[T3] T-4

[Jonathan Stiles]

Let me clarify that statement.

Less (or thinner air) does indeed mean less cooling. However, I was
specifically referring to the cooling through the fan to the heads and oil
cooler. It is more difficult to bake bread up here and boil water, the same
principle works in reverse.

Even water cooled cars have problems up here. There is LESS AIR running
through their radiators, so they overheat. You should see the pull-outs at
every pass in the summer. They are packed with steaming SUV's. :)

Actually carburetor motors that run at higher altitudes run RICH and cooler
but have much less power. The motor struggles harder so the load on the
engine is increased. This load translates into heat which in turn
overwhelms the cooling system, since there is less air to pass through the
system.

A Type 4 motor, properly tuned for altitude will not work nearly as hard as
one running rich and gasping for air. You want to run as close to stoich as
possible to keep everything in range.

I suppose you wouldn't see the effects as greatly on a lighter T3 or T1.
But with a heavily loaded Campmobile, bad things happen very quickly
(especially the much maligned automatic models, *shudder*). The Front Range
of Colorado is literally littered with buses from California, Oregon,
Washington, Texas and the 4 corners. Folks pass over the Rockies in the
summer at high-noon and suck a valve. Not having the money to repair their
T4, they turn the bus over to parts yards like BustedBus dot com. There is
a reason he is located in Metro Denver. My recommendation has always been
to people, unless you KNOW your bus is in excellent shape and in excellent
tune (based off of tuning on a gas analyzer), travel over the passes at
night.

My little family runs our '78 Campmobile at full load with 4 souls and
sometimes one dog all over the Colorado Rockies. It sweats but never
complains or overheats. But I am pretty meticulous about keeping the Fuel
Injection in tune, keeping the engine tightly sealed and watching my oil
consumption. My '68 Double Cab works like a modern truck. It runs dual 36mm
Dellortos on a 1776 T1 motor. After 40K miles of serious flogging, no
overheating problems either. Its all about the initial setup and tune.

I'm just now getting into the T3 world ('70 Squareback waiting on my
storage slab) and I am really looking forward to a different air-cooled
experience. The motor's machining is done and is waiting for assembly.
1776, fully balanced from the pressure plate to the fan with stock FI
(except the fuel pressure slightly increased).

I hope this guy gets his bus figured out, but with those nearly 40 year old
PDSIT carbs that were bad when they were new, it is going to be difficult.

Best,

Jon Stiles


On Fri, Dec 9, 2011 at 4:55 PM, <ftalker at gmail.com> wrote:

> Hi there
> > Less air means less cooling.
> This may seem to be true, but altitude also means that CR is contiguously
> lower which means, (all tuning being accurate), that the engine runs cooler.
> Best regards,
> FE Meek
> Sent from my iPhone
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