Phizinza Posted January 26, 2007 Share Posted January 26, 2007 Bit of a long shot, but. Does anyone know the clearance in between the piston and the valve on a normally running EA81? As in when the piston is coming out pushing out the exhaust how close does it get to the open exhaust valve? Or does anyone know how to figure this out? I'm not that great with math... My idea is to have seperate manifolds for two carbs ontop of each head and to gain compression get the block shaved. This is a cheap and safe way to play with my dual carb heads and try and get cheap power out of an EA81. I relise that I might bend a rod and a valve, but you can always get replacment valves and rods. The point of this... Is to have fun playing with my EA81. Link to comment Share on other sites More sharing options...
[HTi]Savage Posted January 26, 2007 Share Posted January 26, 2007 Are u trying to get higher compression. If so than u could run EA71 pistons. keep in mind this will change it from a 1.8 to 1.6. But high comp. as far as the valve clearance, It might say in a shop manuel if u have one. Ill look in mine when I get a chance. Dont know about shaving the block though. I probably wont give that much more comp. its gonna be a pretty small amount. Lawrence. Link to comment Share on other sites More sharing options...
Phizinza Posted January 26, 2007 Author Share Posted January 26, 2007 Why would it be only a small amount? I'm not planning on having the original manifold, and isn't that the only thing stopping us shaving the heads or blocks on these engines? Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 26, 2007 Share Posted January 26, 2007 Savage']Are u trying to get higher compression. If so than u could run EA71 pistons. keep in mind this will change it from a 1.8 to 1.6. But high comp. Lawrence. Um..... NO! EA71 pistons aren't going to change much at all..... I guess I would know since I'm about the only person around here that's actually measured the difference. The difference is about .25:1 compression increase - and that's being generous. Displacement isn't going to change appreciably - still be close to 1.8. Even stock, the EA81 is really 1.781L anyway. Probably be real close to 1750cc with the EA71 pistons. Frankly they aren't worth using IMO as they have thinner ring lands. EA82 SPFI pistons are what you want my friend - they have cut-outs for the valves , unlike the flat top EA71/81 pistons. With those, you wouldn't have to shave the heads at all, and you would be at 9.5:1. With shaved heads - closer to 9.75:1 or higher. GD Link to comment Share on other sites More sharing options...
Phizinza Posted January 26, 2007 Author Share Posted January 26, 2007 I don't want to shave the heads. I want to shave the block. I already have the dual carb model which I think should have 9.5:1 pistons (I don't know for sure because the block is not the original.) I can't see anything getting in the way of shaving the block execpt for piston to valve clearance, hense the question above. I'm not looking for more power for a car. I simply just want to play with this engine to see what I can do with it. 100hp is boring.. I want to see more out of this engine. I guess I'll have to go out and measure things roughly and take a pot guess at it all. Any idea how far the cam pushes the valves down? That should be in the manual. I'll have a look Link to comment Share on other sites More sharing options...
[HTi]Johnson Posted January 26, 2007 Share Posted January 26, 2007 If you are using a stock dual carb manifold, you will have to watch out for the intake bolts. They will be offset. But since your using a custom intake you shouldn't have a problem. Sorry, I guess this reply was pointless. I guess you can find out how much people have shaved off the heads, go with the most and do that to your block. Link to comment Share on other sites More sharing options...
Reveeen Posted January 26, 2007 Share Posted January 26, 2007 I guess I'll have to go out and measure things roughly and take a pot guess at it all. Any idea how far the cam pushes the valves down? That should be in the manual. I'll have a look The way I always measured piston to valve clearence is to assemble one side without the head gasket using lumps of modeling clay on the piston tops, spin it over, pull the head, measure the thinist section of clay, add the thickness of a compressed head gasket and now you have a number to work with. Link to comment Share on other sites More sharing options...
desertsubaru Posted January 26, 2007 Share Posted January 26, 2007 This might be a dumb Idea but I will say it anyway. If you have the heads off put the piston up to tdc on the exhaust stroke and put some clay in the space (maybe a little more to make up for space in head) thats in the cylinder. Bolt the head on with a gasket and when you bolt it back on have the exhaust valve open . take head back off and mic the clay. If you all think this is a dunb Idea just sat so and I will go away .lol :lol: Link to comment Share on other sites More sharing options...
Phizinza Posted January 27, 2007 Author Share Posted January 27, 2007 The way I always measured piston to valve clearence is to assemble one side without the head gasket using lumps of modeling clay on the piston tops, spin it over, pull the head, measure the thinist section of clay, add the thickness of a compressed head gasket and now you have a number to work with. ... That's what I like. Info I haven't thought of. Thank you very much. Time to get the EJ in and start building that EA ! Cheers, Link to comment Share on other sites More sharing options...
[HTi]Savage Posted January 27, 2007 Share Posted January 27, 2007 Why would it be only a small amount? I'm not planning on having the original manifold, and isn't that the only thing stopping us shaving the heads or blocks on these engines? That and the exhust manifolds. Link to comment Share on other sites More sharing options...
daeron Posted January 27, 2007 Share Posted January 27, 2007 Exhaust is easy, MUCH easier to fabricate than intake. All you need is the flanges from an old manifold, and you can have a muffler shop make you a new one from scratch.. OR just start out with the initial pipe and flange, and build your own Y pipe. aluminum intake manifolds are not as easy to build, for your average do-it-yourselfer. I don't believe I just referred to one of our Subaru Frankenstein Masters as a "do-it-yourselfer," but I meant someone without access to thousand and thousand of dollars worth of machine shop Link to comment Share on other sites More sharing options...
Phizinza Posted January 27, 2007 Author Share Posted January 27, 2007 A mig welder with ally wire and gas, an angle grinder, some ally tube, some brass fittings, a drill, a die grinder, is about all you need if you buy an adaptor to fit the carb you want to use. Oh, and yes you will have problems getting the two carbs running right and the linkage up. But really it just requires a little bit of ingenutity. Link to comment Share on other sites More sharing options...
daeron Posted January 27, 2007 Share Posted January 27, 2007 A mig welder with ally wire and gas, an angle grinder, some ally tube, some brass fittings, a drill, a die grinder, is about all you need if you buy an adaptor to fit the carb you want to use. Oh, and yes you will have problems getting the two carbs running right and the linkage up. But really it just requires a little bit of ingenutity. Well, I was meaning a single intake for both cylinder banks. You more or less eliminated 90% of the difficulty in deciding upon standalone intake manifolds. the exhaust is much easier to build the plumbing to get them all firing out the same place. Although, you could set up some twice pipes, my understanding is that twice pipes without a collector provide horrible exhaust scavenging. Custom Y-pipe seems to me to be a no-brainer, seeing as it can't be that hard for you to put together. I may have some difficulties fabbing something like that up, but you have done much more fab work than I. I've been there, helped out, thought things through.. but not on my car, not doing my work. Im a wrench monkey when you get right down to it.. but I am an observant wrench monkey, who thinks WAY to much about things. Link to comment Share on other sites More sharing options...
Phizinza Posted January 27, 2007 Author Share Posted January 27, 2007 Well, I was meaning a single intake for both cylinder banks. Oh, sorry, mis-understanding. I always think way to much as well. It's time to get out in the shed and start doing.. But everytime that happens I need to get back on the computer and learn how to do what I want. Hmm.. Oh well, all in good time. Link to comment Share on other sites More sharing options...
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