Engine knock?

Hi all,

I just found out my Legacy's engine is out of commission.

Long story short:

I got my car reflashed a couple weeks back and decided to get a burble tune (messed with the fuel map) as well. The car was running fine until it was not. It starts up just fine during cold start but it would struggle to start when the car is warm.

Come to find out this morning, according to these videos, I have rod knock (yay!).

https://drive.google.com/open?id=1cOd-4qKYd4TdQOZFWh3lWCsCAiWqLxa8

https://drive.google.com/open?id=1kLBkcjWGMiSV9U8lwn4IJKopAgPL5hqk

It is an Ej20x motor, because back in 2018 I had to get the motor replaced and could only afford to go with an Ej20x. I am thinking to just get the same motor and put it in myself. Any thoughts/inputs?

Example motor: https://www.ebay.com/itm/04-06-SUBARU-LEGACY-2-0L-4-CAM-DUAL-AVCS-TURBO-ENGINE-JDM-EJ20X/233549132863?hash=item36609cf43f:g:FuIAAOSwRIleiMfd

I might consider doing a rebuild on this (the newer ej20x motor and not my current one) but not sure yet.

I appreciate your insight and thoughts.

Thank you.

Why not rebuild what you have? I’m sure if you caught it soon enough you could save most, maybe replace the crank and rods

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Why not rebuild what you have? I’m sure if you caught it soon enough you could save most, maybe replace the crank and rods

 

 

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Thanks for the response. I did just notice the knocking noise. I lost power a couple weeks back but never drove it after that. However it is my only car and I need it to get back on the road ASAP. I don’t know if it can be saved without opening it up, that’s my only worry. It would be a big loss of time to me. I have a very hectic summer session ahead of me. Not really sure what to do.

If I was to rebuild my current motor, I know I would need the crank and rods, but I am not sure where to get them from. There is not much information on the Ej20x motor and I do not want to end up getting the wrong part(s) for it. Anyone know of any place that could help me?

Thank you!!

You're very likely going to spend more on a proper rebuild versus just buying another EJ20X, factoring in machine shop fees and seals/consumables. The exact cost will depend on the extent of the damage to the motor, if it's been run with a failed bearing.

If you lucked out and the bearing journals, cylinder walls and heads are OK you can punt and just throw new bearings, pistons/rings and maybe rods in it, but you'll still either have to disassemble and clean or replace everything that's touched oil. No guarantee the cam journals in the heads aren't trashed since they don't use babbit inserts like the rod and main bearings, so you might end up needing to look for a replacement set of heads even if the block is fine. You won't know any of this until you pull the motor and tear it down, and after that you'll spend a few weeks waiting on the machine shop to get any parts that need work back to you. Absolute best case, you'll spend half of what another EJ20X would have cost you. Worth doing it for the experience if that's what you want, but really not financially justified IMO.

There's a reason even EJ255/EJ257 shortblocks tend to just get replaced instead of being rebuilt. I've priced/had it quoted out myself, and you'll spend more than a brand new short block (1800) if you need any appreciable machining done.

If you're short on time, I'd just get the EJ20X.

Not quite what you asked, but my .02.

You're very likely going to spend more on a proper rebuild versus just buying another EJ20X, factoring in machine shop fees and seals/consumables. The exact cost will depend on the extent of the damage to the motor, if it's been run with a failed bearing.

 

If you lucked out and the bearing journals, cylinder walls and heads are OK you can punt and just throw new bearings, pistons/rings and maybe rods in it, but you'll still either have to disassemble and clean or replace everything that's touched oil. No guarantee the cam journals in the heads aren't trashed since they don't use babbit inserts like the rod and main bearings, so you might end up needing to look for a replacement set of heads even if the block is fine. You won't know any of this until you pull the motor and tear it down, and after that you'll spend a few weeks waiting on the machine shop to get any parts that need work back to you. Absolute best case, you'll spend half of what another EJ20X would have cost you. Worth doing it for the experience if that's what you want, but really not financially justified IMO.

 

There's a reason even EJ255/EJ257 shortblocks tend to just get replaced instead of being rebuilt. I've priced/had it quoted out myself, and you'll spend more than a brand new short block (1800) if you need any appreciable machining done.

 

If you're short on time, I'd just get the EJ20X.

 

Not quite what you asked, but my .02.

Thank you for this informational comment! I will take this under advisement. Just curious to know what a good upgrade would cost for a rod set? I was thinking, to get some money back, when the old motor is out I will have my friend disassemble it and possible rebuild (depending on how the block and head are). If it ends up being too much I might just sell it as it. Best way to recoup some money. I will also sell parts off the newer motor that I do not need such as the intake manifold, turbo, etc.

I know it is a lot of money upfront (for a student such as me) but not much else can be done.

Also, video links are broken for me in your 1st post, not sure about others.

I have updated the links! Please let me know if it works now.

A lot of variables go into selecting internals, but you can probably budget 500-1000 for a set of forged rods/pistons. Another few hundred bucks for OEM bearings, a fraction of that if you go aftermarket. If you just want to get the motor 'fresh' instead of upgrading, I'd buy new OEM pistons, leave the rods alone if the bearing journals are OK, get some new bearings. You can get a set of OEM pistons for the EJ255/257 for a couple hundred bucks, and a bit more for rods last I recall. Not sure on EJ20, but should be similar.

On the measurement/machining side:

There's a whole rabbit hole you can go down here, but at the very least, you'll want all the bearing journals measured out so you can set proper bearing clearances, and the head gasket surfaces decked. Plenty of other options on getting bores/journals cut and honed to improve surface finish, alignment and form, all of which is a question of your needs and your goals. Heads cleaned/decked/pressure tested are also an adder to the machine shop costs you can expect.

If you want to skip all that, you can go the barebones route of cleaning up the head gasket surfaces yourself, measure flatness with a proper straightedge, and plastigage the rod and main bearings to determine what size replacements you need to buy to get the clearances right. Your results may vary depending on how bad the motor is in the first place.

All that is to say, the total cost will be parts + all the extra work needed to get the motor set up to receive them and make sure you don't spin a bearing or blow a headgasket a few miles down the road, or the motor ends up burning a bunch of oil.

I'm really not sure if there's enough of a market for EJ20X motors with that amount of work put into them, though - maybe someone else can chime in.

Links appear to work now!

A lot of variables go into selecting internals, but you can probably budget 500-1000 for a set of forged rods/pistons. Another few hundred bucks for OEM bearings, a fraction of that if you go aftermarket. If you just want to get the motor 'fresh' instead of upgrading, I'd buy new OEM pistons, leave the rods alone if the bearing journals are OK, get some new bearings. You can get a set of OEM pistons for the EJ255/257 for a couple hundred bucks, and a bit more for rods last I recall. Not sure on EJ20, but should be similar.

 

On the measurement/machining side:

 

There's a whole rabbit hole you can go down here, but at the very least, you'll want all the bearing journals measured out so you can set proper bearing clearances, and the head gasket surfaces decked. Plenty of other options on getting bores/journals cut and honed to improve surface finish, alignment and form, all of which is a question of your needs and your goals. Heads cleaned/decked/pressure tested are also an adder to the machine shop costs you can expect.

 

If you want to skip all that, you can go the barebones route of cleaning up the head gasket surfaces yourself, measure flatness with a proper straightedge, and plastigage the rod and main bearings to determine what size replacements you need to buy to get the clearances right. Your results may vary depending on how bad the motor is in the first place.

 

 

 

All that is to say, the total cost will be parts + all the extra work needed to get the motor set up to receive them and make sure you don't spin a bearing or blow a headgasket a few miles down the road, or the motor ends up burning a bunch of oil.

 

I'm really not sure if there's enough of a market for EJ20X motors with that amount of work put into them, though - maybe someone else can chime in.

 

 

 

Links appear to work now!

Holy moly thank you for the info! I am leaning towards just spending the money on the motor only and then salvage and sell whatever I can from my existing motor and sell whatever I do not need from the new motor.

Also - have you tried draining your oil or even dropping the pan to see if there's any bearing material in there? Does the oil feel 'gritty' when you rub it between your fingers?

I have not, I have my tools at my friends home who lives about an hour or so from me and I don't really have a way to get to him at the moment.

—Bump—

Can’t find anything on the ej20x rebuild kit. Can anyone chime in and tell me if piston rings from a USDM EJ20 motor would work? I can not seem to find much info, stuck in a bind. Thanks!

Edit: I found this website that sells parts for the Ej20x motor: https://www.precisionintl.com/ just not sure if they ship internationally.

Does the smoke slight smoke from the exhaust smell like roasting marshmellows? Best description of the smell of coolant/blown head gasket I can come up with.

The sound in the vid is tough to discern. Hood is closed and mics can play tricks. Not exactly what I would immediately call rod knock. Could be a blown turbo and the wheel is sending aluminum into the engine.

Need to pull the DP at a minimum.

From your posts I would not gather you have the tools or experience to rebuild a block. I would be looking for a reputable shop to assist if you plan on going that route.

Does the smoke slight smoke from the exhaust smell like roasting marshmellows? Best description of the smell of coolant/blown head gasket I can come up with.

 

 

The sound in the vid is tough to discern. Hood is closed and mics can play tricks. Not exactly what I would immediately call rod knock. Could be a blown turbo and the wheel is sending aluminum into the engine.

 

 

 

Need to pull the DP at a minimum.

 

 

 

From your posts I would not gather you have the tools or experience to rebuild a block. I would be looking for a reputable shop to assist if you plan on going that route.

Thanks for the response. I don’t really remember what the smell is like but I will start the car up today or tomorrow and try to figure out what kind of smell it’s close to.

Ah I see, but a blown turbo sending bits into the engine could still very much damage the engine correct?

I will just have the shop that did my tune do the full inspection and see what they say.

I’ll also take another video from the top of the engine.

Edit: Possibly a dumb question, do I need to get another ECU when I get the new engine since I have a tune on it or will it erase itself once I put the new block and head in?

A Tuner should be able to work with your ECU, you may have to get a Cobb AP or a cable for your lap top.

But seems like the Tuners like Cobb AP because they don't have to spend there time teaching you how to use "open Source" tuning. Because they can't charge you for all that time it can take.

A Tuner should be able to work with your ECU, you may have to get a Cobb AP or a cable for your lap top.

 

But seems like the Tuners like Cobb AP because they don't have to spend there time teaching you how to use "open Source" tuning. Because they can't charge you for all that time it can take.

Ugh I hope I do not need a Cobb AP, that will cost almost as much as the engine lol. I do have a OBD2 to USB as I bought a while ago. There is one shop my friend (he has a newer WRX) recommend me that will do a free e-tune if I buy the Cobb AP off them. Promo is till July.

Here are some parts I was finally able to find:

Bearings: https://www.ebay.com/itm/King-STD-Conrod-Bearings-suits-Subaru-EJ20X-EJ20Y-Liberty/303188144853

Rings: https://www.ebay.com/itm/Hastings-Piston-Rings-Chrome-STD-suits-Subaru-EJ20X-EJ20Y-DOHC-16-Valve-Libert/293127710223

Head Gasket set: https://www.ebay.com/itm/JDM-Subaru-Legacy-BL5-BP5-EJ20T-2-pcs-Genuine-EJ204-EJ20Y-EJ20X-Head-Gaskets/122669944969

Now the only thing I am unsure about is if the Bearings and Rings are for the bone stock EJ20X or if they are for modified head/block. I did email the seller, awaiting a response.

An AP is going to cost 10% of an engine rebuild if it is done at a reputable shop.

A standard Subaru engine rebuild should cost $5500+ and include:

crank and rod bearings

piston set w/rings

complete engine gasket set

oil pump

water pump

timing belt kit (belt, pulleys, tensioner)

bore and hone with torque plates

polish crank

refresh heads (valve job, deck, seals)

Highly recommended:

oil cooler

pcv

plugs

accessory belts

vacuum lines, coolant lines/hoses, breather hoses, etc.

Possibilities:

head studs

valve guides

valve springs

valves

the sky is the limit

Free/cheap tunes are not good, and good tunes are not free/cheap.

An AP is going to cost 10% of an engine rebuild if it is done at a reputable shop.

 

A standard Subaru engine rebuild should cost $5500+ and include:

crank and rod bearings

piston set w/rings

complete engine gasket set

oil pump

water pump

timing belt kit (belt, pulleys, tensioner)

bore and hone with torque plates

polish crank

refresh heads (valve job, deck, seals)

 

Highly recommended:

oil cooler

pcv

plugs

accessory belts

vacuum lines, coolant lines/hoses, breather hoses, etc.

 

Possibilities:

head studs

valve guides

valve springs

valves

the sky is the limit

 

Free/cheap tunes are not good, and good tunes are not free/cheap.

Meant to say if I just replaced the ej20x with another ej20x and not do any work to the "new" one.

They have done some great tuning work from what their customers said as I reached out to some. Sadly not many to have legacies. I heard that church automotive which isn't too far from me (granted my car is working by then) does some great tuning as well. A bunch of people recommend me to them.

You can certainly replace the block. I would still have the heads examined at a minimum. Subaru valve guides tend to show heavy wear by 100k miles, heads are prone to warping and valves can many times show damage as well. There are also very small ports that can clog and its good to replace the galley plugs. If the turbo is blown that adds another level of concern about what needs cleaning and/or replacing. I can go on and on...

If you need a good engine build in So Cal, I might know a few people. If you need a good tune in So Cal, I might know a few people. LOL.

I do not know who tuned your car, but do know that there are MANY good options for you in the So Cal area. With a good tuner a Legacy is another Subaru. A Legacy with an EJ20 block is not a USDM Legacy any way. Dont get caught up in all the BS.

You can certainly replace the block. I would still have the heads examined at a minimum. Subaru valve guides tend to show heavy wear by 100k miles, heads are prone to warping and valves can many times show damage as well. There are also very small ports that can clog and its good to replace the galley plugs. If the turbo is blown that adds another level of concern about what needs cleaning and/or replacing. I can go on and on...

 

 

If you need a good engine build in So Cal, I might know a few people. If you need a good tune in So Cal, I might know a few people. LOL.

 

 

 

I do not know who tuned your car, but do know that there are MANY good options for you in the So Cal area. With a good tuner a Legacy is another Subaru. A Legacy with an EJ20 block is not a USDM Legacy any way. Dont get caught up in all the BS.

Thanks for the response. I found out I am getting some money from school which will be enough to cover a newer EJ20X motor. I know which route I am going to go with. I am going to sell off stuff from the other motor that I do not need and try to recoup as much money as possible. Will also replace or rebuild turbo (if it turns out to be fine). Hopefully nothing else is damaged and I can get away with just replacing the head and block.