EA82T sudden loss of power

Ronin · Post by **Ronin** » Tue Jun 24, 2008 11:19 pm

Hello all. Im needing some help again. straight to it:

I just took the subi out to get dinner after doing a oil and filter change (which took way too long due to lack of a filter wrench). I was at some traffic lights and decided to be mr show off and do a short sprint.
The ground was wet, wheels spun and revs went up to probably about 6500-7000. After that it felt like it was running on 3 cylinders, kinda sounds like it too - but if I disconnect a spark lead individually on any of the 4 it gets worse.

It was still boosting under load (not that I really tried as I was a bit scared I could do further damage), but performance was crap regardless of boost. feels even worse than when it used to have the EA71 in it. So I think the turbo is still ok.

Im no mechanic but Im assuming Ive blown a head gasket? Ive never had a car or been in a car or even seen a car with a blown head so I dont really know what its like to have this.
If it is a head gasket, what should I be able to do to confirm this? (Should their be an obvious pressure leak from the head?? Because Ive been unable to locate any such thing - although it is late so Ill have a better look tomorrow)

I feel I should also mention that since I swapped out the EA82 with the EA82T it has performed very well, but Ive always felt like after about 4500, as the revs increase, the power just seems to drop off, so Ive never really gone over because changing gear had a better result rather than holding on longer. Perhaps thats quite normal for this engine?

If a blown head gasket is not the only possibility, what else could it be?
Any help/advice greatly appreciated.
Cheers

chubby37 · Post by **chubby37** » Wed Jun 25, 2008 9:03 am

could have a loose vaccume line...head gasket/check for water in oil or oil residue in radiator..you mite see like an oil slick in the water.could show as bubbles in the radiator too..best way is a compression test.

Ronin · Post by **Ronin** » Wed Jun 25, 2008 9:52 am

Thanks for the reply. All lines appear to be fine. No sign of water in oil or oil in water. Is there a relativly cheap tool for measuring compression? Or will I have to take it to a workshop for that?

chubby37 · Post by **chubby37** » Wed Jun 25, 2008 10:22 am

from memery....old memory...supercheap and other auto shops sell a compression tester for around $30 mark...easy to do...take out one plug at a time,put in tester and turn motor over....will give you the reading on the port...you,ll get some differance from the ports but dont worry unless its a huge amount....is you get a huge drop then you,ll know which side to replace....if you get stuck let us know were you are and someone mite be able to lend a hand to give her a check

chubby37 · Post by **chubby37** » Wed Jun 25, 2008 10:33 am

this is what you need...this is on ebay but can get them from most auto parts shops
http://cgi.ebay.com.au/COMPRESSION-TEST ... dZViewItem

Ronin · Post by **Ronin** » Wed Jun 25, 2008 11:51 am

Cheers chubby. Just biked to super cheap and got one. Same type as that ebay one you posted. I cant do the test at the moment cause the battery is too low, so Ill have to wait until the flatmate or someone can lend a hand.
What is the standard compression for the 82T ??

Point · Post by **Point** » Wed Jun 25, 2008 12:09 pm

take all of the plugs out, and hold the throttle open when you crank it over.

you are looking for a big difference in cylinder pressures, as compression ratios and cam timing will effect what the actual pressure is. if they are all even, then all should be ok. if 1 or 2 are considerably lower than the others, you have a problem

chubby37 · Post by **chubby37** » Wed Jun 25, 2008 12:16 pm

this is what i got off another board....if these figures are out can someone post the right ones...anything between 110-160 is good...as long as each cyl is within 10 psi of each other, its all good.

Gremlins · Post by **Gremlins** » Wed Jun 25, 2008 12:19 pm

Just further on the head gasket, in my experience with EA82T's a blown headgasket doesn't normally result in oil and water mixing which is not to say it can't happen but there's a good chance you won't notice any coolant getting into the oil.

The most obvious indication of a blown head gasket is the coolant expansion tank gets filled right up and can overflow as leaked cylinder compression pressure forces coolant out of the radiator into the expansion bottle. Normally you'll notice coolant going everywhere well before you notice any performance difference.

Sounds like the compression test as mentioned above is a good place to start with this one.

Ronin · Post by **Ronin** » Wed Jun 25, 2008 7:18 pm

Ive got my results (Sorry, I keep forgetting how the cylinders are numbered)

Driver side pair (F/R): 120/95
and the other pair: 130/120

The driver side front cylinder took more compression strokes than the rest to reach its max value. probably about 8 and the rest took 4 or 5. when i was first testing the driver side front cylinder my result was 115 but after the first round of testing I did longer cranks and came up with 120. I duno if that means anything but thought it was worth mentioning.

What do y'all think?

I cant really afford to do a top end re-build. But if I have to, Ill at least do rings. Ive never done any work on the top end of a car engine so at least the experience would make the money worth it (as long as i dont screw it up).

Matatak · Post by **Matatak** » Wed Jun 25, 2008 7:32 pm

Drivers side rear is a bit worrying dude.

top end rebuild is ALOT easier than just rings to.

Ronin · Post by **Ronin** » Wed Jun 25, 2008 7:45 pm

Oh yeah I guess Id have to split the whole engine just to do rings? what a hassle.
Not like the dirt bike where you just pull the barrel off...

I guess i have to at least take the heads off now? and hope its just a gasket

chubby37 · Post by **chubby37** » Wed Jun 25, 2008 7:55 pm

sounds like to me you have a drivers side head gasket letting go...dont think you will need to re-ring her tho...subaru motors take a lot of punishment...the head gaskets are weakest piont and therfor let go long before major damage is done....very common

Ronin · Post by **Ronin** » Wed Jun 25, 2008 8:11 pm

Sweet. Thanks a bunch everyone.
Ill take her back to my parents place and check out the gaskets.
Will I need to resurface?

chubby37 · Post by **chubby37** » Wed Jun 25, 2008 8:21 pm

if ur lucky,no...put a straight edge across the head and see how much gap if u have....you should have a little in the centre but not heaps

r00fi · Post by **r00fi** » Wed Jun 25, 2008 8:59 pm

Hope it's not this but......... I have 3 EA82Ts in my garage with cracks between every inlet and exhaust valve. Isn't always a problem, but all mine have gone through to the water jacket (I have to assume this as all exhibit head gasket failure symptoms but head gaskets have all appeared to be intact, with no oil/water mix)

The annoying thing is they are all stock installs and haven't been thrashed. Grrr

New heads just picked up - hopefully installing this weekend (if these 100kmh winds don't blow my garage down)