Some help here

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Jim B

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Jim
I’m looking at a very clean 1976 Grumman Cheetah, it’s had its engine overhaul in 2002 and states, 209 hours SMOH, Prop time 0 SMOH. 1400 TT. What’s your expert opinion? Is there going to be problems with this engine since it has flown so little. Kept inside hanger whole time.
What do you think?
 
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I think it’s hard to tell without more information. Was the engine pickled or was it only ground run once a year at annual?

If you can get a borescope into the cylinders, that may provide additional context. If you haven’t already found the IA that you’re going to be working with, find him first and ask his thoughts.
 
Ground runs and once around the pattern are the worst.

I’ve dealt with several long term sitters that went well.

Pull LEFT mag and see if rust on Impulse Coupling & scope.
 
I bought a glasair with IO320 that sat for twenty years with 400 hours. Engine has been getting stronger and stronger over past 100 hours with zero issues.
 
Jim B said:
I’m looking at a very clean 1976 Grumman Cheetah, it’s had its engine overhaul in 2002 and states, 209 hours SMOH, Prop time 0 SMOH. 1400 TT. What’s your expert opinion? Is there going to be problems with this engine since it has flown so little. Kept inside hanger whole time.
What do you think?
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Impossible to guess about it.
Got to do some deep inspection like said above before deciding if it's still good or not.
Sitting just kills them all the way around.
I'd want to see some prop hours on it.
 
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209 SMOH since 2002? Nope. Don't trust it. That's a classic case of "Hangar Queen" syndrome.

The little amount it flew means it never got warm enough, long enough, to burn off the corrosive byproducts of combustion—especially the water vapor. Keeping it in a hangar helps the paint, but it doesn't solve the internal mechanics problem. You are buying a 23-year-old engine that's sat dormant. The metal fatigue isn't hours-based; it's calendar-based. The main things to fail will be the magnetos, the fuel pump diaphragms, and the aforementioned cam/lifters. If the price is super low, negotiate another $20k off for the inevitable engine overhaul you're going to face, because that low time will not fool the FAA or an insurance company for long
 
Pull a mag. If there is rust on the gears in the accessory case, there is likely to be rust on the cam/lifters.
 
Arrow67 said:
209 SMOH since 2002? Nope. Don't trust it. That's a classic case of "Hangar Queen" syndrome.

The little amount it flew means it never got warm enough, long enough, to burn off the corrosive byproducts of combustion—especially the water vapor. Keeping it in a hangar helps the paint, but it doesn't solve the internal mechanics problem. You are buying a 23-year-old engine that's sat dormant. The metal fatigue isn't hours-based; it's calendar-based. The main things to fail will be the magnetos, the fuel pump diaphragms, and the aforementioned cam/lifters. If the price is super low, negotiate another $20k off for the inevitable engine overhaul you're going to face, because that low time will not fool the FAA or an insurance company for long
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Thank you very much for that Insite
 
After a similar period of neglect and inactivity, mine only needed a new camshaft*. Whether or not it's worth it to make such an airplane great again is entirely up to you. If you've found The One True Plane(tm), it's only time and money. Be honest, is there anything else you'd rather be doing?

* also master cylinders, plugs, avionics, vacuum plumbing, primer plumbing, electrical...
 
Boroscopes are less than $100. Ground run it and test the oil. With the current backlog of engines I would not walk away from a motor (if I needed one) until after a hands on inspection. Even if an opwner says it was pickled...the preservation oil needs to be reapplied every 90 days and the dessicant (if used) only lasts a week or two depending on the humidity. Some say that dilling the entire case/cylinders with oil is the proper method.... I don't see how that will work unless you seat all the valves, accessory case etc etc etc

See if a local MX has a fiberoptic scope.. those can be fed into some very tiny places for visual inspection.
 
Jim B said:
I’m looking at a very clean 1976 Grumman Cheetah, it’s had its engine overhaul in 2002 and states, 209 hours SMOH, Prop time 0 SMOH. 1400 TT. What’s your expert opinion? Is there going to be problems with this engine since it has flown so little. Kept inside hanger whole time.
What do you think?
Click to expand...
How many of those 209 hours have been flown in the previous 12 months?
 
Roger Wilco said:
How many of those 209 hours have been flown in the previous 12 months?
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That really doesn't matter. The last week to the last month... maybe. But 209 hours on an OH that 20-ish years old? You need to look inside.

An O-320 should allow a scope through the drain plug up to the rear cylinders to look at the cam.
 
Seems like very very low time since the overhaul. Is there more with bore scope photos? Seems like it just wasn’t flown much post overhaul.
 
pfarber said:
That really doesn't matter.
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It would certainly matter to me, if I were the prospective buyer.
pfarber said:
You need to look inside.
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I agree completely, in this and every prebuy evaluation of a used aircraft.

Now that the gear is relatively cheap and widely available, I would be peeking in every nook and cranny I could find.
 
FYI, the TBO of pretty much any aircraft engine is "X hours or 12 years." This is not a 209SMOH engine, it's a runout.

If you buy the airplane priced as if it's out of annual (even if it's not, it's been sitting like it is) and with a runout engine - IE, *WAY WAY* cheaper than an airplane that's been flying, with the idea that you're going to have to overhaul the engine and do a lot of maintenance on it, then you *might* get a good deal if it's not as bad as it probably should be, or you might end up with exactly what you expect.

If you go into it with the idea that you're gonna get a good deal on an airplane, don't do it!

Repeat after me:
There is nothing more expensive than a cheap airplane.
There is nothing more expensive than a cheap airplane.
There is nothing more expensive than a cheap airplane.
 
Roger Wilco said:
It would certainly matter to me, if I were the prospective buyer
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Lets do the math: in 20 years a motor has run 200 hours.

Does it matter if it ran 10 hours a year? 200 hours in the first year and then sat for 19? Or it sat for 19 and ran 200 in the last year?
No, none of that matters. All that matters is when you look inside what do you see.

Because all of the possible corrosion of the first 19 years doesn't simply go away because you ran it 200 hours in one year.

If you are going to go off hours alone then good luck. But an o-320, if its a GOOD CORE, is still worth $10k-$20k.

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A buyer that simply looks at hours, and not actual metal, then I eagerly await the followup thread 'I bought a motor with 200hrs since overhaul and I need a new cam and 4 cylinders... HALP!'
 
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pfarber said:
…when you look inside what do you see.

If you are going to go off hours alone then good luck. … A buyer that simply looks at hours, and not actual metal…
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Just curious: did you read my entire post before replying? (Asking for a friend.)
 
flyingcheesehead said:
FYI, the TBO of pretty much any aircraft engine is "X hours or 12 years." This is not a 209SMOH engine, it's a runout.

If you buy the airplane priced as if it's out of annual (even if it's not, it's been sitting like it is) and with a runout engine - IE, *WAY WAY* cheaper than an airplane that's been flying, with the idea that you're going to have to overhaul the engine and do a lot of maintenance on it, then you *might* get a good deal if it's not as bad as it probably should be, or you might end up with exactly what you expect.

If you go into it with the idea that you're gonna get a good deal on an airplane, don't do it!

Repeat after me:
There is nothing more expensive than a cheap airplane.
There is nothing more expensive than a cheap airplane.
There is nothing more expensive than a cheap airplane.
Click to expand...
That’s pretty much what I was thinking. The Airplane is in CA and I live in PA. A lot of logistics to just look at and fly it. I think I’ll take all your advice and keep looking. Thanks
 
Jim B said:
That’s pretty much what I was thinking. The Airplane is in CA and I live in PA. A lot of logistics to just look at and fly it. I think I’ll take all your advice and keep looking. Thanks
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Where in California? Many, many different climes in California, from bone-dry desert to soupy seaside humidity. Despite the closed hangar it makes a difference.
 
Jim B said:
That’s pretty much what I was thinking. The Airplane is in CA and I live in PA. A lot of logistics to just look at and fly it. I think I’ll take all your advice and keep looking. Thanks
Click to expand...

I don’t know if this will be helpful for you, but here goes.

We closed on a second aircraft for our club. The journey took us about 11 months, start to finish. The first thing we decided on was a mission for the plane. Once we settled on the mission, we did a bunch of analysis and came up with a budget, then narrowed it down to a handful of makes/models that fit the bill.

We kissed a bunch of frogs until we figured out the brokers that were selling the best examples at competitive prices. It took one day, a handful of calls, and we had three candidates to choose from, one if which was off-market.

We settled among the best example, paid about 10% below asking, and closed within three weeks.

The moral of the story is you can spend a lot of time looking or a little time buying. Good luck.
 
Jim B said:
I’m looking at a very clean 1976 Grumman Cheetah, it’s had its engine overhaul in 2002 and states, 209 hours SMOH, Prop time 0 SMOH. 1400 TT. What’s your expert opinion? Is there going to be problems with this engine since it has flown so little. Kept inside hanger whole time.
What do you think?
Click to expand...
Jim B,

Is this 9588U? I found an ad on TAP for an airplane that fits the description. Based solely on the ad, the engine doesn’t scare me. What does scare me is the price. Well, there’s also the paint scheme to be reckoned with. But definitely the price, which is about 2x what I would pay for a Cheetah.

But that’s just me.
 
Roger Wilco said:
Jim B,

Is this 9588U? I found an ad on TAP for an airplane that fits the description. Based solely on the ad, the engine doesn’t scare me. What does scare me is the price. Well, there’s also the paint scheme to be reckoned with. But definitely the price, which is about 2x what I would pay for a Cheetah.

But that’s just me.
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Let’s see. Interesting paint job (cool IMO), nicely done interior, avionics not old (or not new anyway ). But - last annual 3 years ago, unknown flight time per year until sitting 3+ years.

Could be someone’s baby who ran into medical issues and is finally selling, but just let sit too long. At least it seems to be hangared.

I flew a Cheetah for a while. Fun plane. Hope this one finds a new home.
 
A few additional thoughts:

A lot of good suggestions about the engine, but you also have to think about the airframe. Sitting is hard on everything from door seals, pulleys rust up, lack of lubrication on hinges, rodents doing damage, fuel tanks gumming up, fuel valves that don't work properly, cables, etc. Tires are dry rotted, disc brake seals dried out from non use, etc.

Avionics at that age and non use are probably needing to be replaced. Vacuum pump dried out, etc.

Battery aged out and leaking?

Many things besides the engine to look at.
 
pfarber said:
Lets do the math: in 20 years a motor has run 200 hours.

Does it matter if it ran 10 hours a year? 200 hours in the first year and then sat for 19? Or it sat for 19 and ran 200 in the last year?
No, none of that matters. All that matters is when you look inside what do you see.

Because all of the possible corrosion of the first 19 years doesn't simply go away because you ran it 200 hours in one year.
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Not at all. If it's been 10 hours a year, it's probably not great. If it was 200 hours in the first year and then sat for 19, it's almost certainly a hunk of rust. If it was run 5 hours per year for 19 years, then purchased a year ago and run 100 hours this year - And maybe even if it sat for 19 and got all 200 hours this year after extensive work last year - it's probably in much better shape than the first couple of scenarios.
 
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