Sign up to save your podcasts
Or
Share "That's an oft-reported myth"
Share to email
Share to Facebook
Share to X
Share to email
Share to Facebook
Share to X
Or
"That's an oft-reported myth"
Is going past TBO more expensive? Plus fuel vents and turbocharger temps. Email [email protected] for a chance to get on the show.
Join the world's largest aviation community at aopa.org/join
Full episode notes below:
Mike wonders if running past TBO actually costs more. He has
a Mooney and has heard that overhauls far beyond TBO can cost more as a result
of having to replace more parts. That is an oft-reported myth, Mike says. The
only things that can cause an up charge on most field overhauls are having to
replace the case or the crankshaft. Otherwise it’s a fixed price. Paul says the
top engine generally goes into the trash. On the crankshaft, they usually just
have to polish it or grind it. There’s no repairing a crankshaft. If it’s bad,
it was bad because it had some other type of problem. You can go thousands of
hours on crankshafts. Mike said Lycoming had a white paper on their website
that said crankshafts are generally good for 14,000 hours. Cracks on the case can
be welded.
Mark has an early 182 and he’s having issues with the fuel
caps properly venting. He has noticed that once you fill the tanks with cold
fuel, there doesn’t appear to be an outflow vent. Paul said there’s a small
weep hole that allows the expanded fuel to vent. But Mark’s tanks still aren’t
venting. He pulled it out but didn’t seem to find a weep hole. He said it looks
original and has an early Cessna part number. If the fuel is pouring out it
needs to be replaced because the check valve is bad. The wing will balloon and
can cause structural damage without a weep hole. He said when he removes the
cap a big woosh of air will come out, indicating the fuel isn’t venting out as
it expands.
Jim is wondering how TIT and EGT intersect. He flies a turbo
Saratoga and has been experimenting lean of peak and rich of peak. He’s noticed
a significant difference between EGT and TIT. If the TIT is farther away from
the engine, he’s wondering why it’s hotter than EGT. He’s also wondering how
hot he can let the turbocharger get. Mike said TIT is hotter because the EGT
probe is only seeing gas flow for less than a third of the time, and only when
the exhaust valve is open. The EGT probe actually measures a “probe”
temperature that averages the temps over time. When the gas gets to the TIT
probe it’s a constant heat from all cylinders all the time. Redline on his TIT
is 1,650 degrees, which Mike said is a continuous operation limit. Paul asked
what the exhaust system is made of because that matters. He suggests not
exceeding the red line. In cruise, the lower you can keep the TITs, the longer
the system will last. Mike limits his TIT to 1,600.
View all episodes
By AOPA
4.9
265265 ratings
Is going past TBO more expensive? Plus fuel vents and turbocharger temps. Email [email protected] for a chance to get on the show.
Join the world's largest aviation community at aopa.org/join
Full episode notes below:
Mike wonders if running past TBO actually costs more. He has
a Mooney and has heard that overhauls far beyond TBO can cost more as a result
of having to replace more parts. That is an oft-reported myth, Mike says. The
only things that can cause an up charge on most field overhauls are having to
replace the case or the crankshaft. Otherwise it’s a fixed price. Paul says the
top engine generally goes into the trash. On the crankshaft, they usually just
have to polish it or grind it. There’s no repairing a crankshaft. If it’s bad,
it was bad because it had some other type of problem. You can go thousands of
hours on crankshafts. Mike said Lycoming had a white paper on their website
that said crankshafts are generally good for 14,000 hours. Cracks on the case can
be welded.
Mark has an early 182 and he’s having issues with the fuel
caps properly venting. He has noticed that once you fill the tanks with cold
fuel, there doesn’t appear to be an outflow vent. Paul said there’s a small
weep hole that allows the expanded fuel to vent. But Mark’s tanks still aren’t
venting. He pulled it out but didn’t seem to find a weep hole. He said it looks
original and has an early Cessna part number. If the fuel is pouring out it
needs to be replaced because the check valve is bad. The wing will balloon and
can cause structural damage without a weep hole. He said when he removes the
cap a big woosh of air will come out, indicating the fuel isn’t venting out as
it expands.
Jim is wondering how TIT and EGT intersect. He flies a turbo
Saratoga and has been experimenting lean of peak and rich of peak. He’s noticed
a significant difference between EGT and TIT. If the TIT is farther away from
the engine, he’s wondering why it’s hotter than EGT. He’s also wondering how
hot he can let the turbocharger get. Mike said TIT is hotter because the EGT
probe is only seeing gas flow for less than a third of the time, and only when
the exhaust valve is open. The EGT probe actually measures a “probe”
temperature that averages the temps over time. When the gas gets to the TIT
probe it’s a constant heat from all cylinders all the time. Redline on his TIT
is 1,650 degrees, which Mike said is a continuous operation limit. Paul asked
what the exhaust system is made of because that matters. He suggests not
exceeding the red line. In cruise, the lower you can keep the TITs, the longer
the system will last. Mike limits his TIT to 1,600.
More shows like Ask the A&Ps
View all
The Finer Points - Aviation Podcast
374 Listeners
Airplane Geeks Podcast
401 Listeners
AOPA Never Again
237 Listeners
Airplane Owner Maintenance - By Dean Showalter
135 Listeners
Hangar Talk - An Aviation News Podcast
114 Listeners
Pilot to Pilot
953 Listeners
EAA's The Green Dot - An Aviation Podcast
231 Listeners
Aviation News Talk – Pilot Stories, Safety Tips & General Aviation News
783 Listeners
"There I was..." An Aviation Podcast
309 Listeners
Opposing Bases: Air Traffic Talk
934 Listeners
Behind the Prop
136 Listeners
I Learned About Flying From That
213 Listeners
Pilot's Discretion from Sporty's
161 Listeners
Midlife Pilot Podcast
143 Listeners
NTSB News Talk – Aviation Accidents, Safety Investigations & Pilot Lessons
13 Listeners