Sixteen years ago, the MTM restored a 1912 Mack Stage for the Julian Historical Society. It was the first motorized stage to run from the end of the San Diego & Southeastern Railway near Lakeside to the town of Julian, a distance of about 30 miles over rugged mountain roads. Since its first appearance in Julian’s 1999 Fourth of July parade the restored stage has served faithfully in festivals and other functions. Over these years, wear and tear and some functional weaknesses have become evident so this handsome old horse was returned to the barn for some repairs and improvements.
I took on the job of completing the overhaul with the help of Andy Andrews of MTM and Bob Beers, Brian Steutel and David Rabbai.of Julian. Most noticeable among things that needed attention was that the engine was not running well had a tendency to overheat and sounded rather too clattery for comfort. At the back corner of the body, the steel bracket anchoring the roof support stanchion was broken.

Andy Andrews did a skilled repair of the steel bracket at the back corner, adding a hidden gusset to improve strength. There has never been a gas gauge on this vehicle so we made a bracket to hold an appropriate wooden dowel near the
tank-filler cap for convenient probing of the fuel level in the tank. I opened the valve chambers on the engine to find that the lock nuts on two of the exhaust valve lash adjustments had come loose defeating proper operation of the exhaust valves on two cylinders. All the valves were removed; lapping the valves verified they were straight and in good condition. Removing the valves also revealed that one valve spring was significantly mismatched to the others. A better match was scavenged from another engine in the yard.

We put in about three gallons of motor oil and ran the engine for testing. Road tests revealed more engine concerns. Prodigious fuel consumption has always been evident, but lacking experience, none of us were in a position to know what to expect as normal. Other troublesome characteristics have been low power and a tendency to run too hot. The combination of these things and the lack of other explanations began to make me suspect improper valve timing so David and I opened the front of the engine and found that there is no timing mark on the crankshaft timing gear. Careful study and measurement seemed to indicate the timing gears were meshed with the camshaft gear retarded by one gear tooth. The mesh was corrected and the engine front reassembled.