oldeskewltoy Posted September 17, 2015 Report Share Posted September 17, 2015 I recently was sent a 20V Blacktop (Noir Crowning) head...... so once unwrapped and set up on the bench.... inspection begins.... Over all the casting quality has gotten much better. Although there still is port-bowl-seat shift, the shift amount - at least in this head, is minimal. There is one REALLY, and I mean REALLY odd ball bit........ the 3 intake valve seats have NO semblance of an even 3 angle... Looking into the Blacktop service manual the 3 angles are suppose to be 30, 45, 60. Well the throat cut - 60 degree cut, in essence is the bowl angle and so the back of the port (highest pressure area) has no effective throat cut, while if you look carefully, the throat cut at the short radius is so small, it also becomes more or less insufficient... and the the throat cut between the two... is nothing short of an extreme change - from a width @ the back of the port of almost 5mm, to the width at the short radius of the port of less than 1mm. One thing is certain - the factory put a lot more effort in to making the bowls and seats as smooth a transition as the factory could do... the bowl machining marks you see are not by me... those are all factory machining Adding some more info.... The heads thickness measure..... My dial caliper is likely off by .001" and getting a chamber volume and it is very close to SamQ's 37.8cc measurement.... I'm closer to 38cc Further inspection...... shows a few issues on the exhaust side... look @ those casting marks.... as they travel from the bowl to the port. Also the small "step" in the machining/casting hurts flow, especially at lower lifts. More to come........ :D 1 Quote Link to comment Share on other sites More sharing options...
B.L.Z.BUB Posted September 18, 2015 Report Share Posted September 18, 2015 Love your work. Quote Link to comment Share on other sites More sharing options...
bruce Posted September 18, 2015 Report Share Posted September 18, 2015 Are you going to make a silicone RTV mould of the 20V intake port? Would be interesting to compare it with the 16V with the difference in entry height. Quote Link to comment Share on other sites More sharing options...
oldeskewltoy Posted September 21, 2015 Author Report Share Posted September 21, 2015 (edited) Are you going to make a silicone RTV mould of the 20V intake port? Would be interesting to compare it with the 16V with the difference in entry height. Alas... not the intake side.... A friend of mine has done some intake port molds.... My focus will be mostly on the exhaust side. I will be reworking the intake as well, but initial inspection reveals the newer 4AG heads are cast better then many of the older 16V heads.... at least this 20V head is. I begin on #4(left), since the bowls already merge pretty well with the seats, my biggest task is a to "build" a short radius, to minimize the intake guides, and guide bosses, and to gently straighten port/bowl mismatches. #4 is on the left... you can also see where I've done some mild blending in the chamber, of the factory machining marks. And to the exhaust on #4(left).... I seem to remember the info "out there" saying the Blacktop had 35mm exhaust port outlets.... I measured these, they come in around 33.6 ish mm. The ported one is about 33.75mm..... this was before I had an exhaust gasket to know the port limits. Besides the re-taper, I've also "rebuilt" the shape of the guide bosses to minimize their effect on flow past them. I've also added a minor radius to the exhaust guides to further minimize flow disturbances The view from the chambers... With #4 mostly finished(right)... #3 has been cleaned, and #2(left) is still a bit "carbon coated". As I did with the SR20 head, I'll be doing with this one. I'll be mounting this on the flowbench a bit later so that I can test the 3 ports all on the same day, and under the same conditions. This will allow me to quantify the port work. more to come..... :D Edited September 21, 2015 by oldeskewltoy Quote Link to comment Share on other sites More sharing options...
oldeskewltoy Posted September 23, 2015 Author Report Share Posted September 23, 2015 That said' date=' it will be interesting to see the tool you conjure to actuate the valves during flowing.[/quote'] thank you for your contribution.... :) Oh didn't I mention, I'm planning on quantifying the results with flowbench results.... :yes: additionally.... I've made a casting of an exhaust port before... and after.... it will help me see the "positive" of my porting/removal. Kinda like these 16V castings.... These are the castings from the blacktop Speaking about those 16V castings.... and the new ones..... Soon to come flowbench testing......... :D Quote Link to comment Share on other sites More sharing options...
oldeskewltoy Posted September 25, 2015 Author Report Share Posted September 25, 2015 the intake side..... paper towel in exhaust port is acting as a "cork", remember these are used valves, in used seats, and stuffing the opposite port to the one being test allows for honest figures. The numbers @ 28"....... Unported Intake - .050 - 58.15 .100 - 110.87 .150 - 146.30 .200 - 168.30 .250 - 180.08 .300 - 186.65 .350 - 191.22 .400 - 194.10 Ported Intake - .050 - 60.02 .100 - 114.30 .150 - 149.20 .200 - 177.33 .250 - 185.47 .300 - 192.33 .350 - 197.78 .400 - 202.35 There is a glaring error on one reading, can anyone find it??? I likely over adjusted one valve, What should it read (about/approximate)?? setting up to do the exhaust side Unported Exhaust - .050 - 32.45 .100 - 65.52 .150 - 90.95 .200 - 110.12 .250 - 122.80 .300 - 130.25 .350 - 135.48 .400 - 140.43 Ported Exhaust - .050 - 35.38 .100 - 65.88 .150 - 93.73 .200 - 113.50 .250 - 130.63 .300 - 139.92 .350 - 146.33 .400 - 151.20 More to come...... :D Quote Link to comment Share on other sites More sharing options...
oldeskewltoy Posted September 29, 2015 Author Report Share Posted September 29, 2015 (edited) The numbers @ 28"....... Unported Intake - .050 - 58.15 .100 - 110.87 .150 - 146.30 .200 - 168.30 .250 - 180.08 .300 - 186.65 .350 - 191.22 .400 - 194.10 Ported Intake - .050 - 60.02 .100 - 114.30 .150 - 149.20 .200 - 177.33 .250 - 185.47 .300 - 192.33 .350 - 197.78 .400 - 202.35 There is a glaring error on one reading, can anyone find it??? I likely over adjusted one valve, What should it read (about/approximate)?? Anyone??? How about some help..... the glaring error is the ported side @ .200" lift, 177.33 is incorrect.... anyone care to guess about how far off it is???? I had a talk with my client, he is hoping for an exhaust to intake flow ratio approaching 80%. This is going to be extraordinarily difficult because the stock Blacktop flows about 61%, and the first attempt at porting the exhaust side did improve things, now 67%, but a further gain of 13% seems a long goal at best. My first attempt at porting the exhaust was limited because I didn't have a gasket to know where my edges were, and I didn't want to port beyond the gasket, for doing that would cause serious flow issues. So the initial porting on #4 exhaust was from about 33.6 to about 33.7, because not knowing the exhaust gasket left me a bit in the dark. My client sent me the OEM gasket Port on far right is #4, even with the gasket in the "down" position, there is still some room available in the port roof, and room all the way around the port. So now that I had a gasket, work begins on #2 exhaust port. Redline in the 2nd panel is the gaskets edge. A bit more dramatic.... The stock Blacktop gasket outlet is 36mm. Port #2 is now out to 34.8mm(on right), the previously port #4(to 33.7mm) is on left Later this week I'll get this on the bench and see what if any improvement there is over the first numbers. as a reminder.... the numbers @ 28"....... Ported Exhaust (#4 - port on left) - .050 - 35.38 .100 - 65.88 .150 - 93.73 .200 - 113.50 .250 - 130.63 .300 - 139.92 .350 - 146.33 "New" exhaust port readings, #2 port - on right .050 - 34.98 .100 - 65.03 .150 - 93.67 .200 - 113.32 .250 - 131.88 .300 - 142.53 .350 - 150.92 The reason testing stopped @ .350 was my client is limited to 9mm of lift (.354") So now the intake @ .350" is @ 197.8cfm, while the exhaust is now @ 150.9, the exhaust to intake flow ratio is now a tick over 75% at peak lift, and over the lift range the exhaust to intake ratio is now about 71.5% (was 61%) More to come..... :D Edited September 29, 2015 by oldeskewltoy Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted October 2, 2015 Report Share Posted October 2, 2015 That 177 shold be 172. Looks good on a graph anyway... My first experiences with a 4AGE will happen during this coming week. I hope I don't have to open it up before it runs OK, but once being used as a daily I'm sure it will become a test bed. Quote Link to comment Share on other sites More sharing options...
oldeskewltoy Posted October 5, 2015 Author Report Share Posted October 5, 2015 correct on the 172... best I can figure one, or possibly both of the valves were incorrectly adjusted..... for that reading a few views of working the exhaust side..... minimizing the guide boss, and tapering the guide - both to minimize their effect on the outgoing exhaust flow reshaping the exhaust port a bit of before and after.... slightly different perspective... more to come..... :D Quote Link to comment Share on other sites More sharing options...
oldeskewltoy Posted October 7, 2015 Author Report Share Posted October 7, 2015 and now that the one unfinished port get finished..... a bit more to come....... :D Quote Link to comment Share on other sites More sharing options...
oldeskewltoy Posted October 13, 2015 Author Report Share Posted October 13, 2015 #2 on left and #1 on the right On the intake side all I did was knock back the guides, and guide bosses, and made the bowls round to fit/follow the valve seats.... OH I also added a very gentle short side radius.... and opened up the bowls a bit as well. Here we are with 4 chambers, 4 exhaust ports, and 3 intakes finished... More to come.... :D Quote Link to comment Share on other sites More sharing options...
oldeskewltoy Posted October 22, 2015 Author Report Share Posted October 22, 2015 OH I also added a very gentle short side radius.... and opened up the bowls a bit as well. and a bit closer of a view of the worked short radius compared to the unworked side At this point the head was shipped back to my client, so he could have the head re-surfaced and re-assembled. Quote Link to comment Share on other sites More sharing options...
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