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10-08-2020, 04:21 PM | #1 |
Scooby Newbie
Member#: 103245
Join Date: Dec 2005
Chapter/Region:
SCIC
Location: San Diego, CA
Vehicle:1967 912 STi Spec C Ivory White |
Exhaust ports clean vs dirty - help!
Not sure why but hoping not head gasket issue, but trying to find out why one side of engine exhaust ports are clean vs other side which is dirty black. This is a ej207 spec c motor with open source tuning. Custom short exhaust. Rest of motor basically stock. Any insight or help would be appreciated.
I’m getting an endoscope today to look inside cylinders. Would leak down testing or other testing help pinpoint the problem? TIA Right side vs Left side
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Last edited by vitai0; 10-08-2020 at 04:33 PM. |
10-08-2020, 05:03 PM | #2 |
Scooby Guru
Member#: 21145
Join Date: Jul 2002
Chapter/Region:
NESIC
Location: Not in my own time
Vehicle:2002 Enemy of Aku |
Looks like one side is running richer than the other.
- Possible sticking injectors. - Possible bad plugs or bad coils leading to less than complete ignition |
10-08-2020, 08:01 PM | #3 |
Scooby Newbie
Member#: 103245
Join Date: Dec 2005
Chapter/Region:
SCIC
Location: San Diego, CA
Vehicle:1967 912 STi Spec C Ivory White |
Its strange that both cylinders on that head are that way though to be an injector or plug/coil. Wouldn't it be just one cylinder, not both? Or would one bad injector clean both exhaust port on the same head? Any other ways to test or see if HG or some other issue? Am I even looking at the right side? Is the black exhaust port more of concern?
Last edited by vitai0; 10-08-2020 at 08:30 PM. |
10-09-2020, 11:03 AM | #4 |
Scooby Guru
Member#: 21145
Join Date: Jul 2002
Chapter/Region:
NESIC
Location: Not in my own time
Vehicle:2002 Enemy of Aku |
Well, you're not the original owner of this motor.
How long have you had this motor? Has this motor even been installed? What brought you to the conclusion you even needed to look in the first place? Need more info about this motor and your experience with it. If you just bought it and you are tearing it down to go over and replace items before installation, then replace as many and hoses as you can to eliminate possible future issues |
10-09-2020, 11:56 AM | #5 |
Scooby Newbie
Member#: 103245
Join Date: Dec 2005
Chapter/Region:
SCIC
Location: San Diego, CA
Vehicle:1967 912 STi Spec C Ivory White |
Hi Jack - happy to elaborate if that helps....
Had the motor for 7 years or so, bought used on JDM market as it is a EJ207 Spec C motor. Yes, the motor has been running fine in my Porsche now for about 5-6 years or so. My AFRs have been swinging left and right a bit more than usual at idle, i have been getting some backfires more than normal (much more during shifting), and removed header due to checking for exhaust leak. No leaks, as i welded the crack in the header up and tested it with acetone. Was placed back for a bit and even ran an AutoX as is, but noticed it was running rough and not idling great. Looked back at my customer header and removed to see if cracked again, but all ok. Then noticed my right side exhaust ports looked super clean, vs the other side which is black. I always inspect everythign when i can, or while i am in there per say. Will remove plugs and use endoscope to look for issues inside the cylinder and visual of piston top tonight to see. More to come. TIA |
10-09-2020, 03:19 PM | #6 |
Scooby Guru
Member#: 21145
Join Date: Jul 2002
Chapter/Region:
NESIC
Location: Not in my own time
Vehicle:2002 Enemy of Aku |
Ok, things are a little more clearer now.
Agreed it seems a little weird that both cylinders look the same but different on each side of the motor, ie; dirty on one and clean on the other. If you have never changed coils or injectors since you bought the engine, and these are the ones that came with the engine, could all be related. You can't really tell if coils are bad just by looking at them. Same with injectors. Be interesting to see what comes out after the endoscope. |
10-10-2020, 02:20 PM | #7 |
Scooby Newbie
Member#: 103245
Join Date: Dec 2005
Chapter/Region:
SCIC
Location: San Diego, CA
Vehicle:1967 912 STi Spec C Ivory White |
Ok, got endoscope pics to look at things better. So nothing really showing issue yet to me. Plugs look OK, same on both sides of engine. Piston tops a bit dirtier on the "clean exhaust port" side. Valve stem seal a tad worn on one exhaust valve, rest look ok all around. Oil looks normal, no signs of milky white or any other abnormalities. So, only thing I can think of is maybe replace all my coils an plugs, and get injectors cleaned to reset, and then run for a bit and reexamine. Any ideas or thoughts you can help me with?
Also, how to I embed the pics into NASIOC like before. I don't see to be able to do so now for some reason... Plugs: Clean exhaust port piston 1: Clean exhaust port piston 2: Valve on clean exhaust port: Valve on clean exhaust port 2: Valves on dirty exhaust port: Piston top of dirty side: |
10-13-2020, 11:21 AM | #9 |
Scooby Guru
Member#: 21145
Join Date: Jul 2002
Chapter/Region:
NESIC
Location: Not in my own time
Vehicle:2002 Enemy of Aku |
I don't see anything in the pics that stands out.
I would start with the plugs and igniters ( coils ) and see what happens. Just sounds like this is where your issue lies. you have to start somewhere & start eliminating possible issues. If interested PM me. I have the coils from my 207 for sale. Bought new 4 years ago & maybe 25K miles on them a most. I * may * also have a set of plugs as well but I will have to check. |
10-26-2020, 08:03 PM | #10 |
Scooby Specialist
Member#: 515308
Join Date: Jun 2020
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Every time I have wondered if I had a hg issue with a Subaru, I did. Sometimes they leak a lil then nothing for a while then lil missing Coolant then all good then bad hg, esp if they are the old style
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