Rebuilding the Heart and Soul of the Car

Engines are the heart and soul of motoring, but can often seem as complicated as the human heart and soul. The key to understanding a car’s heart is breaking the engine down into specific primary systems and examining each area. You can then see how each component works and how it affects the engine as a whole. During my engine rebuilding class at McPherson College, I have learned a great deal about engine mechanics and theory.

Like many things in the automotive world, sometimes the best way to learn something is by going out and doing it. You can read everything about overhauling an engine from a book, but I personally learn best when the textbook is directly linked to real-life situations. One of my first days of class, we got our hands dirty, as we tackled a 1937 Pontiac straight-6. Not exactly my engine of choice, but you’ve got to start somewhere.

One of the biggest challenges that we ran into while overhauling our engine was cleanliness. Our engine had obviously sat for a very long time and had accumulated a thick layer of grime on top of the already extremely rusted block. After spending many hours (over the course of several weeks) power washing the block with pressurized heated water, we thought we were finally finished with the cleaning stage. The engine was very old and the more we cleaned it, the more dirt came off; trips to the wash bay were frequent events. The components that were not pressure washed were carefully cleaned in the solvent tank. Nothing should be overlooked when cleanliness is required, and the inside of an engine must be absolutely clean.

Now many of you may be asking yourself, “Why would I need my engine rebuilt?” Depending on the situation and the car in question, there may be a number of contributing factors. Engines that aren’t running would obviously be likely candidates, but in the interest of saving time and money, many people may opt to buy a previously rebuilt engine rather than overhaul the original. This should be done with caution, however, because if the car were a collectible or rare model, the engine swap would take away from the car’s originality and value. The decision to replace or rebuild an engine could also be decided by determining the use of the car after it is running; will the car will be a daily driver or driven just a few times each year?

The engine in Wes's car doesn't yet need rebuild, but will one day. Wes will be ready.

Engines that are presently running can also be candidates for rebuilding. After accumulating hundreds of thousands of miles, internal components have experienced incredible amounts of wear under extremely harsh conditions. The main crankshaft bearings, connecting rod bearings, and piston rings are common parts replaced during a rebuild, due to constant friction. Common symptoms of a worn engine can include excessive blowby, which means that unburned fuel and exhaust gases are getting past the piston rings and entering the crankcase. This causes a loss in power and the only remedy is to replace or rebuild the engine.

Finding parts can be a daunting task, especially while working on models that have been out of production for decades. For example, the Pontiac engine that we rebuilt used gaskets and fasteners that were probably found on most GM products of the era. That being said, many of the gaskets were somewhat universal but a few didn’t even fit our engine. This brings me to my next point, which could be viewed as bragging rights for us Mercedes-Benz owners. While rebuilding an engine – or any other part of our cars, for that matter – parts are easily obtained from the Mercedes-Benz Classic Center. Quality replacement parts and knowledgeable advice is only a phone call away.

Wes's W123 and its engine, on display at the recent McPherson Show

As far as my W123’s engine is concerned, I’ve never had a cause to perform a serious overhaul. I’ve rebuilt various components such as the turbocharger and the injectors, but the OM617s have an exquisite reputation for reliability and ruggedness, so I shouldn’t have to rebuild the engine for a very long time. As long as you maintain routine maintenance, these old cars run like clocks. But in reality, I’ve probably spent as much time cleaning my engine bay as someone might spend rebuilding one. But you can’t exactly blame me; detailed engines of yesteryear are true works of art. And I can’t emphasize enough how nice it is to perform routine maintenance on a clean engine. Just because you work on cars doesn’t mean you have to look like you do.

Wes Anderson is an active member of the mbca.org Forums and a freshman in the Automotive Restoration Program at McPherson College, the only college in the country that offers an accredited four-year bachelor’s degree in automobile restoration. In his columns, Wes shares with us the principles and techniques he is learning in his courses.

Wes inspecting Jeff Klepac's car