redskin Posted July 27, 2007 Share Posted July 27, 2007 l have had a spare EA-81T motor laying around the shed for near a couple of years now and recently decided, better do something with it so l have stripped it down for rebuilding, (this was uneventful), and would like a little help with some answers please. My questions are, 1. After pulling the heads and looking in the Exhaust ports l see what looks like tin heatshields inside the exhaust port, l can't remember my other motor having these, it's obvious why they are there but is it normal and as l planned to port the heads, are these easy to remove and should l. 2. Without going crazy, can anybody recommend a suitable grind for the Camshaft. l want to extract more power and still drive it every day. 3. l believe it is possible to have hydraulic lifters rebuilt quite inexpensively in the states, is this correct and any recommendations. 4. What Turbocharger would suit my needs as l plan to make a custom crosspipe and will make the flange to suit. This will do for now. Thanks in advance. Link to comment Share on other sites More sharing options...
Ross Posted July 29, 2007 Share Posted July 29, 2007 1. After pulling the heads and looking in the Exhaust ports l see what looks like tin heatshields inside the exhaust port, l can't remember my other motor having these, it's obvious why they are there but is it normal and as l planned to port the heads, are these easy to remove and should l. Could you post a pic of this? Not quite sure what you mean, but I don't remember anything like this on either of the sets of ea81t heads i have... Regarding the porting, an important area is the join between the manifold and heads - there is a large difference in size between them, and the hole in the gasket is far too small. This was the only area I modified on mine. Link to comment Share on other sites More sharing options...
Hodaka Rider Posted July 29, 2007 Share Posted July 29, 2007 1) Not sure?? 2) Probably stay stock, if it's still in good shape. 3) Not sure. But I've seen new ones cheap on ebay. 4) Use a WRX unit, and mount an intercooler (maybe air-water from Legacy). Keep boost under 10 and it should be exciting without undue risk to the engine. Link to comment Share on other sites More sharing options...
baccaruda Posted July 29, 2007 Share Posted July 29, 2007 My EA81T coupe has an EA82T turbo (same boost but watercoolable) with a WRX downpipe and 2.5" nonmufflered exhaust and it's really smooth. I could have sourced a bigger turbo but I am not keeping this car as a permanent project, and parts are hard enough to find for EA81Ts that I didn't want to steepen the maintenance curve.... the open exhaust is really nice, though, it feels like a whole different car even with the craptacular 3speed auto. I of course have the airbox chopped out too I personally would improve the exhaust (as I've done) and then install a 5-speed in place of the slushomatic, and then work on the rear brakes and add a rear sway bar before I'd worry about putting in a bigger turbo.. but that's me Link to comment Share on other sites More sharing options...
redskin Posted July 29, 2007 Author Share Posted July 29, 2007 Could you post a pic of this? Not quite sure what you mean, but I don't remember anything like this on either of the sets of ea81t heads i have... Regarding the porting, an important area is the join between the manifold and heads - there is a large difference in size between them, and the hole in the gasket is far too small. This was the only area I modified on mine. Yes l can Ross, l'm positive my running engine does not have these either, l got a bit of a surprise when l looked into the ports but l assume without removal of the valves yet these heatshields are probably held in by the guides, will drop a valve tomorrow, check and post a photo. Thanks for the suggestion on the inlet ports, l followed your rebuild recently, did you stay with the stock cam? Link to comment Share on other sites More sharing options...
redskin Posted July 29, 2007 Author Share Posted July 29, 2007 My EA81T coupe has an EA82T turbo (same boost but watercoolable) with a WRX downpipe and 2.5" nonmufflered exhaust and it's really smooth. I could have sourced a bigger turbo but I am not keeping this car as a permanent project, and parts are hard enough to find for EA81Ts that I didn't want to steepen the maintenance curve.... the open exhaust is really nice, though, it feels like a whole different car even with the craptacular 3speed auto. I of course have the airbox chopped out too I personally would improve the exhaust (as I've done) and then install a 5-speed in place of the slushomatic, and then work on the rear brakes and add a rear sway bar before I'd worry about putting in a bigger turbo.. but that's me Thanks, to clarify, the current setup already includes, waic, open exhaust, 2.5" dump through to 3" muffler behind the wheels, EA-82T turbocharger, no airbox, 3" pipe to turbo filter, the new set up includes a 5 speed RX box l have in the shed. Adjustable camber rods, EA-82 control arms and stabiliser, rear brakes are discs. Link to comment Share on other sites More sharing options...
86BRATMAN Posted July 29, 2007 Share Posted July 29, 2007 I just looked at your gallery again. Are you not running a maf? What kind of management do you have? Link to comment Share on other sites More sharing options...
carfreak85 Posted July 29, 2007 Share Posted July 29, 2007 I have not disassembled my EA81T but when I installed my header, I did not notice any tins in the exhaust ports. However, when tearing down a 1600 recently I did noticed tins in it's ports. Not sure why your's has them, but they must be origianl. How many miles on your engine? From your decription of your car, it sounds like you are well on your way to having an awesome Gen 2 turbo. Link to comment Share on other sites More sharing options...
redskin Posted July 30, 2007 Author Share Posted July 30, 2007 I just looked at your gallery again. Are you not running a maf? What kind of management do you have? Your right, l am using a Link ECU cause when l built this car l couldn;t find or justify fitting a s/h 20 year old unit. Link to comment Share on other sites More sharing options...
baccaruda Posted July 30, 2007 Share Posted July 30, 2007 Sounds like you've got it under control Thanks,to clarify, the current setup already includes, waic, open exhaust, 2.5" dump through to 3" muffler behind the wheels, EA-82T turbocharger, no airbox, 3" pipe to turbo filter, the new set up includes a 5 speed RX box l have in the shed. Adjustable camber rods, EA-82 control arms and stabiliser, rear brakes are discs. Link to comment Share on other sites More sharing options...
redskin Posted July 30, 2007 Author Share Posted July 30, 2007 Popped the Exhaust valves and as l thought, trapped by the valve guides although once these are out the shells should fall out. each port has 2 shells split thruogh the centre, 4 in all. What does differ from standard is the 2 little pieces of extra casting around the exhaust port to space the tin away from the port wall, ( effective heat shields), these will be removed if the tin goes when l port them. Link to comment Share on other sites More sharing options...
daeron Posted July 30, 2007 Share Posted July 30, 2007 The final generation of heads that were manufactured for the late model Nissan 280ZXs in 1981-83 had steel liners cast into the exhaust ports that look just like those. This was the last generation of L-series six cylinder motors, there were about ten different head permutations from 69-83. I could dig up pictures if you want, or you could take me at my word. Some people go to the effort to remove them; but it is apparently more difficult than simply dropping the valves on those heads. Most don't think twice about simply leaving them alone. They are designed to get red hot and ignite any unburnt fuel in the exhaust gasses; it is an emissions-type thing, although I have never (in my minimal experience) heard of it on a subaru head. Flow testing, actual dyno charts, and butt dyno experiences seem to say that having these liners in the ports is no detriment to flow characteristics (ie, performance) whatsoever. I cannot say that the same thing must be true for the subaru heads.. but how much area are they really taking up in the footprint of the port? Just a thin line is all. If it is any more difficult than you anticipate to remove them, I wouldn't sweat leaving them in there. If it is easy to yank them, then go ahead, I guess.. I probably would, too. Link to comment Share on other sites More sharing options...
redskin Posted July 30, 2007 Author Share Posted July 30, 2007 The final generation of heads that were manufactured for the late model Nissan 280ZXs in 1981-83 had steel liners cast into the exhaust ports that look just like those. This was the last generation of L-series six cylinder motors, there were about ten different head permutations from 69-83. I could dig up pictures if you want, or you could take me at my word. Some people go to the effort to remove them; but it is apparently more difficult than simply dropping the valves on those heads. Most don't think twice about simply leaving them alone. They are designed to get red hot and ignite any unburnt fuel in the exhaust gasses; it is an emissions-type thing, although I have never (in my minimal experience) heard of it on a subaru head. Flow testing, actual dyno charts, and butt dyno experiences seem to say that having these liners in the ports is no detriment to flow characteristics (ie, performance) whatsoever. Thanks for the info and on closer inspection, with my glasses on, , l see that the shells are welded along the seams of this shielding so your right, dropping the guides is only one bit of removal, best left alone l think as trying to get them out could turn out to be a nightmare. Link to comment Share on other sites More sharing options...
daeron Posted July 30, 2007 Share Posted July 30, 2007 Thanks for the info and on closer inspection, with my glasses on, , l see that the shells are welded along the seams of this shielding so your right, dropping the guides is only one bit of removal, best left alone l think as trying to get them out could turn out to be a nightmare. No problem. That sucks, kinda.. but at least it probably won't have a negative impact; and it might even actually make it burn cleaner, who knows? However, something tells me that if exhaust liners like this were truly that effective, they would be much more common than they are Link to comment Share on other sites More sharing options...
joostvdw Posted July 30, 2007 Share Posted July 30, 2007 if the exhaust liners are meant to be red hot during operation, and you are planning on running more than standard boost (and thus more heat in the exhaust) wouldn't you run the risk of those liners falling apart? I mean, they are getting a lot hotter then they are meant to get. (is this proper english? it seems strange but I don't know why?) Link to comment Share on other sites More sharing options...
86BRATMAN Posted July 30, 2007 Share Posted July 30, 2007 if the exhaust liners are meant to be red hot during operation, and you are planning on running more than standard boost (and thus more heat in the exhaust) wouldn't you run the risk of those liners falling apart? I mean, they are getting a lot hotter then they are meant to get. (is this proper english? it seems strange but I don't know why?) Makes sence to me. In theory, higher boost levels making more heat in the engine, causing the metal to melt. Falling out and getting blown into the turbo. Right? Link to comment Share on other sites More sharing options...
carfreak85 Posted July 30, 2007 Share Posted July 30, 2007 I don't like the idea of any loose metal upstream of my turbocharger. If you are planning on turning up the wick, I would do everything possible to remove those, just to be on the safe side. Link to comment Share on other sites More sharing options...
redskin Posted July 30, 2007 Author Share Posted July 30, 2007 if the exhaust liners are meant to be red hot during operation, and you are planning on running more than standard boost (and thus more heat in the exhaust) wouldn't you run the risk of those liners falling apart? I mean, they are getting a lot hotter then they are meant to get. (is this proper english? it seems strange but I don't know why?) l doubt this would happen as they are quite thick but l s'pose anythings possible. l hadn't planned on going over 10lb of boost, standard is about 7lb, with the EA-82 unit about 9lb. l have often read on this forum if you want the motor to stay together it's not a good idea to go over 10lb on these motors so l'm happy with that, the performance increases l'm looking for will mostly come from the Cam, & heads. Link to comment Share on other sites More sharing options...
86BRATMAN Posted July 30, 2007 Share Posted July 30, 2007 While most people say this about 10 psi. Has anyone ever done it? Most of the people who have them, keep them relatively stock because of the lack of replacement parts. Link to comment Share on other sites More sharing options...
joostvdw Posted July 30, 2007 Share Posted July 30, 2007 l doubt this would happen as they are quite thick but l s'pose anythings possible. l hadn't planned on going over 10lb of boost, standard is about 7lb, with the EA-82 unit about 9lb. l have often read on this forum if you want the motor to stay together it's not a good idea to go over 10lb on these motors so l'm happy with that, the performance increases l'm looking for will mostly come from the Cam, & heads. the stock uppipe on my EA82T has marks of molten metal blobs closest to the exhaust port, and it's all stock! (except the 2,5 TBE) my brothers peugeot 205 (non turbo) has in the "downpipe" as you may call it, a small divider for the cat, that is molten too so it doesn't take that much heat for metal to melt in your exhaust, I would be very carefull with those liners and I would remove them just to be on the safe side (you know, metal liner debris in exhaust, destroys turbo, metal turbo debris in intake, destroy freshly rebuild engine...) Link to comment Share on other sites More sharing options...
daeron Posted July 30, 2007 Share Posted July 30, 2007 joost; i think it just sounds funny because of repeated vowel sounds People turbocharge Z cars with the P79 heads all the time and never have any problem. These engines actually have head studs, and good gaskets, so these guys will run upwards of 20 psi... I cannot 100% confirm that anyone has run a p79 head, turbo'd, at high boost pressure.. but these liners are normally in there solid. You arent increasing the temperature of the exhuast port that much in running high boost, you increase the temperature of intake charge; in any case, there normally isnt a great deal of metal to metal contact to transfer cylinder head heat to these liners. Link to comment Share on other sites More sharing options...
joostvdw Posted July 30, 2007 Share Posted July 30, 2007 joost; i think it just sounds funny because of repeated vowel sounds People turbocharge Z cars with the P79 heads all the time and never have any problem. These engines actually have head studs, and good gaskets, so these guys will run upwards of 20 psi... I cannot 100% confirm that anyone has run a p79 head, turbo'd, at high boost pressure.. but these liners are normally in there solid. You arent increasing the temperature of the exhuast port that much in running high boost, you increase the temperature of intake charge; in any case, there normally isnt a great deal of metal to metal contact to transfer cylinder head heat to these liners. you say you increase the intake charge temp, but the exhaust gasses don't get hotter? how come? where did the heat go? the turbo on my XT gets red hot on the exhaust side after some flogging, and that's after MILES of exhaust (wel, not exactly, but you get my point) so I'm betting that liner is equally hot if not hotter. also, there doesn't have to be metal to metal contact for the liner to heat up, exhaust gasses will do the trick just fine. as a final note, I don't mean to be harsh or anything but your experiences with datsun engines, means squat on subaru's, especially since virtually nobody here has ever seen these liners in subaru's before so nobody knows how they behave. my advice, rip em out! Link to comment Share on other sites More sharing options...
redskin Posted July 31, 2007 Author Share Posted July 31, 2007 ok, after some thought given to your replies on these liners, (thanks guy's), l have decided to use the other set of heads l have as l did mention, the liners will be a nightmare to remove, to start with the seams are welded and will be very difficult to crack, secondly, the valve seats appear to splay out over the edge of the tins to trap them in position, third, extra casting around bottom of port for spacing the tin from the walls may also continue within the port to keep the tin spaced evenly throughout it, only removal of the tin will tell you this, forth, l would need to replace guides, (nothing wrong with them), With all this in mind, why would you bother, l have a good set running now l can use and again as mentioned, it's a very big job. Link to comment Share on other sites More sharing options...
daeron Posted July 31, 2007 Share Posted July 31, 2007 you say you increase the intake charge temp, but the exhaust gasses don't get hotter? how come? where did the heat go? the turbo on my XT gets red hot on the exhaust side after some flogging, and that's after MILES of exhaust (wel, not exactly, but you get my point) so I'm betting that liner is equally hot if not hotter. also, there doesn't have to be metal to metal contact for the liner to heat up, exhaust gasses will do the trick just fine. as a final note, I don't mean to be harsh or anything but your experiences with datsun engines, means squat on subaru's, especially since virtually nobody here has ever seen these liners in subaru's before so nobody knows how they behave. my advice, rip em out! Okay, I brain farted on the heat equation, duh. I was simply relaying common experience in another vehicular world of the same domestic origin and similar era. Also, typically manufacturers dont insert liners like this without making sure they stay in kinda solid. Link to comment Share on other sites More sharing options...
joostvdw Posted July 31, 2007 Share Posted July 31, 2007 Okay, I brain farted on the heat equation, duh. I was simply relaying common experience in another vehicular world of the same domestic origin and similar era. Also, typically manufacturers dont insert liners like this without making sure they stay in kinda solid. yes, that's also very true, but as we all know now, he has a another set of heads laying around, so problem solved :-p Link to comment Share on other sites More sharing options...
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