subaru FB25 engine interchange

PeterfromOz said:

I am sending this from Australia.  I have an 11/2011 build Forester FB25 engine with manual transmission.  It is an oiloholic using about 4qts of oil every 1000 miles. The car has only covered 84,000 miles. Subaru Australia state this is normal.  Rather than swapping engines, I was thinking of just buying a set of standard size piston and rings and honing the bore.  I would replace the big end bearings but probably not split the block and leave the main bearings as is.  Has anyone thought of this as an option rather than taking a chance with a used engine and the problems that might go with it?  I would expect the cost of parts to be cheaper or on par with a cheap second-hand engine.

Decarbonize (or decarbonise, if you prefer) by flowing a lot of carburetor cleaner up the intake for 10-15 seconds or so while the engine is idling, snap it WOT to 4000-5000 a few times to clear it out, then repeat.  Use up two cans of carb cleaner spray.  If the carb cleaner volume is too much and it causes the engine to stall, you may have to meter it a bit. If the engine does not bog down a little while spraying, use both cans at the same time.

Done right you will see a massive blueish/whitish fog from the exhaust when you whack the throttle.  It may even misfire.  That is carbon leaving the engine.

After you do this, you MUST take the car out and do a few WOT pulls until the exhaust stops smoking/engine stops pinging.

(For the American pro techs in the audience - yes, this is essentially a backyard way of doing a Run-Rite or BG induction cleaning)

The oil consumption is caused by the rings sticking in the piston grooves.  Chemical treatment like this will clear it out sufficiently to reduce oil consumption.  I suspect a good amount is also due to the bores glazing, which this process will also break.

If you use synthetic oil, switching to a non synthetic for an oil change will also help.  If your market specifies 0W20 oil, a 5W20 will work just fine.  (I do not think there are any non synthetic 0W20 oils)

Changing the rings in an FB is a pain.  I will note that Honda has an updated ring set for J35 engines that burn oil in cylinders 1-3, I have reringed a few of these in chassis.  The new rings have about twice the free gap on the bench as the old ones, so they do have significantly more spring tension on the bores vs the old ones!

Skenton said:

In reply to Mrme :

Definitely polarity for the Hall effect sensor in the TGV actuator/motor with the black magnets. The output signal to the ECU is 0/5VDC. On the newer ones with the white magnets I believe the output to the ECU is proportional.

The two black magnets are mirror image while the two white magnets are identical.

That is why you need to move both the TGV actuator/motor *AND* the (modified) black magnets from the old motor to the new one and swap sides if it has the new intake with the TGV direction reversed.

The newer FB25 engines seem to couple the TGV with the throttle more that the old ones which are only used at startup for better mixing to reduce cold emissions. The ECU programming is probably quite different in this area.

 

 

This forum is insane! My 2011 Forester just started hammering. Removed the engine and disassembled. The rod/pistons moves back and forth in the cylinder about 1/2". Those main bearings are gone! So on to swapping out an engine. So it seems that 2016.5 are swapable. Finding some 2017s with low miles for around $700.

In reply to Sodapopdave :

Been reading this thread, all 17 pages, and I have a 2011 Forester with a 4AT. Looks like it is possible to run a 2017 in a 2011. Other than swapping the Timing wheels and taking care of the TGVs are there any big deals to this process?

In reply to bpwaldner :

The later engines have significantly different coolant routing and EGR. Swapping the coolant crossover tube on top of the engine let's you keep the 2011 setup which is significantly simpler. You will still need to plug the extra coolant port on the lower passenger side of the block. Possibly swapping the upper oil pan for the 2011 version would also deal with it. Not sure if there are any changes besides a couple bolt lengths though.

I assume you read about the valve and timing cover swaps along with the cam ends.

In reply to Skenton :

Thanks for your reply! Yes I did see the need to change the timing cover, valve cover, and cam sprocket. Looks like I will be swapping out for a 2017. The prices are silly:

2011: $3000

2016: $1100

2017: $700 (which has much lower miles)

The 2016 Forester engine is much more like the 2011 Forester than the 2016 Legacy engine. They were made in different factories and implemented changes on different schedules. Discussed up thread. FYI.

Welp, first problem. The new engine did not come with a throttle body. They do not look like they car cross compatible. Will call up the salve yard and see if they will send me one,

2011/2017 Swap confirmations:

Intake swap will not work. Will need to use 2017 intake. The 2017 intake holes are too large for the 2011 intake. 

Coolant Crossover swap will work. Remove all EGR Cooler components and use the 2011 Intake to crossover metal tube. 

Remove 2011 Knock Sensor and install 2011 Knock Sensor in 2011 location. May need to clean threads. NOTE: It may be ok to leave 2017 knock sensor where it was. Seems 2011/2017 sensor connector is different.

Will need to plug EGR coolant supply as previously noted by Soappopdave.

Crankshaft sensor will need to be removed from 2011 and installed. 2017 is too long as it hits the 2011 tone ring. I swapped the flex plate, tone ring and everything since the 2017 did not come with one. 

Next week on to timing stuff. 

In reply to bpwaldner :

I believe the crank sensor mounting bracket has to be swapped too.

In reply to Dlong :

Feel free to email me at vanpa@cncspecial.com

In addition to the FB25 plates, I can also offer the idler wheel bracket and a longer EGR Pipe.

Cheers! 

Hi all. I've got a 2013 Forester FB25 (non PZEV) and am swapping in a 2016  Forester FB25 (PZEV).  I've read this entire thread and am greatfull for all of the knowledge offered.  Everything seems pretty straightforward with this swap.  One thing I haven't seen mentioned was the injectors.  I was wondering if I need to swap the old non-PZEV injectors over to the new engine.  The connectors are the same and both sets measure the same resistance.  Has anyone run into this scenario?  Thanks

In reply to Dizzhead :

Do you recall if the 14 Legacy engine you swapped in was PZEV?

I have a 13 Forester (non-PZEV ) and wondering if I can keep the PZEV injectors on the new engine in place. 
thanks

In reply to DJFraser :

The injectors should be fine. I don't remember anyone changing them or mentioning them being an issue. As far as anyone could determine, PZEV is solely a function of the ECU programming and the CATs. More of a marketing thing with no internal engine changes.

In reply to VANPA :

email sent

So if I get the newer coil connector pigtail is there any reason to swap valve covers?

Ignition Coil Plug E | iWire Subaru Wiring Solutions (iwireusa.com)

In reply to bpwaldner :

The newer coils would likely work if you adapt the old wiring harness as you move it over. Nobody did that as least that I recall. Several folks made ~1/4 inch plastic or metal spacers with hardware store odd and ends so they could use the old coils and wiring harness with the new valve covers and avoid the swap as you propose. Discussed upthread much closer to the beginning.

Double check the injector connectors to be sure they are the same on the old and new wiring harness. I could be remembering wrong since it has been a while. Feedback appreciated if you do double check.

Hey all!!

My 2017 engine in my 2011 Forester is running! Purrs like a kitten. 

Thanks to Creative CNC I could reuse the 2017 timing cover. The 2011 timing cover oil pump was toast.

Going to take for a test drive this afternoon.

Here is a pic of the idler pulley bracket:

In reply to VANPA :

This is Creative CNC. Buy from him . Excellent communication!

In reply to bpwaldner :

Was your 2017 engine from another Forester or a Legacy? Would you be willing to post a brief description about what you did with wiring, coils, injectors, TGVs, EGR, cams, cooling hoses and covers etc? There was mention of several options.

Also, what sealants and/or gaskets did you use on reassembly.

hi.  I have read all 17 pages of posts regarding this Subie engine replacement.

Thanks to all for the information.  I don't understand why people post all their trials and tribulations, but I am extremely grateful that you do.

I am in the middle of a 2011 Subie Forester engine replacement.  The 2011 engine is toast... done.  I got a 2015 Outback engine for the replacement.  I understand and will replace all sensors, mounts, tone rings, timing cover, etc.

I also understand the headache of what is needed to be done for the TGVs.

My question,  which I did see within this posting, is why can't I just use the heads from the 2011 Forester engine?  Then I would not need to worry about the TGV issue.  From what I see, the heads between the 2011 and 2015 engines seem the same?

Thanks again for everyone who contributed to this posting.  Excellent!!!

kurt

I do not recall anyone trying a head swap. I will dig a bit and post if I find anything about interchange.

It could be that even if they fit folks did not want to deal with setting the timiing and replacing the head gaskets and probably head bolts given the expense.

According to the thread https://www.subaruforester.org/threads/2011-fb25-heads-on-a-2017-fb25-forester-shortblock.840213/ it is rumored to have been done. On the other hand it also refers to this thread, and Sodapop Dave who had the same idea posted here too if you want to search and read his posts.

Looking for head gaskets they say 11-15 so apparently something changed, which makes me wary.

Thanks Skenton for the additional thread reference.

I have both the 2011 and 2015 engines on stands side by side disassembled to the point of removing heads.  I have done Subie head gaskets many times, includeing FB engines, so I am familiar with the process.  The "customer" for this car is willing to pay for head gaskets, bolts, etc so I am going for it.  I will post the results of how it goes.

kurt

In reply to SubieKurt :

Good luck! For some reason I was thinking you had  2017 donor engine. If the 2011 and 2015 head gaskets are the same that is a good sign. I have wondered if the upper oil pans interchange too. That would negate plugging the extra coolant port added on the passenger side across from the water pump for the new automatic transmission cooler. I have seen pictures of supposed later upper pans without the second coolant port. Maybe manual transmission cars? I know from reading the service manuals and bulletins that they increased the thickness of the casting in one place in later years to reduce cracking and thus requiring longer bolt there, FYI.