T

Trooper1276

Member
Was at an aviation junk yard today and they had about seven or eight old airline GPUs (Ground Power Units) lying around two of them had Lycoming 4 cylinder motors and the rest were continental 2 and 4 cylinder types. the old guy running the joint said I could have any one of them for 400.00 bucks. I couldn't get a look at the data plates to tell what versions they were because of the GPU "box" surrounding them. Does anyone know what models they put in these things? Can someone identify it by the pic? I figure it might be worthwhile to pull them and get them overhauled. Any thoughts or clarification would be helpful.


Thanks
 
GPU's

Trooper1276 said:
Was at an aviation junk yard today and they had about seven or eight old airline GPUs (Ground Power Units) lying around two of them had Lycoming 4 cylinder motors and the rest were continental 2 and 4 cylinder types. the old guy running the joint said I could have any one of them for 400.00 bucks. I couldn't get a look at the data plates to tell what versions they were because of the GPU "box" surrounding them. Does anyone know what models they put in these things? Can someone identify it by the pic? I figure it might be worthwhile to pull them and get them overhauled. Any thoughts or clarification would be helpful.


Thanks
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Not trying to discourage the spirit of experimentalism, I offer the following:

The Lycomings are probably O-290-G's They have a very thin crankshaft flange that is not suitable for use in any of Van's RV series aircraft. You would also have to machine off a couple of pounds of aluminum on the nose of the crankcase that was used to bolt the generator portion of the GPU to the engine.

Back in the 60's-70's they were used in some of the early experimentals that flew straight and level. There were some aircraft that were lost due to the crank flange breaking and the propeller departing the aircraft.

With the weak crankshaft flange and all the modifications that you would have to make (not to mention probable extensive corrosion internally from years of sitting in the elements,) RUN---don't walk away from this idea.:eek:

The Continentals could either be a four or six cylinder engine with the same problems. The four cylinder engines won't produce enough power and the sixes won't fit.:(

Oh! I just remembered, the operative word in GPU is; GROUND!!!!!!
 
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The Lycoming GPU's were all O-290's.

At one time a number of them were converted to aircraft use by us experimenters but I wouldn't touch one today.

At best they would put out 125 HP, which isn't that bad but to convert them you need to replace the sump, intake tubes, carb, and grind the flange off where the generator mounted.

Also, for our use, you would have to change the accessory case and add the flange strengthener (Aircraft Spruce has them).

The parts for this engine are hard to come by now, especially the carb, crank, cylinders, etc.

If you want an engine, buy an O-320 and overhaul it and stay away from the O-290. The only reason I put one on my plane was I found one for a good price that was 0 SMHO. Now that it is damaged I can't locate the parts to overhaul it so it looks like it is heading to the dumpster.
 
Oh well...

Thanks guys. Thought for a moment that this might be a great find, but alas the search continues. As a side note the place I went to was amazing they specialized in DC-3 parts and they had TONS of radials, props, wings, landing gear..etc. Anything you would ever need to complete your project DC-3. I had fun just wondering around for a couple of hours.
 
This is the kind of knowledge and experience that is available on this site that makes it well worth the price of entry!;)
 
If memory serves me correctly the 0-290-G has single ignition also, but this can be converted to dual. It uses the same crank shaft as the 0-235 which is 88% as strong as an 0-320 crank. The problems seems to have been caused by changing pistons from 6.5-1 and trying to get more HP out of the engine. Not a bad choice for an engine if you have a tight budget, and if you fly it with respect to it's capabilities. Would not be my first choice.

Several of them flying in older Experimentals around here, they seem to be solid as an aircraft engine.
 
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Trooper1276 said:
....they specialized in DC-3 parts and they had TONS of radials....
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Dude, you just answered your own question on finding an engine. Just think, an R-1830 bolted on the front of your RV-8! Might need a bit of ballast in the back, then extend the gear legs a bit to make some room...

So are you gonna tell us where this treasure trove is or just leave us hanging? Pleeeeeease? I just love airplane junk yards, whether it's prowling around Tucson or ASOD near Dallas. On my way up to OSH I stopped in at White Industries, a huge salvage operation just E of Kansas City. It's just amazing the stuff they have in there, including a couple of ships I've flown years ago.
 
Concerning the O-290G; virtually every single internal part carries the same part number as the "aircraft" version. Though the engine has single ignition, the cylinders are the same as aircraft parts. The conversion to dual ignition involves removing the block off plate on the accessory case and removing the screw in plugs on the heads - then add the ignition of your choice. In fact, the engine is so close to a "certified" model, there are procedures available to "convert" the case and the engine becomes a legal replacement for some factory built applications.

This engine was a solid aircraft engine in the 60's and powered many homebuilts (and yes, the T-18 was designed around the engine). That said, it's a "orphan" now, and internal parts are impossible or very expensive to find these days (price a set of 290 rings sometime!). Unless overhauled and nearly free, you are better off with the 320.

I have one, but I intend to machine the case for O-320 cylinders (someday).
 
R-1320

I don't know John....1320 might be a little small. they had some R-2800s around that would be great. Its just a bolt on replacement for the O-360 right?:D
 
O290 GPU

The O290 GPU has a O235 crank and cam. The O290D has a O320 crank. You can use Sealed Power # 2c 6620 rings (STD).

Bob
 
For $400, I don't know that I wouldn't take one home. Doubt I'd put one in my airplane, but there's got to be something you could do with a Lycoming power cart. Will it run Christmas lights? How 'bout upgrade the Volkswagen with a O-290?

$400 is a good deal for anything greasy that makes noise - airplane or not.
 
Toobuilder said:
Concerning the O-290G; virtually every single internal part carries the same part number as the "aircraft" version...
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BobMoe said:
The O290 GPU has a O235 crank and cam. The O290D has a O320 crank. You can use Sealed Power # 2c 6620 rings (STD).

Bob
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Don't make me get my OH manual out. ;)

My -D2 does not use an O-320 crank or very many other current production parts. If they did, rebuilding the thing wouldn't be an issue.

You can line-bore them to accept the O-320 crank and cylinders but that is not the same. I looked into doing that but by the time you are finished buying the crank, rods, cylinders, pistons, etc, you might as well buy a new ECI kit.

Oh you will also have to an O-320 sump on it as the O-290 uses the O-235 sump which has the MA-3 carb opening.

Yes, the engines WERE used in a lot of experimentals back in the 60?s, but that was when parts were readily available. Today, ?not so much?.

One other difference, they all had manual lifters until you got up to the O-290-D2, which has hydraulic lifters. Unfortunately, they are not interchangeable. I don?t recall on the O-320 conversion if you can mill the hole to accept the hydraulic lifters or not.

It is a nice dream and it is still possible to do the conversion but you had better have a secret stash of old parts laying around.

Having lived with a 135 HP O-290-D2 for 250 hours, it is a great engine but now that it is damaged, I wish I had put an O-320 on it from the start.
 
Shaneo said:
Anyone have a rebuild manual for one of these? Hopefully PDF version.
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Lycoming has them. You use the Lycoming direct drive manual w/ the O-290 parts supplement. The O-290 is very similar to the O-320 & O-360. Some versions do not have hydraulic valve lifters, including the O-290G.
 
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