engine?

does any have the EA IO-360-M1B in thier rv8? I would like to put this engine in my 8 with inverted systems. I was going to put the io390 in it but have heard the airplane will very nose heavy. Just wanted to make sure this was a good decision as the price of the io 390 is same as the io 360. I would like some opions. thanks
scott

I've heard (but not verified) that the IO-390 is actually a few pounds lighter than most versions of the angle-valve IO-360. This makes sense as I understand it because the -390 is basically a bored 360.

If you plan and shop carefully (lightweight sump, light prop and governor. etc) you take take quite a few pounds off the engine installation. Unfortunately, the inverted oil system adds some weight, but fairly close to the firewall.

I'm using an IO-360 (basically stock) and a very light prop (Whirlwind 151) and am very happy with my weight and C of G, even though my Odyssey battery is on the firewall

I don't think you gain anything by going to an IO-360 at the same cost as the IO-390, but there may be other factors I'm unaware of...

James Freeman

Engine ?

I'm using a IO360 A1B6, with a whirlwind prop/woodward governor and an
Odysey battery in the rear of my 8. I have had NO cg problems at all... even
flying solo and I only weigh 160 lbs. there are many things you can do to
counter potential cg problems. I would use the engine you want. My choice
would be the newest with the latest technology. don't worry about a few
extra pounds... build the plane YOU want. TRUST me, this airplane with a
200 HP powerplant is everything you could want !! Mark Cigal N617MC

The fact that you can hang a IO-540 on the nose with the battery in the tail means that the IO-390 with some planning won't be an issue at all. Just be smart about where you put your other weight.

Engine

Contact Dick Martin ([email protected]) for some expert advice on the
IO-390-X engine in an RV-8. He was probably the first to install one in an RV.

I'm sure he'd be happy to talk to you at length on the subject.

Mannan Thomason
Finishing the baffling and cowl

As a point of reference...I am using the IO-360, horizontal induction, parallel valve engine. I chose to go with 180 HP, but you could use higher compression pistons to get it up to 190 HP and I think you can actually get 200 HP. Anyway, this engine is about 20 to 25 pounds lighter and a LOT smaller. A couple of guys near me have the angle valve engines and their cowling is literally stuffed! Although I am not installing an inverted system, there would be plenty of extra room to do so. However, another friend is building an RV8 with an angle valve 360 and he does have the inverted system installed. It fits, but there is not any additional room.
If you talk to VAN's, they'll tell you to forget the inverted system...you won't use it enough (not to mention the weight and cost) and if you are into serious aerobatics where you would, you are probably buildng the wrong plane.
Good luck.

But then again, if you talk to Van's, you'd be installing a Carbed O-320, with a wood prop .

ordered

I ordered the engine from aero=sport the io 360m1b with 10:1 pistons, port and polished. Can not wait to fly it! I will let everyone know what it like. I also have a rv6a for sale if anyone is interested let me know. Thanks Scott email is [email protected]

Heavy weight

The IO-390-X is actually 9 pounds heavier than the angle head IO-360 (309 vs 299). The advantage goes to the IO-390-X if your choices are dependent on HP. The IO-390 uses a standard compression ratio of 8.7:1 as does the IO-360 A/H but delevops more HP because of the bigger bore. The 390 was derived from an IO-360 A1B6 in the 1990's. All the major components with exception to the cylinders and pistons are are the dsame in either engine. And no, Lycoming did not take 360 cylinders and bore them out. They use the same cylinder head, valves, springs and such but manufactured a bigger barrel for the 390. To get the IO-360 to produce the power that the 390 does would require increassing the compression ratio to around 11:1. But this would be detrimental to the life of the engine.

I think that the 10 horsepower I will lose will not be much of a big deal tho, rather have a balanced airplane. I wil be flying fast enough.