Barnhart wrote:
Paul,
The dimensions for the outer TEC oring is 35.31". The inner is 28.625'.
Is this inner or outer diameter?
Barny
Here is how to double check my work. We will do a little reverse engineering.
The O-ring grooves are two half circles connected by straight sections
to form sort of an oval.
Measure across from side to side on the end housing to the inner edge
of the O-ring groves This then is the inner diameter of the half circle.
We will call this dimension SSL. For the inner O-ring this diameter is 7.5"
Outer diameter is is 9.75". These form two circles of 23.562 circumference
and 30.63 circumference. C = D X Pi (3.1416)
Measure the distance up and down to the inner edge of the O-ring grooves.
For the inner O-ring groove this dimension is 9.75 (confusingly).
Outer o-ring groove is right on 12 inches.
We will call this dimension VL for vertical length. VL-SSL gives us
the length of the straight sections. We have two straight sections
9.75- 7.5 or 2.25 inches in length for the inner o-ring slot
and 12 - 9.75 or 2.25 for the outer O-ring slot straight sections.
There fore the inner circumference is 23.562 + 2.25 + 2.25 or 28.062".
Close to the number we got below. Divide by 3.1416 to get the
equivalent diameter.
For the outer o-ring slot the circumference is 30.63 + 2.25 + 2.25 or 35.13.
Also close to the number we got below.
Now to be real precise you must repeat these measurements for
the outer O-ring slot grooves.
Or we could merely take these numbers below as the center line
numbers or OD numbers. In any event you want to err on the small side
as you are going to cut pieces of plywood the exact size
of the inside wall of both slots and slip the o-rings over
this plywood form for for a few days so they will take a set.
Other wise you will play hell getting the o-rings to lie flat
in the grooves when you assemble the engine.
****************************************************************
I will outline what we are talking about for the new people.
There are four coolant sealing O-rings per rotor housing.
Two outer and two inner.
There are also four oil sealing O-rings per rotor. Two on each side of
the rotor proper. These are located on the flanks of the rotor.
Two per side.
Teflon encapsulated silicone O-ring are the best there is for this
application. Teflon is about the most inert material you can
find and it is resistant to most known chemicals. Unfortunately
it is not rubber like and that is where the high temp silicone
rubber core comes into play.
http://www.creavey.com/
1. Inner coolant oring -
circumference = 28.625
diameter = 9.111
slot depth = 0.062
slot width = 0.141
section size = 0.103
2. outer coolant oring -
circumference = 35.62
diameter = 11.340
slot depth = 0.062
slot width = 0.110
section size = 0.093
This is critical! The proper section size is .093. Not 3/32
as a 3/32 O-ring is bigger in section size than .093.
The TES O-ring are stiffer than the stock O-ring. It is harder
to get them to lie in the groove. Even with Vaseline. When you buy
them they don't come flat. I found that using a plywood
form to pre set the slightly under size TES O-rings for a few
days works well. Here is a picture.
--------------------------------------------------------------Oil O-rings.
I checked the installation of the oil O-rings with the new
sizes I got from Creavey. They worked perfectly and were
very easy to install. You will need a little O-ring lube
and a 2 by 8 to install them. They were also easy to remove
with no signs of distortion.
One of the secrets is if you reuse the old oil scraper rings
they must be spotlessly clean inside and out. Soak them
in carb cleaner for a few days. If you use new scraper rings
this will not be a problem of course.
The second thing to watch out for is don't nick the
rotor wall between the two scraper rings when you remove them.
Very very important!!
These can be the same or just a little more than the
stock oil O-rings from Mazda.
The proper oil O-ring sizes are:
0.093" section 4.68 inch ID
0.118" section 4.33 inch ID
I can vouch for the quality of the Creavey O-rings but some
of those water TES o-rings from Mcmaster Carr I have seen
are not as good. This is not to say they won't work. They just
don't look as good around the joints as Creavey O-rings.
Viton is good only to 400 degrees F. The center of the rotor runs
as high as 500 degrees F. I think 400 degrees F leave's too
little of a safety margin when 500 degrees F is available
in TES O-rings at the same price probably.
Paul Lamar.
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