I wouldn't trust my own mechanical aptitude any farther than fixing a flat tire or changing the oil on my motorcycle, but it's fun to pretend

. Recently, the folks at Peterbilt in Denton, Texas, allowed a handful of us journalistas to tear down a Paccar MX engine. Not a real, in-service engine owned by a paying customer, mind you; a training engine that had run some 250,000 miles. It's now painted so the various systems are color coded for easy identification -- even for a humble motor-noter.

There we were in our shop coats and safety glasses -- impact wrenches a-buzz -- as we tore the parts away from the block.

The point of the exercise was to illustrate the robustness of the engine and to highlight some of the design elements that make MX unique among its peers. What better way to make the point than to take an oily finger a point to the parts we had just painstakingly dismantled and laid bare on the workbench?

It certainly more effective than watching a Power Point presentation in a darkened room, and that's why Paccar has now brought nearly all of its real heavy-duty diesel techs into a five-day training program to prepare them for the new engines.

We had but the tiniest taste of the process, and even with my limited mechanical dexterity, I could see some advantages to certain design elements. Nothing like hands-on experience to get the point across.

The following day, I took one of those same MX engines -- in a Peterbilt 587 -- out for a test drive. Oil still under my fingernails and all, I motored around north Texas for several hours, and felt first hand what that new technology can do. (We'll have a report on that test drive in (an upcoming issue). Fortunately for you, dear reader, I won't be writing anything on how to repair MX engines. A real tech would have long forgotten everything I could tell you about pulling wrenches on big diesels.

But as you can see by the concentration on my pal Tom's face, it was fun channeling our inner diesel technician.