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Clevo120Y

crossflow porting results

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Hey guys, I've been flat out and haven't been on. The figures posted by flatchat are huge!!!! if they are at 28in like Tony mentioned, Those figures are top of the food chain stuff at 400hp potential, good stuff I would like to know more also.

What we have to remember when throwing figures around is the context they are achieved, my port is a budget aimed setup, the head is pulled straight off an engine and has a worn but usable seat and stock standard valves, with just some time if you have the tools the results I posted can be achieved with minimal cash outlay.

Tony's head has a little more invested in it and more thought into valve/bore ratio's ect ect and his results reflect that with the topend flow charge, not a massive amount of cash spent I wouldn't believe and he has thought about what needed doing for the purpose it's intended and got excellent results.

Flatchat's head would be a top dollar no expense spared setup I would imagine and to be truthful I haven't seen a crossy head with higher flow figures, not saying it can't be done so don't think I'm doubting the results just saying that's the topend of results there and you should be very happy with that as long as the port size isn't too big for the rev range ect ect.

I have no problem with people posting results of there work on here and if someone gets better results than me than more power to them :) I'm just happy to try some things and sharing the results, if others can have some input and share some insights that's even better and I look forward to seeing it.

 

Gerg, I will do some Cleveland heads in the near future and post up the results, I have a set of open and closed 2V's on the shelf so I will do stock flow test's on both then show some porting work. Cleveland heads don't like a lot of material removed from the short turn but some blending and improving the radius of the short turn does work well, the heads seem to like having the roof raised but these things I will test to prove when I get to them, hopefully soon.

 

I am yet to see a head that doesn't improve from general blending especially in the seat/throat/bowl area. When I port I start at the throat and blending into the seat then the bowl/valve guide areas then the short turn, so I'm work from the valve head back towards the manifold face.

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You need a stray clevo head to hi-port just to see the differece it makes, from what ive heard its supposed to be killer but what its worth on the flow bench would be an interesting comparrison

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Good to see you back in the thread Clevo.  Yeah my head has a lot of thought and maths in it, but not a great deal of dollars.  Cam has found some further gains now that he has started on the actual head.  I will post up the flow figures when it is done, with and without the inlet fitted.  I didn't post the exhaust flow figures in the initial post but I will say that the inlet - exhaust percentages are down below 70% without the manifold fitted which is what we were aiming for, to allow for the reduction when the inlet manifold is fitted. 

I'll be interested to see what final flow figures you achieve when you get a decent seat cut and back cut on those valves. More power to you.

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Yeah I'm still waiting on the head so I have started manifold v2.0, I will post some pics next week in the modified manifold thread of what I'm doing, a lot more work this time but hopefully the results will be worth it.

I went and saw the bloke today and having a chat when he casually mentions that he has all the machining equipment for cylinder heads sitting in corner under a sheet :o so I'm going back there next week and start going through all of his equipment, then I just have to work out how to use it :) can't be that hard can it? LOL I should be able to turn myself into a backyard machinist/engineer with a bit of practise hahahahaha 

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Cheers mate, that's very nice of you. I'm not coming up to Perth any time soon but Tim is coming down here early November, I might see if he can pick them up for me if he isn't too far away. I will drop you a PM thanks :)

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haha no worries ive got two sets so I don't think I need them both :) got ally heads on one and when I build the other id say thatll cop them aswell so otherwise theyre just door stops to me haha

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This is something alot of people should take on board,always wear your PPE.You might feel like a dork wearing it at home when no-ones around but we all need to be thinking safety first.After a while you get use to it and it's benefits...

 

I wear riggers gloves,safety glasses,ear muffs,long sleeves and long pants doing any welding cutting/grinding jobs.

We have to wear all that stuff at work but at home.. Different ballgame. I still got 9 fingers, 90% hearing in 1 eye and can see perfectly out my of ear.

559292_10151279991293738_2144496638_n.jp

 

well ive got a couple of old 2v closed chamber heads youre welcome to abuse any time you want haha! just gotta get them down from rocko :)

Cheers mate, that's very nice of you. I'm not coming to Perth any time soon but Tim is coming down here early November, I might see if he can pick them up for me if he isn't too far away. I will drop you a PM thanks :)

Im heading down to see Sean on Tuesday 5th Nov. im in Leda which is a stone throw away from Rocko. Will organise to pick them up for him before then. I fly home on 31st Oct at night so i can grab 1st - 4th sometime if that suits you?

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Or if u near leda between that time u could drop them at my place. ill make sure my womans home and can stick them in garage. msg me ur number and well talk on phone

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I work on gloves for hand held machines like angle grinders/ welding/ die grinder and no gloves for things like bench grinders/ wire brush, drillpress/ lathe

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Thom's advice is pretty good I think. Our OHS guys tell you no gloves for angle grinders but I just read SafeWork's (SA) guide for angle grinders and it says "Well-fitted gloves that allow a good grip of the tool". Gloves are a definite no no for bench grinders.

 

6321.jpg

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Hey fellas, I was pulling down a 4L OHC head today and I thought I would chuck an intake valve in the crossflow port I did for this thread and run another flow test. The 4L valve is a 1.84in single angle job, so this test is with just the valve change and that is all.

So just to recap.

Test 1: stock C1A port and chamber with stock 1.8in valve

Test 2: modified port, stock C1A chamber with stock 1.8in valve

Test 3: modified port and chamber with stock 1.8in valve

Test 4: same as test 3 but with 1.84in valve

 

                     test1        test2        test3          test4

50                 29.4         30.95       36.08        41.03

100               54            58.34       63.15        67.37

150               77.4         85.6         92.5          98.06

200               98.5         108.98     121.92      130.04

250               121.2       131.56     149.84      155.95

300               141.4       151.05     165.2        171.62

350               162.9       168.79     178.97      179.27

400               177.7       180.13     190.17      193.44

450               184.4       189.02     198.22      200.67

500               186.2       197.22     202.96      209.85

550               189.1       203          207.93      216.8

600                               214.2       213.98      209.59

650                               213.44     213.4        210.02

700                               212.16     212.2

 

So the bigger valve shows good gains in the low and mid lift even compared to test 3, the port has a bit of a stall between 300 and 350 but recovers well after that. The biggest thing that changed was the sound of the port and the air velocity in the port also, the port became noticeably louder from 400 thou up, the velocity was skyrocketing also. My opinion of this is that now the small cross sectional area of the port is becoming a problem, remember that this port has the stock cross section, the port is now suffering from a sonic choke, this is when the airspeed is so high that it becomes turbulant and starts to actually flow less as the results show, when the lift goes over 550 the flow goes backwards and the port starts to scream. At 550 lift the airspeed in the smallest part of the port is reaching over 370 feet per second, I want it down to around 330 FPS at the max lift point which is 550 for this engine, sonic choke starts to become a factor from 340 FPS and up and this is now happening at around 400 lift.

Now the silver lining, in my opinion what this is telling me is that the bigger valve is allowing the port to flow more air and that the short turn and bowl are still stable, that is why the flow is still increasing upto 550 lift even tho the airspeed in the minimal cross sectional area is over 370 FPS so by increasing the port diameter by a little I will be able to reduce the airspeed to an acceptable speed and increase flow at the same time. 

Looking at the results there has been some big gains from the stock port to were it's at now using the small cross section, I will start a new port to suit the bigger valve on Monday and let you guys know how it goes, I think I will develop this port more for a drag racing engine and show you guys the difference between the 2.

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still some mad work in here keep it up mate :)

ive got my old head chart ill see if i can find it, somthing to compare to it worked ok that head bit the port runners where so big i think it was off a speedway car

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