GregP
Major
Want to sit in a P-51? I can help you do that, and maybe get a flight. They smell like fighers ... not necessarily gasoline. The cockpits are full of the smell of old leather, warm electronics, sun-baked paint and bakelite, etc, plus maybe some pilot sweat ... hard to describe but, once you sit in one, you can't mistake the smell of an old warbird. They are all similar with the radials smelling a bit more oily.
About the old engines corroding, I can give you an example. Joe Yancey came across some old Allisons that were formerly used in Hydroplanes. The owner was the wife of a late racer (20 years ago). She had left the Allisons sit out in a field, no plugs in them, unclosed coolant openings, in the weather. They had gone through at least two floods where they were under water for a month or more.
None would turn over when a 10-foot long pipe was attached to prop wrench, even when we put oil for 2 days into each cylinder. That has a few connotations ...
The only pistons approved for aircraft use in a V-1710 by the factory manual are nominal, 0.10" over, and .020" over. The rings will compensate for up to 0.010" of egg-shape. So that means if any of the cylinders are pitted deeper than .027" or so, the liners are shot. The water jacket had water in it for 20 years and had rusted through in a couple of places on 3 of the 4 Allisons, so the blocks weren't any good and the 4th one was probably very close to coming through, too. A pressure test probably would have burst it, maybe not. The cams and were rusted enough to be useless. We never saw the crankshafts, but you can bet they were bad, too, along with the rods.
That means we could probably hydraulic the pistons out once the cams were off (maybe not if we couldn't get the valves closed with a dead-blow hammer against the srpings), but the pistons, liners, rods, and probably the wrist pins were going to be pretty much not usable except for maybe a museum cutaway ($10,000 easily). A cutaway doesn't fly. The cases were shot.
The nose case might have been OK, but the very necessary nosecase bearings probably were too far gone to be recoverable ... you'd have to disassemble it to find out. I do not know the condition of the accessory case and the supercharger. Two of the engines had fallen over and had broken the carburetor and carb mount off the accessoriy cases, so the cases were no good either. The carbs looked like the surface of the moon from Earth.
So maybe we could use assorted nuts and bolts, the valves, valve guides, maybe 1/3 of the valve springs, the valve spring washers retainers, some nuts and bolts but not all, the intake manifolds, probably all the studs, MAYBE the intake rubber pieces (maybe not), the gaskets that seal the valve covers and maybe a few more, perhaps the cam towers and tachometer drive, and accessory plates. That ain't much when you consider a V-1710 has about 7,000 parts. OK, we could probably use all the crankshaft plugs and oil galleys and a few minor but necessary pieces, too. Maybe the mags were overhaulable, maybe not.
The woman wanted $20,000 each and was quite distressed to hear that we pay very much less than that for an engine that turns over, and $200 - $1000 for one that doesn't turn depending on condition. Hers were so bad that Joe wouldn't offer even $500 each. There were that many parts ruined.
Here's the thing ... there are only about 4 - 5 shops in the world that can do a GOOD rebuild of these old Allisons. I'm not too sure about Merlins, but the good Merlin shops in the U.S.A are few and we probably mostly know them in this forum. Only these guys know what to do with old parts to make them serviceable, if possible. To anybody else, the engines are scrap metal. You can't buy a core that turns over from ANY of the shop owners for $5,000 because they are worth $90,000 - $250,000 (depending on mfg model scarceness) or more when overhauled and sold after break-in to an aircraft owner. So why in the name of heaven would anyone sell you one for pennies on the dollar unless he was desperate? None of the owners of the Allison / Merlin overhaul shops are desperate. If he saves it, perhaps it can be overhauled and sold at a later date.
If you are smart,and if there's nothing else going on in the shop, you take the old cruddy engines apart in slack time, recondition the parts to where they are suitable for overhaul, and put them into "overhaulable stock." When you can't make money, it's time to at least stock up on things that will sell when someone wants an engines built from parts. It happens, and usually on SHORT notice, and you either react or lose the money. If you can't react and if you have a pile of old, disassembled engines ... it's YOUR fault. The parts are only sellable when the condition can be seen.
The amount of oil and crud on the engine has nothing to do with it ... it's the internal condition that counts. In fact, the more old, dirty oil and grease on it, the better the condition will be when it is cleaned up and refurbished.
Perhaps you will get an idea when I get some Zero pics this wekend. You can compare the before and after.
These aren't engine parts, but you can see a very noticeable difference between the pics, and it should be obvious why the overhaul was needed.
It is much the same with engines. I'll get a shot of an old Japanese engine recovered from a beach on Yap and post that, too. You should be able to see the issues with overhaul easily.
About the old engines corroding, I can give you an example. Joe Yancey came across some old Allisons that were formerly used in Hydroplanes. The owner was the wife of a late racer (20 years ago). She had left the Allisons sit out in a field, no plugs in them, unclosed coolant openings, in the weather. They had gone through at least two floods where they were under water for a month or more.
None would turn over when a 10-foot long pipe was attached to prop wrench, even when we put oil for 2 days into each cylinder. That has a few connotations ...
The only pistons approved for aircraft use in a V-1710 by the factory manual are nominal, 0.10" over, and .020" over. The rings will compensate for up to 0.010" of egg-shape. So that means if any of the cylinders are pitted deeper than .027" or so, the liners are shot. The water jacket had water in it for 20 years and had rusted through in a couple of places on 3 of the 4 Allisons, so the blocks weren't any good and the 4th one was probably very close to coming through, too. A pressure test probably would have burst it, maybe not. The cams and were rusted enough to be useless. We never saw the crankshafts, but you can bet they were bad, too, along with the rods.
That means we could probably hydraulic the pistons out once the cams were off (maybe not if we couldn't get the valves closed with a dead-blow hammer against the srpings), but the pistons, liners, rods, and probably the wrist pins were going to be pretty much not usable except for maybe a museum cutaway ($10,000 easily). A cutaway doesn't fly. The cases were shot.
The nose case might have been OK, but the very necessary nosecase bearings probably were too far gone to be recoverable ... you'd have to disassemble it to find out. I do not know the condition of the accessory case and the supercharger. Two of the engines had fallen over and had broken the carburetor and carb mount off the accessoriy cases, so the cases were no good either. The carbs looked like the surface of the moon from Earth.
So maybe we could use assorted nuts and bolts, the valves, valve guides, maybe 1/3 of the valve springs, the valve spring washers retainers, some nuts and bolts but not all, the intake manifolds, probably all the studs, MAYBE the intake rubber pieces (maybe not), the gaskets that seal the valve covers and maybe a few more, perhaps the cam towers and tachometer drive, and accessory plates. That ain't much when you consider a V-1710 has about 7,000 parts. OK, we could probably use all the crankshaft plugs and oil galleys and a few minor but necessary pieces, too. Maybe the mags were overhaulable, maybe not.
The woman wanted $20,000 each and was quite distressed to hear that we pay very much less than that for an engine that turns over, and $200 - $1000 for one that doesn't turn depending on condition. Hers were so bad that Joe wouldn't offer even $500 each. There were that many parts ruined.
Here's the thing ... there are only about 4 - 5 shops in the world that can do a GOOD rebuild of these old Allisons. I'm not too sure about Merlins, but the good Merlin shops in the U.S.A are few and we probably mostly know them in this forum. Only these guys know what to do with old parts to make them serviceable, if possible. To anybody else, the engines are scrap metal. You can't buy a core that turns over from ANY of the shop owners for $5,000 because they are worth $90,000 - $250,000 (depending on mfg model scarceness) or more when overhauled and sold after break-in to an aircraft owner. So why in the name of heaven would anyone sell you one for pennies on the dollar unless he was desperate? None of the owners of the Allison / Merlin overhaul shops are desperate. If he saves it, perhaps it can be overhauled and sold at a later date.
If you are smart,and if there's nothing else going on in the shop, you take the old cruddy engines apart in slack time, recondition the parts to where they are suitable for overhaul, and put them into "overhaulable stock." When you can't make money, it's time to at least stock up on things that will sell when someone wants an engines built from parts. It happens, and usually on SHORT notice, and you either react or lose the money. If you can't react and if you have a pile of old, disassembled engines ... it's YOUR fault. The parts are only sellable when the condition can be seen.
The amount of oil and crud on the engine has nothing to do with it ... it's the internal condition that counts. In fact, the more old, dirty oil and grease on it, the better the condition will be when it is cleaned up and refurbished.
Perhaps you will get an idea when I get some Zero pics this wekend. You can compare the before and after.
These aren't engine parts, but you can see a very noticeable difference between the pics, and it should be obvious why the overhaul was needed.
It is much the same with engines. I'll get a shot of an old Japanese engine recovered from a beach on Yap and post that, too. You should be able to see the issues with overhaul easily.
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