate observation.  The 6.0L diesel motor got a bad reputation because of implementation problems related to the Ford trucks.  The motor platform is fundamentally sound and it can be optimized by aftermarket solutions and improvements.  At least I sure hope they can be solved because my truck is a Lemon Law buyback!

 
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