Subaru 2.2 and 2.5

dragonflyerthom

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Arkadelphia, AR
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RAF 2000 GTX SE
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Tim O has made a statement that the converted automotive engines are just a step above the MAC as far as dependability on aircraft applications. Now I understand that these engines need to have a redrive and also need to run at higher ERPM in order to create the horse power needed to run the prop. He also said that if you get past the 40 hour mark then you should have a good one. I now have 42 hours plus the 20 hour run in on mine.


Does anyone have or have you heard any horror stories about these engines? What has been your experience with these engines? You can include any experience with this engine in a car. I know I have heard many about the MAC. This should be interesting since there are a lot of Soob engines on aircraft and gyros.

BARNSTORMER 2 said:
Ok, Here is my first shot...

We have 4 kinds of engines to choose from:

1. Certified Aircraft Engines
2. Un-Certified Aircraft Engines
3. Non-Certified Aircraft Engines
4. Auto engines converted for aircraft use
5. (?) Other engines converted for aircraft use.

1. Certified Aircraft Engines are the most reliable engines you can install in a gyro PERIOD. Also, (unless you get lucky) are the most expen$ive engines you can install in a gyro.

Pros: Designed for aircraft use. Many do not use a redive. There is a network that tracks the parts used in these engines and if anyone anywhere finds abnormal wear or problems it gets quickly reported to you (Airworthyness Directives). This also means that you get a COMPLETE history of all service and repairs ever done on your engine and by whom.

Nearly all of these engines have core designs that have been in use since the 1940's and have seen every kind of service imaginable and had the resulting bugs worked out long ago.

Typically operate at a low RPM compared to converted engines. These engines retain their value even when they have many hours on them. These engines also tend to have VERY long life spans. Typically, aircraft engines run several THOUSAND hours between overhauls and it is not uncommon to find a cylinder with 4000, 6000, or 8000 hours on it after being rebuilt several times and engines with the same kind of hours that have been in service since the 1940s.

Many but not all aircraft engines (such as Continentals, Lycomings and replicas) are direct drive and air-cooled which reduce complexity and help lighten the engine.

Most all of these engines have redundant magnetos (don’t require a working battery to run) and ignition systems.

Cons: $$$ Price. Aircraft Engines range in price from about $5k-$20k for the kinds of engines you would typically put into a gyroplane. Also, unless you are an A&P mechanic you will have to have an A&P mechanic work on your engine or at least approve and sign off on your work.


2. Un-Certified Aircraft Engines These aircraft engines used to be certified but now for some reason have had the certification plate removed. These provide all of the features listed above for the certified aircraft engines except they have no paperwork to go with them.

Pro: Typically much less expensive then a certified engine and very likely a dependable engine.

Con: The con is why was it de-certified? If the reason was so it could be used in an Experimental aircraft and the owner wanted to do his own maintenance then you are likely in good shape. However, you should have these engines carefully inspected for Airworthiness Directives before putting them into service.


3. Non-Certified Aircraft Engines These engines are designed and built to be aircraft engines but the manufacturer sells them for use in non-aircraft applications or for use in Experimental and other non-certified aircraft.

These engines are sometimes identical to the certified engines but just without the FAA paperwork. Rotax is a popular manufacturer of this type of engine.

Also, sometimes Lycomings and Continental engines are used in generator or other applications and the engines are retired with plenty of service life left and sold for surplus (Cheap).

PRO: Often cheaper then certified engines and less likely to have a problem then an un-certified engine. Available in a wide range of weight/horsepower configurations if you are willing to fly a 2-stroke engine.

CON: Typically not significantly less expensive then certified engines for the 4-Stroke models. Many models do not have redundant magnetos and ignition systems. Many 2-stroke models have low TBO (Time between Overhall).

4. Auto engines converted for aircraft use. These are typically used (but sometimes new) engines that have been pulled out of a low-mileage car and converted for use in an experimental aircraft. Some engines are converted by hobbyists others are professionally rebuilt and modified for use in aircraft.

Pro: Used auto engines are extremely inexpensive compared to purpose built aircraft engines. Parts are typically widely available and inexpensive.

Many auto engines such as Subaru, VW, Covair and Mazda engines are able to run under the stress of an aircraft application for more than a thousand hours.

Auto engines are so cheap you can often replace the entire engine core for less then the cost of a cylinder rebuild on a certified aircraft engine. If a conversion package runs well for about 40 hours or so it is likely to be a long lived dependable engine.

Some engines such as Subaru EA-81/82 and EJ-22/25 engines are so popular with experimental aircraft builders that there is widespread help and support to assist you in converting and maintaining these engines.

Cons: Auto engines are not purpose built for aircraft applications and are designed for a lower RPM lifestyle. These engines are the least reliable of the engine choices with the possible exception of aircraft drone engines.

Auto engines professionally rebuilt for aircraft use often cost almost as much or more then a non-certified aircraft engine.

Because these engines are running for many hours at or near their operational limits a small problem can quickly become a catastrophic one.

Most converted auto engines require a substantial redrive to reduce the prop speed down from the engines RPM. Redrives and cooling systems add additional weight, complexity, points of failure and cost ( $1500-$4000) to the application.

Auto engine conversions typically have a very low TBO compared to 4-stroke aircraft engines. Auto engines run such high RPMs, especially in draggy applications like gyroplanes, that they often develop problems so quickly that an oil analysis may not catch premature bearing or ring wear before it fails.


5. (?) Other engines converted for aircraft use. These engines would be sourced from snowmobiles, motorcycles, generators, military aircraft drones or other non-auto, non-standard aircraft applications.

Pro: Often the cheapest engine you can get and some are very similar engines to those implemented as aircraft or auto engines. Some drone engines (such as mac’s) can be professionally rebuilt and offer an amazing horsepower to weight ratio.

Con: The least reliable engine unless you have it professionally rebuilt and often takes a significant amount of work and research to convert to aircraft use.
 
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The relationship with your engine

The relationship with your engine

Hello Thom,

Broken crankshafts and cracked cylinder heads come to mind.

Re-drive belts breaking can be a challenge. The belt re-drive also puts quite a strain on the crankshaft.

Cooling problems are always interesting.

The support systems are responsible for a lot of engine outs.

It appears that if you use a good gear re-drive, pay attention to the cooling system and manage the wiring well that they are very reliable. There are a lot of people with a lot of trouble free hours on both the 2.2 and the 2.5.

The service environment that these engines are exposed is not ideal. The continued high rpm and high output followed by long dormant periods are a challenge to any engine.

At forty four hours, you probably have a good one.

Engines tend to respond to the treatment they receive. Treat them gently and you are more likely to have a positive relationship. Don’t warm them up, use high power and high rpm, don’t change the antifreeze, don’t change the oil often, use bad gas, run your re-drive belt too tight or too lose or use a poor exhaust and the relationship between pilot and engine is not likely to be elegant.

I have held in my hand both successful high time parts and engine out parts.
Treat your engine well because she is an important link in the chain of events that lead to enjoyable aviation.

Thank you, Vance
 
Thom- I cant remain quiet when I read a silly statement how a Subaru 2.2 or a 2.5 is one step above a Mac drone! -I HAD to comment. This isnt the first time Tim O has said something similar, but this time a direct comparison between these car engines, 2 strokes, and the drone -all of which I have a good amount of experience with. So Tim- dont take this personal, but I have to stand up for the 2 best engines I have owned in a gyro- the Subaru Ej22 and the 25. I had 10 forced landings due to Mac attacks. I then started flying a 532 Rotax and had 8 more engine outs. I then bought a new 582 Rotax and was delighted to have 175 trouble free hours. Next comes my first experience with the "one step above a drone" car engine. I was delighted to have 235 of the most trouble free flying of my life in that Sub powered RAF! Next came my 2.5 SparrowHawk. I tell all, and yes I did blow a headgasket, it was a minor 9 hour repair- and later was found out that I all along had a radiator cap that was allowing my water to blow out inflight. One flight it blew out too much and my gasket blew. A new type of cap fixed that and that was the only glitch I had with the 245 hours I had flown on that motor. Now in my own hanger are a Cessna and a Piper- both having of course certified engines. Both have been in the shop several times while I had only one incident in 480 hours in my so called"junkyard engines" I feel as far as a Subaru EJ22- or a 25, that my personal experience with both puts these beautiful running engines a lot more than a step ahead of a drone. STAN
 
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Thats 2 good posts.

Thanks Stan and Vance

Hey good or bad experience please post your experience with Soob engines.
 
a silly statement how a Subaru 2.2 or a 2.5 is one step above a Mac drone!

Stan, no worries, I don't take your post the wrong way.

First of a few corrections.


1. I did NOT say a Soob conversion is a step above a Mac.

Although Thom did a good job of reposting my post and HE did correctly summarize my statement YOU did not.

You may want to go back to the original thread and see some of the other posts about this topic.



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What I was doing is making a condensed GENERAL post about auto-conversion engines with takes into account the entire RANGE of engines.


2. What you take as a "STEP" is likely not what I was trying to communicate. There are 5 "STEPS" which are actually categories.


3. I was comparing categories of engines not specific engines.

If you take one of Richard Whittridge's rebuilt, tuned, tricked out MACs and compare it against many of the VW conversions I have seen bolted on a Benson frame I believe there is a STRONG argument that Rick's engine would be more reliable than many VW conversions out there flying.

The post is not made to compare 'exceptions' to the rule.

There is no question that the Soobs are considered by many (myself included) to be the 'Best in Class' of the auto engines commonly converted to aircraft use.


Stan, you are looking at the 'core' of the engine, you have to enclude the entire engine package.


There is also plenty of my own experience and experience from others to show that Soobs are statistically not as reliable long term as purpose built aircraft engines.

There are plenty of examples of successes and failures of both aircraft engines and soobs but again we are making general categories and NOT discussing specific engine installations in this GENERAL statement.

I know you have not had your soob fail on you. I however, and my friends in my local club have had a number of failures of soob engines, not all of which were related to the conversion but related to employing a USED car engine.

4. The auto-conversion INCLUDES THE REDRIVE and other accessories used in the conversion. In this generalized view a failure of a redrive, such as one chewing a belt or grinding a gear or breaking a shaft or bearing, cooling system malfunction (common in some soob installations ), IS a failure of the auto-converted engine system. Even if the core Soob engine did not fail the installation did fail because of the redrive, cooling system or other componet's failure.


In summary, you are taking words out of my mouth by claiming I said "Subaru 2.2 or a 2.5 is one step above a Mac drone!" I was only discussing CATAGORIES of engines. You can often take a best class, specific example and find it exceeds the worst of class specific example in another category. Second, you are not taking into consideration the many problems people have with the soob accessories, cooling systems and redrives which are NOT nearly as reliable as the core soob engine but count as a failure of the conversion installation.

Your post reinforces my examples perfectly. Your Mac failed in a few hours (Category 5), your soob failed (component failure) before 250 hours (Category 4) and a rotax engine (with specific example removed) should go much more then 250 hours without a failure (Category 3) and a full blown certified engine should go 3000+ hours without a failure (Category 1).

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Stan,

Ok, now that I have the 'corrections' post out of the way. I wanted to ask you if you read my entire post or just read Thom's intro and react?

Did you read:

"Many auto engines such as Subaru, VW, Covair and Mazda engines are able to run under the stress of an aircraft application for more than a thousand hours"

"Some engines such as Subaru EA-81/82 and EJ-22/25 engines are so popular with experimental aircraft builders that there is widespread help and support to assist you in converting and maintaining these engines."

From reading your post it sounds like you did not read my post entirely and reacted to what you thought was a 'put-down' on your EJ's and was certainly not.

If you have three categories 1. Gold 2. Silver 3. Dirt and someone says hey Stan TimO said your Silver is "one step above Dirt" I would expect you to post what you did only if you did not understand the general categories involved.

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Tim- I am not even saying that a Subaru is as dependable as a certified engine. I am just stating my experiences with them. Sure, they have broken cranks and had msc. problems, but NO ENGINE is immune from stuff happening. I am just trying to state that for a small decrease in reliability, a Subaru is one heck of an engine-much cheaper, can work on it myself, and has been a pleasure to have aboard. BUT like you and I have both said many times , any engine can and will let you down. A gyrocopter is the most forgiving aircraft as far as having these engine outs in. I personnly have been forgiven 18 times-so a slightly less dependable engine is a small trade off in exchange for the thousands of dollars saved and the ability to work/modify it. I mean-EXPERIMENTAL -is what its all about, right? Now as far as me flying an experimental helicopter, the ONLY engine I would consider for this application is a turbine-PERIOD. This application requires an engine designed for sustained constant high power output- and be very dependable. B.J. Schramm tried many engines, until the Solar T-62 turbine came along. His search was over. He now had an extremely reliable engine good for 1500 hours, light, no cooling system needed, simple more reliable ignition. This engine , though more reliable than a certified piston engine-still will be flown by myself like its going to fail. One must try to fly any engine like it will fail, because eventually the engine or one of its supporting systems will. I never will forget my dad flying mom and I to New Jersey in dads Cessna 175 Skylark. Even its certified engine didnt get us there and back. We started losing oil pressure and luckily we barely made it to Harrisburg, PA. SO -everyone- whatever you choose to propel you to altitude. RESPECT that engine by flying with no guarantee it will get you to where you want . Stan
 
Stan,

I agree completely and I said as much in my post in the original thread that Thom pulled my post out of and in the post itself.

There was no need for you to 'get all over me' for the statements I made in the post.

And it is unlike you to claim I made a statement that I indeed did not make ("a silly statement how a Subaru 2.2 or a 2.5 is one step above a Mac drone! ")

I did not make that statement at all.


The post agrees with everything you have said.

I think you reacted a bit strongly before thoroughly reading my post or perhaps my post was unclear?

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Auto engine conversions typically have a very low TBO compared to 4-stroke aircraft engines. Auto engines run such high RPMs, especially in draggy applications like gyroplanes, that they often develop problems so quickly that an oil analysis may not catch premature bearing or ring wear before it fails.
Quoted from Barnstormers 2

Now here is something you did post about autoconversions Tim. My TBO is set at 1500 hours. Now as I understand it most certified engines are TBOd at 1500-2000 hrs. Really not much difference here.

I know that on my continental O320 that each time I did the annual I was replacing a jug because of compression loss just to bring it back up. If memory serves me the overhaul had 1200 hours when I bought it and around 1350 when I sold it. I had 3 jug replacements on it. The compression had dropped from in the 70s to 50s. Most of the compression checks on the cylinders were 70s/80 on most of them.
 
Tim: My apologies.......I just read your post as having a Subaru just a step above the Macs. This along with several other posts "sort of" downing the Subarus integrity as a gyro engine...gets any of us tired of our pet engine being kind of put down....and I just came to its defense. Again..nothing against you personally.... I love the Subarus and how you can work on them...modify them.....and all for not much sacrifice in reliablility. Plus..several thousands to go scrounging for another engine when overhaul time is around.

I did not read your posts in its entirety but read is as is was paraphrased in Thoms post. I plead guilty to doing this a lot as this dial up is so s-l-o-w.


We all get passionate about what we choose to fly...so Tim...go enjoy that beautifully running Lycoming...ok?:peace: Its your extra confidence in that nice engine that allowed you to take those nice foggy shots the other day. I trusted my Sub...but not that much.:peace:

Stan
 
Thom,

Your EJ-22 TBO is set at 1500 hours?

Who set that TBO?

So far as I know no one has gone through the considerable testing required to set a TBO for used EJ-22s.

I know some EJ-22 professonal rebuilders have set 'recommended' TBOs but that is not the same process used with aircraft engines and is only for professionally rebuilt engines intended for aircraft use like a Sub-4.

Typically, you dont overhaul a EJ-22 it is cheaper to replace it with a new one unless you do the rebuild yourself.

What is the TBO of your Redrive and your Ignition system?

Sorry to hear about your weak cycliniders on your continental. What was causing the compression loss, rings or valves?

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Gladly accepted Stan, Thank you for going back and reading my post and clearing things up.

I am a fan of the EJ's and that is why I have one in my shop right now ready to go in my next gyro.

You just can not beat Soobs for the reliablitly/price ratio.

The extra bit of reliability you get with an aircraft engine comes at a high price and for those of us that don't have unlimited funds that means you really must have the application for that extra reliability to spend the money (such as a helicopter or a machine you are willing to fly over fog and open water yes?).

I think I gave the engine classes a fair shot for a such a summary and I am glad to update it with any suggestions or better yet make some more guides like a price chart.

I think Vance's post makes some key points that should be explored as well. Engine care is paramount!

For instance I would trust Jonathan (automan)'s EJ-22 as much as I trust my Lycoming. Why? My Lycoming has high time and only gets visited by an A&P once or twice a year. Jonathan's EJ-22 was professionally rebuilt, tested, tuned, tweeked and lovingly monitored every stroke of it's life by a passionate experienced master ASE mechanic. But here again we fall into the trap of SPECIFIC examples. A guide has to be general!

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Tim: It really bothers me when I try to defend something and I dont know how to type it in such a way as to both defend what I am trying to say...without sounding like my pants are in a knot. So...next time I will raise my threshold of when my fingers get triggered to type.


Stan
 
I think Tim's post (that Thom cites) was in general good.

A lot of guys try to save money by using an auto conversion in an aircraft that was designed for am aircraft engine -- Glastar, RV, Long-EZ, etc. This is usually false economy and costs you more in the long run. In the second to the worst case it causes you to be completely unable to enjoy your aircraft.

As Tim points out, the auto engine conversion isn't just the auto engine, but is also all the vital systems: fuel, ignition, redrive. Of these, the least troublesome is a well-designed gear redrive. Gears are not rocket science and most gear drives are seriously overbuilt for the power they will reasonably receive. Belts can be as reliable as gears, over a shorter period, but that depends on the belt drive system being professionally engineered... which most aren't.

Fuel and ignition systems, though, are problematical. Aircraft fuel and ignition demands are completely different from those in the automotive world. Many autoconversions come to grief here.

Not all auto conversions are equal and there are degrees to which each is sorted out. Within the grand world of auto engine conversions, this is about the pecking order of reliability:

1. Subaru 4-cyl.
2. VW
3. Corvair (William Wynne's)
4. Model A (used in Pietenpols)
5. Mazda rotary
6. Subaru 6-cyl.
7. American V-8 and V-6 conversions.
8. Other oddball engines (Suzuki V6, Jag V12, BMW any, etc).

Apart from the top three, you will spend more hours tinkering than flying. The lower entries on the scale pose a threat to life and limb, although the 3l Soob has promise which it hasn't yet fulfilled.

Somebody will ask about the CAM 100 Honda conversion ... how many years has that been unavailable now? Fuggedaboudit.

If you want to fly, get a certified engine or a Rotax, especially a 4-cylinder 4-stroke (which have available FAR 33 certified versions).

It appears to me that the guy who decides he is going to develop a new auto conversion is also the guy who is designing his own rotor blades and his own new aircraft. I call this guy The Napkinslayer. Sometimes he's also working up his own alternative to Newtonian physics.

His grandkids will put his never-flown project on ebay and not even get any money on it, because nobody wants his orphan engine.

cheers

-=K=-
 
Nothing wrong with being passonate about what you care about Stan!

You just have to watch out for the 'telephone game' where someone's words get repeated and start to get taken out of context.


Kevin,

Is the CAM 100 honda related to the VTec engine?

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Auto engine conversions typically have a very low TBO compared to 4-stroke aircraft engines. Auto engines run such high RPMs, especially in draggy applications like gyroplanes, that they often develop problems so quickly that an oil analysis may not catch premature bearing or ring wear before it fails.
Quoted from Barnstormers 2

Now here is something you did post about autoconversions Tim. My TBO is set at 1500 hours. Now as I understand it most certified engines are TBOd at 1500-2000 hrs. Really not much difference here.

I know that on my continental O320 that each time I did the annual I was replacing a jug because of compression loss just to bring it back up. If memory serves me the overhaul had 1200 hours when I bought it and around 1350 when I sold it. I had 3 jug replacements on it. The compression had dropped from in the 70s to 50s. Most of the compression checks on the cylinders were 70s/80 on most of them.

Good luck Thom getting 1500 hours out of your engine! I wonder where that TBO number was arrived at? I mean, how did they decide that is how long before it should be overhauled? I don't think I know anyone personally that has made it that far on the same engine yet.

your plane..... I wasn't even aware that Continental made a O320....? ...... I thought that O320's were made by Lycoming. And overhaul numbers on a certified engine don't mean a whole lot if the plane is left sitting idle for months or even years.

My piper Pacer I bought a few years ago only had a few hundred hours since overhaul when I bought it. I had loaned the plane to my instructor to fly and he ground looped it, causing a prop strike. The engine - last overhauled in the 1960's - was tore down for inspections and found to be in very poor shape from internal rust build up from years of sitting without being flown much. I had to do a new overhaul on it to make it right, and it wasn't cheap.

My next plane, a RV-4 had a Lycoming that was much newer, and had never had time to sit around and rust. It was flown over a hundred hours a year, every year, and had over 2150 hours since new on it when I bought the plane. That engine had never had any work done to it other than adjustments to the carbs and adustments to the mags. There was good compression, no oil leaks and very little oil burn. I flew that plane over another 150 hours before I sold it and it was still running like new when I sold it.

Wanting to make sure my engine on the RV-4 would be okay, running it past the 2000 hour TBO, I talked to many aircraft mechanics and learned that it is not at all uncommon for Banner towing operations and other operations where the planes are flown often, to go WAY WAY WAY past TBO!!!! Most of the banner planes flying Banners in my area are going to 3000 and as much as 4000 hours between overhauls.

I just don't think you will find owners of experimental aircraft flying Subaru or Mazda, or Chevy or Ford, Honda or Suzuki, etc.... that can put on those kinds of hours.

And another difference, is a real aircraft engine with most of the common problems / failures will continue to run, possibly roughly, but will hopefully get you safely to a airport. Most auto conversion engines, when they have a problem, they usually quit cold, almost like turning the key off.

I think alot of having a good auto conversion will depend on how good you set up all the sub systems to make it a conversion engine.

Myself, I have had bad experiences with both the EA-81 and the EJ-22 Subarus on gyros I have owned.
 
You guys are right. I have asked for horror stories and all I have gotten is grief so lets just leave it at that. I have told you my horror story about my 6 cylinder Continental. It was not a Soob so I am just as guilty as you guys. I have heard many stories about certified motors. One of my hanger mates has had to rebuild both of his Lycoming O360s. Oil leaks, magnito problems, fuel pump problems etc. So I will agree that all engines will crap out on us. I have changed the oil and filter on my Soob three times now. every 20 hours. I am having more problems with the tires than anything else. I have already replaced the front tire and tail tire about 25 hours ago now I must replace the mains.
 
One thing I noticed about my Twinstarr is that with the differential breaking it really eats up the tires.

Sorry you did not get what you wanted out of the thread Thom.

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Thanks Tim

I am guilty of believing RAF marketing about the Soob engine. When I unpacked it it had been pickled and sealed. They are the ones that gave me a new engine with chrome molly rings and the statement that it has a 1500 TBO. I have heard rumors about the Soob engine and I have been trying to get some input from other owners of Soob engines to get to the bottom of it. So far it has been a great engine.
 
It is a great engine.

I don't know what RAF does to prep the engines but arriving pickled and a estimated TBO of 1500 are positive signs.

You have 40 hours on your engine and I expect you will get many hundreds if not thousands of hours out of it before you have anything major to deal with.

One thing I did not do with my last soob but I will be doing with my new one is oil sample testing. I started this when I got the Twinstarr on the advise of my A&P. It really is great, it is like x-raying your engine.

I will post one of my sample reports if I can get it down to the forum post size.

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