Intake Cam Jounral Scaring causing p0021?

Hi,

first time posting on subaru forums; tried almost everything I could find about fixing P0021 (Banjo Bolts, AVCS Solenoid, Timing belt, Intake Sprocket, Oil), but I would like some advise before I go and pull a head on my engine. I would feel really stupid pulling a head, and finding out I could have fixed it through something easier. I am not looking for a performance car, I am just looking for a car that will last as long as it can (I have tried to ask the Subaru subreddit for mechanic advise, but it seems like most people over there just buy new WRXs, and never really work on cars).

 

Situation:

I'm getting P0021 after rebuilding my ej255 on my 2008 OBXT (has 205,000miles on it, but it's still a beaut). Rebuilt because of rod knock, and rebuilt by myself. This code is the only problem I have had after the rebuild, and I have only put about 50 miles on the car since the rebuild (currently going through breaking period, so using non-synthetic oil and staying below 4000rpm). The car feels and sounds fine, although this is my first Subaru and i don't really know what is normal or not (also, the car died right after I bought it, so it sounded worse when I got it).

 

What I replaced in the rebuild:

OEM crankshaft, 2x OEM rods, OEM rings, Mahle main and rod bearings, Oil pump, timing belt kit, Melett vf46 turbo cartridge, Intake and Exhuast Valve seals, headgasket and seal kit, seals not included in seal kit, headbolts, bunch of hoses that were like rock. Heads were also honed. ALL Banjo Bolt Filters Removed during rebuild.

What I probably should of also replaced, but cleaned instead:

Oil Cooler, Oil pick up

(Most of the time put into the rebuild was spent cleaning block and heads with PSC 1000 solvent)

 

Replaced/Checked when trying to fix P0021:

- Checked Timing belt

- Replaced AVCS solenoid

- Cleaned/Rebuilt Intake Cam Sprocket

- Replaced with New Intake Cam Sprocket

- Changed Oil to 15w40 from 10w30

 

Things to note:

- All banjo bolts have been removed from the car during rebuild.

- Timing belt has not skipped any teeth.

- When running 10w30, I got the P0011 Code Once. After clearing codes and replacing Intake Cam Sprocket and changing oil, it hasn't showed up again. Would this mean oil is the problem?

 

During the rebuild I noticed some scaring on the Intake Cam Front Journal housing on the drivers side (bank 2). I didnt think much of it because Rod knock was the main problem, but now I think it is catching up to me. Maybe I'm missing something, but the Cam Journal is the last logical reason that I can think of for this problem. Maybe the Oil is clogged upstream of the AVCS solenoid altogether, but I pretty sure I did a good job cleaning everything.

When rotating the Cams into place to install the timing belt, the exhaust Cam always tries to snap out of place (like it should). However, the Intake cam with the P0021 code seems to snap back less easily. I think this is because of the scaring on the head causing additional friction on the intake cam. Should I try to polish it? (then I wouldn't have to remove the head). What I think is happening is that the oil pressure is dropping by bypassing the sprocket and jumping to the other side of the oil feed on the cam, and therefore not pressurizing the intake cam and preventing it from rotating properly.

 

https://legacygt.com/forums/attachme...1&d=1593307285

On the diagram above, I think the pressure is leaking between the Red and Blue oil passageways at the cam journal, or is just leaking into the head itself. Correct me if I am wrong, but the AVCS solenoid changes the direction of flow (Blue to Red or Red to Blue), and a leak between the two at the cam journal would prevent the proper oil pressure from reaching the Sprocket. There are no oil leaks on the exterior of the head.

 

I have not preformed any kind of oil pressure test, and I'm not sure where to do that either. I have a Craftsman OBD2 diagnostic tool, but I am not sure if it can do cam position monitoring on the subaru. I can't find a D25 head locally, so I would probably try to find a shop that is willing to aluminum weld onto the cam journal and then re-cut it (hopefully that is the worst case scenario).

 

Edit:

Posted this originally in the wrong forum, so this was re-posted here. I am purchasing a new Oil cooler (only ran the old, pressure cleaned one for 50 miles, so hopefully I didn't destroy my new engine doing that). Although I won't be able to work on the car for the next week or two, I am still open for hearing suggestions (that I have not yet already tried!). Although this is just speculation, I am betting that the cam journal scaring is causing additional resistance on the cam. This resistance is greater than the force of the oil pressure, so the cam is stuck in a single position as the cam sprocket rotates it clockwise. I'll post photos once I get the cam covers off.

Hopefully someone like "covertrussian" will chime in soon. He's pretty good with these cars.

 

"m sprank" would be someone you may want to PM for help too.

I assume you've replaced both oil control valves?

I would check the oil valves too, easiest with Tactrix cable and Romraider, or Access Port. Mine died around 130k, the CEL didn't come up with it for about 30 miles, but I was data logging and saw the AVCS values jumping around for that specific valve.

 

AVCS cam gear it self might be the culprit too, debris might have gotten into both the oil valves and cam gears.

I would check the oil valves too, easiest with Tactrix cable and Romraider, or Access Port. Mine died around 130k, the CEL didn't come up with it for about 30 miles, but I was data logging and saw the AVCS values jumping around for that specific valve.

 

AVCS cam gear it self might be the culprit too, debris might have gotten into both the oil valves and cam gears.

 

Ill look into electronic problems after putting the car back together, but Im assuming the new OCV is functional. Both OCV and Cam gear have been replaced, new. I'll look into the Tactrix cable and Romraider!

I was able to pull the intake cam from the car, and to my surprise the Camshaft is more scared than the cam journals. My fingernail catches on the camshaft journal, while the scaring on the head and cam cover is not as severe and did not catch my fingernail. Measuring the camshaft, the diameter is around 37.85mm, while the factory diameter size should be between 37.96mm and 37.94mm, so my Camshaft is about .09mm under factory spec (not including the scaring depth). The other cam journals (farther from timing belt) are showing no signs of wear, and are at factory spec diameter. I ordered a new intake camshaft.

Can you drop the pan and check everything in there again? Any chance there's shit in the pickup tube as well? That's something I would have replaced in its entirety after rod bearing failure, although it sounds like you've done a pretty thorough job.

 

Typically, issues with AVCS manifest themselves before about 3000 RPM when the turbo kicks in as that's when AVCS is active. I'm thinking it's also possible that your new OCVs aren't happy because of debris in them if the engine wasn't cleaned out. Sometimes the banjo bolt filters don't get removed properly (you said you removed them, but did they fall back into the bolt holes?) and get caught in the intake sprocket and various oil passages.

 

Ninja edit: I just saw your post from two minutes before me. That's probably your issue. Good luck!

Here are the pictures of the cam journals. The scaring on the head is not as deep as the scaring on the cover, and the cover has a random chunk missing from part of the cam journal (shown on bottom right side of the left image, most likely caused by previous mechanic work). How bad do these look?

Typically, issues with AVCS manifest themselves before about 3000 RPM when the turbo kicks in as that's when AVCS is active. I'm thinking it's also possible that your new OCVs aren't happy because of debris in them if the engine wasn't cleaned out. Sometimes the banjo bolt filters don't get removed properly (you said you removed them, but did they fall back into the bolt holes?)

 

I'm going to try to clean all of the lines going to the OCV before re-installing the Camshaft. Since I am already removing the rear timing cover, I'll remove the second banjo bolt and check it one more time just to be sure the filter isn't there. I don't think it is oil-starved/filled with junk, but its worth a check. Thanks for the advice!

Oh dang, OK, well I'm not an expert but I'd say that you're gonna want a machine shop to look at your engine and maybe spend a penny with them. Your heads may not have appreciated the damage done here.

 

Good luck on that third banjo bolt. Just to confirm, you removed the other two from the top of the engine, right? One right by the driver's side oil control valve and the second by the turbo?

Try PMing BDII as well. He is a long time 4th Gen owner. Maybe he has dealt with this as well.

Initially I ordered a new camshaft, but I decided to return it and get a refurbished cylinder head by Famous Brand through RockAuto ($400 for head, valves, buckets, and camshafts). Although a new camshaft may have fixed the problem, I wanted this project to be finished and not have to take it apart again. Installed a new head gasket, new cam seals and new head bolts during the head installation. I have been driving it for 2 days with no codes, so I think the problem is fixed!

Good to hear. Make sure you update us if things go bad.

 

Will be nice to see how this works out in the long run.

Posted this originally in the wrong forum, so this was re-posted here. I am purchasing a new Oil cooler (only ran the old, pressure cleaned one for 50 miles, so hopefully I didn't destroy my new engine doing that). Although I won't be able to work on the car for the next week or two, I am still open for hearing suggestions (that I have not yet already tried!). Although this is just speculation, I am betting that the cam journal scaring is causing additional resistance on the cam. This resistance is greater than the force of the oil pressure, so the cam is stuck in a single position as the cam sprocket rotates it clockwise. I'll post photos once I get the cam covers off. Kodi nox Edited August 29, 2020 by duard.79

Initially I ordered a new camshaft, but I decided to return it and get a refurbished cylinder head by Famous Brand through RockAuto ($400 for head, valves, buckets, and camshafts). Although a new camshaft may have fixed the problem, I wanted this project to be finished and not have to take it apart again. Installed a new head gasket, new cam seals and new head bolts during the head installation. I have been driving it for 2 days with no codes, so I think the problem is fixed!

 

whaaaa rock auto sells rebuilt heads for 400 dollars ? core charge?

I see sohc for 400, nothing for dohc?

Yeah it was $500 and a $100 dollar core charge. I checked Rock Auto again and it looks like they are out of stock. I too was completely caught off guard by the fact that heads were for sale on Rock Auto. When I got mine there were only 2 left in stock. I have no idea when they will be back in stock, but that was hands down the best deal I have seen for a D25 head.

Yeah it was $500 and a $100 dollar core charge. I checked Rock Auto again and it looks like they are out of stock. I too was completely caught off guard by the fact that heads were for sale on Rock Auto. When I got mine there were only 2 left in stock. I have no idea when they will be back in stock, but that was hands down the best deal I have seen for a D25 head.

 

I think I may have posted a link in JmP's sticky about a place that sells heads.

where is this said post!?

Ok, I guess I was MISTAKEN, ok now...

 

I just asked google and got this. May be one of you younger guys could have figured out to ask google for help...but wait, most guys have a hard time asking for directions... LOL

 

 

https://www.google.com/search?q=reman+heads+subaru+ej255&rlz=1C1OKWM_enUS906US906&oq=reman+heads+subaru+ej255&aqs=chrome..69i57j33.13276j0j15&sourceid=chrome&ie=UTF-8