idosubaru Posted September 30, 2010 Share Posted September 30, 2010 so all the ones you've seen were the exact same valve, not just the same cylinder, check. these are all solid lifter engines? this would be less likely on HLA equipped engines then? Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted September 30, 2010 Author Share Posted September 30, 2010 these are all solid lifter engines? this would be less likely on HLA equipped engines then? Both solid lifter. And if my suspicions are correct, then it couldn't happen on a hydro engine as their valves are never out of adjustment such that the valves hang open. GD Quote Link to comment Share on other sites More sharing options...
daredevil1166 Posted September 30, 2010 Share Posted September 30, 2010 The seat actually looks very nice and my head guys don't even replace them - just the valve itself and lap it in. You mean this valve seat looks nice? Is it possible that the reduced clearance is a RESULT of the burned valve and not a CAUSE of the burned valve? If the valve face burns enough the spring would suck it up into the head and close up the lash, right? Has this valve burned enought that that's a possibility? I'd definetly like to see pics. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted September 30, 2010 Share Posted September 30, 2010 I wouldn't think so. Valve lash clearance is between the cam/rocker and lifter on top of the valve. Normally there should be a small gap there, if that gap closes to 0 clearance the valve face doesn't make full contact with the valve seat, allowing burning combustion gases to escape and superheat that portion of the valve. Having given some thought to the EGR theory - that should actually cause a rich condition because exhaust gasses are inert. The EGR being open will not affect the pusle width of the injector so you would have less intake air for the same amount of fuel. What about if the engine is coming off throttle, might the sudden decrease in exhaust flow be able to pull clean air into the exhaust stream through the EGR valve? Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted September 30, 2010 Author Share Posted September 30, 2010 That's the only issue with the theory - which occured first, the burned valve or the zero clearance..... Here's my thoughts: 1. The other valve in the same cylinder looks just fine and in fact still has the factory clearance on the lash. If a lean condition caused this you would expect the cylinder to be cleaner (due to burning off of the carbon), and at the least you would expect both valves to show signs of damage. 2. The forward valve in the #2 cylinder is down to about half it's lash adjusment. Probably also due to wear. It is not burnt though it does have a slightly different color to it so it's probably running hotter than it's brother. 3. The amount the burned valve has receeded into the head at this point is MUCH more than it would need to have receeded to cause the zero-lash. In fact the margin of the valve has been reduced by (eyeball guess) .050" to .100". It took only .010" to narrow the clearance to zero. There is 5 to 10 times that much material burned away off the face. I would say the clearance reduced to zero and *then* the major overheating started and dramtically accelerated the wear to the face, and eventually led to a section chipping away. 4. The seat looks great. This is exactly what happened with the last engine I did - the seat was fine and the head shop replaced the valve and just lapped it in to the existing seat. Of course it still remains a mystery as to why the forward #4 exhaust valve wears faster than the other's. Though assuming this engine has never had the valves adjusted - it went 60k over the adjustment point. I would be willing to bet that if the valves had been adjusted I wouldn't be looking at this engine today. GD Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted September 30, 2010 Author Share Posted September 30, 2010 What about if the engine is coming off throttle, might the sudden decrease in exhaust flow be able to pull clean air into the exhaust stream through the EGR valve? I see what you are saying - I would have to see that in action to beleive it. The EGR is only open for part throttle cruise and should be closed or closing when you close the throttle (the port for the EGR is "late ported" above the throttle plate). There are too many variables to consider to try and reason that one out in my head - closing time of the EGR valve, relationship of EGR to throttle plate position.... and how the ECU reacts also since on EJ's the EGR is partially controlled via a solenoid valve..... GD Quote Link to comment Share on other sites More sharing options...
johnceggleston Posted September 30, 2010 Share Posted September 30, 2010 Though assuming this engine has never had the valves adjusted - it went 60k over the adjustment point. I would be willing to bet that if the valves had been adjusted I wouldn't be looking at this engine today. GD i wonder just how long these engines would run if ALL the maintenance was done as it should?? Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted September 30, 2010 Author Share Posted September 30, 2010 Pictures: GD Quote Link to comment Share on other sites More sharing options...
daredevil1166 Posted September 30, 2010 Share Posted September 30, 2010 Interesting.... I think I'd better adjust my valves. Quote Link to comment Share on other sites More sharing options...
eppoh Posted October 1, 2010 Share Posted October 1, 2010 That's the only issue with the theory - which occured first, the burned valve or the zero clearance..... Though assuming this engine has never had the valves adjusted - it went 60k over the adjustment point. I would be willing to bet that if the valves had been adjusted I wouldn't be looking at this engine today. GD That cam lobe needs to be mic-ed. If the valve is burnt, Do you know if that valve is original or some aftermarket that was replaced before. There were a batch of exhaust valves labeled as from a popular Italian maker that were counterfeited by some Chinese and they all failed. Oh never mind, I just saw the photos Quote Link to comment Share on other sites More sharing options...
daredevil1166 Posted October 22, 2010 Share Posted October 22, 2010 Interesting.... I think I'd better adjust my valves. Working on it right now.... not fun. Anyway, I noticed something interesting, the intake valve clearance seems to get bigger and exhaust gets smaller. A co-worker has a theory that exhaust valves.... the valves themselves, wear more because they are made of a softer material that transfers heat better. What do y'all think? Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted October 23, 2010 Share Posted October 23, 2010 You can tell that valve was substantially hotter than the other. It burned all the carbon right off and left it shiny clean. Quote Link to comment Share on other sites More sharing options...
WoodsWagon Posted October 23, 2010 Share Posted October 23, 2010 How does tight valves work for ones burned in hydro lash adjuster SOHC EJ22 heads (90-95)? I've burned a couple. And not just burned an edge off, it looked like someone took a cutting torch to a section of the valve face. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted October 23, 2010 Author Share Posted October 23, 2010 How does tight valves work for ones burned in hydro lash adjuster SOHC EJ22 heads (90-95)? I've burned a couple. And not just burned an edge off, it looked like someone took a cutting torch to a section of the valve face. That's what the '97 EJ22 I did looked like - cutting torch style. I replaced the injectors on general principle but it could have been a valve clearance problem - It was so ugly and cought me off-gaurd with it being such a strange failure that I did not have the presence of mind to measure the clearance prior to taking it apart. With a hydro engine..... only thing I can figure is the lifter was bottomed out in it's travel or there was a serious lean condition. GD Quote Link to comment Share on other sites More sharing options...
Crazyeights Posted January 9, 2011 Share Posted January 9, 2011 Like dirty injectors perhaps? I just finished having the heads done on a '93 Leg Hydro EJ22 with about 140k on it and 5 of the 8 exhaust valves were burnt like those in your pictures. Yes, I know it's an old thread - sorry;) Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 10, 2011 Author Share Posted January 10, 2011 Lean injectors would definitely do it - it just seems to not be very common on Subaru injectors. I wouldn't discount the possibility - especially on a hydro engine. You *sure* they were burnt as badly as in the picture? That one valve reduced the compression to 60 on that cylinder. More valves burnt that badly..... I doubt it would run. I have never seen that level of damage on an EJ22 with only 140k (let alone a hydro engine). Usually they look pristene inside. I just dropped one into a GT with 144k and it's spectacular..... GD Quote Link to comment Share on other sites More sharing options...
Crazyeights Posted January 10, 2011 Share Posted January 10, 2011 Not all 5 were THAT bad, but bad enough that they couldn't be ground and had to be replaced. It would have run like it was just not well for very long. I'm still working on it and was thinking of having the injectors checked and cleaned before it goes back in after finding and watching this thread. Once again GD THANKS for the info. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 10, 2011 Author Share Posted January 10, 2011 No problem. The red-top EJ22E injectors are quite cheap. I wouldn't have them cleaned I would just replace them. I think they are about $45 each. I guess that's quite a bit but what is the cost of cleaning? GD Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted January 10, 2011 Share Posted January 10, 2011 I would have to wonder about the knock sensor, and O2 sensor on that engine as well. To melt that many valves, sounds like an engine-control issue. How often do multiple fuel injectors "fail" simultaneously? Quote Link to comment Share on other sites More sharing options...
naru Posted January 10, 2011 Share Posted January 10, 2011 IMO,cleaning the injectors is a good idea. Easy enough for them to "fail" simultaneously" if a load of crud gets past the fuel filter.Or,gum up from sitting. O2 sensor failure almost never leads to lean running. I would check fuel pressure. Exhaust valves wear more because they run much hotter. Quote Link to comment Share on other sites More sharing options...
Ross Posted January 17, 2011 Share Posted January 17, 2011 Same basic deal with the brake booster. It takes air from the intake runner but since the injector is down right next to the head the amount of *fuel* doesn't change. This would cause a rich condition not a lean one. The intake takes air FROM the brake boster, not the other way around. A leaking brake booster would result in a lean burn by letting unmetered air into the system. However, I'm not convinced a brake booster leak would affect clyinder four in isolation anyway, since the plenum/runner assembly is all open.... Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted March 1, 2011 Share Posted March 1, 2011 95 Ej22 at 178k. The grey stuff is valve grind compound. But you can see the important part. Now what I've read about burned valves, it would seem that cheap/bad gas would cause this. But the car was being driven up the long side of a steep mountain road, by a college student, when it "happened". Thoughts? Quote Link to comment Share on other sites More sharing options...
ShawnW Posted March 1, 2011 Share Posted March 1, 2011 Are you saying the lapping compound was left on the valve and not wiped off by the technician that did the valve job? That would certainly let the heat not disburse wouldn't it? Quote Link to comment Share on other sites More sharing options...
Twitch de la Brat Posted March 1, 2011 Share Posted March 1, 2011 No problem. The red-top EJ22E injectors are quite cheap. I wouldn't have them cleaned I would just replace them. I think they are about $45 each. I guess that's quite a bit but what is the cost of cleaning? GD I have a guy who will do a full rebuild on just about any injector for about $20. I don't remember his name right now, but when I do I'll get you his name. He does injectors for people all over and is located in Coeur d'Alene Idaho. Twitch Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted March 2, 2011 Share Posted March 2, 2011 Are you saying the lapping compound was left on the valve and not wiped off by the technician that did the valve job? That would certainly let the heat not disburse wouldn't it? The compound was left from where I used the old valve to clean up the seat before lapping the new valve. All compound was removed and surfaces throughly cleaned before reassembly. Quote Link to comment Share on other sites More sharing options...
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