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RV8 with an IO-320

D Weisgerber

Well Known Member
I'm in the process of building an RV8, I'm planning on putting in an IO-320B1A. The reason I'm going to use a 320 is because have a one with about 400 SMOH. I'm just wondering how many people are using a 320 in an RV8, and are they satisfied with it?
 
I'm in the process of building an RV8, I'm planning on putting in an IO-320B1A. The reason I'm going to use a 320 is because have a one with about 400 SMOH. I'm just wondering how many people are using a 320 in an RV8, and are they satisfied with it?

Look up "Lowpass" here on the forum. He had an O-320 in his -8 and then swapped it out for a 360.

Also check with Jay Pratt, he has flown -8's with the 320, and 180 HP O-360 and 200 HP IO-360. He can give you an unbiased answer.

The other options are to sell the 320 and use the money on a 360 or hotrod the 320 and get the HP up to 180+, which has been done before.

The biggest thing will be to keep it as light as you can.
 
You'll still climb at 1500+ fpm and cruise at 165+ knots. If it's what you have and you are building on a budget then go for it.

I have a 170 hp 360 with a fixed pitch prop. Sometimes I wish I had more power or could climb faster, but then I remind myself that would have added $30k to the price of the plane, so I'm happy with what I have.

I noticed you have an rv 6, I'm sure it will be similar but slightly better performance in the 8 due to slightly less drag and a little less weight.
 
I'd bet you will be quite happy with a O-320 if you go constant speed. I flew the test time off a 9A with an O-320 and MT prop and was quite impressed. An 8 should be better.
 
Like Bob said,

If you go constant speed, you will not miss the 20hp --- our -8A was 160 hp but only had fixed pitch --- it was still a fun machine!

Ron
 
There was an 8 with an O-320 here at our airfield. We questioned it, but everyone who flew it just said ..... WOW !

Yes, MT constant speed.

Yes - a tuned exhaust.

Yes, a balanced motor.

But it was light - and on an 8 that is important for balance and handling.

Do not hesitate, but do the work to extract everything you can from the motor and propeller.
 
There was an 8 with an O-320 here at our airfield. We questioned it, but everyone who flew it just said ..... WOW !

Yes, MT constant speed.

Yes - a tuned exhaust.

Yes, a balanced motor.

But it was light - and on an 8 that is important for balance and handling.

Do not hesitate, but do the work to extract everything you can from the motor and propeller.

This is so true with any RV. Many people that have an O360 and Metal constant speed prop, know what it is like to go fast from point A to point B. But will never know how amazing an RV will handle.... balanced and light.

But if you fly mainly local flights just for fun then re read the red part of the above quote.
 
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Thanks for the feedback. I am planning on a constant speed prop, and I'm going to try to keep the weight down. I have been happy with the performance of my RV6.
 
I'm in the process of building an RV8, I'm planning on putting in an IO-320B1A. The reason I'm going to use a 320 is because have a one with about 400 SMOH. I'm just wondering how many people are using a 320 in an RV8, and are they satisfied with it?

I’d take into consideration resale value down the track. Not many buyers will be happy with the 320 because the 360 is the defacto standard for the RV8 so that might cost you a lot of dollars eventually.
I know, I know....don’t tell me....you’re never going to sell it ....that’s what they all say ha ha ha.
Personally I’d sell the 320 and put the money towards a 360. The small difference in price would be more than offset by the major increase in resale value of the aircraft.
 
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My 8 has an O-320. I bought it that way last June. New to the RV8 world, I had visions of grandeur of picking up an 8 that met all my needs with an IO-360. The problem was last year, they were so hot, some were selling within 15 minutes of being posted on forums and websites if they were nice. I found my 8 and it was extremely well built but didn't have the engine I wanted. As others have said, the price was 20k less than most 8s because of the engine. My guru at my field convinced me that I could buy it, sell the 320 and put the engine I want on and overall spend less with an excellent built plane.

Performance, the airplane flies nice, light nose, fun to fly. I do a decent amount of formation and my bud's 8 is a 200hp, and a bud in an RV7 is a 180 hp. To use his phrase, it was like I was always stuck in 3rd gear.

I looked for a motor for 6 months and couldn't find something to fit my needs. So from a recommendation of an RV4 friend, I sent my cylinders out and had Ly-con do their deal to them and put in higher compression pistons. the instant I sent them out, an io-360 motor fell in my lap.

Once I got the O-320 cylinders back, we hung them and put a different prop on. It is like a completely different airplane. Its performance is equivalent to the 180hp RVs in our group. It is an awesome flying plane, with a light nose. Happy with it, yes but wanting just a little more.

I am still going to hang the IO-360 with CS, but right now flying is good and I'm not in a rush. On the resale market, with a 320, it will take longer to sell and at a lower price.

So, after this long story, my recommendation to you is, hang an io-360, you can still keep it reasonably light and you won't regret it. I haven't ever heard an 8 owner say, man, I wish I woulda put a 320 on my plane instead of a 360.
 
I sold my first 8 back in 2012. Had a heck of a time, because nobody wanted a 320. Airplane flew fantastic, except it was a bit lacking when trying to stay in position in formation. See posts 10 and 11. So now, on my new 8, I've got a 360.
 
I?d take into consideration resale value down the track. Not many buyers will be happy with the 320 because the 360 is the defacto standard for the RV8 so that might cost you a lot of dollars eventually.
I know, I know....don?t tell me....you?re never going to sell it ....that?s what they all say ha ha ha.
Personally I?d sell the 320 and put the money towards a 360. The small difference in price would be more than offset by the major increase in resale value of the aircraft.

You beat me to it, that's exactly what I as gunna say. Resale is something to consider even if it doesn't figure at this time.
My 8 has the Std popular set up IO360 CS, I flew a 6 with O320 FP, was a dog, wouldn't change mine for anything!
 
I overhauled my rv6 0320 engine with 10-1 pistons, port/polish cylinders, dual pmags, the works. Puts out 180+hp. The only reason i rebuilt the engine versus putting a 360 on was that my engine mount is a conical mount. It would have required a mount, cowling and gear leg change to do it. The rv6 can get away with a hopped up 320 engine for resale. While an rv8 might fly great with an engine like mine, very few buyers are going to care. They will want the 360 or you will wind up nearly giving the plane away when you sell it. As a comparison, my engine overhaul was $20k. I saved very little over the 360.
 
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