Welcome to the North American Subaru Impreza Owners Club Monday September 22, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Built Motor Discussion

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.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 07-31-2014, 08:45 PM   #1
TurboQueef
Scooby Newbie
 
Member#: 86700
Join Date: May 2005
Location: Otsego, MI
Vehicle:
2005 STI
Silver/Black,11.44@123.60

Default Drop in oil pressure AVCS suspect?

Good day,

I have been troubleshooting an issue with my engine:

1600 miles ago I was dialing in an E85 tune, I made a pull at 27.5psi and spiked very rich (9:8/1 AFR).. by redline (7500). The engine sputtered (technical term ;-) just before I lifted at red line.

I was datalogging and did not see any knock or abnormal condition with the pull.

Soon after the pull I noticed my oil pressure dropped by 10psi. I pulled a sample and sent to Blackstone.. report came back good (some lead but was due to me cutting pump with leaded fuel before switching to E85. Copper & Tin low to zero ppm.

Engine sounds and runs great ... just lower oil pressure:

Before this issue: cruising at 75mph I had 78psi.. now I have 70.

Peak pressure was 80~83psi before now it is 70~73psi.

My oil pressure is taken from the rear passenger side of block.

Running 20w50 VR1, 11mm pump with 1 extra shim, King XPG bearings.. Oil clearance: Mains = .0018~.0015. Rods .002

I have tried mechanical gauge and confirmed pressure reading is same on both.

Yesterday, on way to work after full warm up the pressure dropped another 10psi. I was catching live data at the time and noticed the AVCS system was not advancing the cams at all in areas where target was 10 degrees. After driving a few more miles after coming to stop.. the AVCS started working again and oil pressure came up 10psi. (no CEL)

I am wondering if the AVCS system is causing my oil pressure drop. I am going to double check but I believe the filters have been removed.

Any leads for areas to check are appreciated.

Thanks,

Jeff
* Registered users of the site do not see these ads.
TurboQueef is offline   Reply With Quote
Old 07-31-2014, 09:20 PM   #2
Juice66
Scooby Newbie
 
Member#: 340526
Join Date: Dec 2012
Vehicle:
2004 WRX STi
s200sx/93oct

Default

Single or dual avcs?
Juice66 is offline   Reply With Quote
Old 08-01-2014, 04:29 AM   #3
TurboQueef
Scooby Newbie
 
Member#: 86700
Join Date: May 2005
Location: Otsego, MI
Vehicle:
2005 STI
Silver/Black,11.44@123.60

Default

Single AVCS 2005 STi
TurboQueef is offline   Reply With Quote
Old 08-01-2014, 11:29 AM   #4
KillerBMotorsport
NASIOC Vendor
 
Member#: 198281
Join Date: Dec 2008
Chapter/Region: MAIC
Location: Virginia
Vehicle:
2005 WRX/STi
WRB of course

Default

Fuel dilution from the dyno/rich fuel would have been my guess, but it sounds like you've done an oil change since.

Single AVCS will not cause the pressure to drop significantly, at least not anything like the 20psi you can see with dual AVCS.

Sounds like something may be starting to go south on you, unfortunately, likely to be something internal. I'd be tempted to pull the motor before it leads to something more catastrophic.

And ditch that 11mm pump while you're at it. They are notorious for aerating once beyond factory redline, especially NOT on a car that needs the extra flow (non-dual AVCS, journal turbo, etc...). It can be enough to skim a bearing for sure, or worse, spin one.

Take your readings off the front of the engine, otherwise you will see lower pressures. The front is going to give the highest most consistent pressures vs after passages start to split and pressure drops.

Good luck!
KillerBMotorsport is offline   Reply With Quote
Old 08-01-2014, 11:44 AM   #5
TurboQueef
Scooby Newbie
 
Member#: 86700
Join Date: May 2005
Location: Otsego, MI
Vehicle:
2005 STI
Silver/Black,11.44@123.60

Default

Thanks for the info KillerB...

I changed oil and sampled three times sense initial drop. Bearing material copper and tin are very low. Lead is slightly higher (6ppm) but I think this is due to the leaded fuel I ran a few changes ago.

Can u tell me how my current oil pressure compares to other builds with similar spec as mine?

Sent from my SCH-I545 using NASIOC mobile app
TurboQueef is offline   Reply With Quote
Old 08-01-2014, 11:57 AM   #6
Juice66
Scooby Newbie
 
Member#: 340526
Join Date: Dec 2012
Vehicle:
2004 WRX STi
s200sx/93oct

Default

Quote:
Originally Posted by KillerBMotorsport View Post
Fuel dilution from the dyno/rich fuel would have been my guess, but it sounds like you've done an oil change since. Single AVCS will not cause the pressure to drop significantly, at least not anything like the 20psi you can see with dual AVCS. Sounds like something may be starting to go south on you, unfortunately, likely to be something internal. I'd be tempted to pull the motor before it leads to something more catastrophic. And ditch that 11mm pump while you're at it. They are notorious for aerating once beyond factory redline, especially NOT on a car that needs the extra flow (non-dual AVCS, journal turbo, etc...). It can be enough to skim a bearing for sure, or worse, spin one. Take your readings off the front of the engine, otherwise you will see lower pressures. The front is going to give the highest most consistent pressures vs after passages start to split and pressure drops. Good luck!
would it be worth it for him to replace 11mm with 10mm first?
Juice66 is offline   Reply With Quote
Old 08-01-2014, 11:58 AM   #7
TurboQueef
Scooby Newbie
 
Member#: 86700
Join Date: May 2005
Location: Otsego, MI
Vehicle:
2005 STI
Silver/Black,11.44@123.60

Default

My initial thought was I damaged bearing but now I am confused.

I researched the make up for King XPG bearings... Top layer is very thin nickel I believe. Second layer (babbit) is alloy: lead is base, copper is 5 to 10 % and tin is 10% . My oil reports have never had nickel and tin has been zero or 1 ppm... copper is 3 to 9 so based on oil I am struggling to believe it is bearing related.

Any thoughts on this?



Sent from my SCH-I545 using NASIOC mobile app
TurboQueef is offline   Reply With Quote
Old 08-01-2014, 12:01 PM   #8
Juice66
Scooby Newbie
 
Member#: 340526
Join Date: Dec 2012
Vehicle:
2004 WRX STi
s200sx/93oct

Default

Quote:
Originally Posted by TurboQueef View Post
Thanks for the info KillerB... I changed oil and sampled three times sense initial drop. Bearing material copper and tin are very low. Lead is slightly higher (6ppm) but I think this is due to the leaded fuel I ran a few changes ago. Can u tell me how my current oil pressure compares to other builds with similar spec as mine? Sent from my SCH-I545 using NASIOC mobile app
my clearances are identical to yours but with a 10mm. I too have single avcs and i see around 80 cruising and 87ish redline with 15w50. If youre out pounding it hard, its not uncommon to see about 7ish psi of drop with how hot the oil gets but that also depends on if you have a stock cooler and what oil
Juice66 is offline   Reply With Quote
Old 08-01-2014, 12:08 PM   #9
TurboQueef
Scooby Newbie
 
Member#: 86700
Join Date: May 2005
Location: Otsego, MI
Vehicle:
2005 STI
Silver/Black,11.44@123.60

Default

It does drop 7 or so under pounding or long 75mph cruise.

I do not run an oil cooler (removed stock)

Sent from my SCH-I545 using NASIOC mobile app
TurboQueef is offline   Reply With Quote
Old 08-01-2014, 12:10 PM   #10
Juice66
Scooby Newbie
 
Member#: 340526
Join Date: Dec 2012
Vehicle:
2004 WRX STi
s200sx/93oct

Default

Quote:
Originally Posted by TurboQueef View Post
It does drop 7 or so under pounding or long 75mph cruise. I do not run an oil cooler (removed stock) Sent from my SCH-I545 using NASIOC mobile app
why......?
Juice66 is offline   Reply With Quote
Old 08-01-2014, 12:47 PM   #11
TurboQueef
Scooby Newbie
 
Member#: 86700
Join Date: May 2005
Location: Otsego, MI
Vehicle:
2005 STI
Silver/Black,11.44@123.60

Default

Remove oil cooler? Axis removed it when built my engine. Ron said for my driving did not need it. He mentioned it restricts flow.

I only drive in summer...no tracking ..other than 1/4 mile every so often.

Sent from my SCH-I545 using NASIOC mobile app
TurboQueef is offline   Reply With Quote
Old 08-01-2014, 03:16 PM   #12
KillerBMotorsport
NASIOC Vendor
 
Member#: 198281
Join Date: Dec 2008
Chapter/Region: MAIC
Location: Virginia
Vehicle:
2005 WRX/STi
WRB of course

Default

Quote:
Originally Posted by TurboQueef View Post
Thanks for the info KillerB...

I changed oil and sampled three times sense initial drop. Bearing material copper and tin are very low. Lead is slightly higher (6ppm) but I think this is due to the leaded fuel I ran a few changes ago.

Can u tell me how my current oil pressure compares to other builds with similar spec as mine?

Sent from my SCH-I545 using NASIOC mobile app
No Problem. I really can't tell you how it compares because you're measuring from the back port. Take a read off the front and we can see how it looks. Spending $15 on a mechanical gauge to verify what you're seeing is cheap insurance and an easy way to know if it's coincidentally a flakey sensor/gauge.

Quote:
Originally Posted by Juice66 View Post
would it be worth it for him to replace 11mm with 10mm first?
IMO this is definitely not an engine built for a 11mm pump. More harm than good can come from running the bigger pump.
KillerBMotorsport 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 02:41 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.