X-Mozilla-Keys:                                                                                 
Barry Gardner wrote:

I got
the car second-hand last June and believed it had a blown engine when I
bought it for $150. It would run but not run well. The odometer reads
105,000 miles. Thought the body is in nice shape, I have no idea how the car
was treated nor how the apex seal decided to give up the ghost.

What I was celebrating in my postscript was that I finally had a firm
diagnosis based on doing a compression test in the fine fall weather that
Chicago experienced last weekend. I unscrewed the Schrader valve on my
compression tester, disconnected the crank angle sensor and fuel injector
fuses, had my wife crank the engine with the accelerator floored while I
watched the gauge under the hood...and there was truth. Front rotor had
three even bounces of about 93 pounds pressure. Rear rotor only had one
bounce, ergo, a blown apex seal between two rotor faces.

I presume the engine is original and hasn't been rebuilt. However, you
shouldn't draw any conclusions about this engine nor its suitability as an
aircraft engine. Indeed, I haven't. When I pull the engine and open it up,
then we'll know more.

I think I'll get my $150 out of it, even it I part it out.

Paul has made a point about the low horsepower requirements that cars
typically produce continuously. He's absolutely right based on the evidence
from my 87 Turbo. I put in a Hobbs meter this summer and can attest to the
fact that, by dividing elapsed mileage by my hours of running time, the poor
car has averaged a modest 22 miles per hour in its life around Chicago the
last few months. Lots of idling at lights. Miles of 30 mph suburban streets.

Even with my consistent jack rabbit starts--lined up on the "runway,"
waiting for the light to turn green--hardly test the engine at all because
the car is so fast. If I shift at the 7000 rpm redline, when it beeps at me,
the problem is that I can be at 60 mph in 7 seconds or so. One can't drive
that way on most streets, so the engine hardly gets taxed. No meaningful
test of the cooling system or anything else other than the peak output of
the engine.

And if the Hobbs told a story that indicated a higher average MPH, that
would only indicate that I had more freeway driving in the mix: 5th gear,
2800-3000 rpm. Even higher average MPH wouldn't make it a good test.

Dyno data is best!

Barry Gardner
Wheaton, IL

Excellent article! Thanks for writing and sending it to us Barry.

Paul Lamar
 
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