coronan Posted February 5, 2015 Share Posted February 5, 2015 (edited) Searching does not yield much for this motor let alone pictures. So I'm going in blind. Maybe I can get some feed back. Or Someone Can learn from my mistakes. What is this ridge about??? Any recommended areas to clean up? Port is already matched to the gasket. Actually the gasket is slightly smaller stock. This head would actually be a great candidate for extrude honing, But thats def out of the budget. Questions... The casting does not have too much flash. Remove all of this valve shrouding? Raise the roof? Remove most of port divider? Shave inside corner? Raise the roof or just polish? Edited February 5, 2015 by coronan 1 Quote Link to comment Share on other sites More sharing options...
coronan Posted February 5, 2015 Author Share Posted February 5, 2015 Phase 1 remove flash, Unshroud intake, blend around valve guide. 60 grit How am I doing? Stay tuned: flow bench build is next. 1 Quote Link to comment Share on other sites More sharing options...
hatchsub Posted February 5, 2015 Share Posted February 5, 2015 Subscribed. I think that ridge your referring to was meant to direct airflow to both cylinders equally. I bet you could cut it down and sharpen it without any ill effects however. In fact i think when i had a set of non-turbo EA81 heads done up he got rid of it all together. Quote Link to comment Share on other sites More sharing options...
coronan Posted February 5, 2015 Author Share Posted February 5, 2015 I'm tempted to get rid of it. Technically the cylinders only fill one at a time. Quote Link to comment Share on other sites More sharing options...
hatchsub Posted February 5, 2015 Share Posted February 5, 2015 I'm tempted to get rid of it. Technically the cylinders only fill one at a time. And the piston pulling back sucks the charge in...so yea I'm really not too sure why they put that in...maybe to lessen turbulence? Quote Link to comment Share on other sites More sharing options...
carfreak85 Posted February 5, 2015 Share Posted February 5, 2015 (edited) Stay tuned: flow bench build is next. Make sure to get numbers for an unmodified head too. As a side note to anyone who reads this thread in the future, simply turning up the boost is a far more economical way to increase engine output on a turbocharged car. Porting can net good gains for a relatively small investment on naturally aspirated engines, but in turbocharged engines, since air is being forced into vs. drawn into the engine, the shape and "straightness" of the inlet ports matters less. Not that there aren't gains to be had. The entire line of FHI engines, save for an honorable mention to the SVX, have pretty ugly intake and exhaust tracts. It's just the nature of the engine layout. It's hard for a manufacturer to sacrifice the packaging necessary to have proper intake plenums and straight ports on any production vehicle. The EA63-81 engines probably have a N/A volumetric efficiency of around 74 to 80 percent. EA82s might peek into the 80s, especially with a "spider" intake manifold. But with the EA81T/82T/EJXXXT engines, you can cheat the compromised engine design a good bit (for refrence, some N/A engines are able to achieve over one hundred percent volumetric efficiency. To contrast, not many engines score below 60 to 70 percent, showing just how bad the EA engines really are.) As far as what you should aim to improve on these heads? Definitely unshroud those valves. You'll want to knife edge the ridge in the intake port, same with the exhaust splitter. In fact, if you could extend the wall of the exhaust side, it would improve the scavenging effect of the exhaust pulses. Also on the intake side, try to make the port as straight as possible with as little material removed as possible. If you can match the profile of the valve guide to its boss, that will help the flow, but be careful not to damage the guide. You may also consider a five-angle valve job done, since the heads will be off the block. These heads, along with just about every other cylinder head FHI has ever cast, can and often do crack between the valve seats. I hesitate to remove material from just about everywhere because of this. Another thing to avoid is excessive polishing of the ports. Keeping the port walls relatively rough will produce a boundary layer between the port wall and the gas column, and will actually help speed up the flow of air into the cylinders, incrementally improving the engine's volumetric efficiency. All that said, you can't really fix the fact that this engine is going to flow like crap no matter what you do to the heads. Turn up the boost and fix what breaks next once you get it back together. Edited February 6, 2015 by carfreak85 1 Quote Link to comment Share on other sites More sharing options...
coronan Posted February 8, 2015 Author Share Posted February 8, 2015 Thanks Carfreak! This is what I consider a "while your in there mod" . I am going to focus on flow balancing the cylinders so the fuel ratios is the same. My time is free. The crude flow bench I am building is going cost less then $100. Can anyone tell me what valve lift is on the EA81T stock cam??? Quote Link to comment Share on other sites More sharing options...
coronan Posted February 9, 2015 Author Share Posted February 9, 2015 (edited) Here is my flow bench. If I had to do this again i would make the box large enough to fit the head in side. I ran into some issues because the walls of the box limited the mounting locations of the studs. I am using 3/8 bolts to clamp the head to the box. It also holds the rocker shaft on. Instead of fabricating an elaborate arm to compress the valves I decided to use the rocker arms and a 3ft pry bar. The pry bar works great I can hold the valve steady with in 0.001". While i read the anemometer. I use some grease around the head gasket opening the aid sealing. When i started i noticed that the head would rock when i pried to open a valve. So i added 2 lag bolts to the intake side through the head bolt holes. The Vacuum is a Rigid 6.5HP running with no filter. The Pyle PMA90 Anemometer. $60 new from ebay. Has a function calibrate it to duct diameter. I'm running 3" PVC pipe with an ID of 3" Back when i used to measure emission on power plants we used a rule of thumb to find laminar flow but i've forgotten it. I believe it was "laminar flow occurs after 3 duct diameters in length after a transition" Can any physics guys confirm this??? My pvc pipe is 36" long. There is 16" of straight pipe before and after the anemometer. Thats 5.3 Duct Diameters. I used a hole saw to cut the opening for the anemometer I placed the core back in to the tube to help fill the gap and leave the walls as smooth as i could to not cause turbulence around the sensor. The system flows a maximum 415 cfm without a head on the box. Pulls almost 1.5" Hg of vacuum with a head on and valves shut. Intake valve open Vacuum level is about 1/2" hg Exhaust valve open vacuum level is about 3/4" hg Each time i mount a head I note how much the system flows with valves closed and subtract that from the flow reading with the valve open. The system usually leaks about 20 cfm. Edited February 9, 2015 by coronan 1 Quote Link to comment Share on other sites More sharing options...
coronan Posted February 9, 2015 Author Share Posted February 9, 2015 (edited) I do not know valve lift for the EA81T. Nor EA81. It is not mentioned in the finley manuals. So ASSUMING A VALVE LIFT OF 0.400". A valve spends more time in the middle of its travel, so i am trying to build for 1/2 lift. 0.200. Its easy. As educational as this is, I don't want to spend all day measuring flows at 10 different increments per valve. Based on what i have read from other DIY port jobs and DIY flow benches: The flow increases linearly with valve lift and the gains from porting are linear. All of my flows will be at 0.2" valve lift measured on by the micrometer. Read em and weep. Stock Flow from an unported head. Intake Cyl 1 - 232 cfm Cyl 3 - 198 Cyl 2 - 253 Cyl 4 - 216 Exhaust Cyl 1 - 214 cfm Cyl 3 - 159 Cyl 2 - 216 Cyl 4 - 146 The low performers are NOT due to the S bend in the exhaust port on 1 and 2. The It is in 3 and 4. The bowl is big and beautiful. You can see the valve from the exhaust port. The problem is the port is damned near tear dropped shape. Reducing in cross sectional area as it approaches the end of the exhaust port. You almost need a borescope to see in there. Pics to follow. Edited February 9, 2015 by coronan Quote Link to comment Share on other sites More sharing options...
coronan Posted February 10, 2015 Author Share Posted February 10, 2015 CYL 3 EXHAUST Quote Link to comment Share on other sites More sharing options...
coronan Posted February 10, 2015 Author Share Posted February 10, 2015 Great article on port volumes and HP. http://www.hotrod.com/how-to/engine/hrdp-1012-ultimate-chevrolet-ls-cylinder-head-test/ Too Bad this guy never finished his project or posted about it. http://www.ultimatesubaru.org/forum/topic/79903-ea81-head-modifications/ Quote Link to comment Share on other sites More sharing options...
coronan Posted February 12, 2015 Author Share Posted February 12, 2015 More homework: http://www.ultimatesubaru.org/forum/topic/149443-improvised-exhaustmuffler-questions-1983-ea81-brat/ Quote from the above thread: Post 8 "What happens is that each bank of cylinders fires then the other. 1-3, 2-4.......so there is a full revolution where one side or the other is not firing. so the exhaust in each tube would slow to almost no flow during each "dead" rotation per side. " Does this justify the poor flow out of 3 and 4???? Is it by design??? Quote Link to comment Share on other sites More sharing options...
coronan Posted February 12, 2015 Author Share Posted February 12, 2015 (edited) So I have removed several ounces of material and not had any improvements in flow. This is my practice head. Cyl 1 Exhaust: Stock bowl. I just roughed it up with 50 grit so i was not taking pictures of black. This is the one that makes the exhaust travel in an S bend. Cyl 3 Exhaust: Sloped Roof around the Valve Guide. Lots of material removed from the right side (middle of the head) to straighten the port. Not as much can be taken from the left inside radius because of the oil return galley / push rod hole. And finally the twin port. Cyl 3 is on the left. Cyl 1 is on the right. Lots of material removed from the Cyl 3 side. Port divider ground back and knife edged. Its ugly but clearly the port on 3 is straighter and larger. Here is what my Flow Meter tells me. Due to temp / humidity / ect flows are only good on that day. Fluctuations will occur day to day. The goal is to equalize. Measurement taken last weekend. Stock, Before removing any material. Cyl 1 Exhaust Stock 239 cfm Cyl 3 Exhaust Stock 155 (65%) Measurement take 2-12 after porting #3 Exhaust Cyl 1 Exhaust Stock 220 cfm Cyl 3 Exhaust Ported 120 (54%) And no, I did not get the cylinders reversed. Clearly I do not know how to improve flow. There is a lesson here. I just don't know what it is. I am glad this is the practice run. Edited February 13, 2015 by coronan Quote Link to comment Share on other sites More sharing options...
coronan Posted February 12, 2015 Author Share Posted February 12, 2015 I switched to blow through the cylinders. (more appropriate for a turbo car and the exhaust ports). Overall the flow numbers came down. But in comparison # 3 cam up 20 %. Making #3 exhaust 75% of #1. I may keep with this blown setup. The other question in my head is what should the tolerance be. 10%. That sounds like a lot in terms of effect on stoichiometric ratio but it may be more realistic. 1 Quote Link to comment Share on other sites More sharing options...
coronan Posted February 15, 2015 Author Share Posted February 15, 2015 Wow crickets huh??? No accolades of wizdom, from the peanut gallery. I have the drivers side head that I can still experiment with. I'm running out of time. I need to get these head off for rebuild before I leave for vacation soon. Ram performance is going to cut the seats for larger valves. Probably the SS harley valves listed above. I'm probably going to spend tomorrow polish the combustion chambers and do a light smoothing of transitions. What is the recommended grit to finish the intake port to keep the injected fuel atomized? 80 grit? Quote Link to comment Share on other sites More sharing options...
TomRhere Posted February 15, 2015 Share Posted February 15, 2015 I haven't tried my hand at porting any heads as of yet, but have done a lot of reading on the subject. Yep, 80 grit for finish on the intake side of things. You want to get the exhaust and combustion chamber as close to a mirror finish as possible to help eliminate, (actually it's "reduce chance of") any carbon build up. Quote Link to comment Share on other sites More sharing options...
coxy Posted February 15, 2015 Share Posted February 15, 2015 Firstly Carfreak85 take note regarding Knife Edging of Dividers fine to taper to a smooth narrow edge but not a Knife Edge on the Exhaust Divider but definitely do not do so for the Inlet, Now I will explain why I say that and hopefully it will make logical sense. Think about the shape of an Aircraft wing and forget the differences for the moment between top and bottom profiles which can all be researched by looking at NASA Aerofoils with a Google search. The Leading Edge is never Knife Edged and they spent thousands of man hours looking for maximum flow at all different air speeds to come up with that which equates to different RPM when talking Port Dividers, However the trailing edge is always tapered as this combination aids higher flow speeds what we are looking for. We are looking for higher flow speeds providing the air speeds do not go Supersonic as the timeframe of a high speed engine requires quick cylinder filling, Not supersonic as Honda found out with some of their two stroke 250cc GP bikes where port speeds exceeded supersonic leading to all sorts of reversal tuning related issues (think internal sonic boom). But the real trick is not just numbers but mixture quality or to be blunt good even fuel distribution and I believe that may be what that small ridge type divider is for on the port floor for the intake. Because of the inherently long intake runners mixture dropout will be a problem with most Subaru engines hence the water heated inlet manifolds to help counter that problem. That is why all thinking Cylinder head experts with the money now use "Wet" Flow bench testing but a compromise can be made by introducing some smoke color to your setup at home allowing you to see to an extent what is going on. Pocket porting does work very well on Subaru's do be very careful about the short side radius as I believe it is not just vital on any cylinder head but of utmost importance in Subaru or other Flat engine configurations, Blend into the valve guide boss if possible do not just remove it as while that can help full Valve lift flow it is only at that point once but at lower lifts twice so going too big will lower port flow. What will work best is a gradual taper of the port dimensions to the narrowest point near the valve guide then opening up in the pocket area behind the valve, That way flow speeds up to that point and then slows behind the Valve helping to minimize turbulence at that point. This will allow a much more even Fuel Air mixture to flow into the Cylinder which aids both power and economy by the production of better Torque figures an aspect of the EA 81 I am sure most realise is one of it's best points. The Long intake runners contribute much to Torque production something not as useful in Light Aircraft use hence why you see them use short runners and dual carburetors on EA 81 conversions in many cases. With the Multi Point EA 81 T engine mixture drop out is not as great a problem but it does occur, At least with modern type injectors that area has improved compared to the original Denso Bosch EV6 type Subaru used back then.Search about EV6 and EV 14 Injectors to find out the why's and where fors that apply especially to Modifying EJ type engines that often find a home in Early Subies. Tom above is pretty much on the money regarding finish but you can go as fine as 120 grit in cartridge rolls for the intake and remember Valves can be shrouded on both sides the exit into the head for the inlet is as important as the entry side and the reverse for the exhaust valve. When thinking flow think Venturi and where the narrow point needs to be and always consider how a River flows fast on the outside of the bend and much slower on the inside, same applies in any bend in a port or for that matter Inlet or exhaust manifolding. That last point can cause mixture drop out and running issues or at least a drop in power and issues getting consistent tuning. Quote Link to comment Share on other sites More sharing options...
Mykeys Toy Posted February 15, 2015 Share Posted February 15, 2015 This is a fascinating thread though much of this is beyond my knowledge. I always interested in mo powa! Quote Link to comment Share on other sites More sharing options...
coronan Posted February 17, 2015 Author Share Posted February 17, 2015 I'm loosing ground. The moral of the story might be if your not pro dont port your head. You will do more damage than good I spent about an hours watching this guy. https://www.youtube.com/user/HeadPorting Warning he is long winded and his videos are in real time. But I learned some things. Move quickly and keep moving. Look for Luster. Switching to the intake: Cyl 1 Stock Cyl 3 with the Bowl cleaned up Cyl 1 Stock 214 cfm Cyl 3 Cleaned up bowl 201 cfm (94%) One thing to note when unshrouding the valve is the short side radius. I can barely stick my pinky finger in there. It feels smooth from the factory. If you mess it up the valve guide blocks you from getting it back. And there is a lot of material to remove to unshroud the valve. Be careful not to make a corner. On to the other end of the runner. Cut out port divider. Tried to remove flash from the bottom of the runner. This is a difficult area to work in. Flows with intake runner cleaned up to 80 grit. Cyl 1 209 cfm Cyl 3 195 cfm (93%) No Gains At this point I realized my lack of skill. Things looked smooth but did not feel smooth to the finger. Its hard to see until its polished that something is still lumpy. There is an interesting ramp before the valve guide here. I'm not sure if its intentional or not from subaru. It may throw air at the shrouded side of the valve. But probably not. I tried taking it out. 80 grit. Cyl 1: 215 cfm Cyl 3: 178 cfm (84%) I LOST 11% FLOW This was also an EXTREMELY DIFFICULT AREA TO WORK IN. You can only use the bottom of a ball shape cutter and the valve guide is constantly in the way. I was super bummed because I thought it would be a great way to add flow to cyl 3 after i had cleaned up cyl 1 intake. Note to self. Do less work with the carbide burrs and more work with the sanding rolls. Also note to self : Do not quit day job. This practice run has been exhausting and demoralizing. My GF hates me and wants to throw my air compressor in the garbage. Good thing its too heavy for her to lift. At this point i am going to proceed to minimally clean up the heads I intend to put on the car. 1 Quote Link to comment Share on other sites More sharing options...
coronan Posted February 18, 2015 Author Share Posted February 18, 2015 Can anyone recommend removing material from areas that i haven't???? Or removing more material from certain areas? Quote Link to comment Share on other sites More sharing options...
DaveT Posted February 18, 2015 Share Posted February 18, 2015 It's been interesting reading this thread. It does bring back memories from years ago when this sort of thing was discussed. The pieces I remember from back then is that there are a lot of things that are not conducive to power in the head design, and porting has little effect because of the other limiting factors. Size of valves being one, all the bends in the passages being another. Quote Link to comment Share on other sites More sharing options...
coronan Posted February 19, 2015 Author Share Posted February 19, 2015 Cracked between the valves and EGR Port. Repairable? Quote Link to comment Share on other sites More sharing options...
Crazyeights Posted February 19, 2015 Share Posted February 19, 2015 (edited) The bridge cracks between the valves are a well known fault. You can safely ignore them in my opinion if they are not cracked clear through to the water jacket. There is a SOA bulletin on this very thing. Gently peen it down and close it if it bothers you, just don't damage the seat. Edited February 19, 2015 by Crazyeights Quote Link to comment Share on other sites More sharing options...
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