No compression right front cyl/120 psi right rear

[Mr Whiskey]

Could this be a timing belt issue or does it have to be cam/valve, rings/piston related?

If bad timing belt, wouldn't it loose comp on both these cyls?

I don't have any experiance with these motors. In your opinion, what would be the most likely cause of 0 compression on the right front cyl.?

I have other post here conserning this vehical, please forgive me if I'm going about asking questions the wrong way. I'm not only new to Subaru's, but new to message boards too.

This is an 85 gl10 wagon, ea82, mpfi, auto, frt whl drive only, with just 60k mi.s. Thanks, peace.

[hatchsub]

Ok lets see if i can narrow it down a bit. First off this is not a turbo motor correct? The turbo EA82 was the only motor to get MPFI in that body style (xt's got it i believe in Non turbo as well). What you have is SPFI (single port fuel injection where the injectors are in the intake manifold instead of directly in the heads.

 

Things that can cause no compression are:

-bad rings

-stuck valve/valves

-blown headgasket

-timing "could" be a factor but if thats the case it would be running on two cylinders ALL the time. In other words the belt that runs the passenger side cam would be so far off time that one valve in each of those cylinders would be left open on the compression stroke.

 

I would be putting my money on either the stuck valves or blown headgasket but only by a bit. Its hard to decide without taking it down. If your getting zero compression from one cylinder only and not the two of them then for me that rules out a timing problem...but then again they do not fire at the same time so timing could still be screwed up but for some reason you could still get a compression reading on one but not the other.

 

How long have you had this car and do you know when certain things were done to it (timing belts and headgaskets in particular)? That could help narrow it down some.

 

EDIT just realized this car has 60k miles on it. I would be willing to bet those are ORIGINAL timing belts and such.

 

My money is moving more towards those belts. They are probably not doing so hot.

Edited December 19, 2009 by hatchsub

[idosubaru]

we only know what you tell us, not seeing, hearing, or smelling the car makes it hard. but we're pretty darn good so more good information would be:

has it always been like this?

 

did it run perfectly %100 and then do this one day?

 

your timing belts could be off. i've never done a compression test on an engine with the timing belts not lined up properly so i'm not sure what the readings would be, but it would be something like what you're getting.

 

either the belt was installed wrong or it could have skipped some teeth.

 

the other likely explanation is bad head gasket. any coolant loss, bubbling in the coolant, overflow, overheating, oil/coolant mixing...etc?

 

good luck!

[GeneralDisorder]

It's unlikely that the belt being off would cause 0 psi in one cylinder and 120 in the other. I would have to really take a hard look at the possible relationship's of the cam and crank to know for sure but the two cylinder's on one side are run off the same cam and a single belt. It sounds like a bad head gasket to me but it's easy enough to verify the timing - just pull the outer covers (6 bolts) and turn the crank till the center of the three valve timing lines are lined up with the arrow. Then you can check the relation of the cams to the crank - one cam mark (hole) should be up and the other down.

 

In order to get absolutely zero compression you would have to have one of the valves open on EVERY upward stroke of the piston. While that is possible, I don't think it's also possible for the other cylinder on the same cam to have compression at the same time. See what I mean? But maybe - definitely check it.

 

GD

Edited December 19, 2009 by GeneralDisorder

[K9WAGON]

Make sure the little holes on the cam sprockets are arranged with one pointing straight up and one pointing straight down . I have seen this problem arise when both holes were pointing in the same direction. There should be some little notches at the top and bottom on the cam belt back covers . The holes in the pulleys should line up with them when sighted from directly overhead.

[Mr Whiskey]

Thank you all, I believe we're closing in on it with your help and advice!

Here's what I now think, tell me if my head's in the right place.

Right side timing belt broke or stripped. I'm figuring if the right side cam isn't turning at all then maybe the front cyl is sitting with a valve open, and the rear is sitting on comp stroke, (valves closed, hence 120 psi reading).

We lost the light before this idea came to us so we'll pull timing cover tommorrow to confirm. Sound to y'all like I'm headed in the right direction? Probability of this is high in my opinion, car sat for 3 yrs or more, I'm sure these belts were brittle.

Son just got car, haven't had it a week. I'm expect these are the original belts.

Was running on 4 cyl fine first couple of days then developed intermittant issues, (would drop what I thought was 1 cyl). Car is now running on left side 2 only, I'm positive. Pulling both right side plug wires doesn't affect it at all.

This is a non turbo. It says mpfi on top but, Hatchsub is right, the injectors are in the intake, not the head. So it's an spfi? Is that correct?

No water in oil, (or vice-versa), no overheating, no coolant loss, etc.

I'm almost sure this wagon is factory original, never been opened up or had any "deep" service in it's life, (like timing belts). I know if I can solve this problem for my Son then these motors run forever and would make an excellent car for my boy.

Here's the trick ? When these motors drop a timing belt, are they known to bend valves? I've driven the car running on 4, it was solid, ran great. I've also had it running on 2 more than once now. What would you say my risk factor might be concerning valves if that cam has stopped turning.

Bless you all and this fantastic site, we're learning, thanks, peace.

[idosubaru]

Beautiful - sounding more and more like a broken timing belt! Woo hoo!

 

No - these are non interference engines so no worry of internal engine damage. Get the belt right and you're golden.

 

Get an ebay timing belt kit - they come with all new pulleys and tensioners. No point in going all that way and installing a new belt on 25 year old pulleys that certainly are devoid of grease now (I have never seen an EA82 with smooth pulleys). Or you can get a $3 needle attachment for a grease gun and shoot some grease under the bearing seal on each pulley - i do that too. Don't overfill or it pushes out as it heats up.

[GeneralDisorder]

Which side are you refering to as "right side"? If it's the driver's side then it can't be a broken belt as that one drives the distributor.

 

Passenger side - yeah I could see that. I thought for sure you were talking about the driver's side but right/left to me is always standing in front of the engine bay...... it's never clear though so it's better to say "Driver's side" and "Passenger's side" so there's no confusion (at least in the US).

 

I just realized you have the (very rare) '85 2WD MPFI setup. It only came on 2WD GL's and only for that one year. Just be aware that parts are nigh impossible to find for that setup as '85's in general are getting scarce and especially the 2WD MPFI's since they were not desireable cars.

 

They had issues with leaking/bad injectors so you might check on that - especially if it's been sitting. I don't think there are any other injectors that are a direct replacement - the late 80's MPFI XT injectors might be but are probably not the right design and definitely not the right volume. '85/'86 MPFI Turbo stuff is similar but the injectors will be too large. Other parts may interchange though.

 

From what I understand, the injector issue can cause burnt valve seats on these. Probably not enough to lower the comp. to zero, but a leaking injector could wash down all your oil and possibly lower the comp. quite a bit. WAG.

 

GD

Edited December 20, 2009 by GeneralDisorder

[hatchsub]

I just realized you have the (very rare) '85 2WD MPFI setup. It only came on 2WD GL's and only for that one year. Just be aware that parts are nigh impossible to find for that setup as '85's in general are getting scarce and especially the 2WD MPFI's since they were not desireable cars.

 

 

GD

 

Oh shoot. SPFI didnt start until later than 85 huh? he says the injectors are in the intake though.

[Cougar]

Since you have some pretty good pressure in one of the cylinders and zero in the other I believe that means you have a valve problem. A gasket problem would not be that low of pressure. It would be good to know what the other side is reading. If the other two cylinders are higher in pressure then you may also have a timing belt problem on the bad side. Which all this has been pointing to.

[GeneralDisorder]

Oh shoot. SPFI didnt start until later than 85 huh? he says the injectors are in the intake though.

 

Right - they are in the intake. It runs EA82 turbo/MPFI heads. It's basically the EA82T fuel/ignition system remaped to run with no turbo on a 9.5:1 block. It's a total oddball thing. It's similar in essence to the late 80's XT's but with the old flapper MAF, associated computer, no multi-rib belts, and 5 less HP

 

GD

[markjw]

I'm going to bet it's a compression ring problem in the "zero" reading cylinder. I believe the compression ring is seized/rusted into it's groove and will not expand to fit the cylinder. I've run into this very problem twice. Both with cars that have sat for years.

 

Here's what I did. I pulled the plug,added a couple three tablespoons of Marvel Mystery Oil and then put the plug back in. It's important to put the plug back in because the idea is to force the Mavel oil into and past the compression ring while cranking the engine. Sometimes you have to repeat the process,but it may work for you.

 

 

Worth a try before you pull parts off the engine.

Edited December 20, 2009 by markjw

[subyleone]

could also be a cracked head. i no its non turbo but iv struck it before. had the usual crack across the bridge of the valves but if you to the inlet out there was a huge crack up the side. it had done high mileage though. have you tried a cylinder leakage test? this blows air down spark plug hole allowing you to listen to the exhaust, intake, radiator, dipstick etc to see were it is loosing compression. this is different to a compression check where you just crank engine. you have to have the suspect cylinder at tdc on compression to test it

[MilesFox]

I would second a stripped timing belt. had it happen to me. it could have lost a tooth and skipped time, then let go entirely, or stripped enough teeth to quit

 

take off the disty cap and check to see if the rotor tuns. pop off the covers and go through the rotaton sequences here:

http://offroadingsubarus.com/timingbelt_ea82.html

[Mr Whiskey]

Dragging this post back to say thank you, and happy holidays to all!

My Son and I couldn't have accomplished as much as we did without the wonderful help and support of the good people on this site.

As promised, here was the final diagnosis: Stuck exhaust valve, right front cyl. We did a leak down test as suggested by Subyleone and the pressure was comimg out the exhaust. Then pulled the valve cover and inspected visually, confirmed, exhaust valve not moving.

Shame too, less than 62k mi's., it's in time, (matter of fact it's actually got new timing belts) but I guess it sat too long.

This is unfortunatly more of a job than I am willing to attempt in the driveway with hand tools, so we're gonna find a shop that works on Subies and pony up the scratch to get her fixed. I'm still sure it will make an excellent car for my boy once the repairs are completed, and I'm also sure we will have more questions down the road.

I'd also like to send a special shout out to GeneralDisorder and Hatchsub who, in there crosstalk, helped greatly with the identification of this particularly unusual incarnation of a great old Subie, (mechanics kept trying to tell us we didn't know what we were talkin about) and we'll watch those injectors. Thanks to all and we'll be seein ya, peace.

[hatchsub]

Thanks for the update. I was wracking my brain trying to figure out how in the world off time could only affect one cylinder. Didnt seem like it would but couldnt figure out anything more plausible. I do believe this is one of the first stuck valves ive heard about on the board. Im surprised too at only 62k. Guess your right and all that sitting did not do that engine wonders.

 

What are your plans for it when it goes to the shop? If your going to pull one head you might as well pull both so that both head gaskets are new. That way they can inspect and fix if necessary any other valves. If you got a few extra bucks you might just want to have both heads gone through by a machine shop and rebuilt. It would probably save you grief down the road.

 

And im glad that GDs and my discussion helped uncover what it really was (aka he reminding me there was such a thing as a MPFI '85 lol). I had completely forgotten about that one year only engine since they rarely pop up. Good luck!

[Cougar]

Thanks for the update and glad you found out the trouble. I thought you would find a valve problem going by what you stated about the compression. By having no compression at all in only one cylinder it had to be due to a stuck or burnt valve.

Edited December 28, 2009 by Cougar

[john in KY]

Definitely pull both heads. If one valve seized from sitting, trust me others will also seize in short order. Had this problem with an old Mopar I inherited that had sat for almost 20 years. The more I drove it, the worse it got. When I found the 5 bent push rods, I knew what the problem was.

 

As far as I know, all MPFI injectors across the years are exactly the same.

[john in KY]

oops.

John

Edited December 28, 2009 by john in KY

[Mr Whiskey]

Plannin to pull both heads when we can afford it. I did enough motor work back in the day to know better than just do one. You'd end up right back in there sooner or later. She's gotta have a valve job so might as well do it right.

Thanks again to all the good folks here, and happy holidays. Peace from DG and Kody.