Servicing the Intake AVCS Gears..

[silverton]

I'm not trying to be an asshole, but armchair logic doesn't really fly here on this forum! Obviously the op hasn't even pulled the timing covers off the engine let alone pulled the motor out of the car otherwise they would know exactly what motor they have and how many avcs gears they have, let alone single or dual avcs and then another person who doesn't even have an avcs car are both giving irrelevant, theoretical information on the 4th gen. Meanwhile information from people who have been in the trenches and the shit who have actually done it are being ignored? If you don't even know what engine is in ur car or have never worked on said engine and pulling reference from old technology then I would listen to the people who have been there and done that! This is why the internet is dangerous, to much information isn't necessarily a good thing. If you #ynansb and your worrying about ur cam gears, then nuff said, u shouldn't be doing this! If you need new cam gears then you need a new short block which is 2 thousand dollars. This entire approach doesn't make any sense. I would be worrying about more important things like turbo, shortblock, heads etc. not cam gears. If you need new cam gears or want to rebuild them then you probably need a new oil pump, oil cooler, etc. None of this shit makes sense! If there was no engine failure why are you even going down this path? If you just want to rebuild your motor, then reuse them and move on. If your rebuilding due to a blown motor/turbo then I could understand this nonsense. But rebuilding the cam gears are the least of your worries! Who is rebuilding the shortblock, who is rebuilding the heads? There are so many other more important things to worry about.

 

And up til this point you haven't even stated the cel you got for the cams. If its the ocv code then your barking up the wrong tree! What code are you getting???? Why do you think you need to rebuild your avcs without an engine failure? Nothing makes any sense! A motor with 210k miles needing an overhaul doesn't mean changing cam gears and timing belts, cause thats pointless. You don't even know the cel code to come to that conclusion, and if ur avcs gear was bad you would know that cause your motor would be toast. I would worry about the shortblock and heads for an overhaul, why are you so focused on your avcs gears, AVCS gears don't cause a car to overheat. Obviously you have other more important things you should be focusing on!

 

QFT :spin::spin:

[RumblyXT]

To properly burp the system I raise the passenger side of car higher via a jack, then let all the air come out. If the pump wasn't changed or is just crap it might not be applying enough pressure. If the thermostat is old it may be giving inaccurate readings. But the main issue is your basing this again on what you THINK is a bad temperature, hence why you need to know the exact temp the coolant temp sensor is reading! Look at your gauge and where is the needle relative to something like a clock or degrees if your mechanically inclined. Overheating is like going past 10 oclock, my car is usually at around 9 oclock warmed up.

 

Right, the coolant gauge definitely gets around 10 o’clock when pushing the car hard.

 

The previous owner told me they had changed T/B and components but like I said, I have no idea what they did there, if the pump is good or even if the thermostat position was set correctly (with the little hole at 12 o’clock right?)

 

That’s why I say I eventually have to get in there and overhaul the motor. To remove the water pump, I have to get to the T/B. Might as well just leave everything for a full motor overhaul, I also wanted to see the condition of the heads, change piston rings, etc.

 

This is why this whole AVCS Cam Pulleys research started for me.. Because I wanted to know about them and not creating a thread for overheating, a thread for AVCS, a thread for T/B, etc..

 

The car runs fine otherwise, if I don’t drive it hard, it runs just fine.

[xt2005bonbon]

For logging, I suggest the BtSsm app (only on Android), which was developed by a fellow forum member. I run this at all times when I drive these cars. Somewhat dormant thread here. I have been running this since 2015! It has saved me many times..

 

 

Regarding coolant temp, the gauge is not linear. It begins moving (from the operating temp position) when you are past ~213-215F. You reach the next tick on your gauge around 230F (10 o'clock or so). I have reached it a few times! But that is when I am boosting for a while AND the intake temps are 115F at 3000 Ft+ elevation AND AC on with a full load in the car (2 adults, 3 kids), bikes on the roof, roof top box, etc..

 

In normal conditions, the coolant temp would usually remain below 195F. My fans kick in at 203F.

[blackobxt]

I quit posting because you were given answers but they didn’t seem to be the answers you wanted because you kept asking the same questions. But since Tehnation hit you with that cold honest slap, there are a few things I feel like pointing out.

 

1. Why are you comparing the difficulty of changing a waterpump to going through the motor? A timing belt and waterpump is like a 2 beer job for someone that knows what they are doing. (Which to be honest it sounds like you have WAY more screen time then wrench time)

 

2. Why are you just assuming the motor needs to be gone through? You don’t seem to know much about the car or it’s history. For all you know the motor has already been replaced at some point. You won’t know the condition till you do a compression and leak down.

 

3. Like Tehnation said, you “think” you have a bad temperature. You mentioned you have a scan tool that you’re checking codes with, I assume it has live data. What temperature does the live data show? It should give you an exact degree so no guesswork there or relying on an analogue needle that moves based on parameters in temperature ranges. (My motor has around 35k miles on it and on a good hot day if I goose it good and hard the needle does go up past the middle line)

 

4. Almost nobody will tell you to keep the banjo filters. You stated that Subaru knew what they were doing by installing them. Well, Subaru must have realized that was a mistake because they quit installing them and I know the dealerships that I’ve been with even recommended removing them.

 

5. When your motor goes, it’s crucial to clean or replace EVERYTHING. The heads will hold a TON of debris. I spent hours on my heads removing oil galley plugs and running rifle brushes through them, it was insane how much debris they can hold even after a thorough douching in the parts cleaner. Replace the oil cooler and may as well just buy a new short block from Subaru since after the cost of machining and assembly you won’t be far off from the cost of new. (But as was stated, you assume you need to go through the motor)

[RumblyXT]

Hey blackobxt, thanks for chiming in.

 

I originally said I wanted to do a motor overhaul because I really like the car and given it has 210K miles, I thought replacing gaskets, O-Rings, piston rings, etc the motor would be in a much better condition to last much longer.

 

I don’t know what was done to this car in the past and quality of the parts that were used. I like to use OEM as much as possible.

 

My previous car was a 2001 Forester L which I had to do a H/G job because it was overheating. But since I was there, I ended up changing the piston rings, and even surfaced the block myself at home with a square granite piece and very fine sand paper. The job ended phenomenal. After checking the block with a straight edge, not even 1/1,000” would go under with a feeler gauge. Obviously the heads were sent out for machining as well.

 

I don’t have a lot of knowledge as a mechanic but I love working on these cars. It’s just that sometimes I tend to overthink things too much, please overlook that part and don’t mind me.

 

I also overhauled the P/S pump, replaced axles, changed front and rear brakes, serviced all fluids, worked on the general suspension components of the car etc.. like I said, minor stuff. I do have a bit of mechanical input from my years working with Landing Gears in Boeing, Douglas, Airbus and Lockeed Martin overhauling all type of landing gear actuators and using their service bulletins where we learned things like small gouges in internal parts could cause big oil leaks and bigger problems later on. Working in the Aviation Industry gave me the basic understanding and appreciation of mechanical things in general. That’s probably the reason why I tend to over analyzing car stuff.

 

Thank you guys again for all your help/input, I really appreciate it. I hope I didn’t come across as bragging, I’m not like that at all.

Edited January 11, 2022 by RumblyXT

[Tehnation]

Ok, so the reason people don't like messing with these motors is because unlike normal 4 cylinder motors the shortblock is two halves, and its horizontal so now you have 2 heads. Basically what all that means is $$$$. The motor in our cars are actually worth more than than the entire car, you can get a used 4th gen with a blown motor for like 1k-2k, meanwhile a complete motor used is like 3k-5k.

 

Rebuilding the block isn't simple either because parts are limited and tolerances are high. You want to do a compression and our leakdown test 1st to test the health of your motor, good compression means leave it alone, and they all should be close to each other, like within a certain psi But those 4 compression numbers will let you know a lot, like if you have 135, 135, 135 and 125, then there might be an issue with that last cylinder. The numbers will tell you a lot right off the bat! Do a compression test 1st, if everything is good then play ball, I think 130-140 psi is the good - excellent range, maybe 135-140. Not sure what fsm says, but I would go by those numbers. If you have bad or inconsistent compression, then you do a leakdown to isolate if its the heads(valves), rings or both. Some people can figure out all sorts of stuff with a leakdown.

 

https://www.motortrend.com/how-to/engine-diagnosis-leakdown-compression-test/

 

What you do should be based on those numbers. If you change piston rings you have to make sure your cylinder walls are in good shape 1st otherwise you need hone or bore the block, meaning you gotta pull it apart. You will need precision tools, like a bore gauge etc. to measure how round your cylinders are and how wide they are, if everything is in spec you can get away with cleaning your pistons and replacing the rings.

 

Your heads you will have to inspect and clean those, gotta make sure all the valves are sealing, and inspect the valvetrain to make sure everything is moving right.

 

If you have excellent compression then there really isn't any point, good and consistent compression then yea why not do the above to get it back into peak shape. But if there is sorta good compression were most are almost the same but you have 1 maybe 2 outliers, then there are other issues going on and you need to deal with that sooner than later. Also take the readings with a warm motor.

 

You can also send out a sample of your oil to blackstone to get a much better idea of whats up on top of the compression and leak down test.

 

https://www.blackstone-labs.com/

 

You will need a master gasket set if you want to rebuild everything, to save yourself time and money hunting for everything, part number 10105AA720 I believe.

 

https://legacygt.com/forums/showthread.php/full-gasket-kit-content-10105aa720-203457.html

 

Next after inspecting the health of the motor you drop the downpipe, the pipe connected to the back of the turbo, then use a ruler to measure how much the shaft moves, there's a tolerance number somewhere on the forums or internet, not sure what it is, but make sure its within spec. If its not then that turbo will likely shoot shrapnel into your motor eventually and thus contaminating it which would eventually lead to engine failure.

 

So after you do those 2 things, then you should worry about whatever it is you want to do. Cause whatever you want to do should always be based on the health of the motor, you don't do surgery on a healthy human being, why would do it on a car. If money isn't a factor, then go for it but thats not the case!

Edited January 11, 2022 by Tehnation

[RumblyXT]

Ok, got it. I'll do an engine compression and cylinder leak down test first, then check turbo shaft play.

[blackobxt]

:woowoo:

Ok, got it. I'll do an engine compression and cylinder leak down test first, then check turbo shaft play.

 

:woowoo good step one. Then check the other stuffs

[Tehnation]

If your doing it yourself, it may be a pita. Getting to the coilpacks and spark plugs are a nightmare on these cars, if you have changed your plugs then you already know. You start the car warm it up, then pull the fuel pump fuse located in the fuse box under the hood behind the battery. Then let the car run until it dies, meaning you drained all the fuel out the system. Remove the coil pack then spark plug, connect the compression tool, then crank the motor... actually , there are videos somewhere, i remember someone posted a video...

 

Compression Test, very good information in this video, shows you how to pull the plugs etc. Watch this if you plan to do it yourself. Just do what this guy does and you will be fine, i think a member on the site made the video. Yep, samuel082799 made it.

 

Leak Down Test, here's a video on what to do for a leak down test, its an older subaru not our engine but the logic is the same. Listen for where the air is escaping.

 

If you plan on paying someone make sure they don't pull the "its bad compression, want to sell your car?" routine, it happens! So find a reputable place, or possibly the stealership, cause they don't really care your just another service ticket. Actually I would probably go to a dealership, cause they know exactly what to tell you.

Edited January 11, 2022 by Tehnation

[RumblyXT]

I was just researching both tests, thanks for the links!

 

Actually, I would rather learn to do this myself, already got the compression tester. Last time I called a local tuning shop, they quoted me $350! for each one of the tests..

[Tehnation]

Yea, no lol. Dealership would charge you for diagnosing, which is like 1 labor hour somewhere around 100-150 bucks. But doing it yourself is best if you want to learn things.

 

In order to do a leak down test, you will need an air compressor. You can do a lot with an air compressor, air tools like a impact wrench, ratchet wrench, chisel/air hammer, air gun, tire inflator, cut off wheel etc. Makes life a lot easier. I would invest in one if you plan on doing all the work on your car yourself. Especially for things like suspension work, wheel bearings etc. And for testing for vacuum/boost leaks nothing beats an air gun. I think I use that the most, blowing air is a very useful thing. You can clean out stuff, blow out fluids in tight places, very practical and useful tool. Compressor has a multitude of uses for things other than automotive as well! Every home should have an air compressor! You can get a decent compressor and some air tools for cheap at harbor freight!

 

Good luck!

Edited January 12, 2022 by Tehnation

[RumblyXT]

I do have a few tools.. A small 12 ton HF press which helped me replaced a couple of rear wheel bearings on the Forester. Will have to replace the control arm bushing on the Outback eventually.. Also got a small compressor, very helpful indeed, know what you mean.

And of course some Company23 Specialty tools. They made working on the Forester a lot easier.

 

I believe in using right tools for the job to avoid to avoid breaking stuff and making.... lol let's not bring that topic back

Edited January 12, 2022 by RumblyXT

[Tehnation]

A lot of guys here use the mevotech if I remember correctly front control arms. They are aluminum and have all the bushings and ball joints etc.

 

https://www.rockauto.com/en/moreinfo.php?pk=6506952&cc=1430733&pt=10401&jsn=833

https://www.rockauto.com/en/moreinfo.php?pk=6506949&cc=1430733&pt=10401&jsn=834

 

100 bucks a piece. Thats what I have as well. Rather than buying bushings pressing them in and out, on top of using the crappy lucking steel ones. These look better and are lighter. They are basically the same control arms on the legacy gt spec b.

 

You can get a set of regular ones as well for like 50 bucks a piece.

https://www.rockauto.com/en/moreinfo.php?pk=10917300&cc=1430735&pt=10401&jsn=894

https://www.rockauto.com/en/moreinfo.php?pk=10917304&cc=1430735&pt=10401&jsn=895

 

 

So depending on what bushing you plan to use it might not make sense to press them out. If your using expensive polyurethane bushings then yea, but if your just using regular bushings then no point in doing all that work when you can get a brand new set for like 100 or 200 bucks.

 

Actually I forgot you have an outback xt, not sure how the suspension works on that car, so things might differ. Check out rockauto! But I believe suspension is the same for legacy and outback for most of the parts.

Edited January 12, 2022 by Tehnation

[RumblyXT]

Pretty cool, thanks for the info..

[RumblyXT]

 

Compression Test, very good information in this video, shows you how to pull the plugs etc. Watch this if you plan to do it yourself. Just do what this guy does and you will be fine, i think a member on the site made the video. Yep, samuel082799 made it.

 

Leak Down Test, here's a video on what to do for a leak down test, its an older subaru not our engine but the logic is the same. Listen for where the air is escaping.

 

I know both these you-tubers because I follow both of them.

 

Didn’t know SW Speed’s name was Samuel. I have seen his videos, very skillful and knowledgeable guy. He actually has my same MY car but manual, he even does his own tuning.

 

And the other one, of course.. MrSubaru1387, who doesn’t know Robert, he’s a great mechanic. Most of the work I did on my older Forester, I learned it at his channel using his videos.

 

Ok, so the idea is to do the compression test with the engine as warm or as close to operating temperature as possible, so the internals have been expanded and therefore getting the most accurate reading possible.

 

I will try, not much clearance there to work quick removing coils/spark plugs but it’s doable.. and yes will definitely be doing it myself. Nothing like learning to fix your own car. Thank you.

Edited January 14, 2022 by RumblyXT

[RumblyXT]

Could a restriction in this pipe/hose to the blow off valve be causing the engine to heat up after driving it hard?

 

 

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[silverton]

If you can measure your turbo shaft play with a ruler, it's already too far gone.

[Tehnation]

Could a restriction in this pipe/hose to the blow off valve be causing the engine to heat up after driving it hard?[ATTACH]294818[/ATTACH]

 

 

Sent from my iPhone using Tapatalk

 

nope, very doubtful.

[Tehnation]

Have you checked your coolant level to ensure its not leaking out somewhere? If its leaking out then yea, thats a problem. Common place to leak is actually the heater core for your interior heating system its behind the center dash. It leaks under the carpets so its hard to notice. My car sat for a long time on a slope so my back seat floor was flooded with coolant, wouldn't have noticed because I don't really touch the carpet floor but I was pulling the carpet to replace and thats when I noticed. So make sure your coolant levels aren't dropping off, you need to monitor it to make sure its all there.

 

Have you flushed your coolant? You usually start there, if you didn't put the coolant in the car then you don't know what is in there and what ratio of coolant to water, or if they used some silicone coolant. I believe we need to use a certain type of coolant without silicone or some type of chemical.

 

Have you inspected, tested or changed the thermostat and coolant temp sensor? Thermostat could be sticking or not working properly or the wrong or cheap one was installed. Get an oem thermostat, and make sure its properly installed. You don't need to pull the timing or anything for that, its 2 bolts, don't even need to remove the hose.

 

Are your fans working? Thats a no brainer.

 

If your motor was an issue you would have some kind of code. So you need to start looking at the cooling system, not the motor. The motor isn't going to get hotter because of vacuum issues! Basically the cooling system isn't pulling enough heat from the motor, and you need to figure out why!

 

And you could just have air in the system! Troubleshooting the cooling system is an isolated thing from the motor, if those 2 systems actually cross each other then you have an expensive problem to fix, ie head gasket, cracked head, etc. Stop assuming the motor is overheating because of some mechanical issue directly related to engine performance.

 

The ONLY engine aspect that would affect the cooling system is the water pump, period. Not the spark plugs, vacuum lines, etc.

 

Motor turns pump, pump moves coolant through the motor, coolant absorbs the heat from motor, coolant goes to radiator with the heat from the motor, radiator plus fans and air absorbs/removes the heat from the coolant , coolant goes back to pump and pushed through the motor, very simple process.

 

So if the previous owner put in a cheap garbage timing belt kit with a crap water pump then .... yea! Thats why when you buy one of these cars used, u always want the information on the timing belt change, things like what kit was used and who installed it. You don't even know if the pump was changed.

 

Grab a beer, grab a wrench, pull the timing covers and get to work! I would inspect the timing belt pulleys to make sure they look somewhat new and check what brand they are and where they were made. I only trust things from Japan! If you have pulleys and parts in your timing kit made in China, then you probably found your issue!

Edited January 14, 2022 by Tehnation

[Tehnation]

If you can measure your turbo shaft play with a ruler, it's already too far gone.

 

Yea, I can tell by feel, but you need points of reference to know what good and bad is. Feeler gauge would probably be easier or a small metric ruler so you can do mm's and not inches. There will always be some play in the shaft. You want to check both axial and radial movement, side to side and in and out.

Edited January 14, 2022 by Tehnation

[whitexc]

I would think a helping hand (magnet) and a dial indicator would be better suited. Trying to hold something in there to measure with and wiggling the wheel seems like hard work.

 

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[Tehnation]

Good point! When I first inspected my turbo I pulled it out completely so it was easier. I wanted to make sure the inlet turbine wasn't touching or scrapping the sides either. I was very anal about it my 1st time around because I couldn't afford the turbo shitting on the motor. But 4 turbos later, I can figure it out just by wiggling the exhaust side with your finger.

[RumblyXT]

If I want to turn my existing CAI into a Short Ram intake, will the car need to be retuned just for the pipe section becoming smaller?

 

I haven’t yet been able to do the Compression test, have way too many things going on..

[Tehnation]

Do you have a 3" downpipe, bigger turbo, injectors??? If not your pretty much wasting your time! I would spend that money elsewhere for the time being.

[RumblyXT]

My DP is 3" yes, regular turbo and injectors. But I'm not asking/looking for any 'performance' gains.

 

I want to get rid of the CAI because we get a lot of rain down here and I drive by areas that get quiet flooded.

 

My concern was if I had to re-tune the ECU when changing from the existing CAI to a regular stock intake or a short ram.