Welcome to the North American Subaru Impreza Owners Club Tuesday April 20, 2021
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
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.







* 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 01-27-2009, 11:59 PM   #1
Splinter
Scooby Guru
 
Member#: 106510
Join Date: Feb 2006
Chapter/Region: VIC
Location: Osoyoos, BC
Vehicle:
98 Widebody 3.4L
Smooth Safety Blue

Default Nasty cam journal

Just tore down my ej22g hybrid block in preparation for the new cams and rods, and I came across this:


Looks like particulate damage to me... but the real question is, are the heads garbage? I'd rather not have to try and source new heads, but I'll do whatever it takes.

I'm trying to max out my TD06H-20G, so 450-480chp, and up to 7800rpm.
* Registered users of the site do not see these ads.
Splinter is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 01-28-2009, 12:20 AM   #2
Sinister redlines
Scooby Specialist
 
Member#: 120641
Join Date: Jul 2006
Chapter/Region: NWIC
Location: Port Orchard, WA
Vehicle:
05 HTA3586,BB 2.5L
CGM

Default

You can have a machine shop line bore the cam journals. They remove a small bit of material from the cap base and then line bore back to proper bore. Its expensive but it works. For what its worth that pic isnt too bad, I have seen way worse. The load is much less than what a engine bearing sees on the rods and mains. It does see some load from the valve springs but not comparable.

Honestly I would just use a very fine croachas cloth and hand polish it. If you really concearned take it to a machine sop and have them mic the bore and check what the max tolerence is...
Sinister redlines is offline   Reply With Quote
Old 01-28-2009, 12:48 AM   #3
Splinter
Scooby Guru
 
Member#: 106510
Join Date: Feb 2006
Chapter/Region: VIC
Location: Osoyoos, BC
Vehicle:
98 Widebody 3.4L
Smooth Safety Blue

Default

We have a machine shop at the auto parts store I work out, one of the only ones in the city, but they mostly do factory rebuilds and SBC builds, I'm pretty sure I've supplied them with half the subaru motors they've worked on

Maybe I'll fire off a pic to Jon at delta... he did my cams afterall.
Splinter is offline   Reply With Quote
Old 01-28-2009, 12:06 PM   #4
[email protected] Auto
Scooby Newbie
 
Member#: 189490
Join Date: Sep 2008
Chapter/Region: MAIC
Location: Baltimore, MD
Default

Get a new head. The info given above is false and you will damage your engine if you will reuse them. How are the other bearings(main, rods) look like?

Artie
Artie@Agile Auto is offline   Reply With Quote
Old 01-28-2009, 12:30 PM   #5
kingsubi
Scooby Specialist
 
Member#: 19239
Join Date: May 2002
Chapter/Region: NESIC
Location: QC / ME
Vehicle:
2011 WRX
SWP

Default

Jon at Delta had to line bore my head as well after a failed rod bearing. Material gets into the oil pathways and then eats the journal. The only real way to do it however is to undersize the journal and then weld on extra material to the cam.

This mates the cam to the head forever...
kingsubi is offline   Reply With Quote
Old 01-28-2009, 12:48 PM   #6
ryan_west06
Scooby Specialist
 
Member#: 139045
Join Date: Jan 2007
Chapter/Region: South East
Location: Clearwater, FL
Vehicle:
05 STI SnowmanTune
Silver

Default

for us noobs, can you please explain what is damaged... I like to learn things everyday.
ryan_west06 is offline   Reply With Quote
Old 01-28-2009, 01:47 PM   #7
Splinter
Scooby Guru
 
Member#: 106510
Join Date: Feb 2006
Chapter/Region: VIC
Location: Osoyoos, BC
Vehicle:
98 Widebody 3.4L
Smooth Safety Blue

Default

Quote:
Originally Posted by [email protected] Auto View Post
Get a new head. The info given above is false and you will damage your engine if you will reuse them. How are the other bearings(main, rods) look like?

Artie
The other cam journals are fine, so my guess is there was some junk in the oil journal right under there that got into the cam journal.

Haven't gotten into the shortblock yet.


Ryan West: The cam journal is the oiling surface for the cams, cams in subaru engines dont ride in bearings, they're not generally much of a wear surface.
Splinter is offline   Reply With Quote
Old 01-28-2009, 02:03 PM   #8
BallPeenHamr
Scooby Newbie
 
Member#: 126526
Join Date: Sep 2006
Chapter/Region: SCIC
Location: Long Beach
Vehicle:
2007 STi Limited
#339 UGM -SOLD

Default

Your head might not be toast. Look at the underside of the cam cap that goes over that journal... because its the cap that bears all of the load. If it is worse than the bottom half, then it might be questionable.. in which case I'd look into having it repaired by a competent machine shop.

Polish up the marking by hand with grey scotch brite... don't dig in much; just remove the high spots. Then dab some oil in the lournals, install the cam (torque it up with the other cam caps too) while it's completely disassembled. Check to make sure the cam spins freely by hand. Setup a dial indicator on the top of the cam, then move the cam up and down. If there is more than .002" of deflection, the head needs to be repaired or replaced. If not, i'd say run it. There should also be .003" to .005" of cam end play as well.

It would be a good idea to remove all of the oil galley plugs on the head(s) and make sure the oil galleys are clean/free of debris before you think about re-using them. I'd get an upgraded oil pump while you are at it too..

.02

It would also help to upgrade the oil pump while the engine is apart too..
BallPeenHamr is offline   Reply With Quote
Old 01-28-2009, 02:38 PM   #9
Splinter
Scooby Guru
 
Member#: 106510
Join Date: Feb 2006
Chapter/Region: VIC
Location: Osoyoos, BC
Vehicle:
98 Widebody 3.4L
Smooth Safety Blue

Default

I'm running a 10mm oil pump, I dont think it's necessary to run bigger than that for my setup (no avcs)

I'm bringing it to a machine shop this afternoon for them to look at.
Splinter is offline   Reply With Quote
Old 01-28-2009, 05:29 PM   #10
Splinter
Scooby Guru
 
Member#: 106510
Join Date: Feb 2006
Chapter/Region: VIC
Location: Osoyoos, BC
Vehicle:
98 Widebody 3.4L
Smooth Safety Blue

Default

machine shop says its repairable
Splinter is offline   Reply With Quote
Old 01-28-2009, 05:48 PM   #11
ryan_west06
Scooby Specialist
 
Member#: 139045
Join Date: Jan 2007
Chapter/Region: South East
Location: Clearwater, FL
Vehicle:
05 STI SnowmanTune
Silver

Default

since im new at this, id still like to know what im looking at that needs to be fixed. can someone school me please?
ryan_west06 is offline   Reply With Quote
Old 01-28-2009, 06:46 PM   #12
[email protected] Auto
Scooby Newbie
 
Member#: 189490
Join Date: Sep 2008
Chapter/Region: MAIC
Location: Baltimore, MD
Default

It's actually very simple. Cams are kept in place by cam journals. Cams are rotating parts in the head and to reduce friction they are lubricated by oil. Cam journals should have a very smooth, mirror type surface. Journals are part of the head casting. Subaru recommends to keep oil clearances (difference between inside diameter of cam journal and outside diameter of cam) somewhere between 0.037 0.072 mm. If the clearance is too big, oil will have less resistance on it's path and oil pressure will drop as a result. If the oil clearance is too small, the parts will not get enough oil to keep them lubricated.





Hope this will help
Artie@Agile Auto is offline   Reply With Quote
Old 01-28-2009, 08:31 PM   #13
Sinister redlines
Scooby Specialist
 
Member#: 120641
Join Date: Jul 2006
Chapter/Region: NWIC
Location: Port Orchard, WA
Vehicle:
05 HTA3586,BB 2.5L
CGM

Default

Yes we know artie, You said the process I described above wont work yet I have seen MANY reline bored and look good as a new head because it will be machined and its the same process the factory uses and the finish dia will be in spec.....
http://www.enginebuildermag.com/Arti...g_subject.aspx
A good read for you to educate yourself...

And yes I have worked in a machine shop that did the process. Its the same setup as reline boring a block for a crank just in a smaller scale and ra has to be finer...
Sinister redlines is offline   Reply With Quote
Old 01-28-2009, 08:59 PM   #14
charliew
Scooby Specialist
 
Member#: 125304
Join Date: Sep 2006
Location: Crawford, TX.
Default

If it was trash in the gallerie it would also be scuffed in line with the oil feed holes. The area past the feed holes looks ok. It seems to me that the head may be warped. That looks like it will take .010 cut to clean it up minimum. Maybe .020 that means the cam will be .010 or .020 closer to the valve stems. That means either all the stems will need to be shortened or new .010 or .020 thinner buckets. That also means the cams will rotate a little in the advanced position. Has anyone tried welding the journal up and putting it back to original? I would rather do that than have a perminately crummy head.
When you line bore a vw and I think a v8 there are replacement oversize bearings that fill the new gap and the crank or cam stays in the same place, not so on the suby the cam is now closer to the valves forever.
A line bore on the cam bores can look great to the eye as it's now nice and shiney but that doesn't make it a good repair. That will also limit the amount of lift that cam can run before coil or seal bind on the valve. If they are 1500.00 heads I would try to get the journal welded and re bored to stock. If they are 250.00 heads do the cheapest repair.

Last edited by charliew; 01-28-2009 at 09:26 PM.
charliew is offline   Reply With Quote
Old 01-28-2009, 09:53 PM   #15
Splinter
Scooby Guru
 
Member#: 106510
Join Date: Feb 2006
Chapter/Region: VIC
Location: Osoyoos, BC
Vehicle:
98 Widebody 3.4L
Smooth Safety Blue

Default

I really don't think it's warped heads for a couple reasons... You can see where grains of something caught and pulled on the aluminum.

The reason that there is a clear line around the oil grove is that on the cam surface, there is a matching machined groove. There is no contact in that area.
Splinter is offline   Reply With Quote
Old 01-28-2009, 10:05 PM   #16
charliew
Scooby Specialist
 
Member#: 125304
Join Date: Sep 2006
Location: Crawford, TX.
Default

Sorry I was looking at the cams in the pictures above. I didn't remember any grooves in the cams I've worked with. It seems that the cap would also be rough. It's like the bore wasn't round. Maybe it was put together real dirty. Do you think plastigage could have been left in it? Usually you would lay the plastigage on top of the cam and put the cap on though.
charliew is offline   Reply With Quote
Old 01-28-2009, 10:09 PM   #17
Splinter
Scooby Guru
 
Member#: 106510
Join Date: Feb 2006
Chapter/Region: VIC
Location: Osoyoos, BC
Vehicle:
98 Widebody 3.4L
Smooth Safety Blue

Default

V4 STI cams

Splinter is offline   Reply With Quote
Old 01-29-2009, 07:24 AM   #18
bluescoobywagon
Scooby Specialist
 
Member#: 14911
Join Date: Feb 2002
Chapter/Region: MWSOC
Location: The land of E85
Vehicle:
Not A Wagon!
2011 WRX - 285s on 18x9.5

Default

Quote:
Originally Posted by charliew View Post
If it was trash in the gallerie it would also be scuffed in line with the oil feed holes. The area past the feed holes looks ok. It seems to me that the head may be warped. That looks like it will take .010 cut to clean it up minimum. Maybe .020 that means the cam will be .010 or .020 closer to the valve stems. That means either all the stems will need to be shortened or new .010 or .020 thinner buckets. That also means the cams will rotate a little in the advanced position. Has anyone tried welding the journal up and putting it back to original? I would rather do that than have a perminately crummy head.
When you line bore a vw and I think a v8 there are replacement oversize bearings that fill the new gap and the crank or cam stays in the same place, not so on the suby the cam is now closer to the valves forever.
A line bore on the cam bores can look great to the eye as it's now nice and shiney but that doesn't make it a good repair. That will also limit the amount of lift that cam can run before coil or seal bind on the valve. If they are 1500.00 heads I would try to get the journal welded and re bored to stock. If they are 250.00 heads do the cheapest repair.
Other than the change to the cam timing, I can't see how any of the other issues you mentioned would be a problem if you properly set the valve clearance after the line bore. You could even correct the timing issue with adjustable sprockets.
bluescoobywagon is offline   Reply With Quote
Old 01-29-2009, 10:04 AM   #19
Thomas Ruble
Scooby Newbie
 
Member#: 12694
Join Date: Nov 2001
Location: Under my car
Vehicle:
02 WRX/JDM EJ207RA
Unabomber Eeee-thug

Default

Here is what I would do based on my own hands on experiences with rebuilding ej20 motors (my personal motors)...

First establish a baseline by measuring the cam/journal clearances of the non damaged journals. Line hone the subtracted difference from the factory absolute limit and then see what you have. After line honing, if the journal surface still looks quite rough, I would then trash the head as previously suggested by Artie rather than continuing to remove more material. Why take the chance with a "high reving application?"

Personally, I would be worried about the excentric forces and early wear issues created by excess clearances within the journals, not only to the journals surfaces, but also to the cam lobes and buckets.
Hidesight can be a real beotch..

Good luck,
Tom.
Thomas Ruble is offline   Reply With Quote
Old 01-29-2009, 10:26 AM   #20
Splinter
Scooby Guru
 
Member#: 106510
Join Date: Feb 2006
Chapter/Region: VIC
Location: Osoyoos, BC
Vehicle:
98 Widebody 3.4L
Smooth Safety Blue

Default

Well the shop says that they can machine rod bearings into the cam caps if necessary, which is expensive but it's better than stock, because after that, it becomes dead easy to replace them down the road.
Splinter is offline   Reply With Quote
Old 01-29-2009, 10:43 AM   #21
Thomas Ruble
Scooby Newbie
 
Member#: 12694
Join Date: Nov 2001
Location: Under my car
Vehicle:
02 WRX/JDM EJ207RA
Unabomber Eeee-thug

Default

Quote:
Originally Posted by Splinter View Post
Well the shop says that they can machine rod bearings into the cam caps if necessary, which is expensive but it's better than stock, because after that, it becomes dead easy to replace them down the road.
That is an interesting alternative if the cost ends up being reasonable, especially if you have previously invested in having some headwork done in the past like I have.

Please keep this thread updated because I would love to add your experience to my memory banks for future reference.

Tom
Thomas Ruble is offline   Reply With Quote
Old 01-29-2009, 02:33 PM   #22
Splinter
Scooby Guru
 
Member#: 106510
Join Date: Feb 2006
Chapter/Region: VIC
Location: Osoyoos, BC
Vehicle:
98 Widebody 3.4L
Smooth Safety Blue

Default

I haven't had any headwork yet, I'm running the 98 DOHC/V4 STi heads, which outflow any of the north american turbo heads by a margin from the factory.

The problem is tho, if the machine work is $400, and another set of used heads is $300, I might end up just inheriting someone elses problem, plus all the work of setting up the DOHC NA heads for turbo
Splinter is offline   Reply With Quote
Old 01-29-2009, 04:06 PM   #23
Splinter
Scooby Guru
 
Member#: 106510
Join Date: Feb 2006
Chapter/Region: VIC
Location: Osoyoos, BC
Vehicle:
98 Widebody 3.4L
Smooth Safety Blue

Default

The managed to repair it, oil clearances are now at .055mm across the board.

They took about half a thou off the bottom of the caps, so the journals are very, very slightly elliptical, but these guys ahve been building high revving engines for years and they said it won't be a problem, especially with the super short subaru cams.
Splinter is offline   Reply With Quote
Old 01-29-2009, 09:17 PM   #24
Sinister redlines
Scooby Specialist
 
Member#: 120641
Join Date: Jul 2006
Chapter/Region: NWIC
Location: Port Orchard, WA
Vehicle:
05 HTA3586,BB 2.5L
CGM

Default

I guess what alot of people are missing is that the caps will be slightly machined at thier base to close the bore, then it will be relined to oe specs. Now yes the cam will sit closer to the valves but it will be half of whatever is removed. So if you close the bore by .020" then after reline the cam will be effectively .010" closer to the valve (this is only in the ballpark as thier are machining tolerences that can effect the final measurement).

Now on to the other issue, the valves on most aftermarket suppliers ship thier valves long to be machined to the use on the head. Plus thier are different bucket sizes to help setup clearences.. This is how most subie heads undamaged are setup with aftermarket valves..

This end result is basicly all in the machinist and engine builders hands and can be made good as new with an experienced machinist...
Sinister redlines is offline   Reply With Quote
Old 12-21-2019, 12:20 PM   #25
Techninety9
Scooby Newbie
 
Member#: 509999
Join Date: Dec 2019
Default 07 outback xt

Quote:
Originally Posted by BallPeenHamr View Post
Your head might not be toast. Look at the underside of the cam cap that goes over that journal... because its the cap that bears all of the load. If it is worse than the bottom half, then it might be questionable.. in which case I'd look into having it repaired by a competent machine shop.

Polish up the marking by hand with grey scotch brite... don't dig in much; just remove the high spots. Then dab some oil in the lournals, install the cam (torque it up with the other cam caps too) while it's completely disassembled. Check to make sure the cam spins freely by hand. Setup a dial indicator on the top of the cam, then move the cam up and down. If there is more than .002" of deflection, the head needs to be repaired or replaced. If not, i'd say run it. There should also be .003" to .005" of cam end play as well.

It would be a good idea to remove all of the oil galley plugs on the head(s) and make sure the oil galleys are clean/free of debris before you think about re-using them. I'd get an upgraded oil pump while you are at it too..

.02

It would also help to upgrade the oil pump while the engine is apart too..
So like said in the thread above subarus don't have cam bearings. The aluminum surface is what the cams ride on. That being said, how long have you guys gotten out of your welded and shaved journals?
Techninety9 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
Boring cam journals for bearings Splinter Built Motor Discussion 36 10-01-2012 05:38 PM
cam journals? Ds baruuuuu Built Motor Discussion 7 09-12-2010 11:00 PM
closed subydude02 Engine/Power/Exhaust 41 08-11-2010 08:29 AM
Cam Journals Victor1620 Built Motor Discussion 0 09-17-2009 05:56 PM
bolts that hold cam journal caps on, ej205 erice1984 Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 3 07-12-2005 01:13 PM

All times are GMT -4. The time now is 07:53 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2021 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.