220 GPU?

Planeguy · Post by **Planeguy** » Fri Oct 09, 2015 10:59 am

Going to go have a look at a boat that appears to have a PE-150 engine installed. I would like to know what to look for to confirm this is a "220 GPU" instead of a stock PE-150 (205 HP max). Is it just domed pistons or something else?

Thank you

jeepinocala1111 · Post by **jeepinocala1111** » Fri Oct 09, 2015 11:13 am

Planeguy wrote:Going to go have a look at a boat that appears to have a PE-150 engine installed. I would like to know what to look for to confirm this is a "220 GPU" instead of a stock PE-150 (205 HP max). Is it just domed pistons or something else?

Thank you

Make them run it for a long period it is very well known to get one that is junk. Compression test leak down test and run it for an hour that will keep you safe. If you cant do these then pass on it or you'll be very unhappy.

Viking Life · Post by **Viking Life** » Fri Oct 09, 2015 11:25 am

Leak down test is the most crucial thing you can do and ask the guy to take you out on it for an hour or so. That'll tell you how much blow by there is and how strong the motor is.

One Eyed Gator · Post by **One Eyed Gator** » Fri Oct 09, 2015 11:30 am

I believe a stock PE-150 is a 220. Just considered to have 220 hp where turn up to 2800 or 3,000 rpm.

Do not think they have domed piston think that is one of the upgrades for a 220.

If you know aircraft motor your good if not find someone that REALLY (Key word there) does know aircraft motor.

Planeguy · Post by **Planeguy** » Fri Oct 09, 2015 12:49 pm

One Eyed Gator wrote:I believe a stock PE-150 is a 220. Just considered to have 220 hp where turn up to 2800 or 3,000 rpm.

Do not think they have domed piston think that is one of the upgrades for a 220.

If you know aircraft motor your good if not find someone that REALLY (Key word there) does know aircraft motor.

I got the 205 HP reference from the overhaul manual on this site. According to the manual, max HP is 205 while spinning 2900 at 60 degrees F. I suppose there could be a newer version of the engine that produces 220 HP stock but without some kind of documentation I have to assume they are all the same unless modified. This particular one has been sitting a while with a broken prop so a run and a leak down test is pretty much out of the question. People put too much emphasis on compression anyway. A Continental aircraft engine can still be considered good (airworthy) at 45 psi on an 80 psi leak down test but people like to start to panic at 65 psi even though they are not likely to ever notice a decrease in performance. It all depends on where the air is going. Borescope and pulling it through by hand will tell more in this case.

Aircraft engines are easy. Generator engines with what appear to be designations pulled out of thin air are confusing to me and I will have to learn what can and can't be replaced with aircraft engine parts if the "right" part isn't available.

Planeguy · Post by **Planeguy** » Sat Oct 10, 2015 10:37 am

I have another airboat rookie question.... I have been seeing reference to something called a 470 GPU but I haven't been able to google up an actual generator designation for the 470 to get any specs. Would this be another PE-150?

dblj006 · Post by **dblj006** » Sat Oct 10, 2015 10:55 am

Planeguy wrote:I have another airboat rookie question.... I have been seeing reference to something called a 470 GPU but I haven't been able to google up an actual generator designation for the 470 to get any specs. Would this be another PE-150?

Yes.

jeepinocala1111 · Post by **jeepinocala1111** » Sat Oct 10, 2015 12:27 pm

Those test have to be done or you will most likely be buying a piece of crap. Damn near every airboated gpu I have seen for sale unless they want a fortune are junk and somone will need to spend that furtune to make it good. Not a fun task trust me on that one as we speak the very last two parts on my boat lets simply say the only two that have not been rebuilt are the alternator and magneto the magneto is being rebuilt now and ive decided to rebuilt the alternator just because its the only thing on the boat that has not been rebuilt yet. Yeah a simple 5 grand boat a year later and 15 grand more its looking nice. But hey good luck with an engine with a broken prop on it. Make your decision with tests if they cant be done dont buy it. Or have your wallet out cause the engine will cost a crapload of money or leave you on the lake pissed off.

mojoe · Post by **mojoe** » Sat Oct 10, 2015 12:52 pm

So I gotta ask: Why is planeguy looking at a GPU? Why not true AC motor?

Comanche-pup · Post by **Comanche-pup** » Sat Oct 10, 2015 2:27 pm

A 470 GPU has same cubic displacement as a 0470 aircraft, many take the GPU cylinders off and put true aircraft cylinders on due to GPU cylinders being not very durable, but like mojoe said, if you know aircraft motors, go with what you know, no need to learn a different platform if you already know a better one

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Planeguy · Post by **Planeguy** » Sat Oct 10, 2015 10:09 pm

The boat in question had an asking price of $1800 rigged and on a trailer with the added bonus of only being an hour drive from here instead being 2000 miles distant. My very strong preference is to have an aircraft engine but I can either wait a few years until I can buy outright or I can buy one that can be upgraded as money allows. I don't mind working on them as long as it isn't at the river.

A compression check is important but it needs to be done as soon as possible after shutdown. Any aircraft/GPU engine that has been sitting very long is likely to show low numbers until it is run hard for a while (hours, sometimes more than 10) before the rings scrub the rust out. Sometimes crud sticks to a valve seat and just needs burned/blown out to allow the valve to seal. Since this engine couldn't be run, the only thing I would be able to determine is if air is passing through closed valves or a crack. I can check the condition of the valves along with the condition of the cylinder wall and piston with a borescope so there was no need to drag a compressor and extension cord with me to look at an engine that I assume isn't going to blow healthy anyway. Broken rings will score the cylinder wall. If it was a boat that could be run had been used this summer then I would take the compressor with me.

Both of the cylinders below (pictures from work) passed a compression check. There was no reason for them not to pass but one of them needed some work.

Planeguy · Post by **Planeguy** » Sat Oct 10, 2015 10:36 pm

By the way.... thank you for the answers and the input.

If anyone wants to read what Continental has to say about how to perform a compression check, they can be found at http://www.continentalmotors.aero/xpubl ... fs/sb03-3/

Comanche-pup · Post by **Comanche-pup** » Sat Oct 10, 2015 10:48 pm

A $1800 GPU sounds like it will soon fail if it hasnt already, it will probably need to be rebuilt from bottom up

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Planeguy · Post by **Planeguy** » Sat Oct 10, 2015 10:58 pm

Ad is gone now anyway so I might have been saved a project.

The only airboat currently listed on craigslist in this area is a $36K Hamant. It would be nice but it is bigger than I want and WAY beyond my budget.

Planeguy · Post by **Planeguy** » Sat Oct 10, 2015 11:04 pm

Correct me if I am wrong but if the hull was usable with a trash motor, wouldn't it still be worth $1800? It still had rigging and a trailer. New hulls I have priced are $3500 to $4000 without rigging or trailer.

Comanche-pup · Post by **Comanche-pup** » Sun Oct 11, 2015 12:16 am

Exactly my point, it was priced for hull and rigging, so motor was probably junk

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Planeguy · Post by **Planeguy** » Sun Oct 11, 2015 7:24 am

We kind of got off on a tangent about the boat but the information you are missing to complete the picture is that I have an O-200 disassembled on a table and an O-540 with a minor crack in the case. I flew the O-540 home last spring so I know it runs good. Using one of these engines would not be my first choice because these are aircraft engines associated with specific project aircraft but I could put either of these on an airboat without inflicting a lot of pain on myself. There is always the run out engine option too.

Junk or not, I still need to be able to identify what I am looking at.

jeepinocala1111 · Post by **jeepinocala1111** » Sun Oct 11, 2015 8:32 pm

If you missed out on that your lucky it is not cheap to rebuild an engine like that the cylinders are hard to find or expensive and thats just a tiny piece of the engine. Find a good motor that hasn't sat.

jopete · Post by **jopete** » Sun Oct 11, 2015 9:03 pm

there are still good gpu's out there, i love mine, it has been a great motor. when mine blows up i will look for one that is on a running boat and the owner wants to sell to upgrade. However, there is more junk out there than good ones. so be carefull. same goes for all a/c engines. heck, same goes for most airboats. lol

only thing that would make me not get another gpu would be a smoking deal on a good 520, or a even better deal on a ls/gearbox. {just being honest}

Planeguy · Post by **Planeguy** » Sun Oct 11, 2015 9:08 pm

jeepinocala1111 wrote:If you missed out on that your lucky it is not cheap to rebuild an engine like that the cylinders are hard to find or expensive and thats just a tiny piece of the engine. Find a good motor that hasn't sat.

Care to explain why this O-540

which was flown last spring and will spend the next 3 years on my hangar floor while I rebuild the airframe or this O-200

would not make good airboat candidates for an appropriate sized hull at a decent price? These are the engines I referenced in my previous post. Maybe $1800 dollars is way too much for a rigged hull with a trailer and not worth investigating?

jopete · Post by **jopete** » Sun Oct 11, 2015 9:17 pm

i don't want to step into a peeing match here, but if you worried about money, airboating and flying airplanes is two hobbies that you probly don't need to be in. lol

Planeguy · Post by **Planeguy** » Sun Oct 11, 2015 9:30 pm

Airplanes are not hobby for me. When finished, that Pawnee could make me as much as $40K for spare time maintenance work. Full time work is maintaining and flying planes similar to it. At best I will break even on the Cessna 150 the O-200 belongs to but getting the hangar so I could have a place to work on aircraft was the higher priority on that deal (package deal for plane and hangar, owner would not separate the two). Any money I spend on aircraft is tax deductible.

jopete · Post by **jopete** » Sun Oct 11, 2015 10:37 pm

sounds like you have a good plan. i'm sure if your patient the right deal will appear. for me at least, waiting for the right deal is the hardest part.

Planeguy · Post by **Planeguy** » Sun Oct 11, 2015 10:57 pm

jopete wrote:... waiting for the right deal is the hardest part.

You got that right but I can be patient when it comes to spending money. Unfortunately, not so patient sometimes in the forums.

Comanche-pup · Post by **Comanche-pup** » Mon Oct 12, 2015 12:43 am

Well hopefully I assisted you some, GPUs come in all sorts and sizes when it comes to mods, a 220 is just a single mag 470 cubic inch motor, then you have dual mag mods, then you have 0470 conversions that have aircraft cylinders on with intakes, then if like me have 0520 conversions with the case bored out and 0520 jugs, and thats just the 6 cylinders, you got the whole 4 cylinder line up along with a few 8 cylinders out there

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