Friday, September 6, 2013

The Hot Head

By Ken Neal

Dad and I were very proud of our new 1948 Chevy. It was a Fleetline, Two-Door, Torpedo Sedan.
      It was black with grey mohair interior. Grey was a change from 1947, a time when Chevrolet model changes consisted of things like changing the color of the mohair.
      Of course it had a set of custom-made, red seat covers. After-market seat covers were a must in those days. The original mohair seats were hot and sticky, particular in the summer months.
      The ’48 Chevy was “our” first new car. There were no new cars from 1942 until 1946 so there was a pent-up demand for cars. When the first new cars were available in 1946, the dealers were getting premium prices. By 1948, production was catching up with demand, but Dad still paid a premium for the new car. Having rejected a $900 offer for his ’39 Chevy during the war, he now about $250 when he traded.
      There was little change in style from 1942 through 1948, and there was virtually no mechanical difference. An oddity plays into this episode of our 1948 Chevy.
      Until 1941, the Chevrolet engines had 14-millimeter spark plugs. In 1941, for some reason known only to the Detroit Auto Gods, Chevrolet engineers decided to change to 10-millimeter plugs.
      Pop never liked the smaller plugs, contending they ran hotter and didn’t last as long as the larger plugs.
      Now for a coincidence. Our new Chevy idled roughly. Dad tuned the Carburetor, gapped ignition points, and adjusted ignition timing to no avail.
      There was a rough idle and a half-miss on a hard pull. Ordinarily, this would have been a dead giveaway to burned valves in the engine. Such allowed compression to drop at low revs. At higher speeds, the miss would disappear.
      But there were those damned little spark plugs.
      At this time, the foreman of the machine shop at Standard Parts in Tulsa was dad’s friend.  His name was Ernie.
      Dad conferred with Ernie. Ernie said his shop routinely bored out the spark plug holes to 14 millimeters. Dad wasn’t the only mechanic who detested the smaller plugs.
      Ernie asked when he could bring the “head” in for the boring. Ernie said the machine work would take a couple of hours and he could do it anytime.
      Dad and I had been overhauling Chevrolets regularly. So, we pulled the head right there in the Standard parking lot.
      I guess we carried our tools with us. I always worked the manifold side of the engine while Pop pulled the right side panel, the rocker arm assembly and the head itself.
      With the head off, Pop discovered the real reason for our “miss.” There was a burned exhaust valve on one cylinder. Pop speculated it was warped, causing it to seal improperly.
In about 45 minutes, we were carrying the head into Ernie’s shop. He grabbed the head, jerked back quickly.
      “Damn, that’s hot.”

      He confirmed Pop’s diagnosis. What the car really needed was a new valve. Ernie thought the burned valve might have been warped, causing a leak in the seal between it and the cylinder seat and thus burning.
      But with the head off, Dad wanted the new plug size. So, not much more than an hour later, we were carrying our reworked head back to the car and the parking lot.
It took us awhile longer to reinstall the head but of course the rough idle was gone and Dad had his new 14-millimeter plugs.
Today, one could probably get all that work done under a warranty. In 1948, it was routine to have such go wrong on a new car.
I remember carburetor troubles on our 1950 Chevy and our 1955 Chevy, both diagnosed and fixed by my dad, who was probably a superior Chevrolet mechanic to most working for Chevrolet agencies.
I know that Midwest Chevrolet tried to hire him after this incident:
Pop liked to hang around the Midwest back shop and visit with the mechanics. Nowadays, customers aren’t allowed.
It was one such visit that got him the job offer.
The ignition in those old Chevies had moveable points that had to have the proper “gap” for the ignition to perform properly.
Usually, only well-equipped garages had electronic measuring tools like a dwell meter, a device to be connected to a distributor to adjust the ignition gap.
Dad had grown up working on the cars without a dwell meter, instead relying on a “feeler gauge” to set the air gap on the ignition points.
That process was tedious. To get an accurate measure, the engine had to be turned so that the stationary part of the “points” was exactly on the lobe of No. 1 cylinder.
Then the “feeler” gauge (.018 to .022) could be used to set the adjustable part of the points.
This was no easy task. First, the distributor was located at an angle low on the engine, so the mechanic had to insert the gauge at the exact angle to get an accurate setting.
It was not easy.
The mechanics at Midwest were accustomed to using a dwell meter that eliminated the need for the feeler gauge.
So they kidded Dad that “no one” could properly adjust the points without a dwell meter, but Pop said he could.
Men being men, they challenged him. Set the points with a feeler gauge, they insisted and the dwell meter will show the gap to be far off.
One thing led to another and so a bet was made.
Dad set the points on a disturbed engine. The Midwest guys then checked with a dwell meter, and sure enough, the “dwell,” that is, the time the points are open, was within specifications.
“That’s an accident. Bet you can’t do it again.”
Dad repeated the process three straight times on “disturbed” engines, putting the “dwell” within specifications every time.
That’s when Midwest tried to hire him. But by then, he had been at American Airlines several years and was making a lot more than Midwest mechanics.
But he was tempted, mainly because he loved autos and working on them. He was a better Chevrolet mechanic as a hobby than most of the guys working full time on them.

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