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Recently, to commemorate the millennium, I began a series of articles posted on our web site, www.iskycams.com,
entitled “Tech Tips 2000.”

The first ten or so are under the heading “Modern Myths of High Performance.” I decided to write them because I didn't necessarily enjoy repeating myself
over and over in order to undo the misinformation rampant in our industry.

So, like “Tech Tips 2000,” Cam Session is intended to set the record straight with the truth, the whole truth and nothing but, so help me.

Ron Iskenderian: will be setting the record straight in each issue of Drag Racing Online. If you have any questions concerning cams or valvetrain components or tech, just email camsession@racingnetsource.com

Cam-Timing Mythology:
No it didn't end with Ancient Greece

In the movie "The Bridges at Toko-Ri", (a Korean war era drama), Frederick March plays a Navy Admiral who is notified of the death of one of the pilots under his command (played by William Holden) who had been shot down during an air raid and was like a son to March in the movie, having given up a successful career to serve his country. The Admiral's tribute, after hearing of the young pilotís death, is one of the classic lines from a bygone era, when unlike today the quality of the script was far more important than any action scene or stunt. “Where do we find such men?” he asked. A great line from a great movie delivered by one of our finest actors (thanks to an excellent screenplay).

Why do I mention this in an article about cam timing? Because the script writers from the good old days of Hollywood aren't the only journalists who have “gone with the wind.” Technical writing has also taken a hit in recent years. In the case of High Performance today, I am generally not very impressed with what I see coming from the magazines. People seem to have forgotten the two most important rules in writing:

  1. Get your facts straight
  2. Omit needless words.

Why? Because all the words in the world won't make up for incorrect assertions and nothing is better than the plain truth, simply stated.

Recently (for the umpteenth time) I received a phone call from a customer who, like many others, had become a victim of High Performance misinformation. He had been told by another misinformed individual that when aligning cam timing marks on a Chevrolet V8 engine (cam mark at 6 o'clock, crank at 12 o'clock) that the crankshaft's keyway slot would be a the 2 o'clock position, and the piston would be at T.D.C. ignition (compression). All true except for one small detail. The piston would be at T.D.C. alright, but not on the compression stroke! Top Dead Center overlap (opposite of compression) is where you would be with the marks aligned in this position. Actual T.D.C. Compression is when both cam and crank timing marks are at 12 o'clock high, one revolution of the crankshaft away.

You're probably starting to get an idea of what came next. “How can I set my ignition timing on overlap?” he asked. I spent nearly 20 minutes on the phone reassuring him that his cam was not ground incorrectly, and let me tell you, it was a struggle. For you see, once something like this gets into print it tends to be taken as gospel, whether or not it is true! What finally turned the tide was when I got him to understand that the engine doesn't know which T.D.C. it is on until the cam tells it. He finally realized that his timing marks were in alignment every other revolution and that he should be observing the motion of his engines valves to verify T.D.C. compression, in order to set his ignition timing.

Where did this misinformation about cam timing marks alignment and T.D.C. come from? His friend had seen it in print somewhere (kudos to some magazines), and taken it as gospel. In fact, like respected engine builder, Joe Sherman, I've seen it in the print media too, along with other inaccuracies (my favorite is “advancing the cam increases top end power but hurts the bottom end torque.” No, I'm not kidding, and it's happened more than once.)

I do not know the name of the person responsible for originally putting out this misinformation. He alone is not guilty however because others have perpetuated it. This is a perfect example of why you should abide by the old adage, “Believe little of what you hear and only half of what you read in the press.” Why?

Because the print media in this country is in a sorry state of affairs.

Newspapers and magazines forsake accuracy in order to slant stories in favor of political and big business interests. Book publishers gleefully distribute a product which is, in reality, often so bad it is unreadable, while talented authors struggle to get published. Is it too much to ask that within the High Performance industry we deserve more than the sub-par performances that some magazines, their writers and editors, have been delivering? We need accurate, concise distribution of technical information within our industry. If it is to happen, we must begin with qualified journalists who really understand what it is they are writing about. Where do we find such men?

 

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