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EJ25 head gasket replacement: Slew of questions


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First: sorry for the long post.

 

Ok, I just started my first 'real' engine project: Head gasket replacement on a '98 DOHC EJ25.

 

The engine is on an engine stand so it's a joy to work on.

 

I have a whole bunch of questions, I'll try to split them up logically.

 

First: timing belt removal.

Before I removed the timing belt I checked the marks on the camshaft sprockets. I could have sworn that all double marks lined up and that all arrows pointed to top right.

But when I removed the belt, put it away and looked at the engine again, I saw that the topright sprocket had it's single mark lined up with the double mark. Could it be that it turned when I took off the belt ? I tried to turn it (really really careful), but at some point the valve hit the piston (I guess) and it would not turn futher.

 

Second: Cam sprocket removal.

Do I really need to get the tool to lock the sprockets in place ? Is it expensive ? Any other safe tricks to lock the sprockets ?

 

Third: Can I remove the cam cover or cylinder head cover (not sure what it is called) without removing the sprockets ? I can't see if the clamp behind the cam sprockets locks the cover in place, and I don't want to use force and screw things up.

 

Fourth (planning ahead) : aligning the cams.

When installing the timing belt, I need to align the marks again. This will take care of the positioning of the cams in relation to eachother. But what about the crank ? How do I know that the crank is in the right position ?

 

Again, sorry for the long post, but I'm a newbie at this and don't want to mess up the engine.

 

Thanks,

 

Rob.

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question 1: the driver's side cam's can possibly rotate when you remove the belt, as it has valves open when all of the timing marks are lined up. mine was balanced on the lobes of the cam, so i rotated each to it's safe landing area (it is outlined in both the haynes and the factory service manual), basically turning the top one ccw and the bottom on cw. rotate them the reverse when installing the belt.

 

question 2: if you remove the valve covers, there is a hex portion ground onto the camshaft. you can put a large adjustable wrench onto the flat portions to hold the cam while you break the bolt free:

 

08-removing_the_cam_sprockets.jpg

 

question 3: you can remove the valve covers without even removing any of the timing belt covers, etc. doing so will help you with question 2.

 

question 4: there is a mark on the crank sprocket to let you know where the crank is in cycle. be sure to orient it in the same way as when you removed the belt. it should be pointing up. also be sure you are using the right mark. on the center face of the sprocket, there is a triangle. that points down as i recall (its not the timing mark). the timing mark is on the back lip, below the lobes for the crank position sensor.

 

i wrote a site with a lot of info about changing the head gasket. you can view it here . it also has details on how to compress the tensioner if you don't have access to a vice, and some other tips collected from this board and others.

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Skip,

 

how easy / hard was it to brake loose the bolts from the cam sprockets. I just tried and they wouldn't budge.

I looked if I could wedge the wrench somewhere so I could use both hands on the socket, but I'm affraid to damage the block.

 

Any hints / tips ? It's normal right-hand thread, right ?

(right = fasten, left loosen).

 

Thanks,

 

Rob.

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been a couple of months, but as i recall, everything was standard thread (no reverse thread). i don't remember the cam bolts being too difficult to remove, though my neighbor had a 20" adjustable wrench, and he was holding the cam while i broke the bolts free. you could try putting a block of wood against the heads and then letting the wrench on the cam rest against that. how hard were you trying? the other thing you may try is to tap/hit the bolts on the head with a hammer to help them break any corrosion that may have formed.

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They are standard thread, and pretty darn tight. I would use a 1/2" drive socket with a breaker bar and a pipe for the sprocket bolt. A piece of wood or a pipe on the wrench might help. Be very careful not to damage anything under the valve cover with the wrench. In skip's picture it looks like the wrench is really close to the head.

 

I used a homemade tool, after breaking the right intake sprocket while following the advice in the haynes manual. I welded a 2-3/8" 3/4" drive socket to a 2' piece of 1" angle iron.

 

Some have said to use a strap or chain wrench. If you choose to try that be very careful not to break the timing covers.

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Well, I've got the cam sprockets off. :clap:

Check out this marvel of (McGyver) engineering:

103_0391.jpg

103_0392.jpg

How's that for a sprocket removal tool ? :headbang:

 

Now, the next challenge: the head bolts ?

 

Looks like I need a special socket for this.

Can someone tell me what these are called and what size I need ?

 

Thanks !!

 

Rob.

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  • 1 month later...

Ok, my project is progressing although extremely slow.

I bought a new gasket set this week and want to install the head back on.

 

Here's my question for the week ;) :

How clean does the head and block surface need to be ?

 

Right now there is no gasket on it anymore, but there is some (carbon ?) residue on the surfaces, especially the 1st ring around the cylinder:

 

EJ25-2.jpg

 

And, what is the best way of cleaning it ?

I'm guessing wirebrushes are not a good idea since I don't want to scratch it ?

 

Thanks,

 

Rob.

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I would avoid using any type of hard scraping tool. Aluminum is very soft; even minor scratches can result in head gasket leakage. Chemical aerosol gasket removers are available. They do an excellent job cleaning the surface like new without scraping; you can use a soft plastic tool to remove any tough residue that a grease rag won't remove. The chemical is caustic and will burn your skin, so protect yourself with gloves.

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I used Scotchbrite pads also with a little

bit of carb cleaner. Worked pretty good.

Thanks to Skip's webpage(thanx, Skip) and a Haynes manual, I got mine running Sunday before last. If you take your time

and follow the book when installing back in the car, you'll have it purring like a kitten like mine.

Good Luck.

 

Dr.F:banana:

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  • 5 weeks later...

Allrightie then, I finally had some time to work on the engine again. (Having an addition to the family sure takes up a

lot of time ;) )

 

Anyway, I've got the drivers side head back on, but when I reinstalled the cams, I noticed that the exhaust cam was binding a bit. I retorqued the bolts, in a different sequence this time, and I was able to move the cam reasonably easy. But it still doesn't rotate as easily as the intake cam (when not lifting the valves of course). Is this 'normal' , or a sign of a problem ?

 

On the passenger side I noticed quite a bit of coolant in the pockets outside the cylinders. This is not supposed to be there is it ? I am guessing this is becuase the gasket was leaking ?

 

Thanks,

 

Rob.

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Boxers: My cams were the same way.

I could turn one by hand and not the other. I could move it with a rag on the end with channel locks. I think it's just the way they are. There's always some coolant left in the block after pulling the motor. Are you using an engine stand?

After I put mine on the stand, I rotated

the engine on it's side to dump out the remaining oil and coolant before the cleaning began. I've put 1k miles on mine and so far so good.

Good Luck.

 

Dr. F

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Guest lothar34
Originally posted by theotherskip

question 1: the driver's side cam's can possibly rotate when you remove the belt, as it has valves open when all of the timing marks are lined up. mine was balanced on the lobes of the cam, so i rotated each to it's safe landing area (it is outlined in both the haynes and the factory service manual), basically turning the top one ccw and the bottom on cw. rotate them the reverse when installing the belt.

 

Which Hayne's manual covers the DOHC 2.5? The most current one I saw when searching for the Forester was the one that went through the '98 Legacy. I thought the Legacy had the 2.2L until the 99 MY. Is that not true?

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This manual covers both the 2.2 and the Phase I 2.5. ISBN: 1563923262

 

My cams all turned smoothly when they were reinstalled. Did you use assembly lube? I would make sure that you got the cams back in exactly where they came from.

 

EDIT: Make sure the cam caps are all back in the correct place too.

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I only did one side at the time, and made sure everything went back exactly the same.

 

I messed around a bit with the 1st cam cap, and was able to get them to turn reasonably easy. But there definately is a difference in force needed between the cams.

 

I'm going to leave it as is right now, I've put the cam sprockets back on and I can turn all cams easily.

 

Thanks for your help,

 

Rob.

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