datsun-roadsters
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New to list w/questions (a bit long)

To: datsun-roadsters <datsun-roadsters@autox.team.net>
Subject: New to list w/questions (a bit long)
From: Robert Giel <giel@earthlink.net>
Date: Sat, 18 Aug 2001 12:03:36 -0700
Hi Group!

I am very new to this list and will introduce myself and my
car in another message later on, if that is appropriate.  I
must tell you, in advance, that my introductions to the
Datsun roadster (back in 1976) were all negative, so you
might not want to hear them!

I have so many questions about my car, but let me start with
one or two.

I have a 1966 SPL311 1600 with the original engine (78K+
miles.)  I am at a major disadvantage regarding this car as
I have never seen (let alone had) the owners manual.  The
few Chiltons service manuals I have are worthless when it
comes to operating the car or what to expect from it.  I
don't know the power curves for the engine, or shift points,
or fuse values, etc. I do know, I am farther from having it
back on the road than I originally thought.

First, Should I feel unfortunate that my car has the
original R engine (with an aluminum head)?  I have been
reading on this list that all roadsters tend to overheat,
and that the thermal expansion difference between the
aluminum head and cast iron block creates all kinds of
problems when (not if) it "overheats".

Is the roadster a reliable vehicle?  I don't notice that any
of you mention "babying" your stock cars on the road.  Among
all the members on this list, it looks like somebody drives
their roadster under almost every possible driving
condition.  So, it appears nothing is preventing the
roadster from going anywhere that other cars go, including
deserts, mountains, in town, coast-to-coast, etc.

Can anyone help me understand the overheating problems
frequently mentioned on this list.  What causes them and
what, if anything, is done about them?

1. The temperature gauge reads from a low of 130 degrees
Fahrenheit up to 250 deg. F with a center reading of 190
deg. F. which implies both a linear gauge, and an
approximate operating temperature.

One of my Chiltons manuals says the R-engine uses a 176
deg. F (80 deg. C) thermostat.  That would mean a fully
opened working temperature of 191 deg. F, (88.3 deg. C.)
which matches the midpoint of the temperature gauge.  Again,
that makes sense, but it does not tell me what temperature
is "overheated" and when to expect potential permanent
damage.

Short of piston seizure or a blown head gasket, what defines
"overheating" in the ":R" engine?   When should I be
worried?  When should I pull off the road and read a good
book, or risk losing the engine?

Strangely, I also read (in the same Chiltons manual): "When
heater output is insufficient, the original equipment
thermostat may be replaced with one having a higher
temperature rating."  It never mentions how much higher but
the idea of making an engine that already tends to overheat
run even warmer to improve the passenger comfort strikes me
as "ill-advised".  Speaking for myself, I think Id look for
another jacket or even a parka if I had to.

What happens when you drive in arid zones like those found
in California or out in Arizona?  What about driving in the
mountains (my favorite kind of driving) and the extra work
of climbing, higher RPMs, and the effects of the higher
altitude when you get there?  The coolant boiling point
drops by 2 deg.F per 1000 feet increase in elevation,
(thats 20 degrees lower at 10,000 ft.) what effect, if any,
does that have on the overheating problem?

The system has a MAXimum coolant system pressure of only 6
pounds.  A 50:50 antifreeze to water mixture boils at 230
deg. F (110 deg. C.)   The boiling point raises about 3.25
deg. F for each pound per square inch (6.895 kilopascals) of
additional pressure. That means the 6 pound system would
start to boil over (and out the pressure cap overflow) at
about 250. deg. F (121 deg. C) which matches the temperature
gauges highest reading (on my car.)  Does that mean by the
time you see white steam, it is too late?

What is everybody doing to keep things cooler and avoid the
heat damage?  Bigger fans?  Bigger radiator (is there room?)
or what?  I was hoping to keep things as original as
possible on this car, but not if it means ruining it.

Finally, is there an archive of this list?  If so, please
let me know where it is, so that I dont have to ask as many
stupid questions in the future.

You folks are really wonderful, and the enthusiasm you all
display for your cars and each other is magnificent,
contagious, and inspiring. I look forward to meeting as many
of you as possible and someday being able to contribute to
the list, instead of just taking from it.

TIA

Bob Giel
--
Life is short, Start with Dessert!
        and remember:
When man ultimately meets his Maker, he will have to answer
to Him
for all of those G-d given pleasures of life, of which he
did not take full advantage.

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