bgd73 Posted November 6, 2006 Share Posted November 6, 2006 1987 GL.One head older asv, the other quite spfi, complete with egr valve (a different looking egr valve, but same size and spot) on passenger side. The drivers side head has the asv, and hla's that won't quit making herendous noise. I am going to change the oil pump to see if it helps, as zero at an idle is not a friendly site on the guage.The pressure does hit into the 80's and above 45 they are almost quiet- that is why I may be scrapping the whole asv head and cam casing. For very cheap I could have my spfi head/cam casing from a 93 to match the heads up with new hlas to the 87. Can I get away with leaving the heads mismatched? I red some interesting info about the 9.5:1 pistons and the 9.0:1 pistons being the same- subaru gained compression by the heads chamber size.If so , I really have a bad mismatch. This contradicts what I have learned here at usmb... what is the facts about the 9 and 9.5? is it the heads or pistons that changed. This could hasten my decision to get out the wrenches in the cold if need be. I do not want to give this one up just yet- it still runs great, even looks good for 20 years. Link to comment Share on other sites More sharing options...
beataru Posted November 6, 2006 Share Posted November 6, 2006 I thought... could be wrong... that the pistons are what make higher compression... Thats just from my limited research.... kinda cool? how many owners has the roo had? Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 6, 2006 Share Posted November 6, 2006 I've told you this before - non-feedback carbed EA82's have a single ASV on the drivers side head, and nothing on the passenger side. That's stock. Heads are all the same casting regardless of SPFI, carb, or even right and left. There is ONE casting used for all, and the needed ports are drilled out at the factory. Some carbs came with 2 ASV's, and some with only 1. Depends on if it needed to meet California emissions or not. Pistons make the compression - 9:1 in carb land, and 9.5:1 in SPFI land. Heads are all the same. Only difference on the SPFI are pistons, valve springs, and cam. GD Link to comment Share on other sites More sharing options...
bgd73 Posted November 6, 2006 Author Share Posted November 6, 2006 I've told you this before - non-feedback carbed EA82's have a single ASV on the drivers side head, and nothing on the passenger side. That's stock. Heads are all the same casting regardless of SPFI, carb, or even right and left. There is ONE casting used for all, and the needed ports are drilled out at the factory. Some carbs came with 2 ASV's, and some with only 1. Depends on if it needed to meet California emissions or not. Pistons make the compression - 9:1 in carb land, and 9.5:1 in SPFI land. Heads are all the same. Only difference on the SPFI are pistons, valve springs, and cam. GD I am going on a thousand posts in about a year- alot to forget, not to mention the repeats I shrug off continuously . If my memory were as strong as my subarus, the decade I will be going on with the ea82 would be a silent breeze The cyl head with asv drops down lower than the spfi one. The y-pipe is even lower on one side than the other.To say they are physically different requiring a different cast entirely is SAFE TO SAY. I just started it cold and no noise. the new oil is taking its sweet time on the bad pump seals. At 85psi it does good. The relief spring in pump must be the nuisance. If seals were good I would just attack that problem quickly.Since they are not, The gaskets coming through the mail are going in my 93 oil pump, and will see what happens with this setup of two obviously different heads. The info I found was for an aviation guru with an ea82. Claimed the heads changed for spfi (obviously physically from the outside) but he was referring to the chamber size.The post also found, related .040 head shaving == .5 up to further compression. Of course that is a direct impact on compression.I could easily check it out with a cc measured vile and valves seated to see how much fluid both take to the level of the deck on my spfi and the asv once out of car.I would believe it to be likely that they be different by more than asv ports. My 87 DL, as we had chatted about did indeed have 2 asv heads. The current 87 is a cross between spfi and the asv- and it has the egr valve like the spfi, unlike my old 87. Did I get an overlapping strangeness from manufacture? spfi and carbs existed simultaneously during that timeframe... Either way, you notes about the chambers being the same will allow me to try just the oil pump resealed first. Thanks for replies and reminding me.. of a conversation I forgot I had already.This also may be a good time for the cam seals- said to be another source of aerating, but far less likely than the pump.I will measure the chambers sometime, if someone hasn't already... Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 7, 2006 Share Posted November 7, 2006 The castings should be identical - the lower y-pipe on one side could be due to a bolt-on spacer under the head. Some EA81's had a similar setup where the y-pipe was shorter on one side. EA81's also had the same situation where some engines had a single ASV, and some had one on each head. I've owned both types on both engines. I've had plenty of these engines apart, including an 87 with a single ASV just like yours, and in all cases the head castings were identical. Lots of engines had the EGR without the anti-afterburn tube. That's also common as some vehicle were not equipped with the same decel system to releive engine vacuum under closed throttle coasting. Cam tower seals should definately be checked. Being an 87 carb it's very possible is has only the rubber o-rings instead of the rubber/metal rings that prevent them from collapsing. Good chance to clean the lifters, and reseal the cam tower and rocker cover anyway. GD Link to comment Share on other sites More sharing options...
bgd73 Posted November 7, 2006 Author Share Posted November 7, 2006 The castings should be identical - the lower y-pipe on one side could be due to a bolt-on spacer under the head. Some EA81's had a similar setup where the y-pipe was shorter on one side. EA81's also had the same situation where some engines had a single ASV, and some had one on each head. I've owned both types on both engines. I've had plenty of these engines apart, including an 87 with a single ASV just like yours, and in all cases the head castings were identical. Lots of engines had the EGR without the anti-afterburn tube. That's also common as some vehicle were not equipped with the same decel system to releive engine vacuum under closed throttle coasting. Cam tower seals should definately be checked. Being an 87 carb it's very possible is has only the rubber o-rings instead of the rubber/metal rings that prevent them from collapsing. Good chance to clean the lifters, and reseal the cam tower and rocker cover anyway. GD I will be under there maybe as soon as tomorrow, will take a pic. It is a droopy fathead all one piece, no spacer- like my other 87, that had two of this head and y-pipe troubles every single year, for the 8 that I had it.The y sat unusually low, (as if they weren't low already) 1/2 inch studs was the finale and ya know what? It still needed a yearly gasket.This one doesn't seem to want to boot the y-pipe off anymore, as there is two large head bolts (3/4+/-) from somebody's frustration already in it. I can't wait to scrap it. cam tower seals is a must do for the cost and time to get to them, even if they seem good. Thanks for notes on changes of the seal.That very well could be part of the aeration prob. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 7, 2006 Share Posted November 7, 2006 I will be under there maybe as soon as tomorrow, will take a pic. It is a droopy fathead all one piece, no spacer- like my other 87 The flange surface where the y-pipe mounts is a machined surface, and depending on application could be milled shorter if needed. So it may be a difference in the post-casting milling process used - just as the passenger side EGR port is not drilled out. But if you look at the heads side-by-side you will see that the casting is the same for both. They are milled, drilled, and tapped differently depending on left or right side application, but the overall casting will be the same. Makes the engines cheaper to produce. GD Link to comment Share on other sites More sharing options...
bgd73 Posted November 7, 2006 Author Share Posted November 7, 2006 The flange surface where the y-pipe mounts is a machined surface, and depending on application could be milled shorter if needed. So it may be a difference in the post-casting milling process used - just as the passenger side EGR port is not drilled out. But if you look at the heads side-by-side you will see that the casting is the same for both. They are milled, drilled, and tapped differently depending on left or right side application, but the overall casting will be the same. Makes the engines cheaper to produce. GD I should be able to just go with the gaskets then counting on the internals being essentially the same.I am immediately taking this car on 80 mile round trips, it got me thinking. I only have one other to compare to, this one is quite stubborn. no serious leaks etc, good oil, and again, the noise stops at 80+psi of oil and hangs on into the 40's. My old one got loud with no exhaust muffler, this recent 87 is running on a glasspack and straight pipe. It is not helping the situation any, but it is cleaning some old gas out . Thanks for info, I will try to make it work pretty much the way it is with new seals and different oil pump. Link to comment Share on other sites More sharing options...
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