Lycoming 125

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Space Monkey
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Lycoming 125

Postby Space Monkey » Thu Jun 14, 2007 8:09 am

I'm looking at an 0290 that needs gone through, I was wondering who could rebuild it? Also is there any kind of mods that can be done to it to get more horse power out of it? Anything at all let me know new jugs, high comp. pistons, cams, carb, turbo, nitrous, or anything else let me know. Thanks for your help.
Currently Boatless again.. Plans are in the works for a LS1 powered, stainless rigged, 14.5' wide track Predator..

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Des Moines Boater
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Postby Des Moines Boater » Thu Jun 14, 2007 8:18 am

Gary Barber of Outlaw Aircraft Engines built an O-290 into a O-320 for one of my boats. He's a member of the forum. I recommend having the the case bored for the larger O-320 cylinders and going that route. I had a boat with the O-290 and the O-320 upgrade was like night and day. There are some other aircraft specialists that can make those mods too in the area.

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speed wheelie
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Postby speed wheelie » Thu Jun 14, 2007 9:29 am

Yeah piston rings for that engine are$$$ Best to go with 0320 cylinders..
You can replace cam with 0360 cam ..Replace rods with 0360 rods.This will make
Lots more power..Tim's not aware that I also build engines ..Have build lots of 0290s
Shoot me a pm if interested!
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Postby Sniper » Thu Jun 14, 2007 10:08 am

I am also in the process of re doing an 0290 but it's going on a small boat so I don't think I will need all that power so far all the internal parts look good but I am going to need some parts mostly intake and exhaust parts and another mag plug wires and probably a few other thing like gasket set
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Postby Des Moines Boater » Thu Jun 14, 2007 11:33 am

Sniper, Speed Wheelie is correct on the rings for the O-290 cylinders. If you are going to do a complete overhaul, now would be the time to upgrade to the O-320. The O-290 has lots of power but parts are getting harder to find and more expensive. You could buy brand new O-320 cylinders if you wanted to. You may not need the extra power but you sure will appreciate it when you have it. I wish I would have done that on the O-290 I had. I had to replace two cylinders and it was a pain to just find two that were any good. Then the rings cost me about $50 more than the used cylinders.


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Space Monkey
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Yeah I'm interested speed wheelie!!!

Postby Space Monkey » Thu Jun 14, 2007 12:25 pm

speed wheelie wrote:Yeah piston rings for that engine are$$$ Best to go with 0320 cylinders..
You can replace cam with 0360 cam ..Replace rods with 0360 rods.This will make
Lots more power..Tim's not aware that I also build engines ..Have build lots of 0290s
Shoot me a pm if interested!




Shoot me a price... 0290 refresh stock and and then something high performance or really high performance. If its not too bad then I'll deff. buy this motor, you've already got me excited!!! What kind of horse power numbers do you think you can get out of it? Thanks for your time.
Jason

PS: I was having trouble with the pm....
Currently Boatless again.. Plans are in the works for a LS1 powered, stainless rigged, 14.5' wide track Predator..

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Postby Sniper » Thu Jun 14, 2007 1:38 pm

Yea I would like to know what it would cost to change over as well my 0290 cylinders are in excellent shape so I can all ways sell them and do you have to change all the other parts out as well or just cylinders and pistons
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Lycoming 125

Postby pirate » Thu Jun 14, 2007 2:16 pm

Another alternative if you don't want to up grade is to use O-435 jugs, pistons, and rings. An O-290 is just an O-435 with two less cylinders. The bore and stroke are the same.

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Postby Sniper » Thu Jun 14, 2007 2:23 pm

What will the 0435 cylinders do for me and what Kind of cost for the change over
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Postby sawsa » Thu Jun 14, 2007 2:51 pm

you guys need to remeber that o290 g's are manual lifter's for oil and the D2'S are hydraulic, if you dont get that one then you have to plum the case. I have one for sale all brand new that's puttin out 190 to 200 horsepower. ma4-5 carb big tube widedeck 200 sump and 2 impulse mag's and starter kit also. the best thing is i can pick this motor up and set it on the bench by myself.

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Tony480
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125

Postby Tony480 » Thu Jun 14, 2007 3:15 pm

Putting o435 cyinders on a 125 does nothing it is exactly what you have,unless they are angle valve and then its only 10 horse power.

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125 Lycoming

Postby pirate » Thu Jun 14, 2007 3:37 pm

That what I said "bore and stroke are the same." Just may be easier to find O-435 jugs, pistons, etc. May also be cheaper for all I know. ECI sells a ring set for the O-435 that's fairly inexpensive. Don't know if it's the same for O-290. Aircraft parts prices are kind of strange.

Ten HP is a fair amount of increase on a small engine.

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Tony480
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o290

Postby Tony480 » Thu Jun 14, 2007 3:47 pm

O290 jugs and o435 jugs are the same,so if eci has inexpensive rings for a o435 then they have them for a o290.Its just like a 360 and a 540.

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125 Lycoming

Postby pirate » Thu Jun 14, 2007 3:50 pm

Whatever

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Postby dblj006 » Thu Jun 14, 2007 4:10 pm

Make sure your ring sets match the type of cylinder you have. There are three different cylinders, Chromed, Nitrided, and plain steel. I imagine that an 0-290g has plain steel cylinders and the ring sets have a chrome finish and thats why they cost what they do.

Sniper find a set of cylinders, a sump, carb, for an 0-320 and have the upgrade done. JMO but you will wish you had. I would like to see some pictures of your engine though.

Generally speaking
0-290 and 0-435 cyl interchange.
0-320 and 0-480 cyl interchange.
0-360 and 0-540 cyl interchange.

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Postby dblj006 » Thu Jun 14, 2007 4:25 pm

The 0-320, 0480 and 0-360, 0-540 cylinders have the same bore. The length of the cylinders are what makes the difference.

But the smaller 0-290, 0-435, are they the same bore? Or are they shorter yet than the others? What makes them the smaller cubic inch? Why would you have to bore a case to make 0-320 cylinders fit if they were the same bore?

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125 Lycoming

Postby pirate » Thu Jun 14, 2007 4:49 pm

For what it's worth. While airboaters interchange parts between engines, Lycoming doesn't. That's why there can be a difference in price.

There are only six models of the O-290 engine. Piston compression ranges between 6.50:1, 7.00:1, and 7.50:1. The pistons may be three or four ring pistons. Four rings cost more.

There are thirty eight different models of the O-435 engine. The compression ratio is 6.50:1 and 7.30:1 Again, may be three ring or four ring.

To me it stands to reason that if there are thirty eight different versions of anything as opposed to six, there would be more parts for the thirty eight than the six and therefore parts would be cheaper. But that's just my opinion. And maybe a little logic.

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Postby dblj006 » Thu Jun 14, 2007 5:46 pm

Actually I believe the math is against that. The more models there are,they more specialized and complicated they become. Now for airboaters that would work to an advantage with a surplus of spare parts. But for aviation it would be another reason for pricing to be higher.

For six engine models there are a finite number of parts. But I'm sure with discontinued items and such all of the pricing for those would be high.

For 38 different models? How any ways can that multiply and specialize parts? Maybe not a whole bunch, but if not why all the different model classifications?

But logic would hold true for sheer production numbers, if Lycoming manufactured a disproportionate amount of 0-435s. How many units of the 0-290s -vs- 0-435s were made?

But this a rant anyway so if someone out there sees ringsets at ECI for cheap not only should they fit the piston, they had better match the freakin cyl they are going into.

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Postby Space Monkey » Thu Jun 14, 2007 6:45 pm

Why are the compression ratios so low on these engines? Aviation fuel is such a high octane I guess I just assumed that all the aircraft engines where high compression. No wonder they only make 125hp in the 7.00:1 range. Is there any way to get it closer to 9, 10, or even 11 to 1? May be then they'll make some torque.
Currently Boatless again.. Plans are in the works for a LS1 powered, stainless rigged, 14.5' wide track Predator..

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125 Lycoming

Postby pirate » Thu Jun 14, 2007 6:47 pm

Huh.....????Why don't you check it out like I did and come up with figures to match what you believe instead of randomizing coming up with...... duh. It's not a rant. It's based o what Lycoming has to offer in the way of parts.

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Postby Sniper » Thu Jun 14, 2007 6:54 pm

the engine I have is a GPU 0290 and it is plain steel cylinders and from the look of every thing there is not much time on the engine it sat in my friends hangar for years and it was real dustyand dirty from sitting around I just decided to pull it apart to clean it up and check every thing out but every thing looks in perfect condition that's why I asked if there was a performance differance in trading cylinders out I just hate to spend money if I dont need to
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Postby dblj006 » Thu Jun 14, 2007 7:07 pm

I was the one ranting dude. And I am disagreeing with you. I'm not sure that should be a problem with you...duhhh...but eyes ees pritty sloe.

But tell me how many units of 0-290 were manufactured, not different models -vs- how many units of a 0-435 were made.

If you take one engine and manufacture it six different ways -vs- one that is manufactured 38 different ways...duh, you think it over. Specially with some of those engines being gear driven and the cranks being what they are...but then again maybe I'm "randomizing"...

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Re: o290

Postby speed wheelie » Thu Jun 14, 2007 7:07 pm

Tony480 wrote:O290 jugs and o435 jugs are the same,so if eci has inexpensive rings for a o435 then they have them for a o290.Its just like a 360 and a 540.
The 0290 piston has a double wedge ring...The 0435 piston has a half wedge ring..therefor the 0435 ring is cheaper :D
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Space Monkey
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Postby Space Monkey » Thu Jun 14, 2007 7:18 pm

Space Monkey!!! wrote:Why are the compression ratios so low on these engines? Aviation fuel is such a high octane I guess I just assumed that all the aircraft engines where high compression. No wonder they only make 125hp in the 7.00:1 range. Is there any way to get it closer to 9, 10, or even 11 to 1? May be then they'll make some torque.
Currently Boatless again.. Plans are in the works for a LS1 powered, stainless rigged, 14.5' wide track Predator..

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125 Lycoming

Postby pirate » Thu Jun 14, 2007 7:37 pm

Thank you Speed, I rest my case.

Dblj006...why try to make it personal? If you disagree fine. That's what makes America great. You have that right

As far as "eyes eess pritty sloe" I'm not responsible for someone else's ignorance. That's on you. You have a nice day.


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