Al Gietzen wrote:

I'm using the stock primary fuel rail and injectors on my

20B,

and a TWM

throttle body with it's secondary fuel rail.  The stock

primary

rail has

a

pulse dampener at one end where I intend to weld on a -6

fitting

for a

series connection from the secondary rail.  It seems easiest

to

just cut

it

off and put on the fitting.  Is there a good reason to keep

the

dampener

on

there?

Thanks.
Al Gietzen

Al, I have a friend in CA who has his own shop repairing Mazda

Rotary

engines for over 20 years.  He says to ditch the fuel rail pulse

dampener as

it is only a matter of time (not if) before the pulser develops

a

fuel leak

due to fatiguing of the dampener disk.  FWIW

Ed Anderson

Snip

       Paul and All,
           I believe we have a major safty problem here. We need to

put

an "AD" out

 to all that plan on flying the 13B or 20B using the stock primary

fuel

rail that

 they should remove the pulse dampener.
           Just a week ago a friend asked me to look at a fuel leak

on a

87 RX-7. It

 was leaking profusely when the fuel pump was activated. To make a

long

story short

 it was the pulse dampener. Since I do not work on RX-7's for a

living I

thought it

 was an isolated incident. Ed's post brought to light that we who

want

to fly these

 things have a inflight fire fed by 40 psi of fuel just waiting to

happen!

          Kelly Troyer

It is true that the pulse dampener is a well known failure point (fuel

leak)

in the Mazda rotary.  Still, Mazda put it there for a reason so I'm

still

using mine.  The purpose is to dampen out fuel pressure variations

caused by

two sources:  1. fuel pump pulsations and 2.  injectors switching on &

off.

Those of you who remove the dampeners could help us all by reporting on

any

anomolies you may notice.  The ones I would expect are EGT variations
between the two rotors.  The variation would likely change depending on
engine rpm.  If you get any unexplained EGT imbalances, let us all know.
EGTs should match within 50 degrees or less.

Tracy Crook
tcrook@rotaryaviation.com
www.rotaryaviation.com

Tracy, I had major EGT variations (as we had discussed previously) while
flying - sometimes as much as 300F that ocurred intermittently and for
durations of 30 seconds to several minutes.  I could never pin point what
could be causing it (although it was limited to the rear/flywheel end rotor)
as it never occured on the ground so that I could check it out. Well, after
probably 30 hours of flying with this condition showing up from time to
time, it finally happended on the ground and turned out to be a fuel
injector sticking open at various times.  At cruise settings the extra fuel
to one rotor did not seem to do much except reduce the rpm vary slightly,
increase the fuel flow indication by 0.2 gph and the drop the rear EGT by
300F.

Replaced the fuel injector and have no such occurrences.  However, I notice
that my "Fuel FLow Meter" continously varies by 0.2 GPH back and forth
around an average number.  I suspect I have turbulence in my manifold
someplace as I assume it would only be the Manifold pressure the EC2 is
sensing that would cause that kind of variation rather than fuel pressure
fluctuation.  Of course, it could be an artifact of the fuel flow meter and
I'm not actually having that kind of change in injection timing.

Thats all I have to report

Ed Anderson

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