I would order the parts separately. Install Teflon Encapsulted o-rings
from Creavy.
You will need new water O-rings so get the Creavey TES versions
as they are better than Mazda and reusable. Probably cheaper too. Same
goes for the oil O-rings on the sides of the rotors.
http://www.creavey.com/
I will outline what we are talking about.
There are four coolant sealing O-rings per rotor housing.
Two outer and two inner. Two on one side two on the other.
If the slots are in the end housings there are two per end housing
surface.
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 = 0.098
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
Paul Lamar
The Rotary Engine NewsLetter. Powered by Linux.
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Copyright 1998-2009 All world wide rights reserved.
Paul-
I started my teardown last night after finally getting a second copy of
the Turrentine dvd. I'm one step away from cracking the case & seeing
what is what. One thing that wasn't in the Turrentine video was how to
remove the counterbalance -- in his video there is a flywheel which I
believe has an integrated counterbalance, vs the stand-alone one on my
engine.
In any case - I'm guessing I'll need to use a puller to get it off. I
tried to give it a wiggle on my way out the door this morning & it
didn't act like it was going to come willingly.
Also - will I be able to reuse any of the seals (since the engine has
what -- a grand total of 10 hrs on it?) or am I replace everything along
the way.
Finally - you alluded in an earlier email to new apex seals... Why?
Again - the ones in there are Tracy's and only have 10 hrs.
Mark Supinski
You must be very careful to record the exact position of all the
rotor seals. They must go back in the slot they came from. Mark the
rotors... rotor one... rotor two. Then mark the apex seal slots on
each rotor ...slot one... slot two... slot three.
Use marked paper cups to separate
all the seal sections so you can get everything back in the
exact same place it came from. Take as much time as it takes to
do this. This is very very important as seals are adjusted to fit.
--------------------------------
A puller will help getting the counter weight off but a tap
by a hammer on the outer edge may be all that you need.
This sets up vibrations in the counter weight that may
free it from the taper.
Hopefully you have the front nut off already.
-------------------------------------------
You will need new water O-rings so get the Creavey TES versions
as they are better than Mazda and reusable. Probably cheaper too. Same
goes for the oil O-rings on the sides of the rotors.
http://www.creavey.com/
I will outline what we are talking about.
There are four coolant sealing O-rings per rotor housing.
Two outer and two inner. Two on one side two on the other.
If the slots are in the end housings there are two per end housing
surface.
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 = 0.098
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.
************************************************************
How-to-measure.txt
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 have always thought of rubber, and that includes silicone, as being
"compressible". What has been brought home to me after reading Tom's
experience is; rubber is no more "compressible" than hydraulic fluid.
Bill hit the nail on the head I think. The O-ring was oversize for the
slot and in the process of tightening down the tension bolts the hydraulic
force of the rubber broke the housing.
Bottom line is measure the O-rings you get and don't use
anything larger than .093" diameter in the outer slot. As Tracy points
out don't use RTV to hold the rings in place as it could harden
and add to your problems. Buy the O-rings slightly under size on the big
diameter (no more than 5% undersize) and stretch them on a plywood form for
a
few days before installing them. They will then lie in the slot perfectly
as
we discovered with Perry's installation. Don't try to stretch the ring
by hand or by another method as you could permanently neck them down.
Be careful when buying standard 3/32 O-rings sizes as they may be larger
in section diameter than .096. They could be as large as .115 or so which
is way too large for the outer slot. Apparently standard 3/32 rings
work OK in the larger inner slot.
Best to buy the O-rings directly from Creavey the manufacturer.
In most case the prices are lower than what Mazda charges for lower
temp stock O-rings.
Here is a part of their catalog again showing the small increments in
section diameter that they sell.
http://www.creavey.com/
Take your time and double check your work.
Paul Lamar ...No rotor no motor.
Paul,
I'm reluctant to bring this up again, but I am ready to order TES o-rings
from Creavey and found a possible discrepancy in the measurements. Below is
a message from Jeff Chrysler (8/2005) stating the different o-ring sizes...
they dont' agree with what's listed above. He states all but one diameter
as .093" where the numbers above show one at .098".
<snip
Hello,
The dimensions and pricing for the 4 sizes are as follows:
.093 x 11.190 ID $8.33 each 3 min
.093 x 8.950 ID $6.60 each 4 min
.093 x 4.680 ID $4.59 each 6 min
.118 x 4.330 ID $4.47 each 6 min
Thank you,
Jeff Chrysler
<snip
I see where the inner coolant slot width is .031" larger than the outer, so
it would make sense to use an o-ring with a larger cross-section. So, I'm
assuming that Jeff made a typo and meant to type ".098 x 8.950". I also
just noticed that he is quoting a dia of 8.950" where you show 9.111". Can
you clarify?
I'll look tonight to see if I can find my 6 year old invoice to see what I
ordered the first time.
Thanks,
Mark
.098 - .093 is .005. You will have a tough time measuring that on a rubber O-ring :)
I just measured the center housing outer slot width at .13 wide and .070 deep.
The inner slot width is .170 and the depth is .070 the same. The depth is what counts
the most.
I think the .093 will work fine. The o-ring might have enough room to move from side to
side on the inner slot. Better to be too small and leak rather than too big and crack
the housing.
Sometimes you get a housing that has been lapped with a shallower slot.
===================================================================================
Inner slot ID calc again.
The inner slot side to side is 7.5 inner walls.
top to bottom is 9.75
so 7.5 times pi is 23.562 inches circum ference
9.75 - 7.5 is 2.25 each stright lenght or 4.5
so total circumferece is then 23.562 + 4.5 = 28.062
28.062 / 3.1416 = 8.93 ID <<<<<check
=========================================================
Outer slot ID calc again
12.05 inchs by 9.75
9.75 x 3.1416 = 30.63
12.05 - 9.75 = 2.3 x 2 = 4.6
30.63 + 4.6 = 35.23 circumference.
divided by 3.1416 = 11.21 ID <<<<<< check
Close enough
Paul Lamar
--
The Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site.
http://www.rotaryeng.net
Youtube key word UTUBPLEASE
Copyright 1998-2009 All world wide rights reserved.