thedoctor Posted April 23, 2012 Share Posted April 23, 2012 I just got my heads back from the machine shop and I welded shut the air pipe stubs. That eliminates a whole bunch of tubing up top, which is great. I understand I have to plug some holes to prevent unfiltered air from entering the carb. Is the EGR valve necessary? If not, do I plug the port in the right cylinder head? If the EGR valve can go, what else can also go? Now is the time. Thanks Quote Link to comment Share on other sites More sharing options...
desertsubaru Posted April 23, 2012 Share Posted April 23, 2012 (edited) Your going to get a lot of different opinions on this. Some will say yes you can plug it others will say its necessary dont plug it . I personally have done it a few times with no ill effects. Edited April 23, 2012 by desertsubaru Quote Link to comment Share on other sites More sharing options...
thedoctor Posted April 23, 2012 Author Share Posted April 23, 2012 Do you mean just let it open to the air? What does it connect to inside the head? Is it the space where the push rods are located? What keeps oil from coming out of this port? Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted April 23, 2012 Share Posted April 23, 2012 You will likely need it to pass emissions. It doesn't harm anything. I would leave it. GD Quote Link to comment Share on other sites More sharing options...
Gloyale Posted April 23, 2012 Share Posted April 23, 2012 Do you mean just let it open to the air? What does it connect to inside the head? Is it the space where the push rods are located? What keeps oil from coming out of this port? EGR = Exhaust Gas Recirculation sooooo....just take a guess.......what could that port be open to???? The exhaust! You don't know what it does, or why it's there....why do you want to get rid of it??? just hook it back up.....it's there to cool cylinder temps under load. Quote Link to comment Share on other sites More sharing options...
desertsubaru Posted April 23, 2012 Share Posted April 23, 2012 I keep forgetting about emissions. If you need to pass them you need it. I have went to a plumbing store though and got a plumbing plug that fits the threads in the head. Quote Link to comment Share on other sites More sharing options...
thedoctor Posted April 23, 2012 Author Share Posted April 23, 2012 You know, a lesser man would be insulted by that tone. Let's just say, this is how I learn. I'm not "afraid to ask questions". I know the veterans "don't bite". But I told you why I am asking. Are you saying nobody disconnects these things like the Air Tubes? Oh. Well those... just cut them off and throw them away. I am asking because the bloody engine is out of the car and now is the time to learn all about what can or should be cut off and thrown away. But thank you to the gentleman who brought up emissions testing. In PA for a 1983 vehicle, emissions testing means a visual inspection and a gas cap pressure test. And guess what has to appear to be there? The Exhaust Gas Recirculation valve! As well as the PCV valve. Hmmm I wonder what that is connected to? Quote Link to comment Share on other sites More sharing options...
nipper Posted April 23, 2012 Share Posted April 23, 2012 EGR should be left alone. This is much different from the 1970's where they robbed some power. It also helps prevent ping. Air tubes (smog pumps?) were basically not needed if you put on a modern cat. Even the air injector which didnt do anything for power (just a reed operated air pump) was only there for the old two stage (two part) cats. Quote Link to comment Share on other sites More sharing options...
desertsubaru Posted April 23, 2012 Share Posted April 23, 2012 EGR = Exhaust Gas Recirculation it's there to cool cylinder temps under load. Then why is it only on one head? Quote Link to comment Share on other sites More sharing options...
skingry Posted April 23, 2012 Share Posted April 23, 2012 It pipes exhaust back into the manifold via a vacuum operated valve (a little goes to each cylinder when the valve is open). Lowering the combustion temps keeps your NOx emissions in check. Quote Link to comment Share on other sites More sharing options...
desertsubaru Posted April 23, 2012 Share Posted April 23, 2012 It pipes exhaust back into the manifold via a vacuum operated valve (a little goes to each cylinder when the valve is open). Lowering the combustion temps keeps your NOx emissions in check. How does putting hot exhaust gasses back into the intake lower combustion temps. Also why did Subaru do away with it in newer models. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted April 23, 2012 Share Posted April 23, 2012 How does putting hot exhaust gasses back into the intake lower combustion temps. Also why did Subaru do away with it in newer models. The exhaust gasses are hot, but not nearly as hot as combustion itself once they have recirculated. The key is that exhaust gasses are INERT. That is they have no combustable components anymore. They are recirculated under part-throttle cruise to displace fuel/air and lower NOx emissions. It does NOT rob power, and it is not a source of component failure generally speaking. It takes exactly one vacuum hose to late ported vacuum to run it. There's no benefit to removing it at all. Since when did they do away with it? I've personally swapped engines on as late as 2006 and in fact it's just the opposite - they ALL have EGR's now - used to be some manual transmission EJ's didn't have them. Now they all do. GD Quote Link to comment Share on other sites More sharing options...
ferox Posted April 23, 2012 Share Posted April 23, 2012 One thing you might do while you have the heads off is clean the egr tube, the metal one that goes from the head to the intake, and clean the egr valve itself. They can get carboned up pretty thick sometimes. Quote Link to comment Share on other sites More sharing options...
naru Posted April 23, 2012 Share Posted April 23, 2012 (edited) How does putting hot exhaust gasses back into the intake lower combustion temps. Also why did Subaru do away with it in newer models. It lowers cruising speed combustion temps because the exhaust gas is made up of a large percentage of water. Water has a higher "specific heat" than most other things. That means it absorbs more heat than most other things before the temp goes up. Removing the EGR w/o modifying the ignition curve will adversely affect ignition timing. EGR also decreases engine pumping losses. Subaru did not do away w/it on newer models. Some models have "internal EGR" that does the same thing w/valve timing and head design(no egr valve). Edited April 23, 2012 by naru + cruising speed Quote Link to comment Share on other sites More sharing options...
thedoctor Posted April 23, 2012 Author Share Posted April 23, 2012 Thanks everyone. Quote Link to comment Share on other sites More sharing options...
man on the moon Posted April 23, 2012 Share Posted April 23, 2012 Even if you get rid of the EGR (which I would keep, personally), you will need the PCV valve! Don't get rid of that one. Things I've dumped over time are the a/c lines (left the compressor in, just dumped it about half-full of motor oil and sealed the oil ports), the electric fan (died and I haven't replaced it, just trashed it), and...hmm. Timing belt covers. I think that's about it for the motor. Quote Link to comment Share on other sites More sharing options...
desertsubaru Posted April 23, 2012 Share Posted April 23, 2012 One thing you might do while you have the heads off is clean the egr tube, the metal one that goes from the head to the intake, and clean the egr valve itself. They can get carboned up pretty thick sometimes.If the tube and valve get carboned up then what about valve seats and stems? That cant be good. Quote Link to comment Share on other sites More sharing options...
ferox Posted April 23, 2012 Share Posted April 23, 2012 If the tube and valve get carboned up then what about valve seats and stems? That cant be good. Yeah, when I recently did the HGs on my '81 the valves were insanely chunked up. I was surprised it ran, let alone ran well. I changed out the intake valve seals, which will help, but the exhaust valves don't have seals. Unless you get new valve guides and valves, I think it's inevitable that there will be some excess carbon build-up over time. Quote Link to comment Share on other sites More sharing options...
Loyale 2.7 Turbo Posted April 23, 2012 Share Posted April 23, 2012 To Discuss about The EGR Stuff in the EA82 Engines is like Open a Can of Worms; but I've an Answer: The EA82 Engines had Three Different Designs on Heads, they're Pictured here: http://www.ultimatesubaru.org/forum/showpost.php?p=1078817&postcount=1204 The Third Gen Heads Doesn't have the EGR opening on it, it's Sealed... so Subaru got Rid of it in that particular Engine, I Wonder if it really isn't very Healthy on that EA82 Design. So, my BumbleBeast, which have Third gen Heads, doesn't have EGR and works Awesome; but the PCV is REALLY Needed. Kind Regards. Quote Link to comment Share on other sites More sharing options...
thedoctor Posted April 24, 2012 Author Share Posted April 24, 2012 Just to follow-up. I just found the thread that gave me the crazy idea to ask the question about blocking off the EGR. http://www.ultimatesubaru.org/forum/showthread.php?t=130635&highlight=transmission Title: What's your gas mileage with what mods? Mugs, Colin823, BratWarrior, and hanyou all got rid of at least the EGR and a couple got rid of all "emissions junk" Quote Link to comment Share on other sites More sharing options...
desertsubaru Posted April 24, 2012 Share Posted April 24, 2012 My set up is 85 2wd wagon 3AT. weber 32/36 no emissions, plugged egr, timing at 12 BTDC. Runs great with no pings or dieseling on shut down. I get about 25 MPG highway and 22 city. The 3ATs are known gas drinkers. Quote Link to comment Share on other sites More sharing options...
Quidam Posted April 24, 2012 Share Posted April 24, 2012 Here's an EGR story... An LS1 Chevy with AFM (active fuel management) and VVT (the variable valve timing) has internal EGR regulated by the overlap built into the camshaft. I've got two EGRs blocked, one functional on EAs. Doug Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.