Hi Guys, Does anyone know what will make an intake port start backing up? I know it's a turbulance problem but with both my Stage 1 SE's and my Stage 2 SE's they both reach peak CFM by about .560" then drop by about 15 or so numbers then start coming back up again.o No: I talked to Bobb Makley about this before and he said he had the same problem at the same lift area. I narrowed it down last light as the the exact point it peaked and then went turbulant. I've noticed that at .550" would be the best numbers then at .600" it would "hicupp" and drop and then start climbing again. ANY ideas as to where/what is causing this disruption?o No: BTW....I don't have my numbers in front of me hear to post but I will add them later tonight. Stage 2 SE NOT TE's, (AM&P) 2.160"I & 1.755"E (11/32's stem). Peak flow of 359cfm @ .560" lift @ 28"H2O on our SF600 with FlowCom. ANY and ALL ideas deeply appreciated!:TU: It's REALLY got me scratching my head (I'd probably pulling my hair out but with a flat-top haircut it's hard to get ahold of anything:laugh: ) as to the cause/causes. Thanks to everyone..
Whenever I run into this, I generally look at the short turn radius. I have also seen where the back side angle of the valve can have huge affects at specific lift points. But this shouldn't be the case with the valves that your using.
Thank you very much for responding Greg! I've wondered if it could be the short-side radius or not.uzzled: So....in your findings have you found the short-side to be not laid back enough or too much?o No: The seat choke is currently at 1.925" (89% of the 2.160"I) but there is a slight straight drop from the short-side to the seat's bottom cut so it's not a complete, uninterrupted radius from the floor to the seat. I haven't even touched the chambers yet. These are going on a 4.375" bore block (also what my Brezsenski Slider Plate is as well as the bore cylinder) so unshrouding will definately be at a minimum to say the least. I'm hoping to improve the low-lift #'s more as the .100" # is only 74.7 as of yesterday. ANY and ALL additional info very MUCH appreciated!:TU:
I still cant believe how forthcoming with information this site can be. When you can get high quality information from the true experts it does nothing but make all Buicks better and a amateur like myself more excited to be involved with Buicks.
Hi Guys, Chris.....I totally agree with you....we are THE BEST group out there and it makes me very proud to be a part of our elite group!:TU: Greg....I went with your advice and sure enough...SUCCESS!! :3gears: Now as promised, some flow numbers for everyone. This is for the number 1 intake port. Blended roof and floor into TA's port-entrance's CNC cuts, opened pushrod choke area (have brass tubes epoxied in), "port intruder" (head bolt boss) opened to steel insert for maximum cross section, guide contoured, bowl opened and blended to bottom seat cut to 1.925". Still no chamber work yet! .100.....74.2 .200....149.2 .300....222.0 .350....255.1 .400....284.6 .450....312.9 .500....338.0 .550....356.9 .600....353.2 .650....357.6 .700....351.4 .750....351.8 .800....353.0 valve held wide-open...358.4 as a side bar I broke it down farther in .005" increments between .550 and .600" to find my absolute peak flow and to pin-point where turbulence sneaks in and air-flow started to drop or "back-up".... .560....360.2 .565....360.6 .570....360.7 .575....361.2 .580....361.7 .585....361.7 .590....360.7 .595....358.4 I've ran 26 tests so far as I "wittle away" at the short-side as I do not want to go to far. More to come as I progress...:TU:
Just to show the actual gains here is the first test, as I received the heads from AM&P. No porting or blending what-so-ever (all rough machined cuts present) with competition 3-angle valve job and back-cut valves. .100....72.2 .200....148.9 .300....217.8 .350....247.1 .400....272.6 .450....290.8 .500....298.1 .550....292.8 .600....295.2 .650....297.9 .700....300.0 .750....301.3 valve held wide-open....305.1 As you can see the low-lift numbers up .300" to have hardly increased at all compared to my numbers above but at .350" started to gradually rise and by .550" is up over 60+ numbers! :shock: As I'm sure many of you can see if that while these heads are great as cast from TA you will be leaving MUCH improvement unopened without soem port work!:TU:
I would guess port volume is in the 240's on that head........ Sounds very similar to mine,Peak flow is at .585,Then falls off,Then climbs again. Kerry, I'd be interested to see the flow #'s of that head on a 4.350 bore...... They seem very similar to mine.
Kerry, Thanks for sharing this info... here is what I have found. Make a template of what you want your port floor to look like. Take and bend a coat hanger around the head of your intake valve. That is the radius that you want your short turn to be. Lay it on the short turn and compare. With the head on the bench push the valve open to the point of where the air stalls. I am guessing you will find is right at the deck surface and you will see where it might be shrouded. What bore is the flow bench your using? I have not had a cylinder head go up in flow past .650 lift. I think its because the valve gets to close to the cylinder wall. The only way to correct this is to angle mill the head and then change all of the angles of the bolt holes. I say this because I had a set of Stg 3s and the head would flow more air with a 2.200 valve compared to a 2.25 valve. I dont have any solid evidence to back this up but it am guessing. If your flowing on a bench that has a cylinder bore of larger than a 4.35 then move the head back towards the exhaust side of the block to make the head seem like its a 4.35 bore. Later
Hi Guys. Adam....at this point I have not cc'd the ports. I do plan on doing it though when I get the port to where I want it. I can compare to the stock port volumes as I am only developing this one intake port, exhaust port and chamber then will go thru and match the rest. Also when I have the ports the way I want them I have rubber mold compound to make molds with.:TU: Gary....I don't have a 4.350" cylinder...yet....only a 4.375" at this time. My chambers are untouched and there is a nice sized area that can be relieved and further unshrouded around each valve. Hoping to find additional low-lift flow there.:TU: How much of a drop did you see with your heads before they started to "come back"? As you can see I've gotten mine to be minimal but would definately like to find the exact spot in that port that is causing the "hicupp" to occur.:grin: John....Thank You for sharing your radius technique! I will definately give that a try.:TU: I agree, shrouding is definately a most-likely and probable cause but I pretty sure that may go away with opening up my chambers to my 4.375" bore. I'll keep everyone updated... We are WAY small on intake valves as compared to "the standard" for wedge heads that says 52% of the bore is what your intake valve diameter should be. On a 4.350" bore that would be 2.262"...on my 4.375" bore that would be 2.275". I have a Breszenski Slider Plate (4.375" bore cylinder and plate). The plate itself has the same head deck dowel locating pins so I can not move the head around as you suggested. Everyone have a great day!:3gears:
Kerry, Bob Bruno owner of Bob's engine research, "well know in the circle track community" showed me a trick he use to use before digitizing came out. Take a piece of sheetmetal shaped like a T, trim and grind to the shape of your short turn and use it to shape the rest of the short turns. Let me know if you understand what I mean. You can make another to shape the bowls, it works great. You wouldn't believe how far off you can get without reference tools. I also agree, this site is great for info like this.
stage 3 heads This is the flow #s for a set I have on my bench. 2.200 Int 1.750 exh int exh .100 70 75 .200 152 127 .300 236 164 .400 301 203 .500 352 234 .540 361 240 .600 345 254 .700 351 263 *NOTE* Air gets turbulent in intake runner after peak air flow 361cfm @ .540 lift. (you could actually here the air crashing in the runner) EXH, No porting,just a blend,No pipe. Cylinder wall shrouding is a problem with the stage 3 heads because they moved the intake valve over .080. I have a set of stage 2 TE's that are going on the 494. They use a 2.260 int 1.810 exh and the intake valve is not moved over .080 like the stage3 head,that should solve the shrouding problem. When the heads are on they engine and running and that intake valve is whipping up and down does the air have time to get turbulent o No: We tried unshrouding the valve by moving the head over on the plate,still crashed but flow#'s improved. When we start the stage2 TE's I will let you guy's know if the turbulence is still there.......Chris
Hi Guys, Jeff....Thanks! Sounds like a good technique...I'll give that one a try. I have some extra plexiglass that I was going to do the same thing with. BTW...I made my own radiused entrance plate with 3/4" thick plexi with a nice 1/2" radius with my router. Bolts up perfectly with TA already CNC'n the entrances. I slotted it so it can be slid between the two siamesed ports. Also to make it work seeing as how the intake bolts go in at an angle (instead of straight-in), I took 7/16" all-thread, screwed it in then marked it. I then took a hacksaw and cut partially thru it then bent them at the proper angle to slide the plate on and use fender washers and nuts to secure it to the head for no leaks. My flow results are now repeatable unlike using clay which no one can ever get the exact same way they had it the last time the port was flowed!:Brow: I would post pic's but my wife's computer won't accept my pic for some reason and I can find my Mavica install disk to install on her computer (probably THE reason). I'll work on that....:grin: Chris....I've found that laying the short-side radius more will raise the point as to where it goes turbulent. And yes...I can hear the air start breaking-up too! Nice exhaust numbers for just a blend, no porting or no pipe.:TU: Please keep us posted as to your findings.
Chris "buicksstage1"....I just noticed but Happy Birthday! I too turned 38 earlier this year back in February.TU:
Thank you Thanks Kerry.How have you been,are you getting any closer to getting a new air pump.........Chris
Your welcome Chris! Actually I just got out of the hospital less than two weeks ago after a 3 1/2 weeks stay for more pneumonia and such. I'm still on home IV antibiotics that are due to end tomorrow. I go back down to St. Louis again Oct 18th for my 6 month pre-transplant check-up to see if that moves me up, down or stay in the same general spot on "the list". It's points system that the National Transplant Listing goes by. But all-in-all I'm still kicking and praising the LORD for each day he allows me to continue to do so!:TU: My buddy's flowbench allows me to get out of the house a few hours a day. No matter how sick I get I'm just really not a stay at home type of person.:grin:
Kerry, If you can post some pics some how, some day, would love to see them. Looks like 1967 was a booming year, i'm another 38 year old. Am I 38 already! ou:
Chris....Thanks for the offer, but I'm not a drinker...except probably milk...about a gallon a day.:laugh: Jeff....It looks as though I got the picture situation solved...I managed to take a quick pic of our coffee, download it then post it on the board last night. I deleted it after I managed to successfully do it. Who would want to see our coffee table anyway??o No::grin: I'll see if I can get some pic's later today and post them tonight. I spent a few hours yesterday disassembling and porting my Indy Head Service oil pan swiveling pick-up (the one John Zerucha "Staged70Lark" posted a couple of days ago in another thread). When I took it apart to inspect it I found that it has no O-ring to seal it so it can probably suck air and that could very well be the reason Doug Hecker had what he suspected to be his problem with it. I will be taking mine to have a rubber O-ring machined into it so I can install an O-ring into and solve that potential probelm I see. Have a great day all...
