0-320 Tri Pacer engine

I found an 0-320 engine (3000 hours TT and no prop strikes) out of a 1957 Tri Pacer that has been torn down by my A&P for rebuilding. He was going to build it for sale and he offered it to me for $4500,
The crank has been sent out and checks good and is standard size. The cases have a small amount of fretting in the center main bearing area so it will go out to be machined and line bored and he is paying for that as well. The rods are also good but it will need new cylinders and pistons. It comes with good used mags, carb, intakes but no exhaust. It does have a place for the fuel pump on the accessory case. He tells me we will have around $11,000 when all is said and done. He said I could assemble the engine myself and he would guide me through it. I understand it will have to stay a 150 HP engine and has conical mounts. Is there any reason not to use this engine in my RV-9A? I really would like to have a brand new engine but this engine is sitting here and I know what I will have when it's done.

O-320

This will make a fine engine for your 9 although I'm sure it can be converted to 160 hp if the front bearing is one piece, (others may argue that point).
Also, you can convert it to any type mount you want.

All you have to do is research.

Roger Ping

My engine came out of a 1961 TriPacer. O-320 B2B that I converted to constant speed prop and added the fuel pump. (gear and plunger added) It is conical mount.

The only thing I will tell you to watch on the engine is the locaton of the carburator on the sump. On my engine, the carb is updraft located as far back on the sump as Lycoming could put it. If you have this sump, I am certain that it will NOT work on an -A model RV as it will hit the nose gear. The sump can be changed and different intake tubes used that will move the carb forward but this is something that should be checked before commiting.

You should be able to convert it to 160 HP. The wrist pins are thicker on the 160 and the pistons are 0.032" higher to raise the compression. There are STCs for certificated aircraft but since your airplane is experimental, you could make the change.

I paid $2,600 for my engine back in 1989. I had $12K in it REBUILT to NEW Specs with 4 NEW Superior cylinders. It sounds like your price is right in line with what my cost were. Make sure what you get for the money. I recommend an overhaul but it should be to new specs not the overhaul limits. When you overhaul to New Specs, I call that a REBUILD. I would recommend spending a little more money to make sure that all the accessories (Carb, Mags, harness, spark plugs) are all new or new spec.

Do not let the conicl mount keep you away from this engine. If you really want Dynofocal, while the case is apart, it can be converted. I think ECI is the outfit that will do this if not, there are outfits in Trade-A-Plane that will.

Gary A. Sobek
N157GS O-320 Hartzell Flying 1,833 hours
EAA TC
FAA A&P
FAA AB DAR

Sounds Good and like a learning experience

RV6_flyer said:

Do not let the conical mount keep you away from this engine. If you really want Dynofocal, while the case is apart, it can be converted. I think ECI is the outfit that will do this if not, there are outfits in Trade-A-Plane that will.

Gary A. Sobek

Click to expand...

Yep ECI will convert to dynafocal and I would do it. Conical is OK but not as good. The price sounds good and the idea he will walk you thru the whole thing spells LEARNING. I think that is priceless and what home building is all about. I HIGHLY SUGGEST YOU BUY THE Sacramento Sky Ranch Lycoming / Continental Engineering manual. It is for everyone and full of info and knowledge you should know before overhauling the engine. I am sure your AP friend is competent, but you need to read this book to know what to ask and do. I don't know how many engines your A&P as overhauled or done recently, and its good to get the wisdom of someone else. The book is well written and easy to understand and full of common errors, critical details and TIPS of what to do and not to do when assembling your engine.

Yes some O320's are not as desirable to upgrade to 160hp, however I had a conical 150hp in my RV-4 and it went very fast. 10 HP is not that much and in a pinch (although I am against it personally) autogas if needed. I must say the conical is not as desirable as the dynafocal and I think the ECI mod (recall about $600-$800 worth it. If you must go to 160hp as an experimental you can do what you want and know besides the bearing and cylinder issues you can do it, but may need to be aware that t/o power should be limited, which is usually not an issue (unless you race WOT at sea level all the time).


I checked in to the STC's to upgrade O320's (Gary can correct me) many if not most can be upgraded officially thru a STC, and some have T/O power restrictions, like time at that power setting while others don't. I assume that has something to do with the split bearing. I don't know off hand about the model you are looking at. I know there are not only issues with some not only regarding the bearings but the cylinders (material, choke). If you Google around you can find the info. There are the desirable models and than the ones that are not as desirable, but physically any can be upgraded. The question is should it. Like I was alluding to I found a C-172 group that listed a STC for the 160HP upgrade for an O320 I was told was less desirable engine, with the power restriction.

The price may be negotiable but $11,000 for a overhauled engine with new accessories? Sounds OK. did you include the overhaul of the carb? Are you going to overhaul the cylinders or by new assemblies? New valves? Are the jugs chrome (you will be stuck with chrome, its OK but there is better treatments now a days)? What's the total hours and has it been overhauled before? Suggest dual EI, but are the mags good or overhaul-able ( Old Bendix have lots of AD's). Do you need a new oil pump (AD)?

Is a brand new engine for $18,000 better? Assume you are up to $12,000 on the overhaul. $6,000 difference. Well obviously for the $6,000 you get NEW engine, warranty and better materials (check ECI, Superior for description of cylinder technology). $6,000 is a lot of money but than if you sold it, you would get your money out of it. going new has less risk in a way and unless the A&P has the resources and test stand and will back it than you can see some of the advantage of the new, justifying the greater cost.

Go into it with eyes wide open and armed with knowledge. Enjoy the journey.

George

Gary, I would leave the engine 150 HP. It sounds like at $4,500 and if I buy new cylinders and pistons I may be closer to $14,000 based on you paying $2,600 and having $12,000 invested. I'll have to think hard about this one.

George, My A&P IA worked in Alaska for years and is a wizard as far as I am concerned. I have complete confidence in him. I will price every single part I think I will need and see what the total is. If it gets within $6,000 I will buy a new engine. A new engine could be bought with a hollow crank for a CS if I decide to go that route later.

Thanks Guys

As George suggests, I would seriously consider converting the case to dynafocal one when doing the case overhaul.
Good Luck,
Mahlon
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Check the oil Sump

I have an 0-320 from a Pacer with the Conical Mounts for my 9A...
Here is what the a rear mounted carb sump looks like..






SO I'll need to change the sump to one that has a more common location..


Paulo

sky ranch engineering

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