Rotating Injectors Among Cylinders

Let me understand this: you achieved smooth LOP operation by playing
"musical injectors"?

Well, no, that wouldn't be legal. But when my engine ran rough, I
suspected injector fouling and cleaned the injectors (my A&P
supervised, and the cleaning was properly logged). Since there was no
rule saying that each one had to be returned to the original cylinder
(they are, after all, identical) I didn't bother with that. Once the
engines started running smooth, I stopped cleaning the injectors so
often. Once a year is plenty. And I keep track of which one goes with
each cylinder. No rule against that, you know.

Michael

Since there was no rule saying that each one had to be returned to
the original cylinder
(they are, after all, identical) I didn't bother with that. ...And I
keep track of which one goes with
each cylinder. No rule against that, you know

Right. With stock injectors all the same size, there is no requirement
that they go back into the same cylinders, and as far as I know,
nothing that really stops you from deliberately moving them around.
Where the FAA has gotten concerned in the past is where they are
specifically sized (TCM, for example, makes three sizes of injectors
for the same engines). What a lot of people were doing was ordering
some of the "other sizes" and swapping them into the mix, in an attempt
to even out the fuel flow. Or worse (in the FAA's mind), simply using
an abrasive wire to open up the injectors themselves.

Where the FAA has gotten concerned in the past is where they are
specifically sized (TCM, for example, makes three sizes of injectors
for the same engines). What a lot of people were doing was ordering
some of the "other sizes" and swapping them into the mix, in an attempt
to even out the fuel flow. Or worse (in the FAA's mind), simply using
an abrasive wire to open up the injectors themselves.

Right. And to get consistent fuel-air distribution on the big
Continentals, you pretty much had to do that (or go to GAMI's). But I
have small-bore Lycomings. They have pretty good fuel-air distribution
to begin with, so the manufacturing tolerances on the injectors are
enough to get the job done. That's why GAMI's are pretty much a waste
of money on small-bore Lycomings. You can get the same effect by
swapping the stock injectors around. They're supposed to be identical,
but the manufacturing tolerances are such that they are not. (My
favorite tall tale is the one about Eli Whitney and the interchangeable
parts.) They make a lot of sense for big-bore Continentals.

Michael