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Ernest Christley wrote:

I've got an experimental engine, with an experimental cooling setup. Do
know for guaranteed that the cooling will be sufficient, so I'll be
keeping a close eye on the water and oil temperatures. But the coatings
will cause more heat to be dumped into both.
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I don't understand the above. TBC's applied to the combustion chamber,
piston crown, valve heads and the exhaust port, tend to reduce the
waste heat that appears in the cooling system while increasing the
waste heat that appears in the exhaust. This is based on comments from
people running turbos who take a particular interest in the exhaust gas
temps and how much energy they can recover from that source.

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How would a typical
homebuilder know the difference between elevated temps due to a more
efficient heat transfer and inadequate cooling?

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I don't know.

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Then there is the issue of what the redline temperatures are set for.
In the rotary, it is for the main bearings. Would the barriers and
dispersants change the thermal characteristics in such a way that the
temps readings taking in the normal places look adequate, but in reality
critical parts are being fried?

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I don't know.

My only direct, personal experience with coatings has been with air
cooled engines. I began experimenting with Tech-Line's coatings in
2001, using a 6cid lawn-mower engine as my test bed. Most of my time
was spent learning how to apply the stuff. Once I was reasonably sure
of I was applying the coatings correctly I began trying to quantify the
benefit, if any. It took about a year to figure out affordable methods
of measuring temperature & torque.

About the best I can say is that I saw some improvement, and that the
coatings proved to be durable. On that basis I went ahead and
assembled a stock VW engine from used (but coated) parts, intending to
run it for several hundred hours, tearing it down periodically.
Unfortunately, when gasoline went above $2/gal I could no longer afford
the luxury of my experiments. At that time the stock engine had
accumulated about 75 hrs and was a perfect null, experimentally, in
that it showed absolutely no signs of wear or deterioration of the
coating(s).

My experiments with TLTD (the thermal disbursant) involved heating
coated and uncoated coupons of cast aluminum and mild steel with the
element from a 100W. soldering iron and plotting their temperature
(convection and conduction) against time.

My goal was to explore possible solutions to well known problems seen
in high-out engines based on VW after-market components. Despite being
unable to complete the full series of tests on the stock engine, I have
sufficient confidence in the coatings to apply them to several other
engines, all of higher output, which I'm in the process of doing. But
with gas now over $3 and still rising there's a good chance I won't be
able to afford running-in the completed engines, let alone fly behind
them.

I resorted to experiments because Tech-Line could not offer any advice
regarding the use of their coatings on air cooled engines. They did
refer me to a couple of coating shops but their claims were a bit
extravagant and they were unwilling to put me in touch with any of
their air cooled customers. Since you are dealing with a water-cooled
engine, perhaps you'll have better luck.

-R.S.Hoover

Interestingly, this series of postings came alone currently with a friend
attempting to introduce me to a network marketed product which claims to
gradually coat the piston tops, spark plugs, valves, and "fire deck" (which
is their name for the surface of the head inside the combustion chamber) of
an engine with a "sacrificial catalyst". My two semesters of college
chemistry caused me to dismiss that description is self contradictory (i.e.
Bunk!); however, I am willing to accept a description such as "continuously
deposited ablative thermal barrier coating".

What makes all of that interesting (to me) is that the manufacturer's claim
equates to 9% to 10% improvement in torque with the same fuel burn, or an
approximate 10% inprovement in fuel consumption. If their theory is
correct, and my recollection of Boyle's Gas Law and of the Karnot Cycle
suggests that it is, then the much more durable Tech-Line Thermal Barrier
coating should have a similar result.

I am quite curious whether your results to date pointed in the same
direction.

Peter Dohm

P.S.: There "aint no free lunch" so I would presume that the overall heat
retained in the engine would be a little less for a given output; but that a
little more heat might be conducted back to the exhaust port area of the
head from the exhaust tubing. I have no idea how much of a problem that
might be on some engines.