Old but low time factory reman

j1b3h0

j1b3h0

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Looking at an airplane to buy that has a 1997 vintage TCM factory reman with only 130...since then (IO-520). In addition to borescoping the cylinders and oil analysis, is there anything one can check to make sure they're not going to get stuck with premature overhaul?
 
j1b3h0 said:
How about Midwest in a hangar?
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You're probably ok. Borescope before you run it, take a test flight at least an hour and pull an oil sample, that's about as good as your going to get.
 
Might be a good idea to pull a few lifters and take a look at their faces and the cam.
 
Norman said:
Might be a good idea to pull a few lifters and take a look at their faces and the cam.
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You need to pull the tappets to do that, and IIRC you have to split the case to pull the tappets. Continental cams are in the bottom of the engine and live in oil, they don't have the same problems as Lycomings.
 
Is that right? The cam and lifters are always covered by oil in Continental 520s? So it's unlikely to have pitted or rusted cam lobes or lifters? I've learned the late nineties TCM remans developed a bad rep for valve guides/cylinder head problems...it would be bad enough to have to do a top overhaul really early, but any problems with the cam or lifters requires a complete tear down, right? The airframe looks nice in the pictures (haven't seen it in the flesh, yet). It's a V-tail. Opinions?
 
j1b3h0 said:
Is that right? The cam and lifters are always covered by oil in Continental 520s? So it's unlikely to have pitted or rusted cam lobes or lifters? I've learned the late nineties TCM remans developed a bad rep for valve guides/cylinder head problems...it would be bad enough to have to do a top overhaul really early, but any problems with the cam or lifters requires a complete tear down, right? The airframe looks nice in the pictures (haven't seen it in the flesh, yet). It's a V-tail. Opinions?
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Depends on how much oil is in it and the sump style, but yeah.

The main thing that causes valve and guide problems is lead and carbon deposits, that is a straight up function of ROP operations. I started flying in the early 90s as well as wrenching on planes and one thing I observed that the guys who flew LOP make TBO and beyond without topping at mid life, and that was with IO, TSIO, and GTSIO-470s & 520s as well as Lycomings. The guys who ran ROP because "LOP burns up your cylinders" were the guys getting 800 hrs out of cylinders.
 
j1b3h0 said:
Thanks, Henning.
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The good thing with low time engines is even if they ran ROP, they didn't run long enough to get a big buildup on the valves, and if you operate LOP, what buildup is there will go away.
 
I would go with a bore scope as a minimum. Would run the engine for an hour or two,then do an engine analysis .
 
j1b3h0 said:
Is that right? The cam and lifters are always covered by oil in Continental 520s? So it's unlikely to have pitted or rusted cam lobes or lifters? I've learned the late nineties TCM remans developed a bad rep for valve guides/cylinder head problems...it would be bad enough to have to do a top overhaul really early, but any problems with the cam or lifters requires a complete tear down, right? The airframe looks nice in the pictures (haven't seen it in the flesh, yet). It's a V-tail. Opinions?
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I thought you were taking a chance with this engine because it was installed in a rare airframe that you desired. There are many V-tails for sale that are run regularly. Remember that the airframe and everything in it has been sitting dormant for the last 20 years also.
It could be a good candidate for a restoration project if the price was right.
 
RichNY said:
I thought you were taking a chance with this engine because it was installed in a rare airframe that you desired. There are many V-tails for sale that are run regularly. Remember that the airframe and everything in it has been sitting dormant for the last 20 years also.
It could be a good candidate for a restoration project if the price was right.
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Depends on the circumstances. My plane had the same basic situation, one engine with 50 hrs, one with 250 hrs but had sat for 12 years while the airframe underwent a $200,000 restoration.
 
Henning said:
You need to pull the tappets to do that, and IIRC you have to split the case to pull the tappets. Continental cams are in the bottom of the engine and live in oil, they don't have the same problems as Lycomings.
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The case does not need to be split on TCM engines. Remove the rockers, push rods and tubes and the lifters slide right out. And, yes, TCM has been having some problems with lifters spalling.
 
Norman said:
The case does not need to be split on TCM engines. Remove the rockers, push rods and tubes and the lifters slide right out. And, yes, TCM has been having some problems with lifters spalling.
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The lifters yes, but the tappets as well? I haven't had one open in quite some time, but for some reason I remember them as big flat tappets with faces larger than the body.
 
Henning said:
The lifters yes, but the tappets as well? I haven't had one open in quite some time, but for some reason I remember them as big flat tappets with faces larger than the body.
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Nope. They're cylindrical. Oh, and they are not submerged in oil when the engine is not running.
 
RichNY said:
I thought you were taking a chance with this engine because it was installed in a rare airframe that you desired. There are many V-tails for sale that are run regularly. Remember that the airframe and everything in it has been sitting dormant for the last 20 years also.
It could be a good candidate for a restoration project if the price was right.
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There must be at least 160 Bonanzas for sale at any given time, you're right. I've been looking for a really nice '68-73 airplane that's in my budget - less than six digits. I'm a cash buyer when I find the right one, but I'm pretty particular.
 
j1b3h0 said:
There must be at least 160 Bonanzas for sale at any given time, you're right. I've been looking for a really nice '68-73 airplane that's in my budget - less than six digits. I'm a cash buyer when I find the right one, but I'm pretty particular.
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Nice S models (best of breed IMO) have been well under 6 figures for a good few years now, even V-35B models you can find for less.
 
I like the S models, too, but Beech just kept refining the airplane...each newer model was really improved. Better speed slope windscreen, heating and ventilation, smoother versions of the 520, large baggage door, etc,. They're like Porsches: They just keep getting better. I'd buy an S if I could find the right one.
 
j1b3h0 said:
I like the S models, too, but Beech just kept refining the airplane...each newer model was really improved. Better speed slope windscreen, heating and ventilation, smoother versions of the 520, large baggage door, etc,. They're like Porsches: They just keep getting better. I'd buy an S if I could find the right one.
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They also got heavier and slower. I still think they had all the good stuff done by the S model.
 
The cam and tappets can be inspected without splitting the case or pulling cylinders. It would be a good idea to pull a cylinder since these were made in the 1990-2000 time span when in all their great wisdon TCM did not put choke in the cylinder barrels. Typically when you pull cylinders mid time to repair the crappy valves and seats the barrels are worn out of service limits to the point where they are beyond being able to be bored to P.015"
Charlie Melot Zephyr Engines
 
My IO-520D needed valve guides roughly every 800-900 hours. Never had to touch the bottom end.

If this is an engine that has not been started in recent years I would combine an inspection with spraying some lube on the cam, etc. Do not rotate the engine until you have slopped lube on the cam. Once you can rotate without scraping the cam, also mist/spray some light lube into the cylinders as you go about doing the borescope. (LP2, or whatever)
All this mickey mouse will reduce the dry start wear when you do fire it up.

In spite of the low hours, the multiple dry starts that occurred given the time it has set around between runs, will have accelerated wear already.
So a 130 hour engine could well be a mid time engine in wear on some components.

And we have the issues of old hoses, dry pulleys, tired gyros, etc. etc. etc. Not trying to scare you off and it may be an excellent airframe. You need to do due diligence.
 
Thanks, good suggestions all. I heard that during that tainted era TCM tried in vain to install valve guides by machine, turns out not all talented workers can be easily replaced. I hadn't heard about the lack of choke.
 
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