Engine-swapping questions from a non-builder…

[Duncannon]

I don’t have the aptitude to build, so I would have to buy an RV that’s already flying. And as someone who just wants to fly, I’m aware that I’d want to buy an RV that already has the engine I desire (don’t buy one with an o-320 if I really want an o-360, or an RV 9 with an o-235 etc.)

If I bought an RV and flew it until time to overhaul the engine, would replacing a carbureted engine with a fuel-injected one be a big deal (o-320 to io-320, etc.)? Another question is replacing a fixed-pitch prop to an Lycoming equipped with CS prop pretty simple? Lastly, is removing an 150 hp o-320 and replacing with a 160 hp o-320 straightforward, or would it be a major project just like upgrading size would be?

Like I said, I wouldn’t buy an RV and then immediately do these swaps. If I come across a good priced RV that passes the pre-buy that just happened to have a 150 hp carbureted motor with a fixed-pitch prop, I’d pounce on the deal and enjoy flying it until time for overhaul.

 

[rockyfatcat]

I don’t have the aptitude to build, so I would have to buy an RV that’s already flying. And as someone who just wants to fly, I’m aware that I’d want to buy an RV that already has the engine I desire (don’t buy one with an o-320 if I really want an o-360, or an RV 9 with an o-235 etc.)

If I bought an RV and flew it until time to overhaul the engine, would replacing a carbureted engine with a fuel-injected one be a big deal (o-320 to io-320, etc.)? Another question is replacing a fixed-pitch prop to an Lycoming equipped with CS prop pretty simple? Lastly, is removing an 150 hp o-320 and replacing with a 160 hp o-320 straightforward, or would it be a major project just like upgrading size would be?

Like I said, I wouldn’t buy an RV and then immediately do these swaps. If I come across a good priced RV that passes the pre-buy that just happened to have a 150 hp carbureted motor with a fixed-pitch prop, I’d pounce on the deal and enjoy flying it until time for overhaul.

First I’m going to assume you are newer to owning aircraft. If you are flying part 91 sole owner, TBO is only a recommendation. I would highly recommend sending an oil sample off for spectral analysis to someone like Blackstone labs. As long as you are making good compression and not making metal you can fly an engine forever. Google mike+busch+savvy+aviation and watch the videos.

Next if you didn’t build it and don’t have the repairman's certificate, or have an A&P license, you will need to either pay an A&P to do the work or get someone to sign off after you. I am an A&P and primarily know certificated aircraft. In the certified world the Owner/Pilot may perform simple assembly and disassembly, and must make a logbook entry.

I have hangar-mates who are I/A’s who have supervised and signed off behind a pilot who does his own complex maintenance. I would arrange all that beforehand.

When you look at experimental aircraft and aircraft engines. There are a number of certified and experimental options to add fuel injection to an engine. The options are only as deep as your budget.

When you decide to upgrade power-plants, you can look at all the combinations. I like the certified engines, but some folks like to experiment with automotive engines. If you don’t replace with same or similar, you will probably change the engine mount and maybe even the engine cowling. Some engines CANNOT accept a constant speed propeller, others can. With either you will have to pay careful attention to weight and balance when you start swapping props and engines.

Decide what you want. Get a good pre-buy inspection. Get a compression test. Get an oil analysis. Decide if it’s what you want at that price. If you’d like a different engine or fuel system, either keep shopping or figure out what the upgrade will cost and whether or not you are either willing to pay now, or upgrade later.

 

[jclark]

I don’t have the aptitude to build, so I would have to buy an RV that’s already flying. And as someone who just wants to fly, I’m aware that I’d want to buy an RV that already has the engine I desire (don’t buy one with an o-320 if I really want an o-360, or an RV 9 with an o-235 etc.)

If I bought an RV and flew it until time to overhaul the engine, would replacing a carbureted engine with a fuel-injected one be a big deal (o-320 to io-320, etc.)? Another question is replacing a fixed-pitch prop to an Lycoming equipped with CS prop pretty simple? Lastly, is removing an 150 hp o-320 and replacing with a 160 hp o-320 straightforward, or would it be a major project just like upgrading size would be?

Like I said, I wouldn’t buy an RV and then immediately do these swaps. If I come across a good priced RV that passes the pre-buy that just happened to have a 150 hp carbureted motor with a fixed-pitch prop, I’d pounce on the deal and enjoy flying it until time for overhaul.

My RV6 started as a 160 HP, Ed Sterba Fixed Pitch Wood Prop, Carbureted plane.
Eventually, this combo became Constant Speed with a Hartzell Prop.

Somewhere past 2000 hours, it became a (new) carbureted O-340 (175+?? HP) with a 3-blade fixed pitch Catto prop. That prop didn't have enough pitch and the wait time at Catto was too long so they refunded me and I got a Whirlwind ground adjustable prop. That worked well but I really wanted CS, so when I found (from Jim Rust) that Whirlwind made a CS prop for that engine, I got one (from a user on this forum who was going to much higher HP).

I never got the carbureted version of that engine working to my satisfaction, so I changed that to an Airflow Performance Fuel Injected system (It helps that Airflow Performance and Don Riviera are "right up the road". We were able to develop a "package" for this setup together.

It can be done.

All of the above was done with the help of friendly A&P's/IA's and builder friends.

Find a solid plane that is working well and just enjoy it. When the time comes, an engine change on it **can** be as easy as changing one on a certified plane (or maybe even easier). Just make sure that you surround yourself with FRIENDLY, KNOWLEDGEABLE people.

 

[Ralph Inkster]

I don’t have the aptitude to build, so I would have to buy an RV that’s already flying. And as someone who just wants to fly, I’m aware that I’d want to buy an RV that already has the engine I desire (don’t buy one with an o-320 if I really want an o-360, or an RV 9 with an o-235 etc.)

If I bought an RV and flew it until time to overhaul the engine, would replacing a carbureted engine with a fuel-injected one be a big deal (o-320 to io-320, etc.)? Another question is replacing a fixed-pitch prop to an Lycoming equipped with CS prop pretty simple? Lastly, is removing an 150 hp o-320 and replacing with a 160 hp o-320 straightforward, or would it be a major project just like upgrading size would be?

Like I said, I wouldn’t buy an RV and then immediately do these swaps. If I come across a good priced RV that passes the pre-buy that just happened to have a 150 hp carbureted motor with a fixed-pitch prop, I’d pounce on the deal and enjoy flying it until time for overhaul.

Hmmm, I think you pretty much answered your own questions in your first paragraph!
Getting into (or getting sucked into) the upgrade / swap game will definitely need you to step up your ‘aptitude to build’ mind set!
Don’t settle for anything less than the plane you really want.

 

[Ironflight]

Next if you didn’t build it and don’t have the repairman's certificate, or have an A&P license, you will need to either pay an A&P to do the work or get someone to sign off after you.

Thsi is incorrect for Experimental aircraft. Since you admit that you’re and A&P who primarily works on certified aircraft, you might be unaware that ANYONE (including the janitor and/or your dog….) is allowed to work on an E-ABand return it to service, even after major maintenance/alteration. The only thing you need an A&P (or the repairman’s Certificate for that aircraft) for is to sign off the Condition Inspection.

If a person has little or no airplane experince or mechanical skills/aptitude, this is probably not wise - but it is legal.

 

[rockyfatcat]

Thsi is incorrect for Experimental aircraft. Since you admit that you’re and A&P who primarily works on certified aircraft, you might be unaware that ANYONE (including the janitor and/or your dog….) is allowed to work on an E-ABand return it to service, even after major maintenance/alteration. The only thing you need an A&P (or the repairman’s Certificate for that aircraft) for is to sign off the Condition Inspection.

If a person has little or no airplane experince or mechanical skills/aptitude, this is probably not wise - but it is legal.

Thank you. I stand corrected.

 

[Duncannon]

Thsi is incorrect for Experimental aircraft. Since you admit that you’re and A&P who primarily works on certified aircraft, you might be unaware that ANYONE (including the janitor and/or your dog….) is allowed to work on an E-ABand return it to service, even after major maintenance/alteration. The only thing you need an A&P (or the repairman’s Certificate for that aircraft) for is to sign off the Condition Inspection.

If a person has little or no airplane experince or mechanical skills/aptitude, this is probably not wise - but it is legal.

I failed to mention that I would likely hire an A&P to remove/install the engine (regardless of swaps or upgrades or lack thereof). I live around 150 nm of Vic in Peachtree City, Ga, so I could go to him if necessary.

 

[Bavafa]

Well, here is another question. If the engine/prop changes in a significant way (HP or Fix pitch vs CS) doesn't have to go back to phase one?
I know this was not the original question but could be relevant or at least to be aware of.

 

[jrs14855]

Fixed pitch to CS requires five hours in phase one IF the operating limitations are written correctly. 150 to 160 hp mod can be most easily done with new cylinders if engine time makes that feasable. The H pistons with new cylinders would bump the power up a bit over 160 hp.
Carb to Fuel Injection requires only A different engine driven fuel pump and some minor plumbing changes. Fuel Injection is more expensive than carb.

 

[blaplante]

... Lastly, is removing an 150 hp o-320 and replacing with a 160 hp o-320 straightforward, or would it be a major project just like upgrading size would be?

...

Many o-320 150 HP engines can be upgraded to 160 HP without removing the engine. Cylinders have to come off... Possibly a carb modification for more flow.
A knowledgeable engine shop can help you know what it would involve.
Baffles are identical for 150 and 160 so it is easy if you did swap the engine.

Fuel Injection:
At least *some* lycoming engines can be changed from carb to Bendix/Precision-Airflow Performance fuel injection. Don at Precision Airflow can help with that. To do that the carb comes off, replace with a fuel "servo". Swap both fuel pumps, and plumb the fuel 'spider', lines, and nozzles.

I did that on my o-320-h2ad

 

[gyoung]

A lot depends on the change and on which model. For instance 150 to 160 hp doesn't change the footprint of the engine but going to CS requires adding a governor, having a hollow crankshaft and maybe a recess on the firewall depending on model. 320 to 360 may require a different engine mount, new baffles and/or cowling changes.If you can't find exactly what you want, ask here again with specifics.

 

[PaulvS]

Here're are a couple of data point examples:

The O-320 E2D for my -6A was upgraded from 150 hp to 160 hp via new pistons without changing the cylinders. It was relatively straightforward from an airframe perpective.

Our club -9A is fitted with a FP 160 hp D2A and we considered replacing it with injected Superior IO320 and cold air sump. The potential implications of this change are: new or changed lower cowl; revised fuel system including HP boost pump and plumbing for return line to tank; new induction system and baffle changes; new exhaust system; new or revised throttle and mixture mounts and linkages. There is a fair bit of cost and labor associated with paying a mechanic to do all of this.

So the feasibility depends on what is the starting and ending point. The amount of time and money can be quite variable.

 

[[email protected]]

All I can say is this is a case of getting the cart before the horse for sure.
You don't know what you want and may find the plane that needs no work for many many years to come. And if you are going to have an A and do all the work anyway why worry about something that may never happen.
How much do you fly a year now? Add that up and see how long you will fly the life out of a 1000 hour old engine that may go 3,000 + hours.
Why worry about something that may never happen.
And if you live near Vic and have him do the work you have no worries anyway.
Doing all the things you mentioned are relatively easy from a mechanical standpoint. Now $$$$ may be a different story.
BUT my luck varies FIXIT

 

[RV8JD]

This chart helps explain who can do what to what:

 

[jclark]

I failed to mention that I would likely hire an A&P to remove/install the engine (regardless of swaps or upgrades or lack thereof). I live around 150 nm of Vic in Peachtree City, Ga, so I could go to him if necessary.

This is what I did. The **reason** is because the guy that I use is so good at it, and fast. Of course "I helllped" (Old timers will remember Shae and Bake commercials ).
What took a few hours with him would have take me days or weeks (I over study and procrastinate).

As others mention, don't worry so much about such a potential future event. Find a good, solid plane and go enjoy it. If you KNOW that you want lots of HP and CS prop up front, then it would be wise (though not necessary) to pick an engine that can more easily accommodate such in the future. If I had "options", I would pick a plane with a hollow crank O-320 or O-360 (Assuming non -10, -12, -14) and focus on "other stuff" like does it have (or can it relatively easily be upgraded to) the type of avionics that I need or want for the type of flying that I do.

 

[Pilot135pd]

You can do it on an experimental aircraft but it's a lot of work, ask me how I know... or just look at the pictures. Original radial engine to IO-540 completed this year.

 

[walkman]

Next if you didn’t build it and don’t have the repairman's certificate, or have an A&P license, you will need to either pay an A&P to do the work or get someone to sign off after you. I am an A&P and primarily know certificated aircraft. In the certified world the Owner/Pilot may perform simple assembly and disassembly, and must make a logbook entry.

I'm no expert, but I'm not sure this is entirely accurate, or complete anyway.

I have done this before - put in an entirely new FWF but that was essentially the same as there previously. I did all the work and that required only A&P sign off. However, I have also modified an existing installation, in my case I replaced a "dual mag" magneto with a modified regular Slick mag and installed electronic ignition. For that the local FSDO boys came out.

I understand there might also be a difference based on how your Ops Lims are written. The plane I modified (about 10 years ago) was on the old style ops lims.

EDIT: I believe the reason for the FSDO visit on the older modified engine was due to them wanting me to go back to Phase I for a few hours, and the way the Ops Lims were written Phase I was halfway across the country, so the Ops Lims needed modification. Anyway, just to point out that all the issues are not necessarily mechanical.

 

[Duncannon]

You can do it on an experimental aircraft but it's a lot of work, ask me how I know... or just look at the pictures. Original radial engine to IO-540 completed this year.

A Wilga! You don’t see too many of those.

 

[blaplante]

Our club -9A is fitted with a FP 160 hp D2A and we considered replacing it with injected Superior IO320 and cold air sump. The potential implications of this change are: new or changed lower cowl; revised fuel system including HP boost pump and plumbing for return line to tank; new induction system and baffle changes; new exhaust system; new or revised throttle and mixture mounts and linkages. There is a fair bit of cost and labor associated with paying a mechanic to do all of this.

To clarify a bit - injected engines can have vertical or horizontal intake. I have a vertical intake servo and so my carb cowling worked. And the linkage issues weren't too much.
A horizontal intake (as I believe PaulvS is discussing above, requires the substantial changes he stated.
The return line may or may not be needed depending on the particular fuel injection system chosen. Mine is a Bendix RSA-5.