Bill Eastman wrote:
>
> Last week I received more ammunition for my continuing "MGA's are God's
> gift to the sports car world" campaign.
>
> On this list we have had a wonderful debate over the advantages of the
> three bearing engine.
Uh-huh. The 'A' and early 'B' motors are great revvers because they have
three bearing cranks. And the S*itfire motor in RB Midgets have weak
lower ends because they have three bearing cranks.
I recently read that the biggest contributor to frictional losses are
piston rings, specifically the oil control ring, and the length of the
piston stroke -- both of which, alas, the 'C' motor has in abundance.
Hey, John McEwen, who appreciates them murdercycles, what allows a 12K
rpm redline on them mid-size street bikes? How many main bearings in a
4-banger Jap motor?
The late 60's Z28 (5 liter) and Boss Mustang (5 liter) could rev to 7
grand (occasionally) and have a long life. What was the secret there? I
understood it to be a combination of high compression, lumpy cams, and
big carb throats. The trick is to have the motor breath at rpm to
overcome frictional losses. You can only make so much power under 3,000
rpm for a given displacement.
My 'C' with three Webers, a mild cam, and dual exhaust starts to fade at
6K rpm. I'm assuming not enough compression and too much valve float but
I haven't checked it out fully.
The TR6 is out of breath at 5 grand but the poor old girl is shackled
with 7.5 to 1 compression that model year.
Bob Allen, Kansas City, 69CGT, 75TR6, 60Elva
"The President has kept all of the promises he intended to keep." --
George Stephanopolous, 1994
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