Mark Steitle wrote:

Paul,
Sorry to bring this up again, but I could use a little help.  I

recently

ordered TES o-rings from Creavey and they arrived yesterday.  The

inner

and

outer oil o-rings fit perfect, but the outer coolant o-ring is too

big by

about a 1/4".  Here's a quote from a recent message on this topic

which is

where I got my measurements.

<snip>
 > 2. outer coolant oring -
 >
 > 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.
<snip>

Please explain what is meant by "diameter".  The measurement of

11.340" is

what I gave Creavey, but they took it as ID.  Now it looks like it

is

actually the o-ring centerline to centerline measurement.  Is this
right?  I didn't know enough to correct it at the time.  Hopefully

they

can

put them in their o-ring shrinker and make them smaller.  Would it

be

better to provide them with the circumference measurement instead?

If so,

what is the correct circumference?  In recent postings I've seen

35.13,

35.31, and 35.62.

Thanks,
Mark S.

Sorry about that Mark. I think that is OD and not ID.
Is the engine apart? If so check the dimensions by measuring
the grooves. My slotted end housing is up at the hangar.

11.340 diameter center line is 35.62. 1/4 inch less on
the circumference would give a centerline diameter of 11.260.

11.340 minus the .1 slot width would be the ID or about
about 11.240 inner diameter. The circumference for that
would be 35.31.

You could cut a small chunk out of the outer ring and place the cut
on the cool side or the top of the engine with a little red RTV
silicone rubber and you will be fine. Or mail the outer back
to Creavey and asks them to make a set 3/8 inch smaller in

circumference.

Also perhaps they can tell you what kind of glue they use to join the

ends.

It is best if the O-ring is slightly undersize as you can pre stretch
it on a plywood board.

35.13 is probably the right circumference number.

Creavey should know by now what the proper sizes are.

Also mic the section of the outer ring and make sure it is
.093 and not any larger.

I may be forced into stocking these O-rings if we continue to be

confused

about the proper sizes. I did not really want to go into business

again

but it looks like that is what is happening with the intake manifold

parts.

BTW Jeff Chrysler if you are reading this Mazda will sell 18,000

rotary

engine powered
RX8's next year in the US.

Paul Lamar

Jeff Chrysler wrote:

Hi Mark,

It is best if you send the o-rings back to be reworked. Silicone glue

is not

very strong without the support of a Teflon jacket to hold it

together.

The rings will be cut down and made to an 11.155" ID so that the ring

OD

will be close to or snug with the outside groove diameter of 11.340.

If you wish the rings to be snug to the groove ID they can be cut

down

to

11.110" ID but this probably is not as ideal due to pressure

traveling

outward.

Awaiting your answer.

Best regards,

Jeff Chrysler

There is your answer Mark. Jeff Chrysler of Creavey is our buddy :)

Paul Lamar

OK, I think I have a handle on this o-ring dimension/sizing problem now.

I

backed up and approached the sizing from a different direction.  What I

did

was to take a 3/32" x 36" piece of aluminum filler rod and shape it

to fit

the

outer water groove.  While holding it in the groove, I cut it off so that

the

two ends just barely touched.  Then I straightened it out and

measured the

length.  This came to 35.625", the circumference.  So, 35.625/3.1416 =

11.340,

the centerline diameter.  (This dimension was referenced in a future

posting

and is what I gave Creavey when ordering.)  The mistake came from giving
11.340 as the ID, rather than the CL.  By using 11.340 ID, the

circumference

ended up at 36", 3/8" too large.  Mystery solved.  I'll call Creavy and

see

what can be done to get them resized.

Thanks for everyone's help,
Mark S.

-Jeff Chrysler wrote:

Hello Sirs,

After further discussion with Mark and using 11.34 as a groove centerline
instead of an OD measurement as mentioned earlier, I believe a seal ID of
11.240 will do the job. It is best to describe all 3 seals in terms of ID
measurement for ease of future reference.

Also- if you wish to obtain a quick and permanent stretch, try heating the
o-ring in boiling water, with a heat gun, or in a 400F or lower oven. The
heat only needs to be applied for 10-20 seconds and from there it can be
placed on the plywood form mentioned by Paul below. The stretched o-ring
will be ready in minutes.

Happy building,

Jeff Chrysler

Thanks for the tip Jeff. It just keeps getting better and better.

Paul Lamar

Paul/Jeff,

I received the re-sized outer coolant o-rings yesterday and they fit
perfect.  The tag shows a dimension of 11.230 ID.  I think there are a few
on the list that were waiting to hear the final word on this
dimension.  So, the final dimension is .093 x 11.230 ID fits for the outer
coolant o-ring.  This dimension forces the o-ring to the outer wall of the
groove, so they could be a tiny bit smaller, but no larger.

Jeff Chrysler of Creavey Seal deserves a big attaboy for all his help and
understanding.  I can't say enough good things about him and Creavey
Seal.  Thanks Jeff for all your help.

Thanks,
Mark

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