What.the…?? Compression challenge

Don't worry, this isn't a noob story or question…I hope, just kinda thinking out loud/online I bought a couple outbacks with bad engines to rebuild cheap. I put a crank and bearings in the first and it's good to go. The second the guy said the timing belt broke, supposedly they went out to start it one day and nothing happened. I got it home and pulled the timing covers, and the belt was not broke. At this point I'm thinking "sweet, I may have hit the jackpot and not have major probs!" When you crank it, it sounds like it had no compression. The timing is dead one, all cams spin with the cranks, all plugs were in. I ran a leak down and couldn't get it to build pressure. I ran a compression test and barely got 10 psi. Both these test were on #1 and #2 cylinders, I didn't see any point in checking 3 and 4. There is no clanking or any noise that shouldn't be there when cranking, so I'm assuming nothing broke internally. All I can think is something with the rings. I'll drain the oil and pull the pan next before I pull the engine and see if I find anything.

A jumped timing belt can bend valves too. Did you check to see if all the marks lined up correctly?

Hello;

Thinking bent valves, sounds like the belt could have been replaced. Last time I checked on epay a complete set was around an ace, Steven.

Like I said in the first post, the timing is dead on, which is the most obvious thing to check on these 2.5's I know. And I doubt it jumped time, bent all valves, then jumped back to where it should be...stranger things have happened I suppose. Timing belt i'm pretty sure hasn't been replaced anytime soon, unless they put an old belt on it. I know the cost of a kit which I definitely wouldn't buy on ebay.

Yeah, I noticed that after I posted what I said. Jumped timing is not probable, but maybe the PO jumped timing and then reset the belt.

Possible they had a shop just stick an old belt on in hopes it was OK?

I'm not a 2.5 guru, but I am pretty mechanically inclined, so I'll just speak of motors in general. I'm sure a lot of this will stuff you've already considered, but you asked for help, maybe something I say will give you a idea to pursue.

 

If the marks are on, and it's not making any unusual noise while cranking over, it doesn't seem like bent valves are the issue. If there were any bent valves, there should be some sort of clanking, or banging while your cranking it over. I mean even if the valves knocked holes in the tops of all the pistons, the valves wouldn't be closing all the way so the rockers would be ticking at the least.

 

So lets say that didn't happen, but maybe the belt slipped just enough the let the pistons kiss the valves. When you did the leak down and compression test, you should have been able to hear the air coming out of somewhere. Maybe make sure your on the compression stroke again, maybe take the exhaust off, and pull the pipe off the throttle body, hook the air back up and see if you can hear where the air is going.

 

If that proves inconclusive, a head gasket failure between the cylinders could be suspected. That would let the air cross over to the next cylinder, failing both tests.

 

Since we can assume the PO didn't tell you the whole story, this has some fishy stuff going on. You don't just go out to start your car and have it do nothing without something happening beforehand, and then assume the worst possible outcome and sell the car.

 

Which makes me ask, you have talked about cranking the car, but no mention of spark? I've see many cars with bad valves and bad head gaskets that will atleast still try to fire. They might not run, or run very well, but they will try. And then you can easily tell if the valves are bad due to the backfires coming out if either the intake or exhaust.

 

Again, I'm not a 2.5 guru, but I've been following this forum and others off and on for many years, and I can't recall anyone ever talking about their piston rings going bad. Maybe someone more familiar can support or rebut that observation.

 

So IMHO, it's either something seriously crazy, like a broken crankshaft, broken pistons, four broken camshafts, or bad rings. Or something not so crazy like the head gaskets went out, they super overheated it, and the heads are warped/cracked. Which could explain the leak down and compression test failures. But I'm still stumped about the spark?

 

As always, looking forward to following this post and hearing about the outcome.

 

Also interested in the crank and bearing replacement on the other motor. What kind of costs were involved with that? Any machine work or just a straight replacement?

Idaho has hit it pretty good and covered anything I was thinking. The big one being a cracked head. HG would make sense....being a 2.5.....hitting both cylinders is a bit strange but weirder things have happened. Could be both the gasket and head that are shot from being driven with the gasket gone.

 

Whats the old test with putting oil in the cylinder to check rings? Pretty sure it doesn't apply when you're only pushing 10psi.

Like I said in the first post, the timing is dead on, which is the most obvious thing to check on these 2.5's I know.

what timing marks are you referring to?

hash marks or arrows?

 

NOT the ARROWS,

NEVER the ARROWS!

 

plus even if the cam hash marks line up,

if you did not remove the center timing cover and the crank sprocket bolt,

you have not completely checked the timing.

you CANNOT see the crank timing mark with the timing cover and the crank sprocket in place.

(if you remove the the crank pulley bolt you can see the crank key way. this is 180 degreees away from the correct timing mark.)

 

but more on point,

if you have ZERO compression there are only a few of possibilities,

1. bad rings (never heard of this in an ej22 or an ej25 engine)

2. bad valves

3. bad timing

4. bad pistons (never heard of this in an ej22 or an ej25 engine)

5. hole in cylinder wall (well maybe, but not in 2 cylinders on opposite sides.)

 

since three of the above five NEVER happen in subarus (almost never),

chances are you have the timing off or bent valves from the timing being off.

CHECK the TIMING.

 

pull the timing covers, all of them,

replace the toothed idler with the bad bearing, (usual cause of failure)

install a new belt, (any correct belt in one piece will do for testing)

set the timing using the correct timing alignment marks,

and see what happens.

 

until you do this,

or pull a head and test it ,

you will never know.

 

or just punt and install a used engine from a 1995 ej22 auto trans legacy.

 

by the way,

what year outback are we talking about?

 

EDIT: is your compression gauge working and accurate?

depending on the year,

valves bend from hitting valves,

not pistons.

 

so there usually isn't any clanking.

Possible they had a shop just stick an old belt on in hopes it was OK?

 

I hope not

 

I'm not a 2.5 guru, but I am pretty mechanically inclined, so I'll just speak of motors in general. I'm sure a lot of this will stuff you've already considered, but you asked for help, maybe something I say will give you a idea to pursue.

 

When you did the leak down and compression test, you should have been able to hear the air coming out of somewhere. Maybe make sure your on the compression stroke again, maybe take the exhaust off, and pull the pipe off the throttle body, hook the air back up and see if you can hear where the air is going.

 

If that proves inconclusive, a head gasket failure between the cylinders could be suspected. That would let the air cross over to the next cylinder, failing both tests.

 

Since we can assume the PO didn't tell you the whole story, this has some fishy stuff going on. You don't just go out to start your car and have it do nothing without something happening beforehand, and then assume the worst possible outcome and sell the car.

 

Which makes me ask, you have talked about cranking the car, but no mention of spark? I've see many cars with bad valves and bad head gaskets that will atleast still try to fire. They might not run, or run very well, but they will try. And then you can easily tell if the valves are bad due to the backfires coming out if either the intake or exhaust.

 

Again, I'm not a 2.5 guru, but I've been following this forum and others off and on for many years, and I can't recall anyone ever talking about their piston rings going bad. Maybe someone more familiar can support or rebut that observation.

 

So IMHO, it's either something seriously crazy, like a broken crankshaft, broken pistons, four broken camshafts, or bad rings. Or something not so crazy like the head gaskets went out, they super overheated it, and the heads are warped/cracked. Which could explain the leak down and compression test failures. But I'm still stumped about the spark?

 

As always, looking forward to following this post and hearing about the outcome.

 

Also interested in the crank and bearing replacement on the other motor. What kind of costs were involved with that? Any machine work or just a straight replacement?

 

I did have the pipe off the throttle body and the exhaust was off, BUT, my quick connect was leaking so it made it hard to hear anything…I know I know. I'll get a new quick connect tomorrow and rerun the test. I had thought head gasket failure too, but since it was happening on both banks, I partially ruled that out for now. I agree the seller wasn't telling the whole story. he lived 150 miles away, and was honest about every little scratch or anything wrong, which wasn't much. With the exception of the engine, the car is in excellent shape for a 97. I did not check for spark, simply because I knew it was something far worse by the sound of it cranking. As far as the crank being broke, I doubt it, I stuck a piece of wire down the #1 cylinder hole and verified the piston moving. The crank and bearing replacement on the other engine was pretty simple, just a straight replacement, runs great.

depending on the year,

valves bend from hitting valves,

not pistons.

 

so there usually isn't any clanking.

 

That's good information, I thought it was always valve to piston contact that was the problem.

what timing marks are you referring to?

hash marks or arrows?

 

NOT the ARROWS,

NEVER the ARROWS!

 

plus even if the cam hash marks line up,

if you did not remove the center timing cover and the crank sprocket bolt,

you have not completely checked the timing.

you CANNOT see the crank timing mark with the timing cover and the crank sprocket in place.

(if you remove the the crank pulley bolt you can see the crank key way. this is 180 degreees away from the correct timing mark.)

 

but more on point,

if you have ZERO compression there are only a few of possibilities,

1. bad rings (never heard of this in an ej22 or an ej25 engine)

2. bad valves

3. bad timing

4. bad pistons (never heard of this in an ej22 or an ej25 engine)

5. hole in cylinder wall (well maybe, but not in 2 cylinders on opposite sides.)

 

since three of the above five NEVER happen in subarus (almost never),

chances are you have the timing off or bent valves from the timing being off.

CHECK the TIMING.

 

pull the timing covers, all of them,

replace the toothed idler with the bad bearing, (usual cause of failure)

install a new belt, (any correct belt in one piece will do for testing)

set the timing using the correct timing alignment marks,

and see what happens.

 

until you do this,

or pull a head and test it ,

you will never know.

 

or just punt and install a used engine from a 1995 ej22 auto trans legacy.

 

by the way,

what year outback are we talking about?

 

EDIT: is your compression gauge working and accurate?

 

Like I said in my first post, this isn't my first engine. I am well aware of all the timing marks, including the crank sprocket mark. I peeked in the exhaust and intake ports tonight after I got the intake off. i can see all valves moving freely and closing as far as the naked eye can see. All timing bearings are good. If I had a hole in one of the cylinder walls, I would imagine there would be coolant in the oil, and vice versa. This isn't my first rodeo with an engine, and I plan on pulling the engine and heads, probably tomorrow night. I just wanted to share a "wtf is going on here" and see if it throws anyone else off as much as it has me And I'm not meaning to come off rude, I do appreciate all the ideas and suggestions

Please keep us posted as to what you find after you pull the engine.

Well, I got the engine pulled apart today. As far as I can tell, the rings are the problem. I can find nothing else wrong. It was leaking oil like crazy from all over though. The oil pump screws were loose, and one of the wrist pins access plugs was loose. Someone has had this engine apart and did a piss poor job on it. One head was torqued more than the other was. There was a ton of oil buildup on top of the pistons and around all the valves on the heads. The #4 cylinder did have indications of a bad ring, from what I have been told. The crosshatches were mostly gone on the upper half of the cylinder. I ran the leak down test again with the everything but the cylinders off. I was feeling and hearing air coming out of the exhaust valves, and very little out of the oil pan. The valves do not appear bent at all. I'm still amazed that I could lose that much compression through rings that didn't appear in too bad of shape, with the exception of the oil rings. They weren't seized or broke. So I guess I'll hone it, put new rings in, all new seals and gaskets and see what happens… :-/

I suppose the oil in the cylinders could also be the valve stem seals

Hello;

Be sure to do a valve job on your current heads, at least lap the valves in. Checking valve stem/guide wear, and replacing stem seals. The rering job sounds like a solid plan, Steven.

Hello;

Be sure to do a valve job on your current heads, at least lap the valves in. Checking valve stem/guide wear, and replacing stem seals. The rering job sounds like a solid plan, Steven.

 

Originally I wasn't going to mess with the heads, but I agree, since I am doing everything else might as well attack the heads too

So, I was tearing down the heads last night to do the seals and some lapping. Well I decided to do another quick leak test, so I turned the heads on their side, filled up the intake ports with brake fluid, and watched. It seeped out real slowly, not too bad but definitely not acceptable. So I did the same with the exhaust ports, and as fast as I was spraying it in, it was straight out of the valves. There was so much oil and carbon buildup on them and on the heads it was ridiculous. I believe that was the majority of my compression problem. Bearings, seals/gaskets, and rings should be in in a couple days.

Post some pics if you can!

Finally got the car back together a couple days ago, been working on small bugs here and there. The knock sensor has been throwing a code, I'm hoping it's just a failed sensor. That's the least of my worries. I get 35 miles on it when all of a sudden clank clank clank! It died immediately and I hit the clutch the split second I hear it. I pull off the road and there is a quarter size hole in the drover timing cover. I pull the cover forward a little and can see the timing belt is off and the intake cam sprocket is gone…awesome. Towed it home and start tearing into it. Everything seems ok except for the sprocket that is in pieces, which miraculously didn't cut the new belt. And the intake cam was completely seized. So I pulled the valve cover, and my best guess as to how it happened is the oil port on the rear cam journal got plugged, because the journal and the cam obviously was starved of oil. I know they were torqued and pre lubed properly so… I'll pick up a new head from a junkyard and used it instead of waiting on a machine shop. So if anyone is looking for a slightly damaged head, I'm your guy :-/

Finally got the car back together a couple days ago, been working on small bugs here and there. The knock sensor has been throwing a code, I'm hoping it's just a failed sensor. That's the least of my worries. I get 35 miles on it when all of a sudden clank clank clank! It died immediately and I hit the clutch the split second I hear it. I pull off the road and there is a quarter size hole in the drover timing cover. I pull the cover forward a little and can see the timing belt is off and the intake cam sprocket is gone…awesome. Towed it home and start tearing into it. Everything seems ok except for the sprocket that is in pieces, which miraculously didn't cut the new belt. And the intake cam was completely seized. So I pulled the valve cover, and my best guess as to how it happened is the oil port on the rear cam journal got plugged, because the journal and the cam obviously was starved of oil. I know they were torqued and pre lubed properly so… I'll pick up a new head from a junkyard and used it instead of waiting on a machine shop. So if anyone is looking for a slightly damaged head, I'm your guy :-/

 

Man, talk about bad luck!!

Here's a simple trick using the leak down tester. First you have to set eat cylinder to its own TDC so it's only one at a time just like the regular leak down test. Pull the intake hose off the throttlebody then the exhaust manifold. Next hook up the LD and run air into each affected cylinder. While the air is pumping into the cyc listen for air at the TB if none then the same at the exhaust ports. Still nothing remove the oil fill cap and listen through there. If you hear air through the TB then it's intake valve, exhaust is exhaust valves and through the oil fill then it's either the rings or pistons. Last thing if nothing is heard in all three, drain the coolant and pull the upper radiator hose. Air cracked block,head or headgasket. GL.

Here's a simple trick using the leak down tester. First you have to set eat cylinder to its own TDC so it's only one at a time just like the regular leak down test. Pull the intake hose off the throttlebody then the exhaust manifold. Next hook up the LD and run air into each affected cylinder. While the air is pumping into the cyc listen for air at the TB if none then the same at the exhaust ports. Still nothing remove the oil fill cap and listen through there. If you hear air through the TB then it's intake valve, exhaust is exhaust valves and through the oil fill then it's either the rings or pistons. Last thing if nothing is heard in all three, drain the coolant and pull the upper radiator hose. Air cracked block,head or headgasket. GL.

 

I believe ericthecarguy made a video explaining this. I'm assuming you watched it. His videos are extremely helpful

Here's a simple trick using the leak down tester. First you have to set eat cylinder to its own TDC so it's only one at a time just like the regular leak down test. Pull the intake hose off the throttlebody then the exhaust manifold. Next hook up the LD and run air into each affected cylinder. While the air is pumping into the cyc listen for air at the TB if none then the same at the exhaust ports. Still nothing remove the oil fill cap and listen through there. If you hear air through the TB then it's intake valve, exhaust is exhaust valves and through the oil fill then it's either the rings or pistons. Last thing if nothing is heard in all three, drain the coolant and pull the upper radiator hose. Air cracked block,head or headgasket. GL.

 

I think this post is about two months too late, but thanks anyway.