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EJ25D/EJ251 Rebuild


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I'm working with an EJ251 out of an 02' Forester and an EJ25D I believe is out of a '96 LGT. The engine is going into the '02 Forester and I plan to use the EJ251 heads on the EJ25D block.

This is the first time I've attempted to rebuild an engine, or even pulled an engine. Anyhow, I've got both engines out of the cars and the EJ251 is already torn apart, I have a few questions though.

When shopping rod/main bearings, pistons rings, etc it gives me oversize and undersize options. I'm just wondering, why would I need an oversize, or undersize rod/main bearing, or piston ring? If I just order the "standard" size would I be ok?

Also I'm looking for the crush gaskets that go behind the expansion plugs, any idea where I could find those?

Sorry if these questions are really stupid. Thanks for any advice!

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If you were going to have the block honed or bored out then you'd need the rings to accommodate that. Otherwise you just need to get the stock ones. You'd only have to hone/bore it if the cylinders are egged or worn out and they need it, or you want to up the displacement.
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If you were going to have the block honed or bored out then you'd need the rings to accommodate that. Otherwise you just need to get the stock ones. You'd only have to hone/bore it if the cylinders are egged or worn out and they need it, or you want to up the displacement.

Thanks a bunch for that info. Does anyone have part numbers for those crush gaskets?

Also how about engine break in, I'm replacing the rod/main bearings, piston rings, and all seals/gaskets. I, however, will not be taking the block or heads to the machine shop.

I will be cleaning everything up as best as possible, I may even attempt to resurface the heads/block at home using the wood block/sandpaper method. I'm not here to be criticized for the way I'm doing this, so please just focus on the question. Do I need to break it in?

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You absolutely need to break it in. I'm not sure what Subaru requires for break in, but it's normally along the lines of, get it up to temp, do a couple rpm sweeps, shut it down, let it cool, repeat, change oil and inspect for metal, and then you're good to drive but don't take it above 3500rpm for like 10k and then you're good to go.

 

Also, the sandpaper and wood technique works but it doesn't really remove any material, it just cleans the surface of old gasket material and makes it look nice. I'd still have them resurfaced even if they haven't been overheated, it's best to only do the job once and at <$50, I'd pay the extra amount to not risk it.

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You absolutely need to break it in. I'm not sure what Subaru requires for break in, but it's normally along the lines of, get it up to temp, do a couple rpm sweeps, shut it down, let it cool, repeat, change oil and inspect for metal, and then you're good to drive but don't take it above 3500rpm for like 10k and then you're good to go.

 

Also, the sandpaper and wood technique works but it doesn't really remove any material, it just cleans the surface of old gasket material and makes it look nice. I'd still have them resurfaced even if they haven't been overheated, it's best to only do the job once and at <$50, I'd pay the extra amount to not risk it.

 

 

Thanks for the info, so the reason I was considering the new rod/main bearings was due to a low oil pressure issue I was having. I did replace the oil pump in the past but the issue was still there, however, the light only came on around 300 or fewer RPMs or so... it had some serious idling issues. Anyhow, after getting the heads off the block, the cylinder walls were gorgeous, they still have the hash marks. I feel like if it’s in this good of condition, then the rod and main bearings must be decent. Would I be wrong to make this assumption?

 

 

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I'm starting to suspect I shouldn't be using the hash marks as a determining gauge of condition for Subaru engines, because every single Subaru engine I've seen inside (which is like 6) they've all had hash marks, no matter the mileage. I'll find out for sure when I open up my 213k ej251. But if you have low oil pressure I'd use that as justification to do a complete engine rebuild. Low pressure=dead engine, if I remember right, the Subaru oil pressure comes on when the engine has 3psi, which is is a dead engine.
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I'm starting to suspect I shouldn't be using the hash marks as a determining gauge of condition for Subaru engines, because every single Subaru engine I've seen inside (which is like 6) they've all had hash marks, no matter the mileage. I'll find out for sure when I open up my 213k ej251. But if you have low oil pressure I'd use that as justification to do a complete engine rebuild. Low pressure=dead engine, if I remember right, the Subaru oil pressure comes on when the engine has 3psi, which is is a dead engine.

 

 

 

Thanks a bunch, I will say that the cylinder walls in the EJ251 were smooth but no hash marks, it had 206k or something in that ballpark. But I have heard of someone with over 300k reporting the hash marks on their cylinder walls, but that was on a very well maintained engine. Anyhow, is there any way to inspect the rod bearings without splitting the case?

 

 

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Well I shot that in the foot, I removed the oil pan and I have play in the 2 front rods. The 3rd is solid and I can't really check the 4th one. So new bearings it is

 

 

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I've never split a subaru block before but there are allen key plugs on the sides of the block, just soak them in PBlaster and then get an allen key on an impact gun or breaker bar. Once they are out, you will have access to the wrist pins.
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There are no screws inside the block.

There is a 10mm at the bottom inside the edge. All the other bolts are accessed from outside.

To get to the wrist pins.Remove the oil separator plate allowing access to #3.

Remove the access plates for the other 3.

 

Line Up (as an instance ) #1 remove ring circlip. Take a stout rod at least 1/4" in dia.

Snake it past the #3 rod from the opposite side until you hit the back of the #1 pin.

Using a light from the side you're tapping out will help you line it up.

Keep tapping it until it falls free. Follow same procedure for the other 3.

Use a 3/4" wood dowel as a drift to install pin and make sure it is fulling seated.

It takes longer to say than to do.

 

O.

 

I always leave the inside circlips in so it will act as a stop for the pin.

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Thanks guys but the screws I was referring to are the ones inside the bell housing, the Phillips heads that hold the separator plate on so I could get to the expansion plug to knock the wrist pin out.

I did finally get them out by just switching to a larger bit, lol. Also, after a bit of struggle, I managed to get a 9/16 Allen wrench on them and put a jack handle on the end of that to gain the leverage needed to break them loose.

All 4 pistons are out and I put them in separate bags with their respective wrist pins and labeled them. Tomorrow, I split the case.

This has been one heck of a learning experience. I’ve been a “parts changer” for a while now but this is uncharted territory, but I catch on real quick. I can’t wait to get it back together and see how it runs.

As for those crush gaskets that go behind the expansion plug, could I just take one to my local ACE and match it up? Also, the screws that hold that separator plate on, could I replace those with an Allen or star head screw?

Thanks for the help guys!

 

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Btw for the surfacing of the heads use a flat surface. Like a glass table. Use glue/tape to get the sand paper on there. Not sure what grit or kind of sand paper is the best. Use a Persian blue machining dye like this to make high spots. Sand until all of the blue comes off. It is similar to scraping a surface flat. Make sure the sandpaper is tightly adhered to the flat surface you are using. Considering that block halves aren't heavy you could surface the block using the same method.
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Resurfacing:http://www.ultimatesubaru.org/forum/topic/122588-diy-head-resurfacing-or-post-apocalyptic-machine-shop-techniques/

Screw replacement on separator plate depends on plate. If you had phillips screws you probably have bevels in the screw holes.

I wouldn't take a chance on any screw which does not fit those.

The new type plate has a flat surface and uses allen screws.

There is an arrow on plate for upper left screw, that one must have rtv on it when installed.

Do you have the fsm?

If you keep on doing this type of work get an impact screwdriver which is what you needed to remove those screws.

 

If you pm me your address, I know I have some of those phillips head type around.

 

O.

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Thanks for the tips, I will be replacing my separator plate with the metal one and I just realized it says it comes with mounting bolts, lol.

Anyhow, do any of you know which head bolts to use. I am ordering new ones but the parts numbers for the EJ25D and EJ251 are different. I'll remind you that I'm putting the EJ251 heads onto the EJ25D block. Do I match the bolts to the heads?

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You don't need new bolts use what you have from the 251 block.

I don't know why so many 3rd party mfgs say head bolt replacement required.

Subaru doesn't do it nor is it listed in any fsm.

This is a common misconception that our bolts are tty. They are not.

 

O.

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You don't need new bolts use what you have from the 251 block.

I don't know why so many 3rd party mfgs say head bolt replacement required.

Subaru doesn't do it nor is it listed in any fsm.

This is a common misconception that our bolts are tty. They are not.

 

O.

You sir, just saved me $50.00

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Hey everyone! Just wanted to post an update, This is going sort of slow but I haven't gotten all of my parts in yet anyway. I'm currently in the process of cleaning the block for paint. I will be just painting the block with a high heat black paint, may also paint the intake manifold.

Anyhow, I ordered all the parts from Rock Auto except for the case bolt seals, which I ordered from the eBay, but they are OEM Subaru parts. I ordered Felpro head gaskets and Felpro lower conversion set for the EJ25D and I ordered a complete upper gasket set for the EJ251, which also came with head gaskets but I won't be able to use them.

As for the crank/main bearings, piston rings, and a couple of exhaust valves, I went with Enginetech.

I was wondering, should I clean the pistons before reinstalling?

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I'd definitely clean the pistons before reinstalling them, using oven cleaner works really well but you have to be careful with putting it on aluminum. Otherwise you can use a soft scotchbrite (white one, not green or brown) and brake parts/carb cleaner.
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I'd definitely clean the pistons before reinstalling them, using oven cleaner works really well but you have to be careful with putting it on aluminum. Otherwise you can use a soft scotchbrite (white one, not green or brown) and brake parts/carb cleaner.

 

 

 

Thanks for that info, when you say be careful putting it on aluminum what do you mean? Don’t leave it on too long, don’t use too much?

Anyhow, things were going pretty decent today, I got the rods reinstalled with fresh bearings and got the crank put back in its place, with fresh crank bearings. Everything seems to move as it should and such.

Just an FYI I am using Lucas assembly lube.

I removed the valves from the EJ251 heads so they can be lapped and I can clean the heads and install new valve stem seals. 2 of the valve are bent and will be replaced. While removing the valve I found that an exhaust valve guide had dropped. Here comes the bad part, while trying to move the guide back into place I broke the darn thing.. so I’ve ordered a new one. Also I’m not using a valve spring compressor, just pressing down on the spring with a large pair of pliers while my wife grabs the keepers with a magnet... it may be a challenge getting them back in that way lol.

Anyhow, I have a question about the valve stem seals. I ordered a set of Felpro valve stem seals and listing said it was a set and included 16. The box I received says 16 are included but it says exhaust on the box. I don’t see the word intake anywhere. There are 16 in the box but they all look identical. I was under the impression that they were different between the intake and exhaust, am I wrong?

 

 

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Don't leave the cleaner on too long, it'll oxidize the aluminum, which is more annoying then anything else but I definitely wouldn't risk it with engine internals like that.

As far as valves go, they are definitely not the same size so I don't know why they are selling sets of 16 of the same valves

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The intake stem dia is listed as 5.950 -5.965 mm

The exhaust is 5.945 -5.960 mm.

There is only one stem guide dia listed, at 6.00 and those clearances are accounted for.

So the same guide is used for both, though the seated length is different from I to E.

Hence the 16.

 

This is listed in the FSM engine section under general specs.

Don't know what auto stores are in your area, but I'd check to see if they have the free loan system that AutoZone and Advance Auto have here.

It will save you a few choice words!

 

O.

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Hey guys, it seems those seals are identical. Sorry for the dumb question but I’ve seen kits with labeled and different colored intake/exhaust valves.

I just got my upper gasket set, now for most of the gaskets, I ordered Felpro but since I wasn’t going to be using the head gaskets from this upper kit I went with the cheapest set possible, I think it was like $38 and it was SKP I believe. However, the set turned out to be really nice for the price, nothing like I expected for under $40. It even came with the crush gaskets for the expansion plugs.

Also I have a question not related to the engine.

Long story short I’ve like $1100 worth of suspension related parts that only have around 500 miles on them, that I am installing of this car that included the rack & pinion, control arms, sway bar end links, ball joints, wheel bearings, CV axles, etc.

Well before installing the control arms I decided to go ahead and torque down the bolt on the rear most front control arm bushing. While trying to install I’m finding it nearly impossible to line up the holes for that bushing. I don’t know of any way to torque the bolt with it installed, my torque wrench will no fit. Should I just loosen the nut, install and get it as tight as possible with a wrench? Perhaps measure the amount of threads is sticking out with a caliper while it’s torqued? Then try to tighten to that measurement with a wrench? What do you guys think?

 

 

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