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IO-390 in an RV7?

Desert Rat

Well Known Member
Hey guys, I thought I'd have more time to make this decision, but with Lycoming's November price increase looming, I'm leaning forward pulling the trigger on a Thunderbolt engine this month, vs. a "normal" YIO engine a year from now. Knowing that there can be up to a year lead on a Thunderbolt, it seems to make sense from both a $$ and a calendar perspective.

The question now is just which one;

The combo I'm thinking of is a IO390, Hartzell prop, and James cowl. This gets off the reservation pretty quickly as far as Vans parts and engineering coverage, so for the of you who've gone the 390 route, would you do it again?

Looking at the announcement from Vans, plus the research, it seems like at a bare minimum, this combo will require a prop spacer, a bigger oil cooler, maybe different engine control linkages, probably different lube and fuel lines, firewall penetrations...

I get that theres no replacement for displacement, but was it worth the hassle of not having an off the shelf firewall fwd kit and having to rework the cowl &/or snorkel, plus the stuff I probably don't know about? If anybody has this combo with a james cowl, did this eliminate cowl/snorkel fitment problems or just trade them for a different challenge? How much time and $$$ did this add to your build?
 
I would suggest you compare it to a Titan IO370, bolt on install with stock parts. IMO very little to gain with the 390 as the HP is very close and the install will be much more 'custom' with the 390 not to mention the weight gain and custom cowl (personally not a fan of prop extensions or James cowls).
 
Performance wise- you won't gain much. Cost wise- you will need deeper pockets. Time wise- custom installations always take the square in time needed. Weight wise- you know the results here. Bragging rights- well, cost/effort/time have to fime their own justification. Sometimes in the processs, the 'Builder gene' becomes dominant over the 'Flying gene'.
Walt's suggestion has good merit.
 
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A lot of stuff to install the IO-390 should be the same as the angle-valve IO-360 FWF kit, right? Why would a prop extension be needed?

An RV-7 seems like a good airframe to do this, since they tend to come out with the c.g. toward the aft end of the envelop.
 
A lot of stuff to install the IO-390 should be the same as the angle-valve IO-360 FWF kit, right? Why would a prop extension be needed?

An RV-7 seems like a good airframe to do this, since they tend to come out with the c.g. toward the aft end of the envelop.

The James cowl requires and extended hub I'm pretty sure.

My CG is on the fwd end at 80"(78.7 - 86.2) with the Van's spec'd 360 and CS prop.
 
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Hey guys- Thanks for the responses.

Just to clarify a couple of points that came up in the responses.

Walt, thanks for the suggestion, but Lycoming is a sister company so we're Lycoming all the way.

According to both Vans & Lycoming, the IO390 only weighs about 8 lbs more than the 180hp IO-360 and actually weighs 22 lbs LESS than the angle valve IO-360

IO-360 M1B (180hp) 300 lbs
IO-360 A1B6 (200hp) 333 lbs
IO-390 A3B6 (210hp) 308 lbs

Somebody asked about my comment re needing a prop extension; I've seen someone here on VAF (sorry, don't remember who) that had installed a 390 and said that the Van's snorkel hit the lower cowl and needed to be reworked. I was thinking about a James cowl anyway and it seems like it might be a way to eliminate that problem, but my understanding is that the James cowl is longer and will need a prop extension regardless of the engine selection.

The difference between the 360 and the 390 is a $5k decision just for the engine. On the surface, that's probably something I could stomach, but if it's going to rapidly turn into another $5k worth of extra stuff to make it work, or if it's going to add months of fitment and flight test headaches to make it all play nice, I'd like to know about it ahead of time so I can make an informed decision about whether it would be worth it!
 
Walt,
Isn't the Titan IO-370 rated for between 187 and 195 HP? An IO-390EXP119 is rated at 215. and the IO-390 A3B6 is at 210. Thats a pretty significant difference I'd think.

I'm also contemplating an IO-390, but going the EXP119 route.

It's also odd that the price increase didn't affect the IO-390 EXP119 this year.
 
Lynn- for what it's worth, I talked to the Thunderbolt rep today and he told me that historical data has shown that the thunderbolts make a few more ponies than their non-thunderbolt cousins and that I could expect a thunderbolt IO390A3B6 to make about 213 hp.

He also said that it would burn about 6% more fuel than an IO360M1B for a given power setting, but I believe that was all the 390s, Thunderbolt or not. I didn't specifically ask, but it seems like with all that HP it would be easy to run over square, so the fuel burn in cruise is likely pretty close to a wash.
 
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Walt,
Isn't the Titan IO-370 rated for between 187 and 195 HP? An IO-390EXP119 is rated at 215. and the IO-390 A3B6 is at 210. Thats a pretty significant difference I'd think.

I'm also contemplating an IO-390, but going the EXP119 route.

It's also odd that the price increase didn't affect the IO-390 EXP119 this year.

The Titan IO-370 with 9.6 compression has a 'rated' power of 195, reliable sources and some dyno runs I've seen indicate around 205 is typical.
Listed weight is 295 lbs.

So by my calculation I save 13 lbs and give up approx 5-10 HP over the 390 (and I'm pretty sure it's much less $$ than the Thunderbolt 390).
Installation is also per the plans with very few/no surprises.
 
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Time, money, delays

Resist the temptation to build a Space Shuttle and install the O360-A1A, plain Jane engine with the standard Van's cowl.
You will save: time, money, weight...and aggravation.
The "performance gain" is modest, RV's are already wonderful designs. You are not building a Formula One race car.
Turn all that extra money into AvGas and get proficient flying. Van wrote an article about that.
Regards
 
Somebody asked about my comment re needing a prop extension; I've seen someone here on VAF (sorry, don't remember who) that had installed a 390 and said that the Van's snorkel hit the lower cowl and needed to be reworked. ...

There was a thread a few days ago discussing how the RV-14/A snorkel & lower cowl are being reworked to provide better clearance and a better entry angle into the injector, can't immediately find a link. Changing cowl is always a lot of work.

Pete
 
390

I put a Thunderbolt 390 with Barrett work done to it in my new 7. Stock cowl, no prop extension. Whirlwind RV74 prop. Custom made plenum. It is tight but works great

I wanted the extra weight due to the 7 being on the back side of the CG with a parallel valve. The CG turned out great with this combo.

The real reason I wanted it was to have a better climb rate. Often when leaving the Phoenix area to the east ATC will clear to altitude early in the climb. There are mountains close by. In the Summer I wanted to be able climb without stair stepping.

I don't think you can go wrong with the 390. My plane is in paint but you can stop by when I get it back and see the install. I'm at Stellar Air Park.
 
Somebody asked about my comment re needing a prop extension; I've seen someone here on VAF (sorry, don't remember who) that had installed a 390 and said that the Van's snorkel hit the lower cowl and needed to be reworked.

This is more a function of the fuel injection servo than the 390 itself. But perhaps with the 390-EXP119 sump and injector, the snorkel would have to be redesigned. So - may be easier/cheaper to make a new snorkel, rather than a long cowl and prop extension.
 
I went in a friends o360 rv7a with a cs prop. It snapped my neck back on brake release. The climb rate and angle blew away every other light ac I ever flew in. Unless your day job is flying f15s you will like it.

Mods to stock has a huge impact on build time. They all say it and it is so true.
 
390... when you want to go UP!

390... when you want to go UP!

ORCA Flight! with 390s by Thunderbolt and Lycon in RV7 and RV8

850-1913-1.jpg
 
.... Often when leaving the Phoenix area to the east ATC will clear to altitude early in the climb. There are mountains close by. In the Summer I wanted to be able climb without stair stepping.

I don't think you can go wrong with the 390. My plane is in paint but you can stop by when I get it back and see the install. I'm at Stellar Air Park.

Darwin, I'm spending about 90% of my time in ICT right now due to family obligations, but I will definitely take you up on your offer the next time I'm out west.

I'm painfully aware of what flying in Phoenix in the summer can be like, but if you don't mind me asking, what issue required you to step climb with the IO360? Overheating?
 
Prop extension..

For what it's worth I'm using a James cowl on my "7" with a YIO-360-180-M1B Thunderbolt (horizontal induction) which requires the "long" cowl and a extension. It's really not a extension but rather a different Hartzell prop hub, the M2YR which is 2" longer than the standard C2YR. Van's will sell either, the M2YR is a ~$250 more, I know as I just ordered it and my engine before the price increases!
 
I think I'd do it again-it's really not that bad. I am not flying yet, but all the FWF is done. If I weren't to do it again it would be more to save weight that hassle of installation.

Curious as to why the SJ cowl? They look and perform great, but the standard cowl worked fine with mine with standard Vans snorkel too.

I went with the Composite Hartz (16-17 lbs ligher than the alu BA Hartz), but I think they have an extended hub for it too. I figure it'll offset some of the 390 weight on the nose.
 
We'll you said it "...look and perform great...". I'm not a fan of the snorkel setup on the standard cowl and like the idea of a straight shot from intake to throttle body. Hopefully it pans out because is a more expensive path and "hoping" not too more work... we shall see.

Back to finishing the #$^% canopy!
 
Occasionally

Darwin, I'm spending about 90% of my time in ICT right now due to family obligations, but I will definitely take you up on your offer the next time I'm out west.

I'm painfully aware of what flying in Phoenix in the summer can be like, but if you don't mind me asking, what issue required you to step climb with the IO360? Overheating?

On the hottest days stair step climbs were necessary. Fully loaded with baggage and fuel. Not too often but it happened.

The 390 when cleared to cruise altitude can handle it. The new 7 has a plenum so I believe the cooling is improved.
 
IO-390 in an RV-7A

FWIW. I built my -7A with the Thunderbolt IO-390 and I've been flying it since early 2017. The engine has performed flawlessly. I used the standard Van's 'smooth' cowl and the Airflow Performance fuel injection. It was very easy to adjust the 'S' intake to fit. The baffles required modifications but not a lot, all things considered. I'm running an MT 3-blade prop (no extension needed) and it's outstanding! I decided to get the largest oil cooler I could find and it has proven to be good choice however, I also decided against hanging it on the rear baffle due to cracking concerns. So, I placed the oil cooler on a frame attached to the firewall on the right side (more available space) and I went with an EarthX battery mounted on the left side of the firewall and have not had any issues with it. I know Dick V has grief with modifying his designs and I respect him for that. Fortunately, the changes I made ended up looking and performing like the new -7A with the Thunderbolt. Bullet dodged. All in all it's worked fine for me.
 
I did the same as N1flyer except standard battery and baffle mounted oil cooler, and had to do the same minor mods to the air filter, duct and baffles. I know a guy that used the RV14 baffle kit for the 390 which eliminated most of the issues of fit that I had. If you go the 390 route I recommend the front mount prop governor I have the rear and it was a pain to install, cable, and adjust. Straight Vans cowl (no snorkel)
 
Hey Guys-

Thanks for all the replies! I'm getting ready to pull the trigger on this and have one final stupid question....What color combo?

Can anybody think of a practical, mechanical reason not to order this with a red case and black cylinders? all red? lycoming gray?
 
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My friend, and formation buddy here at HAO has an RV7A with an IO-390, and a standard Vans cowl. This combination functions very well in his airplane.
 
I went plane jane grey, figured it would be easier to locate leaks if I had them, but do have a bit of color envy when I see some of the pics posted. My plane base color is a light dove grey anyway so I guess it matches a bit.

That said-it's (usually) covered up by the cowl so not too bad. May add some of the billet valve covers at some point to bling it up :)

Pic for reference

80-pxl_20201019_201816856_1__ae56cfd16f4e11267264c3ba0891cec8b4aaacea.jpg
 
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Not grey, want to know it's a thunderbolt.

Black might be hard to see leaks.

That leaves red........... (which is thunderbolt only I think)
 
dreed,

Coincidentally, I had already stolen and saved a copy of that picture from somewhere on the inter web. LOVE the paint job on your airplane and the engine/baffles really set it off. The whole scheme is on my short list to shamelessly rip off...I mean pay tribute too.

Walt...wow. Love that as well, and a similar combo on the Lycoming site is what got me thinking about that particular scheme. Any concerns about seeing oil or exhaust leaks on those ultra cool black jugs?
 
Hey Guys-

Thanks for all the replies! I'm getting ready to pull the trigger on this and have one final stupid question....What color combo?

Can anybody think of a practical, mechanical reason not to order this with a red case and black cylinders? all red? lycoming gray?

As you come over the top on a loop, or roll out to a stop at the grass parking space at Johnson Creek, you can't, and no one else can, tell what color your engine is painted. Who cares!
 
Hey All-

Just wanted to circle back with a resolution and to say thanks for all the opinions both pro & con.

I had originally talked myself into just going with the IO-360M1B due to it's ability to run MoGas without Lycoming likely puking all over the warranty if something went wrong.

However, after making that decision, I almost immediately regretted it and eventually came to the realization that no matter how much gray area there is, I doubt that I'll ever be comfortable running MoGas in a brand new engine that literally cost more than the house I was raised in. Once I acknowledged that point, the decision became a lot easier.

Long story short, I called back and changed up to the YIO390-A3B6.

I'm looking forward to begging for help from those who've gone before as I get into the FWF stuff.

Thanks again for the input,

Terry
 
I get that theres no replacement for displacement, but was it worth the hassle of not having an off the shelf firewall fwd kit and having to rework the cowl &/or snorkel, plus the stuff I probably don't know about? If anybody has this combo with a james cowl, did this eliminate cowl/snorkel fitment problems or just trade them for a different challenge? How much time and $$$ did this add to your build?

Hi, Terry

I have a Mattituck IO-390 engine with a Hartzell 74" Blended Airfoil prop on my RV-7A and love the performance. It climbs like a rocket and is very fuel efficient in cruise. For the baffle, I just used the Van's generic baffle kit for the O-360 engine. Not difficult...just a little tedious with fit and trim like any other baffle. I moved my battery to the back (like the RV-8) to shift c.g. aft and installed a Piper external power adapter on the bottom fuselage for charging. I also used the larger RV-10 firewall mounted oil cooler in place of the battery and installed a butterfly valve on the oil cooler intake to tweak oil temps. I also installed cowl vents on the bottom cowl. If anything, my engine runs way cool.... a good problem to have.
 
I'm also considering an IO-390-A3B6 in my RV-7 and the time to order the engine is approaching. I have read this thread with interest--thanks for all of the responses! I have a few other questions for those who have done this.

1. What exhaust did you use?
2. Any issues with the forward mounted prop governor?
3. Any first-person experiences using the 14 IO-390 baffle kit in a 7?

Thanks!
 
I'm also considering an IO-390-A3B6 in my RV-7 and the time to order the engine is approaching. I have read this thread with interest--thanks for all of the responses! I have a few other questions for those who have done this.

1. What exhaust did you use?
2. Any issues with the forward mounted prop governor?
3. Any first-person experiences using the 14 IO-390 baffle kit in a 7?

Thanks!

Hi David,

On my 390 I used the Vetterman 4 pipe with custom isolation mounting system. Works great.

The forward mounted governor is not an issue.

The baffling kit for the 390 and the 14 is exactly what you want. It fits nice with little messing around. Sadly, it came out just after I finished with the old Angle valved 360 baffle kit.

I highly recommend a 1/2" prop extension and extending the cowl the same. The engine is a very tight fit on the right front between the cowl and the engine/baffling. I made a plenum for mine to improve cooling.
 
More HP, more heat

Generally the more HP you make, the more waste heat you need to get rid of.

If the concern is avoiding stair step climbs in hot temperatures... My 0.02 is that putting a bigger engine in with no changes to cooling will not fix the issue.

For another way to look at this, let's say your 1966 Mustang with the 6-cyl overheats in Phoenix while climbing. So you put in the V8, and leave the same radiator in place. Whatcha think will happen?

Also - will *any* of the engines you are considering run on 94UL? If I was about to buy an engine that's something I'd give a bit of thought to.

Having flown the SW in late summer... your problem may be not baking in the cockpit even if you have the ideal engine / engine cooling.

I have a non-standard engine in my plane - the baffle and cowl mod hassles were greater than imagined.

OTOH - bigger is always better, no? [or is it?]
 
Any opinion on the IO-360 A1B6 ? It is a bit heavier but at 200HP seems about right.

I am interested on the acro abilities of RV7 so I tend to think that 200HP should be required. I cannot go on the route of IO-390 as local laws don't allow me to exceed 200HP for home built.
 
Any opinion on the IO-360 A1B6 ? It is a bit heavier but at 200HP seems about right.

I am interested on the acro abilities of RV7 so I tend to think that 200HP should be required. I cannot go on the route of IO-390 as local laws don't allow me to exceed 200HP for home built.

You might consider the TCM IO-370, won't run auto fuel "rated" at 195HP but in reality, it's closer to 205HP. Lighter than IO-360/IO-390 angle valves.
 
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