10-4 Magazine - For Today's Trucker

February 2007 - Performance Zone
IMPROVING YOUR CAT
By Performance Specialist Bruce C. Mallinson

I started turning wrenches on gasoline engines in 1965 and switched over to diesel engines in 1977. Since then, I have worked with some good, some great and many poor engines. Yes, the great ones are easy to make run better, but those poorly-designed engines can be very trying at times. I’ve spent many late night hours in the shop and sleepless nights, along with thousands of dollars on time and parts, to come up with solutions for the undesirable engines out there. Although I will be addressing the problems of one particular engine this month, please don’t think I’m picking on this manufacturer, because all of them have had engines that did not perform to the standards of most owner-operators. They may have performed to the standards of fleet owners, however, the owner of a fleet of trucks does not usually have to drive one of his or her trucks with one of these unresponsive engines under the hood.

Manufactured in 2003 and 2004, the “Bridge” (MBN) Caterpillar engine has had some problems. Although I have met a few truck owners operating these engines and not having any problems, most of them suffer from insufficient power, poor mileage and blown head gaskets. The head gaskets are prone to fail because of a low liner protrusion. When the liners are too low in the block, the ring can’t hold the compression. When we build a high performance NTC Cummins, we set the protrusion at .007, not .003 to .006 like the repair manual calls for. I guarantee that if you build an NTC and set the protrusion at .003 the head gasket will not hold. The Caterpillar MBN engine calls for a liner protrusion of .0015 to .006. Every one of these engines that we have seen that has blown a head gasket was set to .001 to .003 liner protrusion (and it’s usually the #4 liner that goes).

When repairing one of these blown gaskets, most dealerships will only replace the head gasket. If you just replace the gasket, it will blow again. It’s not the gasket. It’s not how much power the engine is producing. It’s not your driving. It’s the liner protrusion! If you blow a head gasket, check the liner protrusion, and don’t settle for the term, “It’s within specs,” because the spec is too low. Remove the liners and pistons, cut the upper counter bores, install stainless shims, and set the liner protrusion at .006 on all of the cylinders, and your head gasket problems are over. Be careful not to exceed the .006 measurement, or damage to the liner flange could occur.

When addressing the other problems the “Bridge” Caterpillar engine has (low power and poor fuel mileage), there is a cure for these ailments but it’s fairly expensive. The average price is just under $2,000 – but spend the money and the problems are fixed. You can install the parts yourself in your driveway. The engine will not only improve in performance, but some owner-operators are reporting gains of as much as 1 mpg. One truck we worked on was getting 4.6 mpg and now it gets 5.6 mpg (sometimes as high as 6.1 mpg). By the way, we are NOT talking about installing the Pittsburgh Power Computer on these trucks to fix the MBN’s problems – we are working with what the engine already has. Naturally, if you want the ultimate in performance, you can install one of our computers to the fixed MBN engine. One of our owner-operator friends did just that and recently found himself climbing over Raton Pass on I-25 South in New Mexico at 67 mph on power level 3. Needless to say, that was really good. This trucker was high on life, thanks to his strong-running truck. His little Kitty was finally purring like he always knew she could!

This particular owner-operator had been a victim of many engine failures, but now the problems are gone. I will not discuss to you in this article how we fixed the problems, but if you call us (724-274-4080), we will discuss what is necessary over the phone. Because of his truck’s poor efficiency, the owner-operator I just mentioned spent an additional $29,365 in fuel during the past 300,000 miles, not to mention how many times his engine was down for repairs and what this cost him in dollars and downtime – which is all the more reason to fix these problems sooner rather than later.

Let’s switch gears now and look at another issue: blow-by. Let’s face it – all engines have some blow-by coming out of the breather tube. Back in my road racing days, we had a catch-can mounted under the racecar to catch the oil from the blow-by tube or breather. Now, here we are, 30 years later, and there are still no catch-cans on the breather tubes of semi trucks. Did you ever wonder why the underside of your truck gets so dirty? Well, about every 10,000 miles there is about half a cup of oil omitted from the breather tube of an engine that is in good shape. That oil ends up on the underside of your rig and collects the dirt being kicked up by the tires, and it doesn’t take long for your truck to get filthy underneath.

One day, not that long ago, an owner-operator called and told me about the catch-can he had developed for his truck. Right away, I thought back to my days of road racing and wondered why I didn’t think of such a simple thing. I had the trucker send one of his catch-cans to me and I was impressed at how nice and simple it was, so we struck up an arrangement. Pittsburgh Power is proud to present this new product, called “The Oil Trap,” priced at only $196. The product’s creator still does all of the fabrication, but then our local welder does the welding. We even paint them to match your engine!

To all of the truck and engine manufacturers out there, we at Pittsburgh Power are only trying to help a few owner-operators in this world that are looking for more than what is available to them. We do not mean to be rude or disrespectful to you, we are just looking for something different. And if we can improve the fuel mileage on every truck in the United States by just 1/2 mpg, not only would these truckers save a lot of money, but we could also save 36,350,000,000 gallons of fuel per year. That decrease in fuel consumption would also reduce much of the pollution in our air today. Just something to think about. Remember, you don’t have to sacrifice power for efficiency. If you have any comments or questions, please send me an e-mail to bruce@pittsburghpower.com or call (724) 274-4080.