sniped..

The outer slot has an area of .13 by .070 or .0091

square inches.

so the radius squared would be .0028966.... working

backwards.

The square root of that is .0538.

So the largest section diameter to fill the outer slot

would be double

that or 0.107640. That lends credence to Bill's theory

as a 3/32

section diameter ring is not .096 section diameter but

is about

0.11 section diameter or about 14 thou larger (.014).

And then you have the O-ring tolerance on top of that.

Some might be 0.005

under and some might be 0.005 over. Also any crude in

the slot will not

help matters. Make sure the slots are spotlessly

clean.

Perhaps Mazda themselves ran into Bill's contention

back around 88 and

that is why some housings cracked in this area.

Perhaps they reduced

the section dimensions on the stock O-rings slightly.

This is why we call them experimental airplanes.

Bill, do you happen to know what the coefficient of

thermal expansion

is for red silicone?

The bottm line is measure your water O-rings and make

sure they are

less than .093 +/- .005 section diameter. Particularly

the outer

one.

Paul Lamar

Hi Guys;
      I'm in full agreement with Bill's synopsis, and
can personally attest to it by identical experiences in
designing Pharmaceutical equipment.
Paul your numbers are good ones, you are close, but for
practicality this is what we practice when retrofitting
exotic seals (Rings) in general...................

I'll use the 13B existing gland design:

Brand new groove is.............130 x .070 = .0091 area
Lapped groove is................130 x .067 = .0087  "
Ideal o-ring (.094d)+ max tol (.005)...... = .0077  "

This will give you a net area of .0010 or 11.5% for
MAXIMUM thermal expansion of the seal.

So the question remaining is, What is the thermal
expansion of these composite seals?
The manufacturer NOT the Rep is supposed to have this
information thru the Lab(s) who performed the tests.

The other downside is that this type of seals vary in
diameter throughout the same seal.

                                     Butch

Yes there is some variation around the ring and they also appear to be oval
in some areas. Hang in there I will heat one up tonight.

So the one to use then is the .093 as I guessed.

Paul Lamar

Will this really give you useful info if you don't contain
the linear (circumference) growth?

Charlie England

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