Paul:

   I have purchased the RX8 water pump block from Jeff D. (pic attached)
   but cannot find the exact radiator cap bung (o-ring sealed) that will
   fit it.

   Do you know exact supplier or part #?

   Thanks and regards,


   cozyflyr


   I can't find it either. I looked recently. Apparently the company
   went out of biz.

   Did you check speedwaymotors.com <http://speedwaymotors.com> ?


   They have a small weld on that my ace tig welder could weld but there
   would be a charge.

   They have a bolt on that might fit if turned down.


   If you find a larger one I will turn it down on my lathe no charge.


   Randy, we need to redesign this part.

   Paul Lamar

   Question The photo here with this pump is specially made for
   improving cooling efficiency? If so who is making it? I'm
   Interested.

   For the cap bung, it might be a metric one, that maybe the reason you
   don't find it. If you can give to me some measurements, then, I can
   look for it as in Europe metric is common....

   Pascal

   I believe the pressure caps are standardized through out the world.

   I think Randy in Colorado will be making those in the future. It is an adapter to the RX8
   water pump that is designed to clear the p-port slide throttle. Here are some more
   pictures and 3D's. The radiator works best on the cool side of the engine so this gets
   the coolant going in the right direction. The muffler shown in these 3D's is obsolete
   as we have come up with a much better solution.

   Here is Neal Ungars experience with the install.

   Quote.


   To those as stupid as myself,
                                                   I have the renesis motor with Jeff
   Doddridge’s  water block to replace the original  manifold.  It fitted beautifully
   but once I filled the coolant I noticed a slight leak at the bottom.  Cursing myself
   for having not fitted it properly I removed it (along with the slide throttle and
   pipes, an hours work) to find what seemed not enough clearance between the block and
   a washer.  I cleaned everything up, filed more clearance between the block and the
   surrounds, refitted the water manifold, and no leak, Eureka!!  A few days later I
   noticed a slight water leak down the front of the motor, and next day the same water
   leak at the bottom of the manifold once again.  This was with no pressure in the
   system at all, so it could not go “as is”. Once again I removed everything and again
   could not see anything wrong, clearances were not the problem. I now suspected the
   welds on the manifold block.  Much filing and probing with a needle revealed no
   possible hole in the weld.    Then it finally dawned, I am totally stupid!!

      When I had put the manifold on both times, I had been very economical with the
   gasket putty so as to not have too much squeezed out into the water channels.
   Therefore I simply applied the gasket goo to the surrounds of the manifold holes.
   Lovely job I did too.  What I forgot however was that Jeff Has put 2 internal
   mounting bolts to hold the manifold onto the engine block, again nicely done.  In my
   effort to minimise the gasket goo, I omitted to surround both bolt holes with gasket
   maker.  That allowed the coolant to seep down the bolt holes and out. It was
   impossible to pick up the source of the leak being so slow. Well I fixed it!
   There is probably so much RTV on the join now that I have probably blocked both
   manifold holes!  Actually all I did was to put a smear around the head of both
   internal cap screws so that the coolant is prevented from passing the head of the
   screw.  Why did I not pick that in the first place??  Hopefully it will prevent
   someone else from getting into a temper.

   Neil. Unger

   end quote.

   Paul Lamar


If it is leaking out bolt threads that go into the coolant system such as the p-port seal blocks, use copper or aluminum washers under the bolt threads. The bolt hole around the bolt can fill up with coolant or if going into an oil area the oil will fill it but can not make it out under the bolt head. You may have to search for a source as not all part stores stock them, but should be able to bring them in.

Dale Davies


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