The series 4 had cooling problems as the water traveled through the
engine too fast, there is a vast difference in output hp and the

series

6

of mine runs cool even in high temps over high speed hours of running.
The aluminum water pumps on series 4 and 5 are an after market supply
and cost around $90 Aus.
Regards Don

Sure is a bargain on those Aluminum aftermarket pumps.  Only US source I

saw

wanted $500.00 for an aluminum pump cartridge.  I wouldn't mind having one
of those series 4 jobs.  Anyone else interested?

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

I'll bring one back  in my check on :-)

Paul Lamar

    Paul,
     I presume series 4 is 86-88 & series 5 is 89-91.

I think you are right.

 The main difference I
 observe between them is larger shaft on series 5. try to find a reliable
 supplier while down under. I am with Tracy, I want one also. Maybe we can
 get up a group order before your trip.

    Kelly Troyer

I'll see what I can do but my wife says I am on vacation!

Paul Lamar

      Paul as a point of interest my 93+ Cosmo 13B turbo has the same pump
 as the 89-91 13B. The Cosmo uses ribbed belt(standard rotation) instead
 of V-belt. 20B Cosmo owners speak up and compare their pumps to 13B pump
 and note differences for the group.

      Kelly Troyer

I think we are talking about the same kind of belt. Ribbed belt = poly V belt.
Yes you are right on the rotation for some 93 and later engines. Does your 
pump say Kubuto on it? As I recall those engines with the Kubuto pump run 
the pump backwards.
 
Paul Lamar

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