Porting feedback

[adrianphu123 73]

Hey guys, just looking for feedback on 2 inlet ports I roughly ported this afternoon. First time porting so Im sure there are many improvements to be made.

 

 

 

 

 

 

 

 

 

Im practicing for an early unmarked head to suit cam 234 deg @ 50 and 0.550" valve lift.

 

 

thanks guys,

 

adrian.

[XFGHIA747 76]

Looking like a good start mate.. dont be afraid to open up the area from the valve seat down to the guide and it doesnt hurt if you round a bit of the guide off either try and make a slight channel from the the back where you havnt touched down past the guide.. remember your trying to port in the direction of flow so looking up your inlet port you want to picture where your fuel and air need to travel, but id work around the valve seat, and guide abit more.. but hey im just a back yarder so i could be just talking shit theres a few good guys on here that no there shit they might have some good advice,

one good thing that is very hand is some long carbide bit with a few different shapes i normaly only us one or to never the ones with the sharp squared off endes as the dig into much.

Also might sound stupid but a old bloke told me one day if your doing some porting on aluminum cook up some chops the night before and get all the fat and every so oftern dip your bit in to stop it cloging up.. all i ever do now..

cheers Jake

Goodluck.

[ando76 4,354]

Kerosene works just as good as chop fat and is much easier to source. 

 

Not a bad start to the porting exercise.  What has already been said about the guide and seat area is correct in my view.  You want to aim for 85-88% of valve face area in the bowl.  work out what that is and then put an old valve (exhaust valves are usually pretty close) in the lathe and machine it down to size.  Use that to help you make sure you are taking material from the right area. 

 

have a look in the old 'Crossflow porting results thread"  - some good info in there.

[gerg 10,871]

Yeah as the others said, looking good. It could have a bit more off from the sides of the guide boss so the air isn't pushed too far out from it, also the sharp corners off the front of it might be a bit turbulent.

 

Other than that, as said already a bit more out of the throat wouldn't hurt.

[broken-wheel 659]

before you go further buy some inside callipers and start taking measurements, don't be scared to open up below the seat a little and don't try and make air flow go where you want it to go! use blueing ink and paint the ports then vacuum some media though the port and see where it hits the blueing ink at different valve openings, you will be surprised how well the standard head flows if you only touch a few things in the throat. Don't lay back the short turn, it will stall the air massively instead take quite a bit from the bellow the seat. Hard to explain but you're aiming for the throat to be like a hour glass.

 

Don't open up anything from the bowl to the manifold, it's enough to flow 350hp, in fact don't touch that side of the port, don't even "polish" it. You can get the stock head to flow 300hp with just a little pocket work and a really good seat. I know it's hard not making it look good but don't touch anything from the pocket to the face of the intake manifold, that part of the port has a weird shape as it bends, don't try and straighten it as the flow will separate and it will start howling at anything over 400 lift. 

 

Good luck!

[adrianphu123 73]

Hey guys, took your suggestions on board and did a bit more work this afternoon. I had trouble getting to the back of the valve guide, i didnt have a burr that would fit so thats next on the list along with some inside calipers.

 

Ando, the 85-88%, is that for the bowl or the throat?

 

I made about 3 light passes in the bowl area and did a bit of work around the valve guide. The intake tract and short turn was only textured by the burr using 1 light pass at slow speed.

 

I also tried to round off the front of the guide boss but i think it still needs more work.

 

 

 

A few questions,

 

Does it matter if I nick the valve guide?

 

Do I go to the gasket line on the inlet manifold face?

[broken-wheel 659]

ignore the valve guide, normally I pull press it out and take everything off then press it back it and use the valve guide as a set point for measurements, this is how I copy one port to the other with an internal calliper 

 

I'd cut the head so you get two cylinders so you get 3 lots of 2 to play with. Only play with one of the two! and try different things then take them to a flow bench and see how well you've done, you'll find that the boss around the guide has fuck all restriction hence I don't waste time I just press it out and cut the boss out, you can then taper the valve guide if you want, again i found less than .5 CFM there so it's not worth the time.

 

Do not go to the gasket anywhere! cut the gasket to match. This is one thing where everybody who don't have a clue fuck up, never port match to gasket! port match is between the head and the manifold, intake or exhaust, the gasket is 1mm makes no difference, if you're anal you can epoxy in the rest where the gasket don't match so you have very good transition but in reality you will never get the intake manifold (4bbl or 2bbl) to outflow a good xflow head. 

 

remember, it's easy to take metal away and hard to put it back, you can Tig it back on an start again but yeah ...

[ando76 4,354]

broken wheel some good solid advice there - it sounds like you have done a few of these heads.  Would be really interested to see some flow bench figures from your heads.

Adrianphu - I'd just have a good look at what Sean has done over in the crossflow porting results thread and stick to making your bowl work look like that.  He has posted up the flow figures showing the improvements each change has made.  In my opinion you would be mad not to use that resource.

 

Pretty sure I put Thor's head flow figures up in that thread as well.  Don't think you will get close to them but if you can make good solid gains in the low lift areas, then you will a noticeable difference. 

 

Try not to hammer the guide too much if you can. 
 

[broken-wheel 659]

i only got to about 351hp (yeah weird number) at .550 lift but that was with a close to 1.9" valve, biggest I can fit before it kisses the exhaust valve but I'm not a head porter, i just tried what I have seen, again most of the time it's all in the valve job rather than porting, sometimes I cannot stress enough how much a good valve job makes a difference. I started to stall at around 340HP @.550 lift and go backwards at .600 lift but a new seat profile pushed it to 351hp at .550 and 350@ .600 lift, i can't get more flow past .600 but one of the best guys in the country is going to share some info with me soon, basically once you get past 600 lift chamber and cyl wall  shrouding becomes critical all other things being equal, anyhow it's all pointless as most manifolds don't flow that

 

you should be able to make 1.3hp per cubic inch or else you're not even trying, 1.5hp per cubic inch can be achievable on a crossy then use pipemax and see what you gain from cross sectional area and valve surface area

[ando76 4,354]

Do you have CFM figures rather than HP as they can be a bit tricky. 

 

I hear what your saying about the manifolds not flowing as good as the heads but don't get to caught up on this.  I have seen good heads overcome the 'restrictions' in the manifold experienced on the flowbench - once they are in real life.

 

+1 on the valve seat.  The greatest airflow gains are experienced at the seat - and also the way the back surface of the valves are done.

 

Having said that Adrian - your porting efforts so far will help.  Don't forget that once you have ported all the intake runners you will need to fit the valves and then CC all your intake runners to make sure they are all the same.  No point doing all this and having one cylinder performing better than the others.  Are the fun of porting heads. 

[gerg 10,871]

Broken-wheel I think 1.5 hp per cube on a crossy is at the extreme end of the performance scale. I've met Adrian personally and can tell you that his car is a very neat streeter and not an all-out race car. If his aim is to boost performance and have some driveability (still possible with that cam) then one horse per cube would be more realistic. Even at that, some rpm would have to be on board to achieve it, again not something easily done with a stock bottom end.

 

Realistically, I think 200 hp is a great achievement for a street crossy. It is after all more than a 50% increase over stock.

[broken-wheel 659]

agreed, 1.5 is a lot to ask for the bottom end but 1.3 is enough to wake it up and hold together, I think the notion of using a big carb and chasing revs is the problem, if you're not into drag racing then a T5 with 3.45 or 3.7 gears and just a good valve job and very minor porting on a aussie speed with a 600 vac carb would smoke the rears everywhere and put a lot of cars to shame, use the gears instead of raising the revs and you've got a tree stump puller that will love you long time 

 

ando, the stock port orifice (not the whole port just the orifice, i used a pipe with the same diameter) flowed 249 with out any aids (plasticine/flared ends) 227@550@28" is what I got up to, i expect to get 235@600 from 300 to 400 lift there is a gain of over 30cfm so it's obviously stalling after that a little 

 

i had a 30degree back cut on the valve, might put a radius on that on the stem side and see if it makes a difference, there are good gains to be had right behind the seat, hard to explain but if you look at the type r DC2 motor youtube video you'll see where the japs polished behind the seat, that was 5cfm

 

also the E2 stamped heads are better flowing than the C2 if you only lay back the chamber a little around the intake valve, i know it goes agains the grain but yeah the chamber design is quite good

 

problem with the aussie speed manifold is that it has ok distribution but shit flow potential which is not their problem really it's a design flaw, the plenum is quite big in order to make the distribution ok, the problem is the fuel suspension really suffers and drops off by the time it his the port at low RPM so it will be a pig, now add reversion and air being sucked from other cylinders due to the overlap of a big cam and you quickly get a very cranky engine at anything under 2500 rpm, it will get OK by 3000 rpm and run out of steam at 5500 rpm so you really have 2500 rpm of usage.

 

add 6 trumpets and you can really crank lift and overlap without any problems, other thing is everybody knows IDA's and DCOE's love timing!

[Mustardxf 29]

Hey guys, what do you think about this head and specs. 

[Mustardxf 29]

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[wagoon 2,429]

Whats the intended use for the head/car mustardxf

[ando76 4,354]

at 500 your intake to exhaust percentage is 68%

at 400 its 72%

at 300 its 76.5%

at 200 its 87%

at 100 its 96%

 

what does all this mean - your exhaust flow needs to lift to match the inlet and improve you inlet to exhaust percentage.  Or bolt on a four barrel manifold and flow the head again.  Then you will get your true inlet to exhaust percentages.

 

What does that mean - well if you don't have good inlet to exhaust percentage you will need a camshaft to suit otherwise you will not be able to take advantage of all that intake flow.

 

But hey - I'm only one man with one opinion on what makes engines go....

[NZXD 2,328]

at 500 your intake to exhaust percentage is 68%

at 400 its 72%

at 300 its 76.5%

at 200 its 87%

at 100 its 96%

 

what does all this mean - your exhaust flow needs to lift to match the inlet and improve you inlet to exhaust percentage.  Or bolt on a four barrel manifold and flow the head again.  Then you will get your true inlet to exhaust percentages.

 

What does that mean - well if you don't have good inlet to exhaust percentage you will need a camshaft to suit otherwise you will not be able to take advantage of all that intake flow.

 

But hey - I'm only one man with one opinion on what makes engines go....

 

Interesting reading Ando.

 

What would the ideal percentages be?

[Mustardxf 29]

Whats the intended use for the head/car mustardxf

Just a street strip car. It will be my first car.

 

 

 

at 500 your intake to exhaust percentage is 68%

at 400 its 72%

at 300 its 76.5%

at 200 its 87%

at 100 its 96%

 

what does all this mean - your exhaust flow needs to lift to match the inlet and improve you inlet to exhaust percentage.  Or bolt on a four barrel manifold and flow the head again.  Then you will get your true inlet to exhaust percentages.

 

What does that mean - well if you don't have good inlet to exhaust percentage you will need a camshaft to suit otherwise you will not be able to take advantage of all that intake flow.

 

But hey - I'm only one man with one opinion on what makes engines go....

nice read, makes sense.

The motor has a 4 barrel Aussie speed port matched with a 600 holley. I don't know whether the flow test was with the 4 barrel or not. the cam was a solid custom grind to best suit the head setup.

[ando76 4,354]

Port matched aussiespeed - hello big alarm bells ringing.  why do people not read the instructions on the website.  bet they have matched the ports 100% to the head, as you would in a v8.  Big no no in an I6 manifold.  If that has been done you can just about guarantee that manifold is fukd. Just 1mm removed from the high speed side of 1 & 6 increases flow in those cylinders by 8cfm and trust me they don't need touching there.  Shame there are a lot of people out there that think they know what they are doing when the 'port match' an I6 manifold without any thought to the manufactures recommendations.

 

If those figures are with the manifold fitted - which I highly doubt - then you better send the head back to the porter to speed up the exhaust - otherwise it will not achieve its full potential. 

 

As to ideal intake to exhaust percentages - depends on application and your teacher.  I have a percentage which I aim for but am I sharing that knowledge - nope. 

[matt_lamb_160 252]

Anything over 60% is ok. But closer to 75% would be better. You can have loads of exhaust flow so long as it doesn't mean a big port or hindered intake flow, but volumetric efficiency does not improve (measurably) once you pass 80% and chances are you are hurting something else.

[ando76 4,354]

Matt Lamb another student of Vizard...  yep not far off what I aim for.  depends a lot on application and cam but yes good baseline info from Matt.

 

P.S. Matt - did I ever send you that stuff on 'No loss exhaust systems' by Vizard????

 

 

[Mustardxf 29]

Port matched aussiespeed - hello big alarm bells ringing.  why do people not read the instructions on the website.  bet they have matched the ports 100% to the head, as you would in a v8.  Big no no in an I6 manifold.  If that has been done you can just about guarantee that manifold is fukd. Just 1mm removed from the high speed side of 1 & 6 increases flow in those cylinders by 8cfm and trust me they don't need touching there.  Shame there are a lot of people out there that think they know what they are doing when the 'port match' an I6 manifold without any thought to the manufactures recommendations.

 

If those figures are with the manifold fitted - which I highly doubt - then you better send the head back to the porter to speed up the exhaust - otherwise it will not achieve its full potential. 

 

As to ideal intake to exhaust percentages - depends on application and your teacher.  I have a percentage which I aim for but am I sharing that knowledge - nope. 

Non of this work is on my end. It might not of been port matched I might just be thinking that(after reading that I am hoping it was just a thought). The head porter himself was very happy with how this head turned out and the engine builder was very happy with it as well, Guess ill just wait and see how it performs.

[ando76 4,354]

We are all different and we all have different thoughts as to what works - look at V8 supercars - 100 different ideas and they all end up pretty close.  Don't take what I say as gospel mate - im just one small time engine builder.  plenty of better builders out there.  I'm just offering my thoughts.

[matt_lamb_160 252]

No you didn't Ando (you did try at one stage), but I'd like to read it. Vizard just stole(possibly a bit harsh as he has contributed) what he presents about flow percentages unfortunately. It was published by someone (Charles Taylor) along time before him, Vizard just cashed in in it (with little to no reference to the original work). In saying this, yes, I do always like reading what he has to say. He is a bit condescending in person, but a smart guy who has got to play with cool things for a long time.

 

Oh, and I say listen to Ando on the port matching (if you just take material out of the Aussiespeed you will probably make it worse) and I will go further and say the inlet port on any engine should be slightly smaller than the head.

[wagoon 2,429]

This is the flow figures from my cylinder head I am using on my build. As you can see the figures on the right (test was with manifold attached to head) changed a lot compared to the figures on the left which were head only. All testing was done by the same person on the same bench. This head was ported for short circuit type racing where punch/torque out of the corners is more important than all out flow/horsepower