O-290 on a 105T

[D.A.]

I know there are a number of mods that have to be done to a 105T in order to put a 150/160 on it, but do you have to do the same mods to install an O-290? Do you have to weld in the 3/8" tubes in the back of the fuselage?
Thanks

[1934A]

I wouldn't think any fuselage mods would need to be done, as long as you aren't trying to raise the fross weight. The 105T cubs did have the same 1500# gw as the 125hp models, didn't they?

[skywagon8a]

Look at the TC 1A2.

Engine Models PA-18 and PA-19:Continental C-90-12F or C-90-8F (Uses carburetor setting No. 530726)(See Item 106 for Models PA-18 "125" and PA-18A, Item 108 for Models PA-18 "135" andPA-18A "135", and NOTE 3 for Model PA-18 "105" (Special))(See also Items 101, 106 and 108 for optional engines)

106. Lycoming O-290-D engine. Install in accordance with Piper Dwg. No. 12447. Use actual weight change Fuel - 80 min. grade aviation gasoline Engine Limits - For all operations, 2600 r.p.m. (125 hp.) Oil Capacity - 8 quarts at (-36) Items 104, 601(b), and 401(f), 401(g) or 401(p) are required. (See Item 3 for propellers.)

108. Lycoming O290-D2 engine. Install in accordance with Piper Dwg. No. 12447. Use actual weight change. Fuel - 80/87 min. grade aviation gasoline Engine Limits - For all operations, 2600 r.p.m. (135 hp.) Fuel Capacity - 36 gallons at (+24) Oil Capacity - 8 quarts at (-36) Items 102 and 109 are required. See Item 4 for propellers

Look here for the drawing 12447:

The Unofficial PA-18 Drawings Viewer (supercubproject.com)

[D.A.]

Look at the TC 1A2...

Thanks Skywagon. I took a look at "12447" (Thanks Christian) and from what I can see, all the mods to run an O-290 are FWF? Please correct me if I'm wrong.

[supercrow]

Thanks Skywagon. I took a look at "12447" (Thanks Christian) and from what I can see, all the mods to run an O-290 are FWF? Please correct me if I'm wrong.

Yes, that may very well be, it that is what the drawing relates. Always check drawings very carefully for footnotes etc.. Sometimes they require other mods that are not obviously seen on the drawing.

[skywagon8a]

Yes, that may very well be, it that is what the drawing relates. Always check drawings very carefully for footnotes etc.. Sometimes they require other mods that are not obviously seen on the drawing.

Yes, that is part of any drawing. The "in accordance with drawing #" (in this case 12447) may instruct you to refer to another drawing as well. And that drawing may ...... as well.
All the part numbers on the assembly drawing have drawings of their own which may also refer you to another drawing. Read everything.

[Airwrench]

DA, I used to maintain a factory PA-18-125 and it did not have the 3/8" tubes - that was part of the 1500 / 1750 GW increase requirements, as I recall - Steve