Welcome to the North American Subaru Impreza Owners Club Thursday March 28, 2024
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo)

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 02-01-2018, 05:11 PM   #1
AspirinWhite
Scooby Newbie
 
Member#: 90982
Join Date: Jul 2005
Location: Norman, OK
Vehicle:
2003 WRX w/ V7 EJ207
Sonic Yellow

Default EJ207 Cold knock or piston slap?

I recently completed my version 7 EJ207 swap into my 03 WRX and it fired up with a noise that was similar to a engine knocking noise. However when the engine was warmed to temperature, the noise disappeared.

I've been looking up through a lot of threads and most of the answers leaned toward piston slap while a handful claimed it was rod knock.

I'm quite stumped about this problem and really paranoid if the engine I've purchased was bad from the start. I tuned the engine immediately via open source to eliminate the possibility of pinging/detonation due to crappy California 91 gas. The engine runs very strong but the cold knock doesn't seem to go away.

Any help would be great.


Last edited by AspirinWhite; 02-04-2018 at 05:01 PM. Reason: video upload
AspirinWhite is offline   Reply With Quote
Old 02-01-2018, 06:16 PM   #2
danger1138
Scooby Specialist
 
Member#: 279525
Join Date: Apr 2011
Chapter/Region: Tri-State
Location: QUEENS NY
Vehicle:
06 Fxt

Default

You just said the noise goes away after it warms up. So essentially you have no issue.
danger1138 is offline   Reply With Quote
Old 02-01-2018, 06:45 PM   #3
AspirinWhite
Scooby Newbie
 
Member#: 90982
Join Date: Jul 2005
Location: Norman, OK
Vehicle:
2003 WRX w/ V7 EJ207
Sonic Yellow

Default

Quote:
Originally Posted by danger1138 View Post
You just said the noise goes away after it warms up. So essentially you have no issue.
So is it pretty normal make that noise when cold? I will post a vid of the sound once the car gets cold again
AspirinWhite is offline   Reply With Quote
Old 02-01-2018, 07:57 PM   #4
danger1138
Scooby Specialist
 
Member#: 279525
Join Date: Apr 2011
Chapter/Region: Tri-State
Location: QUEENS NY
Vehicle:
06 Fxt

Default

Well,
For the most part yea; it is normal. Ive had a built motor that was pretty noisy, particularly when cold. But remember it was a built motor.

My stock ej251 on my 04 legacy wagon is also loud and has piston slap when cold. My oil levels are above the "F" mark btw too. So not a low oil scenario in my case.
danger1138 is offline   Reply With Quote
Old 02-01-2018, 08:02 PM   #5
AspirinWhite
Scooby Newbie
 
Member#: 90982
Join Date: Jul 2005
Location: Norman, OK
Vehicle:
2003 WRX w/ V7 EJ207
Sonic Yellow

Default

Quote:
Originally Posted by danger1138 View Post
Well,
For the most part yea; it is normal. Ive had a built motor that was pretty noisy, particularly when cold. But remember it was a built motor.

My stock ej251 on my 04 legacy wagon is also loud and has piston slap when cold. My oil levels are above the "F" mark btw too. So not a low oil scenario in my case.
I'm running with valvoline synthetic 10w30 and I religiously check for oil levels to make sure it's in the right level as well.
AspirinWhite is offline   Reply With Quote
Old 02-01-2018, 08:16 PM   #6
Cobrakai
Scooby Specialist
 
Member#: 176408
Join Date: Apr 2008
Chapter/Region: SCIC
Location: South OC
Vehicle:
2005 EJ207 STy
White

Default

I'm in the same boat, my V7 swap is noticeably loud during cold starts but it quiets down at operating temperature.

It's a slapping/knocking sound only audible on reversing and taking off in first during cold engine conditions.

The car has been looked at by numerous Ej207 guru's and Subaru Mechanics, they've said everything is A-OK, which puts me at peace.
Cobrakai is offline   Reply With Quote
Old 02-01-2018, 08:26 PM   #7
AspirinWhite
Scooby Newbie
 
Member#: 90982
Join Date: Jul 2005
Location: Norman, OK
Vehicle:
2003 WRX w/ V7 EJ207
Sonic Yellow

Default

Quote:
Originally Posted by Cobrakai View Post
I'm in the same boat, my V7 swap is noticeably loud during cold starts but it quiets down at operating temperature.

It's a slapping/knocking sound only audible on reversing and taking off in first during cold engine conditions.

The car has been looked at by numerous Ej207 guru's and Subaru Mechanics, they've said everything is A-OK, which puts me at peace.
That does put me in the ease a bit. How many miles have you put on your engine so far?
AspirinWhite is offline   Reply With Quote
Old 02-01-2018, 08:32 PM   #8
Cobrakai
Scooby Specialist
 
Member#: 176408
Join Date: Apr 2008
Chapter/Region: SCIC
Location: South OC
Vehicle:
2005 EJ207 STy
White

Default

Quote:
Originally Posted by AspirinWhite View Post
That does put me in the ease a bit. How many miles have you put on your engine so far?
~2800.

Few late night canyon carving sessions and daily WOT pulls on the freeway onramps, hasn't gone boom yet.

If the noise is present at operating temperatures I'll start worrying haha.
Cobrakai is offline   Reply With Quote
Old 02-01-2018, 09:04 PM   #9
AspirinWhite
Scooby Newbie
 
Member#: 90982
Join Date: Jul 2005
Location: Norman, OK
Vehicle:
2003 WRX w/ V7 EJ207
Sonic Yellow

Default

Quote:
Originally Posted by Cobrakai View Post
~2800.

Few late night canyon carving sessions and daily WOT pulls on the freeway onramps, hasn't gone boom yet.

If the noise is present at operating temperatures I'll start worrying haha.
Yours is still relatively new then. I officially went through one full tank so far. Lots of power for sure but that cold slap/knock really is annoying.

Did you get yours tuned at Churchs?
AspirinWhite is offline   Reply With Quote
Old 02-05-2018, 01:29 AM   #10
Cobrakai
Scooby Specialist
 
Member#: 176408
Join Date: Apr 2008
Chapter/Region: SCIC
Location: South OC
Vehicle:
2005 EJ207 STy
White

Default

Quote:
Originally Posted by AspirinWhite View Post
Yours is still relatively new then. I officially went through one full tank so far. Lots of power for sure but that cold slap/knock really is annoying.

Did you get yours tuned at Churchs?
No but I wish I had.

I went with another big name shop in socal, good tuner - terrible customer service.


From what everyone tells me Church is fantastic with a 207, if I had the choice to do it over again I'd go with him.

Quote:
Originally Posted by AspirinWhite View Post
video uploaded

That's exactly how my car sounds.
Cobrakai is offline   Reply With Quote
Old 02-01-2018, 10:55 PM   #11
2slofouru
Scooby Guru
 
Member#: 90539
Join Date: Jul 2005
Chapter/Region: South East
Location: SWLA
Vehicle:
My BOV goes
COVFEFE!

Default

Forged piston cold slap, normal. Even my 97 ej20k with cast pistons did it, worse in cold weather, but ran silky smooth and never skipped a beat. I believe the flat engine design makes it easier to hear as well.

It could also be the timing belt tensioner, did you replace it with new?
2slofouru is offline   Reply With Quote
Old 02-05-2018, 02:05 PM   #12
AspirinWhite
Scooby Newbie
 
Member#: 90982
Join Date: Jul 2005
Location: Norman, OK
Vehicle:
2003 WRX w/ V7 EJ207
Sonic Yellow

Default

Quote:
Originally Posted by 2slofouru View Post
Forged piston cold slap, normal. Even my 97 ej20k with cast pistons did it, worse in cold weather, but ran silky smooth and never skipped a beat. I believe the flat engine design makes it easier to hear as well.

It could also be the timing belt tensioner, did you replace it with new?
I haven't yet but it won't be a bad idea replacing all the idlers and belts
AspirinWhite is offline   Reply With Quote
Old 02-01-2018, 11:01 PM   #13
2slofouru
Scooby Guru
 
Member#: 90539
Join Date: Jul 2005
Chapter/Region: South East
Location: SWLA
Vehicle:
My BOV goes
COVFEFE!

Default

2slofouru is offline   Reply With Quote
Old 02-06-2018, 10:10 AM   #14
Samurai Jack
Scooby Guru
 
Member#: 21145
Join Date: Jul 2002
Chapter/Region: NESIC
Location: Not in my own time
Vehicle:
2002 Enemy of Aku

Default

Quote:
Originally Posted by 2slofouru View Post
Tensioner noise. Imagine how many subaru owners have gotten screwed out of money or even sold their cars because they were told it was a "spun bearing".
I'd lean toward this ^^^ before cold piston slap.
There have been a number of posts re: people having what they thought was rod knock only to discover later that it was a bad tensioner.

... and no, I'd say it is not normal. I don't have cold piston slap on mine.
I think many people just call it piston slap because the v7s have forged pistons so they call it normal, because they are comparing it to a built motor w/aftermarket forged pistons.
Easy answer so they don't have t look into it.

You should check the tensioner to be sure before it's too late.
Samurai Jack is offline   Reply With Quote
Old 02-06-2018, 10:21 AM   #15
AspirinWhite
Scooby Newbie
 
Member#: 90982
Join Date: Jul 2005
Location: Norman, OK
Vehicle:
2003 WRX w/ V7 EJ207
Sonic Yellow

Default

Quote:
Originally Posted by Samurai Jack View Post
I'd lean toward this ^^^ before cold piston slap.
There have been a number of posts re: people having what they thought was rod knock only to discover later that it was a bad tensioner.

... and no, I'd say it is not normal. I don't have cold piston slap on mine.
I think many people just call it piston slap because the v7s have forged pistons so they call it normal, because they are comparing it to a built motor w/aftermarket forged pistons.
Easy answer so they don't have t look into it.

You should check the tensioner to be sure before it's too late.
Is the bad tensioner noise temperature dependant though? The noise I'm hearing disappears once it's warm and appears only when lower rpm from cold start.

The tensioner noise sounds like it's constant
AspirinWhite is offline   Reply With Quote
Old 02-06-2018, 12:19 PM   #16
Samurai Jack
Scooby Guru
 
Member#: 21145
Join Date: Jul 2002
Chapter/Region: NESIC
Location: Not in my own time
Vehicle:
2002 Enemy of Aku

Default

Quote:
Originally Posted by AspirinWhite View Post
Is the bad tensioner noise temperature dependant though? The noise I'm hearing disappears once it's warm and appears only when lower rpm from cold start.

The tensioner noise sounds like it's constant
It may only be the tensioner. It may be showing up when it's cold, but could continue to deteriorate. Worth checking the tensioner than just ignoring it and wish you did. All I am saying is it is worth checking now just to rule it our, or in
Samurai Jack is offline   Reply With Quote
Old 02-07-2018, 01:13 AM   #17
AspirinWhite
Scooby Newbie
 
Member#: 90982
Join Date: Jul 2005
Location: Norman, OK
Vehicle:
2003 WRX w/ V7 EJ207
Sonic Yellow

Default

Quote:
Originally Posted by Samurai Jack View Post
It may only be the tensioner. It may be showing up when it's cold, but could continue to deteriorate. Worth checking the tensioner than just ignoring it and wish you did. All I am saying is it is worth checking now just to rule it our, or in
Well, I ordered the Gates blue kit and gonna change everything when it comes in. It may or may not fix the issue but I think it's a good idea to change it.
AspirinWhite is offline   Reply With Quote
Old 02-15-2018, 09:58 PM   #18
2slofouru
Scooby Guru
 
Member#: 90539
Join Date: Jul 2005
Chapter/Region: South East
Location: SWLA
Vehicle:
My BOV goes
COVFEFE!

Default

Quote:
Originally Posted by AspirinWhite View Post
Is the bad tensioner noise temperature dependant though? The noise I'm hearing disappears once it's warm and appears only when lower rpm from cold start.

The tensioner noise sounds like it's constant


There is a similar issue with the honda V6 motors, as the tensioner ages it loses pressure and gets softer. When they are about done, they will rattle so hard you think it's a rod bearing. They first become obvious on really cold mornings and the noise goes away as it warms up because the heat of the engine raises the tensioner's internal pressure and helps it stop rattling. As it gets worse, the rattle stays longer every drive, until eventually it doesn't matter if the engine is warmed up.

I haven't watched your vids yet, because I'm too much of a wimp to check anything other than youtube hosted videos
2slofouru is offline   Reply With Quote
Old 02-16-2018, 11:02 AM   #19
Samurai Jack
Scooby Guru
 
Member#: 21145
Join Date: Jul 2002
Chapter/Region: NESIC
Location: Not in my own time
Vehicle:
2002 Enemy of Aku

Default

Quote:
Originally Posted by 2slofouru View Post
There is a similar issue with the honda V6 motors, as the tensioner ages it loses pressure and gets softer. When they are about done, they will rattle so hard you think it's a rod bearing. They first become obvious on really cold mornings and the noise goes away as it warms up because the heat of the engine raises the tensioner's internal pressure and helps it stop rattling. As it gets worse, the rattle stays longer every drive, until eventually it doesn't matter if the engine is warmed up.
This has shown to be the case multiple times with Subarus. There are posts here discussing that as well as YouTube hosted videos of the noises with thread followups confirming that the tensioner was bad.

Last edited by Samurai Jack; 03-06-2018 at 09:09 AM.
Samurai Jack is offline   Reply With Quote
Old 02-04-2018, 05:19 PM   #20
AspirinWhite
Scooby Newbie
 
Member#: 90982
Join Date: Jul 2005
Location: Norman, OK
Vehicle:
2003 WRX w/ V7 EJ207
Sonic Yellow

Default

video uploaded
AspirinWhite is offline   Reply With Quote
Old 02-05-2018, 09:19 PM   #21
CarmelValleyWRX
Scooby Specialist
 
Member#: 453872
Join Date: Sep 2016
Vehicle:
2005 wrx wagon
48w

Default

my car does that too (exactly the same sound when blip the throttle) but its an EJ205 stock motor. it did not always do it. it slowly got louder. i replaced all my pulleys because i thought it was timing belt related. it still runs ok but it makes noise when hot too now. i dont trust my det cans now because the mechanical noise is so loud i cant hear anything.
CarmelValleyWRX is offline   Reply With Quote
Old 02-06-2018, 10:26 AM   #22
silvercookie
Scooby Specialist
 
Member#: 180033
Join Date: May 2008
Chapter/Region: Tri-State
Location: Queens, NY, 11385
Vehicle:
2005 WRX
PSM

Default

My IAG stage 1+ block does the same thing on cold start especially in the winter.

Just piston slap from having forged pistons until they expand when they warm up.
silvercookie is offline   Reply With Quote
Old 02-06-2018, 12:17 PM   #23
Samurai Jack
Scooby Guru
 
Member#: 21145
Join Date: Jul 2002
Chapter/Region: NESIC
Location: Not in my own time
Vehicle:
2002 Enemy of Aku

Default

Quote:
Originally Posted by silvercookie View Post
My IAG stage 1+ block does the same thing on cold start especially in the winter.

Just piston slap from having forged pistons until they expand when they warm up.
You can't compare a "built" motor to an OEM motor. "Built" motors do normally have some piston slap. How much is dependent on which brand pistons you use and the piston material and how the builder set the PTW clearances.
Samurai Jack is offline   Reply With Quote
Old 02-08-2018, 02:28 PM   #24
D-Rodman
Scooby Specialist
 
Member#: 110078
Join Date: Mar 2006
Location: Long Island N.Y.
Vehicle:
02 Bugeye JDM STi
OBP BLACK

Default

My v7 ej207 piston slaps at cold start but quiets down fairly quick, under a minute. Keep in mind when buying a used motor you are trusting the vendor is representing the mileage accurately. A higher miles motor will have more wear and looser tolerances.
D-Rodman is offline   Reply With Quote
Old 02-08-2018, 02:56 PM   #25
Cobrakai
Scooby Specialist
 
Member#: 176408
Join Date: Apr 2008
Chapter/Region: SCIC
Location: South OC
Vehicle:
2005 EJ207 STy
White

Default

Quote:
Originally Posted by D-Rodman View Post
My v7 ej207 piston slaps at cold start but quiets down fairly quick, under a minute. Keep in mind when buying a used motor you are trusting the vendor is representing the mileage accurately. A higher miles motor will have more wear and looser tolerances.
Same, sometimes a bit longer in colder ambient temps.
Cobrakai is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -4. The time now is 05:43 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2024 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.

When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission
Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.