Vibration through entire plane

[Steve Pierce]

That is usually from a pushrod tube leaking where it goes into the head and runs down between the fins and onto the intake flange.

[FFSchooley]

Ok, I will check that again. Thanks!

[Stephen]

How are your EGT's. Any chance you have a significantly higher reading on number 1? This would indicate a sticking valve not necessarily a worn guide. But....

[FFSchooley]

EGTs are ok, 1 and 3 run lower than 2 and 4. Regardless, I found it! It is a pushrod tube leaking. That’s not grounds to ground it is it? Do I need to fix it ASAP or can I fly??? I have a lesson planned for Friday. It obviously was there before and explains the burnt oil filth all over that cylinder. I didn’t loose much oil at all in the 10 hours I have flow it, so it’s not that bad.

brett

[Stephen]

EGTs are ok, 1 and 3 run lower than 2 and 4. Regardless, I found it! It is a pushrod tube leaking. That’s not grounds to ground it is it? Do I need to fix it ASAP or can I fly??? I have a lesson planned for Friday.

brett

Oil leaks are not uncommon. I was working with someone who was loosing a quart every hour. He had to land every couple of hours and put in oil. Not ideal.

[violinmaker]

Have you checked while in flight by first trying full power and then either go to idle or shutdown and put the nose down to maintain the same power-on cruise speed--- and see if the vibration is still there---- that would differentiate between power
plant/prop and the airframe. Have you checked for wear/slop in the aerolon hinges ?
Clocking the prop-vs.-crank could be an issue if the prop has been off and back on.
Any chance a crank counterweight could be stuck ?
Maybe also check the jackscrew for slop-- and make sure it isnt loose where its bolted in---- if that was loose the horizonal
could be oscillating in pitch...... wouldnt take very much of that to feel it I would think------
Same with the strut fitting I would guess----
Just brainstorming here....

PS:----- sorry I didnt notice there were 9 pages to this thread--- but now that I have
read them all---- I didnt see where you told us where the mystery vibration was coming from--- only that it was better----- was you mechanic and IA able to pinpoint it ?

[FFSchooley]

I’m not sure what else could be contributing to it, but it’s better. Hopefully Different prop indexing and a dynamic balance will further smooth it out. I will continue to look at the other things suggested and see if anything else comes up.

[AK-AV8R]

My first thought was an incorrectly indexed prop. On our baby airplanes these two bladed props are extensions of the crank shaft and should be aligned with the rod bearing journals of the crank. Also helps for propping one off when your stuck out in nowheresville. Weirdest one i ever had was on a 520 where an inner valve spring had broken and was causing horrible float at certain power settings.

[AK-AV8R]

Here Ya go

Propeller Installation on ShortWingPipers


Remove #1 spark plug. Rotate crankshaft till pressure begins to build
(place thumb in spark plug hole to feel/hear pressure building).
You are coming up on TDC for #1 cylinder. Continue rotating crankshaft
until #1 piston is TDC (use timing mark on back of ring gear aligned
with crankcase split or use markings on front of ring gear aligned
with punched hole in starter housing).


With #1 cylinder on TDC, the prop should be installed such that it is
Horizontal, ie level to the ground.


There should be a small "no 1" stamped near the hub on one prop blade.
That blade goes "over"/"toward" the No. 1 cylinder. It is permissible
to install the prop "180° out", but only as a "fix" for a SLIGHT vibration
at cruise. Nine times out of ten, it will NOT be an issue. Torque prop
correctly (visit Sensenich's website for detailed instructions or see pdf
file on this site) and safetie prop bolts, reinstall spinner and spark plug.
Button up airplane. Your prop will now be in the PROPER position not only
for handpropping, but more importantly will also be "timed" to best act as
a "flywheel" with the crankshaft.

Don't forget that this is not Preventative Maintenance, and requires
a Logbook entry by an appropriately rated Mechanic.

[walt.buskey]

So... any further info on this vibration? My plane was just about to be finished when my A&P put an electronic accelerometer-thing on it to check vibration; the plane didn't feel at all different than it ever has to me (with my limited experience), but his device indicated "DANGEROUS VIBRATION / REDUCE TO IDLE IMMEDIATELY".

Had the prop overhauled (ouch, but it was ready), tried again, same result. Tried 2300, 2000, 1700 RPM and each time max acceleration registered was less, but still too much. Pretty sure prop is properly (get it? --sorry) indexed, but will re-check that as well. Just went through all plugs & HT cables and ready to try again, but I doubt there'll be any change. One opinion has it that perhaps the crank is worn.... engine has about 700 hrs SMOH, but that was quite a few years ago.

Any thoughts on MY vibration issue? Schooley -- how's yours doing?

Walt, STILL trying to get 57A in the air...