10-4 Magazine - For Today's Trucker

February 2006 - Performance Zone

ENGINE CONSTIPATION
By Performance Specialist Bruce C. Mallinson

To run properly, an engine must be able to get rid of its exhaust efficiently. That is just common sense. To my owner-operator friends out there, below is an e-mail I recently received from David Brumbeloe. I think you will learn a valuable lesson from his experience described here.

Dear Bruce,
I am an owner-operator of a 1999 Freightliner Classic XL with a 12.7L Series 60 Detroit. I have spent the last several months talking with lots of people and trying lots of things to get better fuel mileage. My fuel mileage dipped as low as 3.9 mpg and I could never get above 5.7 mpg. No matter how hard or easy I drove the truck, my fuel mileage was 4.6 to 5.1 mpg. When loaded, the engine coolant would heat up quickly and even overheat on steep grades if I didn’t keep a watchful eye. The truck strained to maintain a constant speed of 65 mph on the rolling hills of the interstates. On flat ground, it would not go faster than 76 mph - even when empty. Freightliner and Detroit said I probably needed the overhead adjusted. That didn’t fix the power problem. Also, they determined that my injectors were firing at the correct intervals, but could be suspect. The computer was reset and a suggestion was made to redo the overhead and do a more thorough inspection of the injectors. More dollars I didn’t have, trying to feed this beast. Freightliner decided that the fuel return lining and fittings were the wrong size and needed to be replaced. $1300 later, including the addition of four new shutoff valves on the water lines, the issues still persisted. This ruled out the heater cores and suggested that the thermostats were going south. But thermostats weren’t the problem either. Freightliner determined that the charge air cooler was probably bad and needed to be replaced. Still the fuel mileage didn’t improve. I was still at 4.6 to 5.1 mpg. I was told the intake had to be restricted. I had the intake air path checked and the air cleaners replaced, even though they looked almost new. I was then told that I must have excessive blow-by and that I may need a rebuild soon, however the truck didn’t smoke or use any oil. I argued that the truck doesn’t have excessive blow-by and that I could go 15,000 miles and still be on the full mark on the dipstick. Every 15,000 miles I get the oil changed and do an oil analysis. The analysis showed soot, oxidation, viscosity and water levels in the oil were very high and my TBN (total base number) was severely low. The numbers kept climbing while the TBN was falling off the bottom of the chart. At this point, the fuel injectors were all that was left, so I thought they must need replacing. I set up a Saturday appointment to have the injectors checked and replaced. The day before my appointment, I heard a rattling inside one of my mufflers while pulling a hill. The power came up instantly and I got 5.6 mpg on that trip. Could it be I needed the mufflers replaced? Four months earlier I purchased your straight-through mufflers because you promised me a quarter mile to the gallon improvement in my fuel mileage. Because of time restrictions, I had not had the mufflers installed yet. I had them installed the next day and my problems were solved! I called Freightliner and cancelled the appointment for the new injectors. My fuel mileage is now between 5.7 and 8.2 mpg, depending on how I drive. Foot on the floor and fully loaded, living in the hammer lane, I’m getting an impressive 5.7 mpg, which is considerably better than the 3.0 mpg I was getting before. If I behave and average about 65 mph, my fuel mileage is between 6.4 and 7.0 mpg and if I stay between 55 and 60 mph, I average between 7.4 and 8.2 mpg. The TBN levels are now good, viscosity is now 14.3 (it was 17.4), water is .3 (was 1.2), and the iron particles have dropped to 22 parts per million (before the muffler change, it was a staggering 48 ppm). Oxidation is 4.7 (it was 10.9) and the soot level is 2.1 ppm, down from 4.2 ppm. All I can say is that you were right - the mufflers paid for themselves in the first week. Just think how much money I would have saved if I had put the mufflers on when I bought them!

Sincerely,
David L. Brumbeloe Jr.

Is your truck constipated like David’s was? If you have stock mufflers (or worse yet a single stack) your truck is being chocked on its own exhaust. Why do some electronic engines have to be rebuilt around 500,000 to 800,000 miles and some run over 1 million miles without a rebuild? Look at David’s iron particles - 48 parts per million - that’s terrible. Do you know how many iron particles are running through your oil? When was the last time you did an oil analysis? Iron particles and silicone (which is ingested dirt that gets through the air filters) is what wears out an engine. After changing the mufflers, his iron particles dropped to 22 ppm. If he would install a Spinner II or a Harvard Luberfiner, the iron would drop to about 12 to 18, which is where it really should be. David is like everyone else out there - he has little or no time to make the needed changes to the truck that makes his life possible. However, he does take the time to have his oil analyzed. Do you? I used to, but I have to admit, I haven’t for several years. After reading David’s letter, I was reminded of the importance of oil analysis and will start having it done again on my vehicles. Again, especially if you have a single stack truck, get a straight-through muffler installed. It will save your engine, improve your fuel mileage and end your problems with engine constipation once and for all. Ahhhhh!
By the way, David now has a new turbocharger for his Detroit that is 15% larger. Once installed (don’t wait this time David), he will see another improvement in fuel mileage and less soot and iron particles in his engine. For more information about power and performance, visit www.dieselinjection.net today.