Ed Wrote:


 

    Hi Dave,
         Thanks for the reports, I don't feel so lonesome {:>).           Regarding SAG - my analysis is that susceptibility to SAG is
    proportional to combustion chamber pressure at ignition and the
    condition of the plugs.  The more pressure - the harder it is for
    the spark to jump the gap, so if your plugs are getting coated
    with lead/carbon, I would expect to see more SAG with More
    manifold pressure.  Tracy and I have found the same thing
    (unturboed).  At high power setting (higher manifold pressure) the
    problem becomes more aggravated.  Reducing throttle setting helped
    - but, replacing (perhaps cleaning the spark plug center ceramic
    cone) is the cure.  I must have a fortune in little-used spark
    plugs setting around waiting for me to have nothing else to do but
    clean spark plugs {:>).

 
Ok, that fits except for the fact that at increasing altitudes, the MAP at which the SAG occurred was lower (eg. 36" at s.l. but only 26" at 10k').   So something else is involved but I don't know what.  Time to order more spark plugs.  :-)

         I only use STEEL for my alternator arm - too much vibration there
    for aluminum (my opinion of course, but having had aluminum brake
    line fail - I'm a little leery of the stuff {:>)).
     
 
Yes, mine was steel too.  But it was a soft/cheap hardware variety steel.  Time to get some good stuff.

 

Thanks for the comments.

-- Dave Leonard
Turbo Rotary RV-6 N4VY
http://members.aol.com/_ht_a/rotaryroster/index.html
http://members.aol.com/_ht_a/vp4skydoc/index.html