Lycoming 290g Questions

[Mike]

Hello All,

An "exhaustive" internet search regarding the 0-290G has left me with
several unanswered questions. I understand that the EAA published a
conversion guide years back that would be very helpful. In the mean
time, I am hoping some of you out there can answer any of the
following questions:

1) Which cylinders may be used (i.e. bolt-on) on the O-290G? I
understand that the stock cylinders, other 0-290 cylinders (D, D2
etc), and 0-435 may be bolted on and used.

2) Which pistons may be used (in native/unmodified form)?

3) Which cranks may be used (in native/unmodified form)? I understand
that "any" 0-320 crank may be installed without modification.

4) What "slight" modifications can be used to up the HP to 150hp?

5) Is the "converted" 0-290G still heavier than an 0-320? Why?

6) Any known sources for 0-290 parts?

Thanks for any help,

Mike

[Orval Fairbairn]

In article >,
(Mike) wrote:

> Hello All,
>
> An "exhaustive" internet search regarding the 0-290G has left me with
> several unanswered questions. I understand that the EAA published a
> conversion guide years back that would be very helpful. In the mean
> time, I am hoping some of you out there can answer any of the
> following questions:
>
> 1) Which cylinders may be used (i.e. bolt-on) on the O-290G? I
> understand that the stock cylinders, other 0-290 cylinders (D, D2
> etc), and 0-435 may be bolted on and used.

There are two kinds of straight valve cylinders military (O-435-C) and
civilian (O-435-A) -- both are acceptable in any combination.




> 2) Which pistons may be used (in native/unmodified form)?

It is best to use the 3-ring pistons, rather than the old 4-ring
pistons. You can get 135 hp, if you use the O-290-D2 pistons (7.5:1,
rather than 6.5:1 compression ratio)

Piston Top Comp 2nd Comp Oil ring
125 hp 69958 62916/LW-13883p Same as #1 69401ca/68338pa
135 hp 69481 Same Same Same

> 3) Which cranks may be used (in native/unmodified form)? I understand
> that "any" 0-320 crank may be installed without modification.

I don't know this one, as I use the O-435.


> 4) What "slight" modifications can be used to up the HP to 150hp?
>
> 5) Is the "converted" 0-290G still heavier than an 0-320? Why?
>
> 6) Any known sources for 0-290 parts?

El Reno Aviation
1994 S. Country Club Rd
PO Box 760
El Reno
OK 73036-0760

Ph: 1-800-521-0333

The entire top end of the straight valve O-435 series is the same as the
top end of the O-290 series. The only differences in hp are the pistons.

You can use the same tappets, lifters, push rods in O-540, )-360, etc.

[Ed Sullivan]

On 3 Dec 2004 19:52:31 -0800, (Mike) wrote:

>Hello All,
>
>An "exhaustive" internet search regarding the 0-290G has left me with
>several unanswered questions. I understand that the EAA published a
>conversion guide years back that would be very helpful. In the mean
>time, I am hoping some of you out there can answer any of the
>following questions:
>
>1) Which cylinders may be used (i.e. bolt-on) on the O-290G? I
>understand that the stock cylinders, other 0-290 cylinders (D, D2
>etc), and 0-435 may be bolted on and used.
>
>2) Which pistons may be used (in native/unmodified form)?
>
>3) Which cranks may be used (in native/unmodified form)? I understand
>that "any" 0-320 crank may be installed without modification.
>
>4) What "slight" modifications can be used to up the HP to 150hp?
>
>5) Is the "converted" 0-290G still heavier than an 0-320? Why?
>
>6) Any known sources for 0-290 parts?
>
>Thanks for any help,
>
>Mike

I saw an ad, I think in the latest Sport Aviation wherein someone
wrote a new manual on the conversion. Price was $40.

EBS

[Drew Dalgleish]

On Sat, 04 Dec 2004 18:01:41 -0800, Ed Sullivan >
wrote:

>On 3 Dec 2004 19:52:31 -0800, (Mike) wrote:
>
>>Hello All,
>>
>>An "exhaustive" internet search regarding the 0-290G has left me with
>>several unanswered questions. I understand that the EAA published a
>>conversion guide years back that would be very helpful. In the mean
>>time, I am hoping some of you out there can answer any of the
>>following questions:
>>
>>1) Which cylinders may be used (i.e. bolt-on) on the O-290G? I
>>understand that the stock cylinders, other 0-290 cylinders (D, D2
>>etc), and 0-435 may be bolted on and used.
>>
>>2) Which pistons may be used (in native/unmodified form)?
>>
>>3) Which cranks may be used (in native/unmodified form)? I understand
>>that "any" 0-320 crank may be installed without modification.
>>
>>4) What "slight" modifications can be used to up the HP to 150hp?
>>
>>5) Is the "converted" 0-290G still heavier than an 0-320? Why?
>>
>>6) Any known sources for 0-290 parts?
>>
>>Thanks for any help,
>>
>>Mike
>
>I saw an ad, I think in the latest Sport Aviation wherein someone
>wrote a new manual on the conversion. Price was $40.
>
>EBS
>
H Mike I can't answer any of your questions but as an owner of an
0-290 D my advice is. These are unsupported engines parts are hard to
find and brutally expensive. If you need cylinders and a crankshaft
it's probably cheaper to buy an 0-320. If you want 150hp you should
buy an 0-320. If you do all the work needed to make it airworthy it
will still be worth next to nothing