Sticking Lycoming O-360 valve again?

: How often do you change oil? Confirm you have a full flow filter (it
: reads like you do). Does your oil filter have gray (lead) sludge in
: it?
Full flow filter, 50 hours, Aeroshell 80/100 depending on winter/summer. No
lead sludge in the filter, and very tiny (i.e. normal) amount of metal and carbon in
the filter and its element.

: What fraction of the time since you got the engine has been 100LL vs
: autofuel? I assume the autofuel has to be 91 octane autofuel to handle
: your compression?

93 A.K.I autofuel is used for local cruise. Generally at least 25% 100LL on
the takeoff tank. I'd say in the 3-400 hours since we've run it, probably about 60%
on autofuel.

: Have you ever tried to do a mag check at cruise? (i. e. could one mag
: be somehow intermittent at temperature?).

Done in-cruise mag checks. All fine. I generally check it along with my
leaning to verify no rough on just one mag.

: Be sure to check inside the rocker covers to see if the rocker shafts
: are wearing on the cover sides. I found one (but only one) in my 172M
: (1700 TT over 31 years) that was worn substantially. Later shafts have
: a nylon thrust boss.

Will look when I get them off. Probably take a look on Saturday.

: You gotta post what you find. THX

Will do.
-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

I just remembered a local chromed C-85 engine that would "sag" on
takeoff after an overhaul. It was supposedly traced to inadequate ring
gap. I find it hard to believe in your case though after your amount of
time since OH.

You might check the carb floatbowl fuel level with the clear flex
standpipe connected into the carb drain port method. I'm otherwise
outta ideas.....

I just remembered a local chromed C-85 engine that would "sag" on
takeoff after an overhaul. It was supposedly traced to inadequate ring
gap. I find it hard to believe in your case though after your amount of
time since OH.

You might check the carb float bowl fuel level with the clear flex
standpipe connected into the carb drain port method.

Make sure the correct rocker arms are in the correct locations. On
some Lycomings they are different for the intake & exhaust. The
exhausts have oil squirt holes in them as I recall.

I'm getting outta ideas.....