Help me understand runouts please

[JohnAJohnson]

This is hypothetical. I'm trying to learn and can't find engine questions of this nature anywhere. I'd like to buy a plane with an engine (Lycoming O-360) close to or over TBO. The engine runs fine and compression is ok. It is 30 years old and has never been overhauled, but had a "top" 600 hours ago. From what I've read, it costs approximately $12,000 - $18,000 to overhaul an O-360. Is the variance in price because some items might not need to be changed, such as the crank, cylinders/valves, etc.? Or does an overhaul always require replacement of certain parts, and the $12-$18k variance reflects different overhaul shops? What I'm getting at, is that after purchasing such a plane, is it possible to find out that the engine is NOT overhaulable or that it would take a lot more than $18k? When buying a runout, is it safe to pick a figure as the absolute worse case scenario? There is a big difference between $18k and the $27k that a new engine would cost. Thanks

 

[Checkout_my_Six]

If the engine has never had an overhaul, then, likely most of the internal parts like the crank and accessory gears, oil pump....should be reusable. Common wear parts like bearings, piston rings, valves, valve guides, would all be replaced at an OH either way.

There are various grades of Overhaul. I'd suggest going to the Textron Lycoming website and reading what they are. There are subtle differences between them, ranging from a factory new zero timed engine to a field over haul performed by an A&P at your local field.

The biggest differences is in the inspection quality and the spec range for the parts. Will the parts be measured to the serviceable range or to new specs? If to the new part spec then a lot of parts will likely be replaced (higher costs). If you are willing to leave the serviceable parts and only replace those parts out of serviceable limits costs will be lower.

For now, I'd start an oil analysis program to monitor if the engine starts making metal. When it does that's the time to go for the OH. Also, it doesn't hurt to keep a close eye for oil leaks, increase in oil consumption, & to have the cylinders/valves boreascoped as they get older for cracks.

With overhauls I'd plan for the worst and hope for the best.

 

[Ed Guthrie]

This is hypothetical. I'm trying to learn and can't find engine questions of this nature anywhere. I'd like to buy a plane with an engine (Lycoming O-360) close to or over TBO. The engine runs fine and compression is ok. It is 30 years old and has never been overhauled, but had a "top" 600 hours ago. From what I've read, it costs approximately $12,000 - $18,000 to overhaul an O-360. Is the variance in price because some items might not need to be changed, such as the crank, cylinders/valves, etc.? Or does an overhaul always require replacement of certain parts, and the $12-$18k variance reflects different overhaul shops? What I'm getting at, is that after purchasing such a plane, is it possible to find out that the engine is NOT overhaulable or that it would take a lot more than $18k? When buying a runout, is it safe to pick a figure as the absolute worse case scenario? There is a big difference between $18k and the $27k that a new engine would cost. Thanks

"Overhaul" according to the FAA means disassembled, inspected, all parts found not to be within service limits repaired or replaced, some mandatory parts replaced with new, re-assembled, and test run. Shops vary as to what they do when they "overhaul". Some up the anty and insist on "new limit" for some critical parts; others go with the FAA "service limit" on all parts. Obviously replacing more parts means more cost, but it also means a better engine. OTOH, some shops simply charge more, so price isn't always the indicator. While it isn't required, some shops replace (or overhaul) some accessories, too. Again, more cost. The sad truth is that you can't simply compare prices when shopping overhauls, you must compare work, too. You must ask which parts will be new, which will be overhauled, which will be new limits, which will be service limits. Only when you know these criteria can you compare prices and quality.

What could go wrong? Well, most overhaul prices assume that several very expensive parts will be servicable. The crankshaft, the engine cases halves, the accesory case cover, the accessory gears, etc. As an example of how bad it can get, for an IO-360-A1B6D (common early Mooney 201 engine), 6 years ago a crankshaft was $10k used, $13k new. Ouch if yours happens to be beyond service limits. Big ouch.

 

[Ed Guthrie]

There are subtle differences between them, ranging from a factory new zero timed engine to a field over haul performed by an A&P at your local field.

Other than a zero time logbook there need not be any physical (mechanical) difference between a field A&P overhaul and a factory zero time overhaul. None at all.

 

[Henning]

This is hypothetical. I'm trying to learn and can't find engine questions of this nature anywhere. I'd like to buy a plane with an engine (Lycoming O-360) close to or over TBO. The engine runs fine and compression is ok. It is 30 years old and has never been overhauled, but had a "top" 600 hours ago. From what I've read, it costs approximately $12,000 - $18,000 to overhaul an O-360. Is the variance in price because some items might not need to be changed, such as the crank, cylinders/valves, etc.? Or does an overhaul always require replacement of certain parts, and the $12-$18k variance reflects different overhaul shops? What I'm getting at, is that after purchasing such a plane, is it possible to find out that the engine is NOT overhaulable or that it would take a lot more than $18k? When buying a runout, is it safe to pick a figure as the absolute worse case scenario? There is a big difference between $18k and the $27k that a new engine would cost. Thanks

Well, you've hit several of the key issues there, and the answer is....all of the above. I know you didn't want to hear that, but it's the truth. No, not all the parts have to be replaced, but yes, there is a list of requireds, and if an old part doesn't meet spec, it needs to be replaced. On those engines, camshafts are common. Now you say the engine is 30 but has never been overhauled, that is a good sign, as parts like the crankshat will probably be good. If you have 600hr cylinders, they can probably be reused. There are two ways I would go with this situation, cheap-as, or all out.

Cheap-as would have me disassembling, measuring everything for spec, recondition the rods/new rod bolts line bore the case, toss bearings in and put it together with the jugs you have, and whatever other required parts. Some new hoses, and back on the plane.

All Out. Factory New with the roller cam, and do the whole thing Firewall Forward.

Now, the way I would determine this is "Is this the plane I want to be flying in 5 or 10 years?" If not, cheap-as. If yes, Then the All Out method is probably the better choice.

Note: I make this last statement based on the assumption I drew from your post that you are not a mechanic, and will not be doing the work on your engine. BTW, the longer you run past TBO, the more likely you are to have a more expensive overhaul.

 

[JohnAJohnson]

Not a mechanic, but have overhauled a few boat, motorcycle and automobile engines in my younger days. Of course I sent parts out for machine work (boring, turning, etc.). I didn't think it was allowed to do the work myself but now that you mention it, I could do it under an A&Ps supervision and probably save a few bucks. Something to consider. The big thing I'm looking for is the variation and the possibilities of it going astronomical. This would be a plane I would want to overhaul as soon as possible, and keep for 1200 hours or so.

$13k for a crank? From tooling that was built 50 years ago? You have got to be ****ing me!

Wish I had a business selling low tech engines that turn 2700 RPM, have low compression and power and cost a fortune to buy, maintain, and overhaul. There is either extreme liability associated with selling/overhauling such an engine, lots of regulatory $ eating at the profit, or just lots of profit.

 

[Tom-D]

Lycoming is famous for their lawyers selling parts by changing the mandatory parts replacement list given in the overhaul manual..

Be careful who you have overhaul any Lycoming engine. You could get a unairworthy engine if they don't have a subscription to the Lycoming overhaul manual.

 

[jesse]

There is either extreme liability associated with selling/overhauling such an engine, lots of regulatory $ eating at the profit, or just lots of profit.

All of that is pretty much the true.

 

[Ken Ibold]

Wish I had a business selling low tech engines that turn 2700 RPM, have low compression and power and cost a fortune to buy, maintain, and overhaul. There is either extreme liability associated with selling/overhauling such an engine, lots of regulatory $ eating at the profit, or just lots of profit.

All of that is pretty much the true.

Another big kicker is that the volume is not very large. You have a lot of shop costs and labor overhead amortized over a relatively small number of products.

 

[poadeleted20]

Be careful who you have overhaul any Lycoming engine. You could get a unairworthy engine if they don't have a subscription to the Lycoming overhaul manual.

If you have your engine overhauled by someone who doesn't have a subscription to the Lycoming manual, you have chosen the wrong shop, but the same goes for having your Continental engine overhauled by a shop lacking the current TCM manual, or your airframe worked on by someone who doesn't keep a current copy of the maintenance manual for your airplane, or your radios worked on by a shop that doesn't have the factory books on your radios. IOW, that seems like basic common sense to me, not a Lycoming-specific issue.

 

[NC Pilot]

This is hypothetical. I'm trying to learn and can't find engine questions of this nature anywhere. I'd like to buy a plane with an engine (Lycoming O-360) close to or over TBO. The engine runs fine and compression is ok. It is 30 years old and has never been overhauled, but had a "top" 600 hours ago. From what I've read, it costs approximately $12,000 - $18,000 to overhaul an O-360.
Thanks

Don't forget to include items like remove/inspect/repair the motor mount, Engine mounts, propeller (even fixed pitch should be inspected), vacuum pump replacement, magnetos, carb. etc...

It can add up to quite a significant addition to the price, but that is the right time to do this work.

 

[Ed Guthrie]

Not a mechanic, but have overhauled a few boat, motorcycle and automobile engines in my younger days. Of course I sent parts out for machine work (boring, turning, etc.). I didn't think it was allowed to do the work myself but now that you mention it, I could do it under an A&Ps supervision and probably save a few bucks. Something to consider.

I took the "do it yourself" route when my Mooney's engine needed an overhaul. I used the cost savings to buy new parts versus re-conditioned. At that time (~10 years ago?) Pen Yan would do the cleaning, inspection, & manage any necessary repair stuff for a flat inspection fee plus the shop costs for any necessary repairs (line bore crankcase halves, fix cracks, etc.). IIRC, the flat fee was on the order of $1500 and everything that was either good as inspected or good after repair was returned to me tagged as good for re-install and I received a copy of the inspection log to document parts status. I used the savings to purchase a new camshaft, new cam followers, new cylinder assemblies, new oil pump gears & body, etc. Essentially when completed the engine was new except for the crankshaft, counter weights, connecting rods, accessory case, and accessory gears. Total cost to me with new parts, inspection costs, repaired parts costs, overhaul manual and SL&SI&SB subscription, some specialized tools & an engine stand, and including overhaul of the prop governor, prop, fuel injector, and magnetos was ~$13k. The same was estimated at $18k-$22k at Mattituck, etc., sans the reference materials and tools.

 

[Checkout_my_Six]

Other than a zero time logbook there need not be any physical (mechanical) difference between a field A&P overhaul and a factory zero time overhaul. None at all.

Yes there is a difference, inspection isn't exactly equal. The factory is gonna have better equipment with standard practices and do a more thorough job. The factory can also do a better job of measuring as well.

Most mechanics do not come with pin gages and elaborate measurement tools (optical comparators, 6 dof equipment, granite tables, etc....).

Lycoming might still do plant tours. I suggest taking one.