Time for an Eng. Overhaul?

J

JC150

Pre-takeoff checklist
Joined
Apr 22, 2013
Messages
491
Display Name
Display name:
JC150
I have a Lyc IO-360 with 1400 hours SMOH. I was told by the shop that there is wear on the cam lobe inside the crank case and I need to replace the cam shaft. After talking to the shop, I have 2 choices... First, I can do a complete engine overhaul. Second is to split the shell and have a new cam shaft installed - and then doing a "top overhaul".

What would cause wear on the cam lobe inside the crank case? Running the engine too hard? I heard IO-360's were "bulletproof" and always made TBO so this is surprising that its having this issue at 1400 hours.

I'm considering the overhaul because I'm going to have to spend some serious money no matter what and I wanted to sell the plane in about 5 years. If I did the cam shaft replacement, the engine is still at 1400 hours, and by the time i'm ready to sell, it will have 2,000 hours so essentially any money I spend doesn't go towards increasing the value of the plane.

Since I have to spend money no matter what, I was thinking why not spend it on an overhaul and raise the value of the plane? I wanted to ask the POA community what you would do in this situation? Someone suggested doing the overhaul and selling right away and upgrading now. Is this a wise strategy?

Also, is it worth the extra money to go for a Lycoming Factory Reman instead of a field overhaul?

Thanks
 
JC150 said:
What would cause wear on the cam lobe inside the crank case? Running the engine too hard? I heard IO-360's were "bulletproof" and always made TBO so this is surprising that its having this issue at 1400 hours.
Click to expand...
It was theorized when I had that happen that the airplane sat to much. The oil film runs off the cam, it starts to rust, with rapid wear when it's next run. A few cycles of that, and you have prematurely worn cams.
 
Get a second opinion from reputable source.
 
murphey said:
Get a second opinion from reputable source.
Click to expand...

That.

Also if needed, a top overhaul is sill just TBO it, way better ROI.

I’d also look into bigger engine swaps or anything like that
 
If you are going to keep the airplane I would do an overhaul. Now there are several different types of overhauls. Field overhaul by an A&P or IA. the parts only have to be within serviceable limits. That means if something is just barley in limits it can be used even though it will be worn out soon. Overhaul by a reputable engine shop will usually be done to factory new limits with new cylinders. Factory reman is also done to factory new limits that is considered a 0 time engine. The factory reman is the most expensive but again is a 0 time engine and usually has a substantial warranty.
 
Also if you just have the cam replaced the labor is very close to the labor of an overhaul.
 
Run the numbers.
What is the airplane going to sell for if you do plan A.
What does it cost to do plan A.
What is the airplane going to sell for if you do plan B.
What will it cost for plan B.
Add in emotional values (these are not to be disregarded) and you have an answer or at least an approximation.
 
The surface of the cam lobes is a hard steel for long service life. The interior is a softer, less brittle steel.
Lycoming cams are on top of the engine which can make them more susceptible to corrosion than Continentals. If the engine sits idle for an extended duration and the cam surface corrodes from moisture in the crankcase it compromises the thin, hardened surface. That risks spalling of the surface when the engine is again run, and once that hard surface is lost the rest of the cam lobe will wear down very quickly.
 
I would go to a well known shop. Best value. As a buyer I would heavily discount a field overhaul done by your local mechanic.
 
1) As a buyer, would you value a factory reman over a well known shop field overhaul?

2) This is a Piper Arrow III

3) I"m starting to think overhaul the engine and then try to sell right away and get most of my money back from the overhaul?
 
JC150 said:
1) As a buyer, would you value a factory reman over a well known shop field overhaul?

2) This is a Piper Arrow III

3) I"m starting to think overhaul the engine and then try to sell right away and get most of my money back from the overhaul?
Click to expand...
An overhaul will run $20-25,000. Did one on my cherokee in 2011, plain O-360 Lycoming.
 
Was this from the batch that was recalled and offered replacement cams 15 or so years ago?because of a metallurgical issue?


Sent from my iPhone using Tapatalk
 
JC150 said:
1) As a buyer, would you value a factory reman over a well known shop field overhaul?

2) This is a Piper Arrow III

3) I"m starting to think overhaul the engine and then try to sell right away and get most of my money back from the overhaul?
Click to expand...

1. Not necessarily, it depends. First overhaul, or is this it’s 2nd?
Problem with factory remans is you don’t know the source of the parts, may have come from a engine that had a prop strike. Some say it doesn’t matter because they are still within spec.
2. Go online and check prices of PAIIIs with recent overhauls, that will give you a benchmark.
3. No, you are probably best off flying 300 hours to work out any bugs. Chance of engine failure go up with new overhauled engine, not down. After 300 hours you’ll have a history of oil changes, etc to show buyers that the engine has been properly maintained and is dependable.
 
GRG55 said:
The surface of the cam lobes is a hard steel for long service life. The interior is a softer, less brittle steel.
Lycoming cams are on top of the engine which can make them more susceptible to corrosion than Continentals. If the engine sits idle for an extended duration and the cam surface corrodes from moisture in the crankcase it compromises the thin, hardened surface.
Click to expand...

How long does it have to sit idle for this process to start becoming a problem, any guess? And I guess it makes a difference whether it's sitting idle in Miami vs Phoenix too...
 
deyoung said:
How long does it have to sit idle for this process to start becoming a problem, any guess? And I guess it makes a difference whether it's sitting idle in Miami vs Phoenix too...
Click to expand...


tealeafreading11.jpg
 
Premature cam wear can happen if corrosion sets in on either lifters or cam, destroying the hardened surface. BTDT. My lifters started spalling at 1800 hours due to corrosion and that accelerated cam wear to the point that something had to be done. At 1800 hours on someone else's field overhaul, the decision was easier for me once the case had to be split. I overhauled. Good thing, too, as the crank was out of tolerance and unserviceable.

At 1400 hours, the decision is harder for you. What quality overhaul was the last one? If it was a field "to limits" OH, I might seriously consider doing a proper overhaul and consider checking out the crank while the case is split. If the last overhaul was a quality "new limits" OH then you might well consider replacing the cam and lifters and any other top end parts only and flying it past TBO with more confidence. A full OH will be in the $30K range.
 
Cold starts with inadequate preheat can also cause cam lobe scoring. Where/when have you been operating? Do you have documentation on the lobe/rocker arm lifts? Continued operation may fill the engine with steel and do a lot of further damage.
 
MauleSkinner said:
It was theorized when I had that happen that the airplane sat to much. The oil film runs off the cam, it starts to rust, with rapid wear when it's next run. A few cycles of that, and you have prematurely worn cams.
Click to expand...

The same thing happened to my camshaft in a 360 on a Maule. It flew regularly once a week but I had a situation where I shared my hangar with a Cub. Whenever my hangar mate flew, Maule had to be repositioned and the easiest way was to start it up for less than a minute. I can imagine a scenario that might cause the condition.

I had about 1,000 hours and just had the cam replaced. It was a lot less than an overhaul. I sold it as is around 1800 hours and fully expected it to operate past TBO.

Are you sure a top overhaul is needed?


Sent from my iPad using Tapatalk Pro
 
Bill Watson said:
The same thing happened to my camshaft in a 360 on a Maule. It flew regularly once a week but I had a situation where I shared my hangar with a Cub. Whenever my hangar mate flew, Maule had to be repositioned and the easiest way was to start it up for less than a minute. I can imagine a scenario that might cause the condition.

I had about 1,000 hours and just had the cam replaced. It was a lot less than an overhaul. I sold it as is around 1800 hours and fully expected it to operate past TBO.

Are you sure a top overhaul is needed?


Sent from my iPad using Tapatalk Pro
Click to expand...
I don’t see how an overhaul can cost much more. Almost all the labor is the same. In my opinion, you’d be crazy to pay to break a case open and not check everything while it’s open. At least do an IRAN on the bottom end. The top end? Not relevant from what you’re saying.
 
My cherokee six ended up crapping the cam and tappets after ~900 hrs SOH. It was brand new when I had it and always did well with CamGuard and was flown at least once or twice a month. The new owner chose his own ops and maintenance and let it sit out in the nice San Diego sun for a year or two with minimal use or treatment. The next owner had to do a complete overhaul after 900 hrs since a factory, Lycoming, overhaul.
 
PaulS said:
Spalling can also occur because of improper heat treatment.
Click to expand...

Yes, that has certainly happened, but one won't normally get 1400 hours out of the engine (and maybe many more than that on this camshaft if it's not a first run engine) before that sort of problem usually shows up.
 
Not sure where folks get the idea from that replacing a cam+lifters is close in labor to an overhaul.
- you don't do any work on the cylinders beyond removal and reinstallation
- no disassembling and sending the bottom end for testing.
- no work on the components (carb/FI, magnetos, alternator...)
.
.

Get a quote for both from a reputable engine shop. You want whoever puts it back together to be really good at doing so. Getting all the torques right on reassembly is not trivial and you want to leave that part to someone who does this on a regular basis.
At 1400, and if the cylinders have good compressions, I would consider just doing the repair and fly the thing for another 1000hrs.
 
weilke said:
Not sure where folks get the idea from that replacing a cam+lifters is close in labor to an overhaul.
- you don't do any work on the cylinders beyond removal and reinstallation
- no disassembling and sending the bottom end for testing.
- no work on the components (carb/FI, magnetos, alternator...)
.
.

You have to disassemble the whole engine to change the cam!
Click to expand...
 
weilke said:
Not sure where folks get the idea from that replacing a cam+lifters is close in labor to an overhaul.
- you don't do any work on the cylinders beyond removal and reinstallation
- no disassembling and sending the bottom end for testing.
- no work on the components (carb/FI, magnetos, alternator...)
.
.

Get a quote for both from a reputable engine shop. You want whoever puts it back together to be really good at doing so. Getting all the torques right on reassembly is not trivial and you want to leave that part to someone who does this on a regular basis.
At 1400, and if the cylinders have good compressions, I would consider just doing the repair and fly the thing for another 1000hrs.
Click to expand...
Besides the oil pump, and removing the conn rods, what part of the bottom end do you not disassemble to change the camshaft and lifters? Relatively speaking those are small labor items.
 
murphey said:
An overhaul will run $20-25,000. Did one on my cherokee in 2011, plain O-360 Lycoming.
Click to expand...

We did a major overhaul a few years ago on the 172. The engine shop removed and re-installed the engine. We did new Lycoming cylinders and not overhauled units. The complete bill was $11,200 for a 0 time since major overhaul. That price included R&R engine.
It helps to check around and have connections. I would never pay $25,000 to overhaul a Lycoming 320!
I talked to the engine guy about the high dollar overhauls. He just couldn't figure out where their prices come from. I guess they charge double because they give a warranty???
 
Last edited:
Keep in mind only Lycoming reman can be 0 time, And all factory remans now come with roller tappets. FYI just food for thought
 
Salty said:
Besides the oil pump, and removing the conn rods, what part of the bottom end do you not disassemble to change the camshaft and lifters? Relatively speaking those are small labor items.
Click to expand...

You have to split the case to get the cam in and out and that requires taking pretty much the whole engine apart. Of course I've only built four Lycomings so I guess I don't know enough yet. Western Skyways charges $8,000 to do a teardown inspection witch is complete disassembly and re assemble. Perts extra.
 
JC150 said:
I have a Lyc IO-360 with 1400 hours SMOH. I was told by the shop that there is wear on the cam lobe inside the crank case and I need to replace the cam shaft. After talking to the shop, I have 2 choices... First, I can do a complete engine overhaul. Second is to split the shell and have a new cam shaft installed - and then doing a "top overhaul".

What would cause wear on the cam lobe inside the crank case? Running the engine too hard? I heard IO-360's were "bulletproof" and always made TBO so this is surprising that its having this issue at 1400 hours.

I'm considering the overhaul because I'm going to have to spend some serious money no matter what and I wanted to sell the plane in about 5 years. If I did the cam shaft replacement, the engine is still at 1400 hours, and by the time i'm ready to sell, it will have 2,000 hours so essentially any money I spend doesn't go towards increasing the value of the plane.

Since I have to spend money no matter what, I was thinking why not spend it on an overhaul and raise the value of the plane? I wanted to ask the POA community what you would do in this situation? Someone suggested doing the overhaul and selling right away and upgrading now. Is this a wise strategy?

Also, is it worth the extra money to go for a Lycoming Factory Reman instead of a field overhaul?

Thanks
Click to expand...

What is the price for the cam and top job?
 
busa2r said:
Keep in mind only Lycoming reman can be 0 time, And all factory remans now come with roller tappets. FYI just food for thought
Click to expand...
I don’t think the roller tapper thing is true for all lycoming engines.
 
Wait. Why are you being told to do a top overhaul ?

Between doing a camshaft replacement and a 'top overhaul'* one one hand and a full overhaul on the other, there shouldn't be much of a cost difference.
Between doing 'just' a cam and a full overhaul there should be a considerable difference in price.

Whatever you do, if your cam and lifters are spalled there is a chance that once they take the engine apart you'll get a recommendation for a full overhaul based on damage they encounter (e.g. scored main bearings).





* I know dear, that term is not officially defined, but everyone seems to know what it means.
 
Last edited:
You must log in or register to reply here.
Back
Top