snips..

I understand there is a pusher in Fla. with a 13b

that uses a combination alternator, vacuum pump off of
a  chevette diesel engine (izusu?) I haven't checked
into it yet, but it might be a good way to reduce
weight.   Comments?  Jim Coffman

That sounds like Greg Richter's Cozy according to Chrissi it failed.
At OSH he had a aircraft vacuum pump on there and that failed on
the way up.

Paul Lamar

My personal experience using aircraft vacuum pumps with the 13B was
unsatisfactory.  The small  aircraft engine vacuum pump is not designed for
operation higher than around 3600 rpm - maybe 4000 rpm for limited amount of
time.  I found that when I had the pulley sized so that it provided adequate
vacuum at low rpm (below 3000 engine rpm) the pump was soon  worn out and
graphite dust at the higher engine rpms.  When I increased the size of the
drive pulley so that the vacuum pump lived at engine speeds of 5500-6000
rpm, it did not produce adequate vacuum at low engine rpms.

I went through two aircraft vacuum pumps in six months and decided to go
with the Mazda smog pump even though it was heavier.  I have found it works
fine - just damn heavy. Perhaps someone else who has tired aircraft vacuum
pumps has a success story.  Lets hear from you.

Ed Anderson

 
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