> Hello all,
      > > This is in regard to the spark plug cool that is being discussed. I
    came
      > across this on the RX7club.com site. I pleasantly
     surprised to see the
      > amount of technical experimentation that some on this board try. I send
      > the good nuggets I come across.
      > > http://www.rx7club.com/showthread.php?t=751977
      > > > Rob Woods

    Interesting thread. So far it has been unnecessary to modify the rotor
    housings
    for rotaries used as aircraft engines. These guys may be at the 150 to
    200 HP per rotor level. Here is a trick all should do if they get a chance.
    It relives any steam pockets that may be generated around the spark plug
    area.

    Also the 3rd gen water pump and RX8 water pump are less than ideal.
    The Rx8 in particular as it is much smaller than the 2nd gen water pumps.
    Somebody is already making a better impeller for the RX8 engine but I
    have not
    tracked it down yet.

    The bottom line is you need to know what is happening and the only way
    to know that is measure the "cylinder head" temperature with
     thermal
    couples
    embedded in the roto housings.

    Paul Lamar

    Paul,
    Do you know if anyone has tried a better water pump? By that I
    mean a separate engine driven after market pump. I have found at least 2
    examples Mazarre (sic) makes a engine driven pump intended to replace a
    standard pump on a V-8 chevy. They have a performance chart for the pump
    on their site explaining that the pump requires about 4.8 HP to
    move 60gpm "with normal engine back pressure." They do sell the
    electric water pumps, but only claim they are good for drag racing, NOT
    for road use. As we have told people forever it seems. 5 HP sounds about
    right on their engine driven pump if they are moving that much water
    without cavitation. The Wisconsin powersport guys said they had tested
    the standard second gen pump and it was topped out at 53 gpm at the
    verge of cavitation. I wonder if we could move more water and solve that
    problem?
     I also like the original PowerSport efforts into center feed
    cooling. That seems like a better idea over all if you are going to run
    at those power levels. Perhaps Steve might tell us if that was ever
    followed up on?
    Bill Jepson

    Cooling with a 2nd gen pump is just not a problem for aircraft use.
    Mark Steitle with the installed thermo couples is not reporting
    any problems so far. Mazda data at 7000 RPM has the "cylinder head"
    temperature
    100 F lower than a water cooled Continental aircraft engine like the one
    that went around the world in the Voyager.

    There is an after market pump that Jim Mederer used on one of his
    1200 HP turbo 3 rotors. It is used on 800 HP sprint cars and it is made by KSE
    as I recall.

    Changing the cooling system from series to parallel As P.S. attempted and NSU
    used  would be a worth while thing to do but it is near impossible without a
    complete redesign of the engine.
     The fact of the matter is nobody, unless they
    are building a Reno racer, are going to demand much over 300 HP as they
    don't
    want to burn the fuel.

    Paul Lamar


When you read the Kenichi book it reads pro-circumferential cooling vs
axial in every way. The only reason he mentions in the book axial
cooling is good for is reducing cost of manufacturing. I am super
interested in Steve's files that were mentioned were being worked on.

Rob Woods

One thing I will say for the early NSU one rotors. The rotor housing cracked
right through the spark plug hole :) I also think the water was going the
wrong way. IMHO the cool water should go in the cool side of the engine first
and then to the hot side. The NSU did it the other way around which could
have been responsible for the cracks.

Paul Lamar