> There has been a discussion on the nopistons forum about TES
o-rings. The installation
>
> method that some of the guys used may questionable, but I
thought
it may be good to discuss here.
>
> http://www.nopistons.com/forums/index.php?showtopic=67208
< http://www.nopistons.com/forums/index.php?showtopic=67208>
>
> Post 35 on the second page has some pictures of the o-rings
after
a tear down.
>
> What are your thoughts Paul?
>
> Heath
>
> I am not allowed to access that forum :) Obviously they >> don't
want the truth :)
> If you want to cut and paste the message to an email and
send it
to me I will comment.
>
> If they are too big they WILL cause BIG problems. People >> have
to
> buy the exact right size directly from Creavey. What they >> sell
elsewhere
> may not be the right size. For an example a 3/32" dia. O >> ring
will not cut it and
> will cause problems as it is not .096" in diameter as one >> would
think.
> It is .108" inches in diameter. TOO BIG!!!!!!!!!!!!!!!
>
> Here is a pdf file on the subject.
>
> Paul Lamar ...No rotor no motor.
You have to register and sign in to view the post. I PDF'd the
post
in case you
don't want to register. The post is concerning TES o-rings >> Tracy
sells, and I
assume he followed your guidelines when putting the package
together. This may
very well be a case of operator error as far as proper
installation
as some people
that responded to the post had good luck and others did >> not. One
person did reference
your website and write up on TES o-ring selection.
Heath Holbrook
I don't register and I don't require people to register here. I
ask
people here
to sign their name. Sometimes they don't but I know who they >> are.
I don't know what register is about but I think they are just
gathering information
for marketing purposes.
No comment on the pdf as I don't know who "B" is :) He could be
working for
Mazda Parts Department :) The thing about the Internet is >> there
are
shills lurking
about. A shill is a person that is paid to discredit certain
products and services
and sell other products or services instead. I have certain >> ways
of
detecting shills
with about 12 years experience on BBS's and the Internet. If >> I
told
you about the
ways I would have to kill you :)
I will say "B" is not providing the required details on >>
diagnostics
of his alleged overheating.
For example; Does the water jacket hold pressure? Is there a
coolant
loss?
As far as I can tell "B" stands for Bull shiter :) Also the >>
O-rings
he is talking
about did not come from Creavey and I have no idea what size
they are.
>>
-------------------------------------------------------------------------
---
-
I take it back about "B" and I apologize to him. I checked >> back
on
the old messages
and he was on the list for awhile. His name (I think) is >> Brian D.
Cain. He seems reasonable.
What he apparently refuses to do is store the TES O-rings on a
board
for a few days
to flatten them before using. This is IMHO absolutely >> essential.
Also people complaining
about over heating with these TES O-rings are not >> pressurizing
the
cooling system to check
for internal leaks. All real mechanics know how to do that. >> Over
heating can be caused by a
myriad of factors of course.
The TES O-ring splitting is unheard of using Creavey O-rings.
Somebody somewhere
has a quality control problem. It could be Creavey as I >> don't
know
where these
TES O-rings were purchased. Looking at the McMaster TES >> O-rings
one
can tell they
obviously are made by some one other than Creavey. Perhaps >> made
in
China.
Mic those O-rings when you get them for being the proper size.
Paul Lamar ...No rotor no motor.
Paul,
I'm wondering if the engines that had problems also had lapped side
housings. It looked to me that at least one of the TES o-rings were
pinched and later failed. If you grind/lap the side housings a few
thousandths, wouldn't you need to change to smaller cross-section
o-rings?
BTW, my TES o-rings were easy to install, once I got the correct
lengths. No leaks either, and I'm running a 25# pressure cap. I >>
used
Hylomar to hold them in place. The guys on the No Pistons list talk
about using Vaseline. Maybe that's why they're having trouble? >>
Just a
guess...
Mark St.
A few thou should not make a difference. 10 thou or more is another
matter.
Vaseline is the Mazda recommended stuff. The main seal is metal >>
to metal
as Hylomar won't take that heat directly. I know people use it and
get away with it but I would not recommend it for this application.
The O-rings are there to keep the coolant in the water jacket and
not seal the combustion gases. However even the stock square seals
have a
layer of Teflon on one side. Mazda calls it white paint in the shop
manuals
but it is Teflon which becomes obvious when they are removed from a
used engine.
The Teflon goes on the OUTSIDE of the seal because of the exhaust >>
gases
recirculated in the rotor and end housings are very close to the
O-rings... I think.
No oil is allowed on the silcone rubber as silcone is attacked by
hydro carbons. That is another reason TES O-rings are better.
Paul Lamar ...No rotor no motor.
Reminder.. Please sign your posts..
Thanks,
Matt-
Hi guys,
I'm still a member of this newsletter. Have been since 1998. Since
I'm
finally responding to the few posts, I'd like to have a chance to
defend
myself against a couple of things that were said as well as comment
about
the original thread I created on NoPistons.com.
I'm not a shill. Never heard the term before, but based on Paul's
explanation, it doesn't fit me in the slightest. I'm a personal
business
owner and have been for 5 years. I have no particular relationship
with any other business that would otherwise preclude me being
someone who'd commit some sort of product espionage or false
advertisement, etc. Quite frankly, that's ridiculous. I'm a guy
who builds rotary engines for the street car enthusiast as well as a
guy who travels the nation tuning these things typically for power
production. My interests therefore involve the use of good, high
quality products. "I don't build junk" is a phrase I use with most
people who've never met me who are also considering doing business
with me. My name is too important to me to be put on stuff that I've
built that'll fall apart in short order. I take my work very
seriously.
This
is what I live to do.
Which leads me to the reasons why I posted what I did about the
Rotary Aviation o-ring set. There's no malice intended here. I don't
have any personal beef against Laura or Tracy Crook; on the contrary,
they seem like real nice people. There's also no promotion of another
product by way of proxy here. It's a straight-up, customer-oriented
review of their o-ring product. Up until fall of last year, I was a
very
consistent user of their o-ring kit and had been since late '03. I'd
used
them in almost every engine I'd built in that period of time. In my
opinion,
based on the steady use of their product for that nearly 3-year
period of
time,
I think it makes me a pretty good customer and certainly someone
who's
worthy to give his input. Their response to my complaint wasn't >
reasonable,
atleast whomever the person was who responded to the individual on
that
forum that forwarded them the thread wasn't. I would think the proper
one would be somewhere in the neighbourhood of wanting to in the
least
take a look at the issue and see if it has merit, let alone take >
measures to
fix the problem so it doesn't occur again.
Paul, what kind of details am I leaving out? I thought I'd described
this failure and my theories behind why quite well. I feel as if the
array of pictures I've posted speak for themselves. Is there
something
else that you'd like to know about that might help form a better
opinion?
You also mentioned that I should be storing (forming) these o-rings
around a wooden template as per pictured on your website.
http://www.rotaryeng.net/O-ring-size2.html Like I've already
mentioned,
why in the world should I? Do you see any information on their
website
that demands any such thing? >
http://www.rotaryaviation.com/o-ring_kits.htm
I sure don't. Let's look at a couple of other factors: One, this
o-ring
kit is
made to be easily purchased. They've got Paypal links on there.
Secondly, it's evident that these kits are targetted for not just the
aircraft
guys but also car guys like myself. Therefore, the target market is
much
more broad and encompassing. If there's supposed to be some sort of
instruction when it comes to the "proper" installation of these
o-rings,
given the target market, does it seem therefore reasonable that
they're
at fault for not providing that said instruction? They're selling the
product;
it's their responsibility to serve their market rightly. How in the >
world
can
a guy like me or anyone else for that matter be blamed for their
o-rings
going bad, all the while ignoring the clear evidence of the teflon
jacketting
splitting long-ways for no apparent reason? I'm not at fault for not
building
some wooden template. I can't read minds, and when I buy a product
that's clearly advertised for the engine I'm using, that lacks *any*
other
(allegedly) critical information regarding its installation and use,
why
should I
be held responsible? That's silly.
I don't know who the manufacturer of these o-rings is and quite
frankly
I don't care. I'm an engine builder and a customer and I demand
satisfaction from not only what I buy for myself but also
what I buy and therefore build for others that has my name on it. I'm
still
very upset from the fact that I've had to shell out money of my own
to
repair several engines now (the count is up to 7) because of the >
glaringly
obvious defect of this product, whether it be a material or
application
error.
Having to tear a motor apart because of an o-ring that splits along
the
edge,
having nothing to do with installation, is just absurd. I'm also
still > upset
at RA's very arrogant and condescending response to my complaint
about
their product, implying that since I'm not a "commercial builder", or
however they exactly characterised it, and since they've only seen >
some ridiculous
"0.001% failure rate" that my complaint (implicitly) therefore
doesn't
matter. What hogwash.
Someone mentioned that I seem reasonable. I like to think I am as
I believe the strength of an argument rests solely on its merits.
Here's
a (hopefully) reasonable question, I think: Given the vastly higher
standard of quality and workmanship that's demanded in aircraft use
vs. that of automotive, wouldn't it be reasonable to suggest that not
only these o-rings be applied (or manufactured, whichever it is) >
correctly,
but also be sold and delivered in a way that's replete with this said
"instruction" of forming them for the factory o-ring land and
anything
else for that matter?? You guys are using these in airplanes, for
crying
out loud. Have an odd overheating symptom that produces an >
out-of-nowhere,
symptomatically stratospheric water temp or rock-hard radiator hoses
for
no apparent reason?
Good luck pulling over to check why while at 10,000ft.
B
_________________________________________________________________________
__
Brian D. Cain -/- Dallas/Ft. Worth, TX -/- bdc@bdcmotorsports.com
BDC Motorsports | Performance Rotary Engines, Specialized Porting,
EFI
System Installation & Tuning
http://www.bdcmotorsports.com -/- http://bdc.cyberosity.com
The only missing information I need to know about Brian is the exact
section diameter of the O-rings shipped to you. I would like to know
who supplied them to Tracy so we can avoid that source but so far
he is not fourth coming with that info. I have in the past
recommended
only Creavey as we had some bad results with McMaster Carr.
Again I am sorry about the bad things I said about you after reading
the no pistons post.
Paul Lamar ...No rotor no motor.
Paul,
There are two methods in common use for applying the Teflon coating to
a
cylindrical substrate. An older method involves a spiral or helical
wrap of Teflon ribbon. When the wrap is complete, the adjoining edges
of ribbon are fused someway to form a continuous covering. If one
examines a variety of Teflon insulated wire samples some will clearly
show this helical wrap pattern in the insulation. A newer method that
is more difficult and more costly involves extruding the Teflon onto
the
surface of the substrate to form a continuous and seamless coating.
The cracks that are apparent in these two photos that Brian posted seem
to indicate a helical pattern. Rotary Aviation could have received a
batch of defective O-ring material or received the wrong material
(wrapped instead of extruded). It may be worthwhile to destructively
test some samples of TES O-ring material to see if cracks similar to
those shown in Brian's photos can be produced.
Aubrey Thompson
In the case of Creavey I think the Teflon is extruded first and the
silicone
is
injected in the liquid state. This is probably done in a mold so the
pressure
required to inject the silicone does not expand the Teflon. I could be
wrong.
On the other hand I think air may be required to convert liquid
silicone to
the rubber state. That is why they call it RTV or Room Temperature
Vulcanizing
I think.
These picture you attached look like very poor workmanship was used to
make
these O-rings.
I have never seen a TES O-ring that looked anywhere near that bad
including
the
ones we bought from McMaster car. Creavey quality control on the other
hand
is
excellent. It is on the cool side of the engine as well. The O-rings
look to
be the proper cross section size however. Perhaps they were well under
diameter
and somebody stretched them to fit. If you try to do this one section
of
the Teflon will yield while the rest of it remains the same. Perhaps
this
is what happened some where along the line.
I have always thought of rubber, and that includes silicone, as being
"compressible".
What has been brought home to me after reading some bad O-ring
experiences
years ago
is; rubber is no more "compressible" than hydraulic fluid. Furthermore
silicone expands
greatly when heated. If it is contained in a closed chamber without
expansion room such as an
O-ring slot it will generate tremendous forces. Enough to crack cast
iron
and bend steel.
Therefore it is extremely important to have the right section diameter
when
installing
O-rings.
If the O-ring is oversize for the slot the process of tightening down
the
tension
bolts will cause the hydraulic force of the rubber to break the cast
iron
end housings.
The problem will compound itself when the engine is warmed up to
operating
temperature
as the silicone expands.
The last picture is what happens when the TES O-ring is too large in
section
diameter for the size of the slot. You can see that the Teflon was cold
extruded
into the space between housings prior to final torquing of the tension
bolts.
The date on this photo is March 2003.
Paul Lamar ...No rotor no motor.
Now I'm getting very concerned! I've installed these o rings in my 20B
and
now I'm wondering if I should tear it down and replace them with
factory o
rings. I'm getting very close to my engine installation and would
rather do
it now than after the installation. Do we know of success stories with
these
o rings? Or should I just change them...
Bob Mears
Supermarine Spitfire
Bob, If the parts were fairly fresh, (didn't require machining), you
should be fine. You will be able to get the engine plenty hot on the
ground to check anyway.
Paul, To Revisit the slot depth idea. Parker (world o-ring leader?)
specs the slot depth + or - .002 inches. My guess would be that if the
plates have been surfaced at all the slot depth is out of spec. I
understand about nitriding, I've used the service frequently in the
past. Crankshafts usually had as little as .0005 inches thick nitride.
Any grind job would take that off! We should ask B if the failures he
had were on ground side plates. The TES-o-ring is a harder durometer
which usually means less flexible. I'm thinking slot depth and diameter
would be more critical.
Bill Jepson
Creavey calls out plus or minis .005 on the section diameter.
You can get the TES O-rings with a hollow core which reduces the durometer
in effect. I don't see the need for it yet but if I were using them
in an extremely low pressure situation like the LP mechanical fuel injection
I would consider that option.
Paul Lamar
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