flyingcheesehead
Touchdown! Greaser!
Whole bunch of stuff here. Mainly, overhaul/replacement questions.
The engine in question is a Continental O-470-R in a Cessna 182N.
TBO is 1500 hours, engine is currently at about 2450 hours (overhauled in Dec. 1995) and there was a post-prop-strike inspection done (and overhauled prop installed) 1664 hours and 6 years ago.
12/07 compressions: 69, 60, 70, 70, 64, 54 (/80)
12/08 compressions: 68, 72, 70, 76, 70, 78 (/80)
Oil analysis has not shown anything unusual, though it's been a while since we had one. (Hopefully a new one will be on the way in the next week or two.)
Symptoms: High oil consumption. This began roughly last August. Since then we've averaged nearly 1/2 quart per hour (75 quarts added in 155 hours, and we probably burned some extra that was added during oil changes and annual.) It seems to go in spurts, needing 3 quarts sometimes, and others being just fine.
This may partially be due to the number of people that fly the airplane but may not know its individual quirks, so I put a note up on our scheduler to inform people to maintain the oil level between 8 and 9.5 quarts and to make sure to twist the dipstick at least 1 full turn to get an accurate reading of the oil level. FWIW, there are about 10-15 people who fly the plane.
Where is the oil going? It seems to come mainly out of the breather tube, sometimes making a small (4-in. diameter max) pool underneath while it's parked, and the belly is pretty dirty. Sometimes the liquid coming out of the breather tube looks "sandy" but could that just be froth or something? (Kinda looks about the same as the head on a fresh pour of Guinness.)
I've also noticed that the upper case half bolt on the left side of the engine (right as you're looking at it on preflight) has a tiny amount of oil coming out around it, enough that the front left (#1?) cylinder looks "wet" (the two behind it do not).
A new problem is that the prop governor is slow. While adding power (throttle) the RPM will go up ~100 RPM until the throttle stops moving, and it'll go down ~100 RPM when pulling the throttle back (both with gentle changes). It'll also fluctuate ±150 RPM or so with airspeed changes. This may be completely unrelated as it just started happening a couple days ago, but I thought I'd throw it in in the interest of full disclosure.
What's NOT happening is any loss of power. The bird still climbs like a homesick angel and gets off the ground in a hurry. As long as we feed it like it's a radial, it seems to be happy.
But, we're considering our options. If the compressions indicate that one cylinder is having problems, is it worth replacing on an engine this old, or should we just go ahead and do the complete overhaul? If we do need an overhaul in the short term (ie during prime flying season), we'd like to get the bird back up in the sky ASAP - Can we get an overhauled engine as a swap, or do we have to buy a new one? Where do we go for either case, IE does TCM sell direct or through dealers or service centers?
Our most likely choice for an overhaul shop is Poplar Grove Airmotive, and since it's not completely toast yet we'll probably ferry it down there.
Thoughts as to what is going on with the engine and/or prop, whether or not to go with a full overhaul, how to minimize downtime, etc. are much appreciated.
The engine in question is a Continental O-470-R in a Cessna 182N.
TBO is 1500 hours, engine is currently at about 2450 hours (overhauled in Dec. 1995) and there was a post-prop-strike inspection done (and overhauled prop installed) 1664 hours and 6 years ago.
12/07 compressions: 69, 60, 70, 70, 64, 54 (/80)
12/08 compressions: 68, 72, 70, 76, 70, 78 (/80)
Oil analysis has not shown anything unusual, though it's been a while since we had one. (Hopefully a new one will be on the way in the next week or two.)
Symptoms: High oil consumption. This began roughly last August. Since then we've averaged nearly 1/2 quart per hour (75 quarts added in 155 hours, and we probably burned some extra that was added during oil changes and annual.) It seems to go in spurts, needing 3 quarts sometimes, and others being just fine.
This may partially be due to the number of people that fly the airplane but may not know its individual quirks, so I put a note up on our scheduler to inform people to maintain the oil level between 8 and 9.5 quarts and to make sure to twist the dipstick at least 1 full turn to get an accurate reading of the oil level. FWIW, there are about 10-15 people who fly the plane.
Where is the oil going? It seems to come mainly out of the breather tube, sometimes making a small (4-in. diameter max) pool underneath while it's parked, and the belly is pretty dirty. Sometimes the liquid coming out of the breather tube looks "sandy" but could that just be froth or something? (Kinda looks about the same as the head on a fresh pour of Guinness.)
I've also noticed that the upper case half bolt on the left side of the engine (right as you're looking at it on preflight) has a tiny amount of oil coming out around it, enough that the front left (#1?) cylinder looks "wet" (the two behind it do not).
A new problem is that the prop governor is slow. While adding power (throttle) the RPM will go up ~100 RPM until the throttle stops moving, and it'll go down ~100 RPM when pulling the throttle back (both with gentle changes). It'll also fluctuate ±150 RPM or so with airspeed changes. This may be completely unrelated as it just started happening a couple days ago, but I thought I'd throw it in in the interest of full disclosure.
What's NOT happening is any loss of power. The bird still climbs like a homesick angel and gets off the ground in a hurry. As long as we feed it like it's a radial, it seems to be happy.
But, we're considering our options. If the compressions indicate that one cylinder is having problems, is it worth replacing on an engine this old, or should we just go ahead and do the complete overhaul? If we do need an overhaul in the short term (ie during prime flying season), we'd like to get the bird back up in the sky ASAP - Can we get an overhauled engine as a swap, or do we have to buy a new one? Where do we go for either case, IE does TCM sell direct or through dealers or service centers?
Our most likely choice for an overhaul shop is Poplar Grove Airmotive, and since it's not completely toast yet we'll probably ferry it down there.
Thoughts as to what is going on with the engine and/or prop, whether or not to go with a full overhaul, how to minimize downtime, etc. are much appreciated.