Ok, went out to airport and checked my water pump.  It has four bolts
retaining the pulley, however, there are holes for 8 bolts.  I am

pretty

certain it came with 4 bolts and the pump is an 86 model.  I do have

two

observations which may (or may not) have bearing on the failure mode.

My

belts run on both sides of the pully.  One wraps around the main

pulley,

around the water pump pulley and then down to the airpump pulley.  The

other

one wraps around the main pulley, around the opposite side of the

water

pump

pulley and then around the alternator.  Don't know if this presents

more

of

a balanced load on the pulley or not, but would think so.

Also, my main pulley is an underdrive pulley by 20% and I rarely run

the

engine higher than 6000 rpm (cruise around 5300-5700), so those

factors

MAY

reduce the stress on the stock water pump pulley.  Did not do a dry

crack

check, will do that later.

Ed Anderson

Hi Ed
How about installing 4 more bolts. Just for me! Tracy has 8.
I am going to check pulley runout with a dial gauge this weekend.
My main pulley is also 20% underdrive. I cruise at WOT leaned off the scale
at 6200rpm. 500kn miles with 1 hour reserve.  Eaten into reserve twice now.

Ian, (8 bolt Beadle) Australia.

Ian I would like to hear the story of how you got a new pulley 
while stuck in the outback, got the airplane fixed and flew it home :)
What town was it in? I would love to see some pictures.
Here are a few I took when I was flying around over there 
just to give the new people a feel for the place.
Here too is a picture of Ian and his rotary powered RV6.

Paul Lamar
 
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