A friend owns a 182 that he wants to put an O470-S engine into. There is an old STC to do the conversion but he's not able to find the STC holder. The STC is #SA2890SW by Texas Aviation Engineering Co, Meacham Field, Ft. Worth Texas.

Does anyone have any information on the STC? If anyone has the shop instructions would you be willing to share?

Google crosses the address to: Uel Stephens ... age 90-something.
There is also a Uel J. Stephens, Jr.
I did not dig on the genealogy sites ... but it seems that both may have died.

You should also try Cessna Pilots Assoc. They're not real good at searching their archive. On a couple of occasions I have inquired about Field Approvals that I know exist ... and they claim to have no paperwork/knowledge. Once I scrounge the info and offer them copies, they reply that "Why are you sending us this info? We already have it in our files."

Why put an S into a 182? The only good reason I can see is for noise if you are overseas. Otherwise the R is a better engine.

Hi Scott. What makes the R a better engine?

The S was made to make the 230 HP 200 RPM less than the other 470's to minimize the noise signature. As you climb the S runs out of steam sooner than the R model. So if you need an S then get one but otherwise stick with the R. The S cannot use mogas whereas thousands of R models are flying around using both types. I used a lot of mogas. Many buyers would reject outright any 182 with an S for this reason.

Scott, I think you are thinking about the O-470U model in the 1977 and later models. This engine was 8.6:1 compression with a 2400rpm limit compared to the earlier ones which were 7:1 compression with a 2600rpm limit (and ability to run autogas). They also have 4 counterweights rather than two. It is john Jewell that has an STC for the O-470U to up the RPM limit to 2600 and 250hp. As far as I recall, there aren't major differences between an R and S model which is why I was asking.

Yep, you're right, I confused the two. Avoid the U.

Thanks Doug. He's joined the Cessna assoc. but hasn't been confirmed yet.

Thanks Geoffery and Scott. He already owns a nice O470-S and want's to put it in his airplane (if he can get the STC).

If he's set on the -S for some reason (maybe he has one that he got cheap), ignore this.

If he just wants more power, I put a PPonk conversion on mine during the last overhaul and I'm a huge fan of that conversion. It gives up the ability to burn mogas, but the takeoff and climb power is immediately noticeable. At overhaul time, the increased cost was very reasonable, before I added the new 3-bladed prop. (I forget if that's required or not.)

He does own a nice S that he obtained at a reasonable price.

I've got the pponk on my 61 182,,,,,,,, Nice little combo there.

pponk works good.

However honest truth: Unless he's in love with the plane, sell it, but buy an old straight tail with it in it. You'll come out ahead.