Mailing List Message #54856
From: Al Gietzen <>
Subject: RE: [FlyRotary] Re: water pump housing
Date: Wed, 4 May 2011 10:49:29 -0800
To: 'Rotary motors in aircraft' <>

Tom; et al,


The 12A front cover fits the 20B without modification; does have a bit different bolt pattern for the pan.  It allows some different pump choices and gives a lower profile than the stock cover.  I then went to the Mazda parts department and looked through parts lists at the exit necks (thermostat housing cover) for various models, and picked one with low profile.  I don’t know the model years of either the pump or the exit neck.


Don’t know that this meets your requirements – photos of my setup attached.




P.S. Also note that the timing point on the 12A cover is not consistent with marks on 20B pulley.


-----Original Message-----
From: Rotary motors in aircraft [] On Behalf Of Mark Steitle
Sent: Wednesday, May 04, 2011 8:43 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: water pump housing




You are correct that the Renesis front cover can be made to fit on a 13B/20B, but the pan bolts are a different pattern which will require modification to your oil pan.  Also, the 20B front counterweight is larger than the Renesis causing the cover to interfere with the 20B's front counterweight.  Material will need to be milled out for the cover to fit, but in doing that, you will end up cutting through the cover which will require tig welding the holes.  Finally, the RX-8 front cover is heavier than the 13B/20B front cover with Renesis water pump.  Personally, I don't see an advantage to using the Renesis front cover.   

Mark S.
(Been there, done that.)


On Wed, May 4, 2011 at 11:11 AM, Kelly Troyer <> wrote:



    One additional thing comes to my mind...........I do not have a RX8 Renesis front side

housing (cast iron) but from all of my research of photos I am fairly confident that the

RX8 front housing (aluminum) will bolt directly to the 93-95 13BREW and Cosmo 13B

and 20B with some minor mods (to possibly clear bolt heads on the 20B front side hsg)

and the drilling and threading of 1 to 3 existing bosses for 8 mm x 1.25 studs or bolts..



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