Time to re think the water pumps mods we did back in 2007.
It was necessary for the KIS cruiser and some Lancairs as
the top of cowling was right down on the engine.

Most rads are now being mounted vertically on the spark plug
side of the engine with more room above the engine.
Unfortunately the water pumps output hot water on the exhaust
side of the engine.

Here are the old mods.

The low profile water pump mods.

Step one. cut off top of pump.

Step two. This is what it looks like after the top is cut off.

The lower passages is the bypass return which we will no longer
need. It will be milled out.

Step three. Here it is in the mill.

Step 4: Milled out

Step 5: Overall scheme.

Step 6: with partition but not welded yet.


 Step 7: With straight neck. No longer recommended unless NOT
using rad under engine.

Step 8: Best to weld on 160 degree bend for use with rad
under engine. Use .125 wall 1-1/2 inch tubing minimum for strength.
Here is a 3D.

Step 9: None of this will be necessary with the RX8 engine as the pump
is low profile, built into the front cover  and there is no bypass passage.

Also I might add, unlike the 2nd and third gen pumps, there is no water
passage restriction on the outlet side of the block on the RX8 engine.
Just a nice big hole.


Both the 13B and the RX8 pumps will accept a 90 degree bend
welded on the top pointing to the spark plug side for the rads over there.
The exhaust side outlets can be blocked with a welded on plate.

Good idea for you Tango builders. It is cheap mod I can do for
about $75 labor and shipping. Plus the cost of the 1.5 inch OD 90
degree bend.

I will modify the pump on my RV4 to simplify the plumbing.

Paul Lamar