Engine Builders Only,... What Is The Cause Of FA20 Failures
 

What is causing so many FA20 engines to FAIL?

We have two 2013 FR-S's, one with 180,000km's and going strong (at least it seems to be), the other has 71,000km's, and although it is has no engine knocking, it is showing signs of distress! Pulled the engine to do a reseal job, and found that the cams/cam carriers show A LOT of wear (just on the bearing journals, not the lobes). I've not inspected the rod/main bearings, but suspect I'm going to find issues with them as well,.........again no rod/main bearing knock can be detected currently.

I guess my question,....... to those that have engine building experience is, what is causing so many of these FA20's to fail?

It seems like most failures seem to relate to oiling issues, but in the case of this 71,000km example, it has not been driven hard, or seen any road course use, so I'm kind of at a loss as to why it appears to be eating itself up? Is there any parts of the oiling system that is known to be lacking/subpar,....or?

I have limited experience with these Subaru FA20 engines, have a LOT more knowledge when it comes to conventional pushrod V8 engines. That being said I've owned many 4 cylinder Toyota engines (22R, 22RE, 3S, 2ZZ's) and they have all been BULLETPROOF!! Now I get into these Subaru FA20's and they seem to be prone to fail with a fraction of the mileage I'd expect an engine to last.

Biggest reason I can imagine in general is low cost of entry = poor maintenance and habits.
Not changing the oil timely

High load low RPM stints where there's not enough oil pressure to combat the heat generated by the rotating assembly (6th gear pulls to reach higher speed when there's a slow down on the interstate, for example. Rather than down shifting to the appropriate gear, flooring the gas pedal and waiting for 45 seconds it takes to go from 40 to 80 MPH)

Aftermarket changes that do not help longevity (lightweight pulleys, headers without heat shielding, poor quality maintenance replacements like cheap ignition coils, sparkplugs, etc)

Aftermarket changes that affect the engine tune negatively (Including poor tuning itself, which is far more common than anyone would admit since it's very easy to get wrong, and difficult to perfect on a per-car basis)

With your car in particular that's experiencing wear, what weight of oil are you running? Is it seeing a lot of cold weather starts, long bouts of idling? Any modifications at all?
Sometimes you just are going to have drawn the short straw and that can't be avoided with any car.

All the crank bearings are very narrow. It doesn't take much to ruin them. I suspect driving it a bit to hard on cold oil kills them quickly.
And when the oil is hot, 0w-20 is very thin. I prefer to use 0w-30 and be patient and let it heat up before driving. Not driving hard, just driving. I'll let it warm up while I eat breakfast. The oil takes a good 10-15mins to get hot. Most people are unlikely to accept that kind of inconvenience I think.
Maybe some amount of detonation from low octane fuel hammers out the very narrow big end bearings? In Australia the cars have a sticker under the fuel door, 98 octane only. I've seen across the forums that people use much lower octane than that. It's a marvel of engineering that an engine can run with 12.5:1 compression at all, let alone on rubbish fuel.

Fuels are measured differently in some countries. 98RON is identical to 93AKI

The lower mileage car is going to be used for our winter car, so yes I will likely either continue with the 0W-20, or possibly up the viscosity a "tad" to 0W-30. The fuel is always premium unleaded, here in Canada the best you can do out of the pump is 90-94 octane,....98 octane is unobtainium,....unless you fill up gas cans at an airport using LL100 aviation fuel.

You do raise an interesting point, that If guys are trying to skimp on fuel, and are putting lower octane fuel in their cars, that could definately have disasterous results when detonation rears its ugly head, FOR SURE,.......especially if they are being driven hard!

We are both senior citizens (in our early 60's) :) and don't drive these things very hard at all. We are Drag Racers, and have a purpose built race car to take care of the need for speed:)

I guess that I should also update my original post to say that I have now pulled the upper oil pan assembly, and checked the rod bearings. They look pretty decent, and show very little wear, with only a few tiny specs of debris inbedded into the bearing surfaces. Rod journals all look good. Is I mentioned in my original post, I full well expected to see serious wear with the engine bearings/crankshaft journals, after seeing the damaged cams/cam carrier bearing surfaces. Not sure what is going on in the top end of the engine, but kind of releived to see it is somehow not happening in the bottom end?

Has anyone experienced excellerated wear with camshafts/cam carriers?

Use good 5-30, not 5-20 IMO. Definitely let the car warm up before you rev it out. a 1/2 Qt overfill is also not a bad idea.

I didn't know that many were failing. I've had a couple high mileage cars come into my shop for maintenance. My car has 100k on it. We're long past the recall failures.

This entire thread is pretty common when it comes to single perspective, effected people of such a failure. Basically, it's about the same as asking anyone in the repair business for pretty much anything why something seems to "always fail". Since they are in the repair business, they really only see things that are broken. Therefore, the more they see of something, the more "all of them" are broken. They don't ever seem to hold that up against the rest of the data like sales counts, etc.

Year Scion FR-S Subaru BRZ Toyota 86
2013 18,327 8,587 (FR-S sales)
2014 14,062 7,504 (FR-S sales)
2015 10,507 5,296 (FR-S sales)
2016 7,457 4,141 2,354 (as 86)
2017 Discontinued 4,131 6,846
2018 0 3,834 4,133
2019 0 2,334 3,398
2020 0 2,267 2,476
2021 0 2,320 1,044

So, that's 111,018 units sold.

I know it's hard to wrap our heads around it but the alleged high failure rates are likely overblown (pun intended).

Without knowing the failure rates in detail, there isn't really an easy conclusion as to why they "always seem to fail".

As to the topic at hand, I think everyone that has looked into Subaru boxer engines, the failure causes are reasonably well documented.

• Poor maintenance
• Poor oil maintenance
• Low oil
• Driver abuse

The FA20 in the 86 platform is a 12.5:1 CR engine. Bad/inadequate octane fuel doesn't help with engine life or performance.

Boxer engines lack the design of a traditional inline or V style engine so oiling can be a challenge. Again, not a guarantee of engine failure but a contributing factor when you think about the rest of the issues.

In my personal situation, I have a 2013 that has the "weakest" of all the engines apparently. I have beat on it at the track and at autocross. I boosted it last winter and managed to "blow it up" over the summer. The autopsy only seemed to reveal a blown head gasket and even that wasn't a significant failure. My symptoms before tear down were that it got hot under boost. That was after unknowingly popping a lower coolant hose and dumping all of the coolant and running it for a week to try and troubleshoot the problem without realizing it was completely empty. My stupidity aside, the engine still ran fine other than overheating under boost and the only obvious indicator of failure was a slight coolant combustion test failure (indigo blue to just off that color in the tester). During tear down, all engine components were pristine including the bearings. The only point is; my alleged bad engine/model year was almost perfect and I beat the hell out of it. However, what I didn't do was the list above. I changed the oil at an extremely frequent rate. I also ran about a 1/2 quart more oil in my ownership. I ran an oil cooler as well.

So, in conclusion (for me at least), the causes of failure for these engines are pretty straightforward. Given how they are maintained and treated by their owners and compounded by the physics of the engine design, any failure makes total sense to me.

I don't really think many are at all. It's like anything that requires customers to report an experience -
Good is seldom reported
Bad is always reported and embellished

Imo for winter stick with 0w20.
I've been running Valvoline restore and protect last 3 oil changes at 6000km intervals. Car idles smooth with 190k km.
I also add a bottle of redline injector cleaner every change to help keep DIs clean as possible.

Adding half quart extra oil is not going to be helpful. My oil catch can gets filled up when I add extra oil. When I fill properly at the mid level between min and max of oil stick, oil catch can does not even fill up until the next oil change. Adding extra oil only clogs the injectors and hurts the engine. If I add even more, I am sure the engine will lock and blow up. The only way to increase oil pressure is changing the oil pump and enlarging the oil channels. I would not try anything else.

Just in case, wanted to post the warning.

Adding to that, as posted above, low rpm high torque boosted tunes are not good. This is not a muscle car. Even when boosted, the tune should have low torque at low rpm. Do not just floor the accelerator without downshifting.

And, revving the cool engine is the other killer cause.

I run almost a quart over and never get anything in my catch can.

You don't know what you are doing or talking about.

Sure don’t :bonk: