Welcome to the North American Subaru Impreza Owners Club Wednesday June 29, 2016
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC General > Motorsports

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 07-02-2009, 12:37 AM   #26
generalee69
Scooby Specialist
 
Member#: 106470
Join Date: Jan 2006
Chapter/Region: NWIC
Location: Kent WA
Vehicle:
2004 GT-1 ICSCC #9
www.ClintonRacing.com

Default

Ugh... game over!!

Compression test #1,#2,#3 -- 140psi..............#4 - 95psi

Leakage 80%

We're gonna get it out Friday morning, and start tearing it down. I think this time I am going to do the teardown and rebuild (with the assistance of my mechanic). We'll send it out for machining. But I wanna know everything is good while we are putting it back together.

We'll see how bad it is and go from there.

Thanks for all the help everyone.
* Registered users of the site do not see these ads.
generalee69 is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 07-02-2009, 01:07 AM   #27
mick_the_ginge
Citizen Mick
 
Member#: 27646
Join Date: Oct 2002
Chapter/Region: NWIC
Location: Portland, Oregon
Vehicle:
2003 Sleeved 2.5
Oil Dry Sump Goodness

Default

That sucks, good luck with the rebuild.
mick_the_ginge is offline   Reply With Quote
Old 07-02-2009, 01:41 AM   #28
grippgoat
Scooby Specialist
 
Member#: 62182
Join Date: May 2004
Chapter/Region: NWIC
Location: Kirkland, WA
Vehicle:
2005 STI
White

Default

Sorry to hear about that. Hopefully everything goes smoothly with the rebuild.

-Mike
grippgoat is offline   Reply With Quote
Old 07-02-2009, 02:15 AM   #29
3barboost
Scooby Newbie
 
Member#: 73609
Join Date: Nov 2004
Chapter/Region: International
Location: Johannesburg South Africa
Vehicle:
2002 wrx
White

Default

the other thing you need to school yourself about - is ecu behaviour

the ecu has tables to reduce timing once intake air temps reach a certain point - dont leave at stock settings for track use

the ecu also has tables to reduce timing based on coolant temparatures reach a certain point - again dont leave stock settings for track use

fact = stock settings interpolate and do bring ign timing down
3barboost is offline   Reply With Quote
Old 07-02-2009, 11:12 AM   #30
generalee69
Scooby Specialist
 
Member#: 106470
Join Date: Jan 2006
Chapter/Region: NWIC
Location: Kent WA
Vehicle:
2004 GT-1 ICSCC #9
www.ClintonRacing.com

Default

Thanks guys

So this begs the question, what is the root cause?

2 engines, same result -- Killing #4 cylinder.

Other than the block and pistons being different on the second engine, they were the same (same heads, tune, intake, turbo, exhaust, etc).

Where do I start looking for a root cause? The CEL for misfire in the #4 cylinder came long after the symptoms started. I believe my loss of power at PIR was due to losing compression in hole #4.. then I ran it pretty much all day at Mission until the CEL popped (roughly 50 minutes of track time).

Is there something notorious I am overlooking? Poor intake manifold flow, bad/failing coil pack on that cylinder? Cobb stage 2 tune NFG for the track (I know quite a few other people who use this at the track with no issues)? Head flow issue?

Some more insight would be helpful.
generalee69 is offline   Reply With Quote
Old 07-02-2009, 11:25 AM   #31
mick_the_ginge
Citizen Mick
 
Member#: 27646
Join Date: Oct 2002
Chapter/Region: NWIC
Location: Portland, Oregon
Vehicle:
2003 Sleeved 2.5
Oil Dry Sump Goodness

Default

We need to see the piston that failed to make a better guess of what is happening.

I think you are making it overly complicated, so back to the basics. Remove and flow check the injectors, then get them cleaned and flow checked again. The flow check first will identify if you had an injector issue.

The misfire may have been caused by the failure and could be a red herring. (English term for it maybe sending you down the wrong path)

Coil packs could be an issue but in my experience it's usually #3 that goes as it's the one getting hotter near the turbo uppipe.

What is NFG? If this was not a dyno tune then you really need to get a dyno tune next time for safety sake.

I would bet the damage was knock related, the track pushes the car far harder than street driving and your track driving I expect is harder than a quick HPDE
mick_the_ginge is offline   Reply With Quote
Old 07-02-2009, 11:34 AM   #32
MasterKwan
Scooby Guru
 
Member#: 98961
Join Date: Oct 2005
Chapter/Region: MAIC
Location: NOVA
Vehicle:
2003 WRX
Black

Default

This is a stock tune? You running 100 octane gas while on track? Until you get it apart and see what the damage actually is, I don't think you can guess.


Quote:
the ecu has tables to reduce timing once intake air temps reach a certain point - dont leave at stock settings for track use

the ecu also has tables to reduce timing based on coolant temparatures reach a certain point - again dont leave stock settings for track use
I don't get your point. Are you saying for max power you have to tweek these value or that you need to tweek them to save the motor?

I do think these motors have an achillies heel, the ECU CAN'T measure actual intake air temps. It just guesses because of the location of the air temp sensor. Your inter-cooler could be completely missing yet the ECU can't tell because the air temp is measured at the MAF and not post-intercooler. So, you might go out on track completely heat soaked but, the ECU can't tell and can't pull timing. It's one reason I always run 100 octane on track myself. To protect the motor.


Quote:
The misfire may have been caused by the failure and could be a red herring.
I agree. Down on compression, the cylinder will mis-fire.
MasterKwan is offline   Reply With Quote
Old 07-02-2009, 11:57 AM   #33
STi-MAN
Scooby Guru
 
Member#: 70252
Join Date: Sep 2004
Vehicle:
05 STI
blue

Default

^true, much more accurate to run a blow by maf setup.

I wouldnt track a modified car on the stock ecu map.
STi-MAN is offline   Reply With Quote
Old 07-02-2009, 12:33 PM   #34
generalee69
Scooby Specialist
 
Member#: 106470
Join Date: Jan 2006
Chapter/Region: NWIC
Location: Kent WA
Vehicle:
2004 GT-1 ICSCC #9
www.ClintonRacing.com

Default

Quote:
Originally Posted by mick_the_ginge View Post
We need to see the piston that failed to make a better guess of what is happening.

I think you are making it overly complicated, so back to the basics. Remove and flow check the injectors, then get them cleaned and flow checked again. The flow check first will identify if you had an injector issue.

The misfire may have been caused by the failure and could be a red herring. (English term for it maybe sending you down the wrong path)

Coil packs could be an issue but in my experience it's usually #3 that goes as it's the one getting hotter near the turbo uppipe.

What is NFG? If this was not a dyno tune then you really need to get a dyno tune next time for safety sake.

I would bet the damage was knock related, the track pushes the car far harder than street driving and your track driving I expect is harder than a quick HPDE
Not trying to over complicate things, and I agree that I need to reserve judgement until I have seen what the issue is. STILL -- I don't think it is a coincidence that I lost cylinder #4 both times.

I think you are correct about the problem causing the misfire.. and not the other way around. That was my point of saying I lost power at PIR then 2 weeks later (and another 50 min of track time) I popped a CEL.

Also kind of odd that the stock temp range plugs looked good (even #4) after the CEL showed up... The colder range plugs I pulled out yesterday were very oily -- especially #4

NFG = No [email protected] Good.

I think -- depending on what I find in the engine. This thing will be going back together with the FP Green, bigger injectors, and a dyno tune. I don't see any point (other than learning what happened to cause the failure) to flow test the injectors.

Right now I'm just trying to get a sense of the range of inherent problems that may cause #4 cylinder to fail twice.

When I get it disassembled I'll post up some pics.
generalee69 is offline   Reply With Quote
Old 07-03-2009, 08:23 PM   #35
generalee69
Scooby Specialist
 
Member#: 106470
Join Date: Jan 2006
Chapter/Region: NWIC
Location: Kent WA
Vehicle:
2004 GT-1 ICSCC #9
www.ClintonRacing.com

Default Mods -- This should probably be moved to the built motor discussion now.

Got the motor out today. Really not that bad of a job.. the more I do it the better I get 3 hours by myself including a good portion of the tear down. It's down to a long block now, but I haven't started taking the timing/heads off.

So I discovered today the source of all the oil in the valve cover breather can. There are 2 breather lines off of each valve cover. I had one from each valve cover routed to the catch can. The second line off the valve covers are attached together... in the middle of that line is a second breather off the crank case.

I previously thought (and didn't remember when I dressed the engine back up last time) that the only breather off the crank case went through the PCV.

What was happening is that oil was pushing out of the crank case and into the valve cover. Then out of the valve cover and into the catch can. I'll probably re-route this when I start putting the engine back together... just not sure how yet.

The PCV catch can must have been too much of a restriction, so the oil was pushing into the valve covers.

On a bad note--- There was metallic shinyness to the oil when I drained it. I was hoping to just drop in a new piston and go... don't think that is going to happen now. We'll have to take a look at the bearings, etc. Oil pressure was fine, while it was running... so I am not sure if it was just a matter of time or if the filter was stopping oil from getting into the bearings.

When I get the heads off I'll get some pictures of the bore and piston.

I am starting to suspect that the pistons were the Mahle 4032's not the 2618.... Anyone know a tell-tale way to verify this visually?? I know I asked the builder to get the 2618's, but with the other s@#t they pulled I wouldn't be surprised if he went cheap (against my will).

Also, I was under the impression that the 2618's would not break ringlands even under harsh conditions? Can anyone verify this?

On another note -- Turbo looks ok... no shaft play, no oil in the exhaust side... big crack in the wastegate as typical with the VF39's. I'll get some pics to see what you guys think also.

Quick summary:
How do I tell (visually) the difference between the Mahle 4032 and 2618 alloys?
Has anyone heard of cracked ringlands on the 2618 alloy pistons?
generalee69 is offline   Reply With Quote
Old 07-13-2009, 11:20 PM   #36
generalee69
Scooby Specialist
 
Member#: 106470
Join Date: Jan 2006
Chapter/Region: NWIC
Location: Kent WA
Vehicle:
2004 GT-1 ICSCC #9
www.ClintonRacing.com

Default

An update:

Check out the below pics.

The pistons lined up from left to right are 1,2,3,4.

The #4 piston ringland folded over on itself!? Seriously... what happened? The ring was broken into about 6 pieces at the area where the ringland had collapsed.

I think I'm get on the phone with Mahle tomorrow to try and get their opinion.. I had not seen these pistons before they went into the engine, but I can't believe the ringland has a v-groove in it! It seems destined to fail, very thin. Are any of the other aftermarket EJ25 pistons like this??

No signs of detonation that I see..

Any ideas?







generalee69 is offline   Reply With Quote
Old 07-14-2009, 10:35 AM   #37
CoolRex
*** Banned ***
 
Member#: 85813
Join Date: Apr 2005
Chapter/Region: South East
Location: Myrtle Beach, SC
Vehicle:
2002 E46 M3
2006 RC51

Default

Subscribed.
CoolRex is offline   Reply With Quote
Old 07-14-2009, 10:41 AM   #38
generalee69
Scooby Specialist
 
Member#: 106470
Join Date: Jan 2006
Chapter/Region: NWIC
Location: Kent WA
Vehicle:
2004 GT-1 ICSCC #9
www.ClintonRacing.com

Default

I got an email into Mahle, with pics. If I don't hear anything back today, I'll start calling tomorrow.

Any ideas, similar stories, etc from people would help.


EDIT: The pistons are the 2618's forgings. Mahle electroetches the part number on the top of the piston. I verified the part number through Mahle's catalog. WRX209937P22
generalee69 is offline   Reply With Quote
Old 08-07-2009, 05:47 PM   #39
subyfisher
Scooby Newbie
 
Member#: 84606
Join Date: Apr 2005
Chapter/Region: SCIC
Location: SoCal
Vehicle:
2004 WRX
PSM

Default

Hi generalee69, was there any cylinder wall damage? Just curious, I damaged my exhaust valve in cylinder #2. I am also concerned that the piston ringland might also be damaged. We're just replacing the valves and putting it back on the block. The mechanic and I looked at the cylinder wall, and there's not damage and the factory swirl marks (hones) look fine compared to the other cylinder wall. Thanks!
subyfisher is offline   Reply With Quote
Old 08-07-2009, 06:06 PM   #40
generalee69
Scooby Specialist
 
Member#: 106470
Join Date: Jan 2006
Chapter/Region: NWIC
Location: Kent WA
Vehicle:
2004 GT-1 ICSCC #9
www.ClintonRacing.com

Default

Quote:
Originally Posted by subyfisher View Post
Hi generalee69, was there any cylinder wall damage? Just curious, I damaged my exhaust valve in cylinder #2. I am also concerned that the piston ringland might also be damaged. We're just replacing the valves and putting it back on the block. The mechanic and I looked at the cylinder wall, and there's not damage and the factory swirl marks (hones) look fine compared to the other cylinder wall. Thanks!
Yeah the cylinder was garbage. But then again I ran another 50+ minutes of track time (and track RPM) on it after the symptoms started.

When I broke a ringland last fall the cylinder wall looked good, no scratches.

A compression and leak down tests will definitely find the problem. The other un-scientific sign is to take the oil filler cap off while the engine is running. If you get a puff puff puff, you are getting compression past the rings and into the crankcase. Sometimes the puff puff puff is visual, sometimes you can just feel it with your hand.
generalee69 is offline   Reply With Quote
Old 08-07-2009, 06:10 PM   #41
generalee69
Scooby Specialist
 
Member#: 106470
Join Date: Jan 2006
Chapter/Region: NWIC
Location: Kent WA
Vehicle:
2004 GT-1 ICSCC #9
www.ClintonRacing.com

Default

It's probably a good time for an update also.

Mahle examined the pistons and believe the cause to be the ring ends touched due to overheating of the #4 cylinder.

Still not sure if this is due to a lean fuel mixture, but I am leaning that direction.

Like I said before, there were no signs of detonation.
generalee69 is offline   Reply With Quote
Old 08-07-2009, 06:11 PM   #42
subyfisher
Scooby Newbie
 
Member#: 84606
Join Date: Apr 2005
Chapter/Region: SCIC
Location: SoCal
Vehicle:
2004 WRX
PSM

Default

Quote:
Originally Posted by generalee69 View Post
Yeah the cylinder was garbage. But then again I ran another 50+ minutes of track time (and track RPM) on it after the symptoms started.

When I broke a ringland last fall the cylinder wall looked good, no scratches.

A compression and leak down tests will definitely find the problem. The other un-scientific sign is to take the oil filler cap off while the engine is running. If you get a puff puff puff, you are getting compression past the rings and into the crankcase. Sometimes the puff puff puff is visual, sometimes you can just feel it with your hand.
Thanks for the response. Since the cylinder head is off, is there any way to check the ringlands on the piston without tearing down the block? We found the problem with the exhaust valves when we did the compression and leakdown test.
subyfisher is offline   Reply With Quote
Old 08-07-2009, 06:17 PM   #43
generalee69
Scooby Specialist
 
Member#: 106470
Join Date: Jan 2006
Chapter/Region: NWIC
Location: Kent WA
Vehicle:
2004 GT-1 ICSCC #9
www.ClintonRacing.com

Default

Quote:
Originally Posted by subyfisher View Post
Thanks for the response. Since the cylinder head is off, is there any way to check the ringlands on the piston without tearing down the block? We found the problem with the exhaust valves when we did the compression and leakdown test.
hmmm... I don't know.

Mine was easy enough to look into the cylinder with the piston still inside and see a gap between the cylinder wall and the piston. But the engine was out of the car.

Also, since about an inch of the ring was broken it was pretty easy to see. If the ringland is just cracked and the ring is intact, you probably won't be able to see anything.

You could bolt the head on with the head gasket and run another leakdown test on that cylinder... I think. You wouldn't need to put the cams in, so the valves would be closed. Then just spin that cylinder over to the top.
generalee69 is offline   Reply With Quote
Old 08-08-2009, 10:57 AM   #44
dunk
Scooby Guru
 
Member#: 15359
Join Date: Feb 2002
Chapter/Region: MAIC
Location: Fairfax, VA
Default

What was your ring gap set to?

-Duncan
dunk is offline   Reply With Quote
Old 08-09-2009, 04:29 AM   #45
nickrice20
Scooby Specialist
 
Member#: 95153
Join Date: Sep 2005
Chapter/Region: International
Location: Deutschland
Vehicle:
2016 BMW F48 X1
Mineral White

Default

That is a huge bummer Steve!!!!! I am sorry to hear about your motor problems I hope the next build lasts longer.
nickrice20 is offline   Reply With Quote
Old 08-09-2009, 02:57 PM   #46
generalee69
Scooby Specialist
 
Member#: 106470
Join Date: Jan 2006
Chapter/Region: NWIC
Location: Kent WA
Vehicle:
2004 GT-1 ICSCC #9
www.ClintonRacing.com

Default

Quote:
Originally Posted by dunk View Post
What was your ring gap set to?

-Duncan
I can't say for sure because I didn't assemble the motor. They were supposed to be set at .019"

Quote:
Originally Posted by nickrice20 View Post
That is a huge bummer Steve!!!!! I am sorry to hear about your motor problems I hope the next build lasts longer.
Thanks nick
generalee69 is offline   Reply With Quote
Old 08-10-2009, 11:34 AM   #47
KNS Brakes
NASIOC Storefront Vendor
 
Member#: 125739
Join Date: Sep 2006
Chapter/Region: South East
Location: Raleigh, NC
Vehicle:
2015 WRB WRX
Need Brakes? 919.420.0021

Default

I didn't read all - but I had a similar fate so I thought I'd post up quick

cliff notes:

20G STi w/ 50-60k miles -

I had lots of blow by (a quart every 1-2 sessions)
Definitely detonated - it blew a hole through the piston (stock)

The octane of oil is like 2 - lots of blowby at high RPM/boost - ouch?

I had so much blowby the hoses all blew off/things caught fire etc

(don't mount your a/o separator anywhere near a turbo !)
KNS Brakes is offline   Reply With Quote
Old 08-21-2009, 12:16 PM   #48
generalee69
Scooby Specialist
 
Member#: 106470
Join Date: Jan 2006
Chapter/Region: NWIC
Location: Kent WA
Vehicle:
2004 GT-1 ICSCC #9
www.ClintonRacing.com

Default

I have really only heard 2 possible reasons why the engine failed the way it did.
1) CYL #4 was lean (but not detonating). Which caused it to be hotter than than it should have been. The ring expanded more than it should have, the ends of the rings touched, and it was all over.
2) The ring end gap was set incorrectly during assembly

I am leaning toward answer #1 since this is the second engine that I have killed #4 on (First engine was stock pistons).

Any other possible explanations?

Also, to combat this issue this time around I am planning on
- Going to headers (according to an EGT thread I read, should lower the EGT's by 100*F).
- Installing a 2 channel EGT monitoring system, this one : http://www.exhaustgas.com/ProductDet...pID=&BasketID=
- Going to a bigger turbo, injectors, fuel pump, etc. And getting a custom tune (previously on the Cobb OTS stage 2).

Anything else I should be looking into?
generalee69 is offline   Reply With Quote
Old 08-21-2009, 12:45 PM   #49
CoolRex
*** Banned ***
 
Member#: 85813
Join Date: Apr 2005
Chapter/Region: South East
Location: Myrtle Beach, SC
Vehicle:
2002 E46 M3
2006 RC51

Default

Are you still on stock fuel rails? If so that could be your issue.
CoolRex is offline   Reply With Quote
Old 08-21-2009, 01:24 PM   #50
generalee69
Scooby Specialist
 
Member#: 106470
Join Date: Jan 2006
Chapter/Region: NWIC
Location: Kent WA
Vehicle:
2004 GT-1 ICSCC #9
www.ClintonRacing.com

Default

Quote:
Originally Posted by CoolRex View Post
Are you still on stock fuel rails? If so that could be your issue.
Yes, I am. But I have read mixed opinions about aftermarket fuel rails actually doing anything positive.

This EGT/header discussion thread really pointed me in the direction of headers and exhaust flow being the culprit more so than fuel delivery. http://forums.nasioc.com/forums/show...=4+channel+EGT
generalee69 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

Similar Threads
Thread Thread Starter Forum Replies Last Post
Coolant Problem; so what do these symptoms add up to BHawk Factory 2.5L Turbo Powertrain (EJ Series Factory 2.5L Turbo) 2 01-20-2006 11:46 AM
What do these symptoms indicate? 20mm Brakes, Steering & Suspension 7 04-04-2003 06:21 PM
Do these EGT's sound right- Compare RichinAZ Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 10 03-10-2002 04:25 PM
Do these prices sound right? Aaron Silidker Transmission (AT/MT) & Driveline 6 12-06-2001 01:02 PM

All times are GMT -4. The time now is 07:27 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2016, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2016 Axivo Inc.
Copyright ©1999 - 2016, North American Subaru Impreza Owners Club, Inc.