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Lycoming O-435

1:1 Scale

Well Known Member
I'm considering buying a plane with an O-435 in it as a time builder/family hauler while I'm building my -7. I was wondering if there's anything worth knowing about these engines as far as parts/reliability, or if they're pretty standard Lycoming? Thanks!
 
I dont know a lot about the engine, but it was a popular conversion for Stinsons years ago, and I came close to getting one.

Problem I discovered was not the engine, but the prop used on it------and what you are looking at may be different------ but they had a prop that was very problematic due to an oil diaphragm, IIRC.

Good luck.
 
I'm considering buying a plane with an O-435 in it as a time builder/family hauler while I'm building my -7. I was wondering if there's anything worth knowing about these engines as far as parts/reliability, or if they're pretty standard Lycoming? Thanks!

I'm no engine expert but with some O-290 experience here's my two cents. I would be cautious of this engine. The Lycoming O-435 is a six-cylinder, horizontally opposed fixed-wing aircraft and helicopter engine. The engine is a six-cylinder version of the four-cylinder Lycoming O-290. As far as I know, much like the O-290 the O-435 is no longer supported by Lycoming. Now that said, I do love my O-290, but finding parts for it is hard and getting harder and more expensive. Bill R. can attest to this. For example, you won't find any new jugs for this engine if one decides to fail. You'll have to hunt one down that is either OH (good luck) or find one that can be OH (again good luck). The same is true for the cam, crank and case. Since the jugs on the O-290 and O-435 are the same the pistons, rings and other misc can be found at places such as ACS or Gibson's in OK. It can be done but there will be alot of leg work.
 
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... I do love my O-290, but finding parts for it is hard and getting harder and more expensive. Bill R. can attest to this...

The O-290 was a good engine and I have flown behind the O-435 once and it is a nice running engine, same as the O-540.

ECi sells +.010 over rings for the cylinders and the valves should have been changed over to O-320 valves by now.

The O-290 had a 1500 hour RTBO, which may be the same for the O435. Which means you will have to overhaul it sooner.

The engine is a 190 hp six cylinder thus it will be heavy when compared to an IO-360 (~364 lbs vs. ~293 lbs).

As much as I loved my little O-290-D2, I would run away from this engine.

To put this in perspective, the lowest quote I received to major my O-290-D2 after the prop strike was $32,000 and even at that price they weren?t sure they could find parts, regardless of the hours in service. Once I instead that no part had more than 1,000 hours on it, all the engine builders stopped returning my calls.
 
....but it was a popular conversion for Stinsons years ago, and I came close to getting one...
Funny you should mention Stinsons....;)

Lots of good and interesting info from everyone, thanks! The one that caught my eye has less than 400 SMOH, so I was figuing it still had plenty of life left in it, but you never know. And IF something were to happen with it, it sounds like I'd be best just selling the plane.....Or converting to the O-470...:D;) Guess I'll just keep doing more research, but I think I'd rather see something like a nice Stinson when I open hangar doors than a 172.
 
The O-435 is obsolete and an orphan, yes, but so is the Merlin and P&W R985... There are still plenty of parts around, they're just not at Aircraft Spruce. I know a guy who had boxes of BRAND NEW cams, followers, and other stuff for the 435. There are several good flying O-435's on my airpark and they make good power, run smooth as butter and are reliable as a stone axe. I'm looking to build one for one of my future projects. (I'm going with 320 cylinders though).

If you're looking for the level of support that you get for the modern engines, then yes, run away. On the other hand, if you're willing to do a little digging for some parts (if needed), and you get a good price, it's a fine engine.
 
Actually, the lyc still sells some parts for the -435 and the 480, but not the 290. I suspect that may be because the plethora of conversions of -290's that lyc wanted to orphan so they weren't liable for them. -435 cylinders do bolt on to -290's as well.
 
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