Atkins Rotary Kit - Viton Oil Control Ring O-Rings

"Brian D. Cain" wrote:


Hey fellas.  I'm assembling an engine tonight

and am using the Atkins

Rotary

Kit that comes with the corner seals/springs,

apex seals/spring, etc.

along

with their supplied (aftermarket) Viton oil

control ring o-rings.  Has

anyone had any experience building rotors

using these o-rings in the

control

ring casings?  I'm having a heck of a time

getting these things in the

control ring grooves in the rotors; it's

almost as if they're a few

thousandths too thick or something.  Any tips?

Thanks,

B

I don't recommend Viton. Teflon encapsulated

silicone is good for 100

degrees

F higher temp. The TES sizes we use slip right

in. Perhaps the Teflon

coating

helps.  http://www.creavey.com/ The cost is no

higher.


Paul Lamar

Brian, I also used Atkins Viton oil control ring

0-rings on my last engine

rebuild (before the TES were readily available)

and you are right, they are

tough to get seated in the grooves. Much harder

than the stock rings from my

experience with both.    I lubricated the "O"

rings with vasoline, placed

them in the metal ring holder and then placed the

assembly over the groove

in the rotor.  Then I got a piece of 2x6 plank and

placed it over the metal

ring and by pressing my upper body weight on the

2x6 (trying to keep the

force centered on the metal ring center point, I

could get them in.  If you

let the metal ring slant to any side, even

slightly, it tends to bunch up

(outside the groove) on the opposit side.  Not

high tech, but it worked for

me.

Ed Anderson


Spend a few bucks more Brian and put in teflon. Your
customer will appreciate
it the next time his engine overheats :) Maybe you
can sell those viton rings
to one of your rotary engine building competitors :)

Paul Lamar

 Paul,  I seem to remember you had the sizes posted

for the O rings.  I looked in my archives and couldn't
locate them.  Are they ordered direct from Creavey or
a distributor?  Thanks Jim Coffman


I am not sure who is carrying them in stock but you can get them
directly from Creavey. If people don't start stocking these I will.
In this case there is no excuse for putting in  less then the best.

http://www.creavey.com/

Paul Lamar
 
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I will outline what we are talking about.
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-rings 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 - 
    
    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-rings are stiffer than the stock O-rings. 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 leaves's too
little of a safety margin when 500 degrees F is available
in TES O-rings at the same price probably.