Welcome to the North American Subaru Impreza Owners Club Tuesday March 19, 2024
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Normally Aspirated Powertrain

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 03-26-2007, 09:31 PM   #1
Mike1967
Scooby Newbie
 
Member#: 87762
Join Date: May 2005
Default Leaking Valves?



Seems like my luck keeps taking a bad turn on this project.

I recently had a valve job done on my heads. I cannot remember if I checked them before bolting my engine back together (what can I say...it has been a hectic month) :-( Anyway, I strapped everything back together and fired her up 2 weeks ago only to hear the same clicking clatter that I had heard before I tore her down and did the valve job. I then did some research and learned about spun rod bearings. I pulled the pan and saw significant metal shavings in the pan, so I am very confident that I had a spun rod bearing in my shortblock.

Anyway....I have since bought a replacement block ( I will post pics of that further down this thread). Since I was tearing down my old engine rebuild I decided to do a quick flashlight test on the valves........upon doing this test I discovered that I could see light through one of the valves. So I assumed that I had either bent a valve from the piston with the faulty rod bearing, or the machine shop did a crappy job.

So this morning I decided to fill all 4 intakes with tranny fluid based on feedback from another member of this forum. When I came home from work today I noticed that I not only had 1 leaking valve....but 4. The 2nd valve from the left had a completely empty intake reservoir....all the fluid leaked out. This valve had shown no indication of light when I did the light test. The valve that had the light showing through had a reservoir that was half full. Note: The heads sat with the fluid in the intake ports for approximately 9 hours.

First Question: Is this definitely indicative of a faulty valve seating?
Second Question: Could a spun rod bearing have cause damaged to the valves? When I put it back in, weekend before last, I had it idling for a total of approximately 20 minutes while I tried to isolate the sound with a stethoscope. So I suppose I could have damaged the valves while it was idling?

I am already leaning on the machine shop to redo the job....but I do not want to hold them accountable for something that I could have caused
* Registered users of the site do not see these ads.

Last edited by Mike1967; 03-26-2007 at 10:10 PM.
Mike1967 is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 03-26-2007, 09:57 PM   #2
Mike1967
Scooby Newbie
 
Member#: 87762
Join Date: May 2005
Default

Pistons on the replacement block. I have not cleaned them yet.



Mike1967 is offline   Reply With Quote
Old 03-26-2007, 10:03 PM   #3
Mike1967
Scooby Newbie
 
Member#: 87762
Join Date: May 2005
Default Cracks in block

Are these cracks normal and only cosmetic???????????


Mike1967 is offline   Reply With Quote
Old 03-27-2007, 12:03 AM   #4
my4isflat
Scooby Newbie
 
Member#: 120002
Join Date: Jul 2006
Chapter/Region: RMIC
Location: Colorado
Vehicle:
2000 2.5 RS, '95
Legacy w/325k mi (RIP)

Default

Yeah, they're normal. They're left behind from casting flash (grammerer?), if you were to look at almost any cast aluminium block closely you would see them. Just surface inperfections.
my4isflat is offline   Reply With Quote
Old 03-27-2007, 03:46 AM   #5
Mike1967
Scooby Newbie
 
Member#: 87762
Join Date: May 2005
Default

Quote:
Originally Posted by my4isflat View Post
Yeah, they're normal. They're left behind from casting flash (grammerer?), if you were to look at almost any cast aluminium block closely you would see them. Just surface inperfections.
Thanks!

I was pretty confident that these were nothing to worry about....but that nagging doubt would not go away
Mike1967 is offline   Reply With Quote
Old 03-27-2007, 04:24 PM   #6
Mike1967
Scooby Newbie
 
Member#: 87762
Join Date: May 2005
Default

Well...my posts should be entertaining if nothing else

I ran a modified valve leak test last night per a previous write-up on this forum. I laid the heads flat, combustion side up. I then filled the combustion area with tranny fluid....after screwing in the spark plugs.

After letting it sit all night.....you can see that there was very very minimal leakage. (see pic below)



Only two things changed between the test in my first photo at the beginning of this thread and this test in the photo above.

(1) I removed the rockers
(2) I poured the fluid in the combustion area instead of in the Intake ports.

I do not expect that a valve would only leak one direction and not the opposite direction.....so....I do not think that variable #2 above was the cause of the change in results between the two experiments.

It has to be tied to the rockers....which means that my lash adjustment procedure was for crap. But what has me scratching my head is the fact that I was able to insert a feeler gauge between the spring pin and the valve pin. I would expect that if there were enough force on the spring to be pushing the valves open even a few mils....then I would not be able to insert a feeler gauge between the end of the valve and the end of the spring.

But incorrect lash is the only thing that I can see that would cause the results to change. Unless I am wrong about valves not leaking in one direction.

If it is the lash...then that would also explain why my leakdown readings were for all over the map...prior to my last tear down.

I am going to reinstall the rockers and then repeat this test procedure to see if the leaking reoccurs.

If it does, then I will adjust/loosen the lash settings on my rockers and redo the leak test per the above photo.

Pretty sad when you cannot even do a basic procedure with feeler gauges.
Mike1967 is offline   Reply With Quote
Old 03-27-2007, 06:15 PM   #7
Matt Monson
Scooby Guru
 
Member#: 832
Join Date: Jan 2000
Chapter/Region: RMIC
Location: Teh Ghetto Garage, CO
Vehicle:
99 2.5RS, '85 911
'73 914 and 2012 BRZ

Default

#2 is the reason for the change in results. Think about it for a bit. You will get it.
Matt Monson is offline   Reply With Quote
Old 03-27-2007, 06:23 PM   #8
Mike1967
Scooby Newbie
 
Member#: 87762
Join Date: May 2005
Default

Quote:
Originally Posted by Matt Monson View Post
#2 is the reason for the change in results. Think about it for a bit. You will get it.
Hmmm...I am thinking 1 of 2 things.

One - the valves are designed to keep pressure in....not keep pressure out
Two - there is more weight from the fluid due to the depth of the intake bore?

Am I warm?
Mike1967 is offline   Reply With Quote
Old 03-27-2007, 07:09 PM   #9
Mike1967
Scooby Newbie
 
Member#: 87762
Join Date: May 2005
Default

Can anybody else answer this riddle ?
Mike1967 is offline   Reply With Quote
Old 03-28-2007, 10:38 AM   #10
Mike1967
Scooby Newbie
 
Member#: 87762
Join Date: May 2005
Default

Bump

Mike1967 is offline   Reply With Quote
Old 03-28-2007, 01:47 PM   #11
crampfan
Scooby Specialist
 
Member#: 74321
Join Date: Nov 2004
Chapter/Region: MWSOC
Location: clarksville AR
Vehicle:
2004 wrx wag
black UTEC stg 4

Default

You might want to recheck your valve adjustment. If the rocker arms are installed you might see some leakage if the adjustment is off, also some noise. valve noise sounds alot different than rod bearing noise.
It does not make a flip on what side you pour fluid in, if the valve is unseated it's going to leak.
Did you buy a used short block? you may want to take a look at the bearings on that one if you did.
and just to clear things up for me, you did adjust the valve lash after the valve grind.
crampfan is offline   Reply With Quote
Old 03-28-2007, 02:01 PM   #12
Mike1967
Scooby Newbie
 
Member#: 87762
Join Date: May 2005
Default

Quote:
Originally Posted by crampfan View Post
You might want to recheck your valve adjustment. If the rocker arms are installed you might see some leakage if the adjustment is off, also some noise. valve noise sounds alot different than rod bearing noise.
It does not make a flip on what side you pour fluid in, if the valve is unseated it's going to leak.
Did you buy a used short block? you may want to take a look at the bearings on that one if you did.
and just to clear things up for me, you did adjust the valve lash after the valve grind.
I did reset the lash after I got the heads back.

The noise I heard after I put everything back together was definitely not the valves. I am pretty sure it is rod bearing knock. I dropped the pan and found about 2 tablespoons of metal flakes. Also, there was no indication of valve to piston knock when I tore the engine back down this past weekend.

I did drop the pan on the new block and there is no metal in the pan. The engine only had 23K original miles on it....so I was not expecting any issues with rod bearing throw. This came out of a car with massive backend damage and some front end damage. The driverside Cam Sprocket was shattered, the timing belt cover was shattered, and the thermostat was shattered. But the Cams were in one piece and the heads appear to be in good order. The Block looks new other than the gunk that has built up from sitting in the yard for a period of time.

I just want to make sure that I got a fair job for what I paid for on the Valve regrinds. This particular machine shop mainly deals in larger engines. I am down here in Texas...so a lot of V8's. I am thinking that their tolerances are not as fine as what I would get from shop that specialized in high RPM engines like the Subaru.
Mike1967 is offline   Reply With Quote
Old 03-28-2007, 03:31 PM   #13
crampfan
Scooby Specialist
 
Member#: 74321
Join Date: Nov 2004
Chapter/Region: MWSOC
Location: clarksville AR
Vehicle:
2004 wrx wag
black UTEC stg 4

Default

Valve jobs a valve job, you should not see any daylight past the valve seats. If you can see daylight past the valves, take the heads back to the machine shop, and tell them they owe you an gasket kit too.
crampfan is offline   Reply With Quote
Old 03-28-2007, 03:40 PM   #14
Mike1967
Scooby Newbie
 
Member#: 87762
Join Date: May 2005
Default

Quote:
Originally Posted by crampfan View Post
Valve jobs a valve job, you should not see any daylight past the valve seats. If you can see daylight past the valves, take the heads back to the machine shop, and tell them they owe you an gasket kit too.
Sounds good
Mike1967 is offline   Reply With Quote
Old 03-28-2007, 03:41 PM   #15
Mike1967
Scooby Newbie
 
Member#: 87762
Join Date: May 2005
Default

Quote:
Originally Posted by crampfan View Post
Valve jobs a valve job, you should not see any daylight past the valve seats. If you can see daylight past the valves, take the heads back to the machine shop, and tell them they owe you an gasket kit too.
Gasket kit meaning head gaskets only? Or exhaust gaskets as well?
Mike1967 is offline   Reply With Quote
Old 03-28-2007, 05:20 PM   #16
crampfan
Scooby Specialist
 
Member#: 74321
Join Date: Nov 2004
Chapter/Region: MWSOC
Location: clarksville AR
Vehicle:
2004 wrx wag
black UTEC stg 4

Default

Gasket kit, what ever you had to use when you put the heads on. If they goofed it why should it cost you? If I installed a set of heads that did not work the machine shop would be paying my parts ,antifreeze and oil as well as my labor. (if they wanted my business again anyway)
crampfan is offline   Reply With Quote
Old 03-28-2007, 08:34 PM   #17
Tim Sanderson
Scooby Guru
 
Member#: 6486
Join Date: May 2001
Chapter/Region: MWSOC
Location: S.E. wisconsin
Vehicle:
00 Impreza 2.5 RS
Blue Ridge Pearl

Default

Mike I believe the answer to your riddle is during your first test you only tested the intake side. During this test you tested both sides. You can see the fluid coming out of the exhaust port.

Did I win?
Tim Sanderson is offline   Reply With Quote
Old 03-29-2007, 11:26 AM   #18
Mike1967
Scooby Newbie
 
Member#: 87762
Join Date: May 2005
Default

Quote:
Originally Posted by Tim Sanderson View Post
Mike I believe the answer to your riddle is during your first test you only tested the intake side. During this test you tested both sides. You can see the fluid coming out of the exhaust port.

Did I win?
Nope

It leaked a lot more when I only had fluid in the intake ports. It leaked much less when I turned the heads on their sides and put fluid over both the intake and exhaust valves.

One would think it would leak faster in the second instance because now you have 8 seals instead of just 4.

I believe that it is a combination of the weight distribution of the fluid and the angle cut of the seats. The fluid is much more concentrated with more weight at the seal on the first example. Also, the angles are cut to keep pressure in...not out....so I beleive that from the backside of the valve the cuts actually channel the fluid into the seal thus causing more leakage.

But I am pulling all of that out of my butt.
Mike1967 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
FS : heads cams valves springs reatiners, valvelocks fastlanerex Engine/Power/Exhaust 51 09-30-2010 06:17 PM
Leaking valves stitchbad Built Motor Discussion 21 03-29-2009 11:17 AM
Checked for boost leaks, purge valve leaks, any ideas? overdose Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 16 07-05-2005 03:55 PM
Leaking valve stem -- Bridgestone or Subaru's warranty? roadtrip Warranty Issues & SOA Problems 1 02-15-2002 08:04 AM
Leak-testing heads/valves... 8Complex Normally Aspirated with bolt-on Forced Induction Powertrain 3 07-23-2001 11:09 AM

All times are GMT -4. The time now is 01:48 AM.


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.