Subaru EA82T compression comes and goes

[K-dog]

My latest acquisition, a 1988 RX coupe, has an interesting problem. It has a virtually brand new engine, that's been sitting for 14 years. Ran good for a week, went to fire it up one day and it sounded like it had no compression when cranking. Then, like voodoo, it suddenly had compression, and fired up. FF to yesterday, it had compression on the pass side bank and not the other, but was quiet, and again, fired right up. Air puffing from the intake told me it had a stuck valve. Couldn't find any issues with the valves, so I reassembled the towers, it fired right up, and magically had compression again. Now, it has no compression in the two forward cylinders. Still quiet as a mouse. Runs good (just to see if I could find a funky sound), and has bad reversion on the intake and exhaust corralating with the two cyls without compression. Leakdown shows similar, air past the valves on both cyls, intake and exhaust. The borescope doesn't suggest a ring  issue, or foreign objects in the cc. No HC in the cooling system, no water in the ports. Thegine is pretty clean on the inside, as it was stored properly, and has very good oil pressure. This leads me to believe that it may need the lifters cleaned and reprimed after having sat for well over a decade. Can the lifters stick in the fully pumped position and lead to low compression? I assume this would hold the valves open, given enough lifter protrusion. Just want to be sure before I tear down (what was/is) a perfectly good engine, only to have been able to fix it easily, and without significant downtime. Might add that the timing IS CORRECT. Both valve and ign timing as per the Mitchell book, and being new, the belts and tensioners are in great shape.

[Steptoe]

How much do you trust the word of the previous owner as to its nearly new condition? 

Just seems to be the worst to let a car sit too long

I have had a car that sat eight years with crusty stuff building up on the sides of the fuel tank, drained it added fresh fuel but i feel it leached nasties out of the crud and it seized up two inlets on EA81.

I have also found EA82T that was a mystery to previous owner that had been to Subie experts and still shrugged shoulders. Valve was worn into the guide so was intermittent problems. New K-lines inserted and she has been fine apart from a new mystery - loses power twenty kms into towing 250kg trailer. Is fine when cools down to cold, not that engine itself got hot but I think my 22 DBTDC was a bit harsh under loads - this was NA block using turbo heads with LPG, so 14 degrees beyond std timing.

Another mystery I have had was weak valve springs on EA82T thought to be due to heat from turbo ratting number two exhaust springs. New resolved that one, only afer head place insisted springs were to spec. Called BS after I fitted new lifters and problem was worse.

Still running EA82T so beware the nay sayers we have in here

Edited July 7, 2019 by Steptoe

[el_freddo]

When you say timing is correct, how was the procedure done/how do the cams and crank line up?

If it’s correct, all EA82s will have one cam in the 12 o’clock position, crank in the same and the other cam at 6 o’clock. 

I say this as my first thought was that both cams and crank were lined up at the 12 o’clock position then the belts were fitted. This produces an engine that runs only on one bank. 

To check this theory you can either check the timing, or get it running and pull the leads on one bank, if it stalls, restart with all leads connected then try the other side. 

If one cam is out, it will continue running exactly the same with the leads pulled on the bank that has the cam out of sync.

Lifters will not hold a valve open unless there’s something majorly wrong with it, in which case you’ll have other issues. 

@Steptoe - the NA MPFI runs 20deg BTDC, so it’s really only 2 degrees advanced on the NA block. 

And what you found with the valve spring tension was quite the find and not something I’d ever look into! 

Cheers 

Bennie

[K-dog]

16 hours ago, Steptoe said:

How much do you trust the word of the previous owner as to its nearly new condition? 

Just seems to be the worst to let a car sit too long

I have had a car that sat eight years with crusty stuff building up on the sides of the fuel tank, drained it added fresh fuel but i feel it leached nasties out of the crud and it seized up two inlets on EA81.

I have also found EA82T that was a mystery to previous owner that had been to Subie experts and still shrugged shoulders. Valve was worn into the guide so was intermittent problems. New K-lines inserted and she has been fine apart from a new mystery - loses power twenty kms into towing 250kg trailer. Is fine when cools down to cold, not that engine itself got hot but I think my 22 DBTDC was a bit harsh under loads - this was NA block using turbo heads with LPG, so 14 degrees beyond std timing.

Another mystery I have had was weak valve springs on EA82T thought to be due to heat from turbo ratting number two exhaust springs. New resolved that one, only afer head place insisted springs were to spec. Called BS after I fitted new lifters and problem was worse.

Still running EA82T so beware the nay sayers we have in here

I got the car from a close friend of mine, who installed the reman in 05 when I was a kid, only to have a bunch of wiring issues and trouble passing smog. Lol

 

I never really thought of the condition of the fuel, it was empty when I got it. Everything looked clean, but I suppose the injectors and fpr could have been hiding something. Suppose the only thing to do is take it apart and figure it out. Gaskets are cheap, screw it. 

[K-dog]

So, an autopsy confirmed my fears, valves are sticking intermittently. More followers fell out simply cranking by hand, valves are definitely stuck open today. Guides look really bad. Doesn't look like corrosion, more like deposits from the bad fuel. Deposits have the consistency of partly cured JB weld, and stink. So.... Lesson learned. No matter how well an engine was stored, a decade is too long to sit. Could have gone thru the fuel system and probably saved a lot of headaches. Learn from my mistakes.... Spent my lunch break tearing it down with high hopes too. Lol

 

Good news is that I have plenty of experience working on engines, have a machine shop at my disposal, and found a REALLY good parts guy for vintage subies (Viva la socal). So, all is not lost, only postponed. 

[Steptoe]

I found shiny black layer of what I think we're a combination of guns and varnishes that are said to be a byproduct of stale fuel on my valve stems.

It smelt of stale fuel 

Here in Oz a really nicely rebuilt and modified with things like ceramic coated crowns hit its end of life when the owner used an upper cylinder cleaner foam stuff and had it stall soon after application. Never got it started again. Theory was the cleaner dissolved crud but never got to do its job properly for the stall. Crud then found its way to valve stems. Autopsy led to being parted or junked

[czny]

Marvel Mystery oil in fuel tank & crankcase with fresh fuel in tank.

Helps a gummy engine with top end lubrication.

After draining old fuel tank & lines first of course.

Edited July 9, 2019 by czny