I question things which people take for granted. I would have been that kid who said the emperor was naked. In real life that kid would probably have been lynched, but I'll take my chances...
I believe truth inherently valuable, no matter how well intentioned the ideology it dispels may be.
I also write about random interesting things from my personal life.
(Just want tips for swapping a BW T-19 for a ZF S5? Skip to tips. Not swapping a Ford truck transmission? Skip to the end for the results.
Continue reading for all the gruesome details of my project. Hopefully
my trails and tribulations can at least provide you some
If you’ve never driven a vehicle more than a couple
decades old, you probably take overdrive for granted. You may not even
have a clear idea what that term means.That 5th or 6thgear,
with a ratio smaller than 1.0 (meaning the driveshaft is turning faster
than the engine) lowers the engine RPM speed on the highway, and can
make a huge difference in the fuel used to go the same distance at the
same speed.Gears on a car are just like gears on a bicycle; imagine
trying to ride a bike with only a small chainring and big cog, and
having to spin your legs like crazy to get anywhere at a decent speed.
Lower RPMs means less internal friction, less internal reciprocal
motion, and therefore less wasted energy.
If, like me, you
don’t care to spend the money for a new – or even remotely new-ish –
vehicle, you may have noticed that overdrive was once upon a time not
always standard equipment, or even available as an option.
Ford F-Series of trucks has been one of the most popular vehicles
world-wide for decades, and though much has changed over the years, many
of the internal design factors stayed the same from one generation to
the next. They were rather reliable, so a good many older ones are
still on the road. Those two factors mean that there is much
interchangeability of parts among different generations, and those parts
are easy to find.
The 7th generation F-series
(1980-1986) had a couple of manual transmission options, all of them 4
speed. My own 1983 diesel F-250 ¾ ton truck came with a Borg-Warner
T-19, in which the 1st gear was an extra-extra low granny
gear (6.32) which is normally not used. For all practical purposes it
is a 3-speed. No overdrive gear. In fact, even 4th gear isn’t quite direct drive, at a 1.1 drive ratio.
This means shifting into top gear at 25mph, and 2400 RPMs at 55mph.
means each piston is going up and down 40 times every single second,
which means the mass of the piston head has to stop, change direction,
move a little, stop, change direction again, 80 times every second (once
up, once down, for a full rotation). This is bad enough is a small
engine with light parts and a couple cylinders (like a motorcycle) but
in a heavy V8 diesel engine, a lot of inertia is going to waste.
a terribly big deal in 1983, when the national speed limit was still
55, but post-embargo gas prices had dropped again; the lack of stock
overdrive leaves a lot of potential for increasing highway fuel mileage.
The addition of an overdrive gear reduces engine speed from 40 cycles per second down to only 28, a 30% reduction.