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Lets See some Pics of Ported 20V heads!

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 Post subject: Lets See some Pics of Ported 20V heads!
PostPosted: Sat Feb 19, 2011 4:22 am 
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In the process of cleaning, resealing, lapping, decking, water manifolding a 7a head. Was looking at the ports right under each valve seat, and the look pretty shitty. I know I could do a light dremel job and make it way nicer than whats there. I dont wanna go to crazy, and unmatch the flows, but they probably arent to close anyway. Show me some pics

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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sat Feb 19, 2011 7:24 am 
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Give me a few hours and I can show you an unported one

Pics up later im out the door to go scoop a 7a head :D

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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sat Feb 19, 2011 5:43 pm 
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Its tough to see from my crappy photo but the marks from where the gasket was shows an even amount on all 5 exh. that could go. This thing needs to be hot tanked bad :roll: . I need a better flash or something to light up in the ports to show the casting marks and how much can come off. These shots are pretty much useless for what your asking let me try search. couldve sworn I saw ported pics somewhere.
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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sat Feb 19, 2011 5:53 pm 
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Found these :pics: using search. They are cuatrokoop's and Josh's. (not necessarily in that order)
:wtf: :D

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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sun Feb 20, 2011 9:03 am 
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All 7a's there. thats what i have but its gonna be used for a 2.6 stroker N/A. The intake I just want to clean up a bit. but the exhaust is sloppy as shit. U can even see it in ur pics, theres a huge lump at the bottom.

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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sun Feb 20, 2011 9:31 am 
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you can knife edge the center dividers, you can clean the casting marks off the walls, and can loose that lump on the bottom of the exaust ports and smooth the transition. you can even widen the mating surface to match the gasket. DO NOT change the angle of the ports just under the valve seats. DO NOT polish the intake ports as a rough surface keeps incomming flow statically turbulent to help atomize.

I would also recommend some thing a little bigger than a dremmel. it will take for eeeeevvvveeeerrrrr.... and the small tools will gouge and ruin what you want to accomplish. if you have a die grinder, use that. 1/8" arbor. google porting tools to see whats available.

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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sun Feb 20, 2011 9:34 am 
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o, and low speeds. high will just load up the tools with aluminum. you can lube the cutters to help with that also.

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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sun Feb 20, 2011 11:08 am 
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This is supposedly Hap's old head that's on my car now.

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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Tue Apr 05, 2011 3:08 pm 
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Today I cleaned up the exhaust ports in my head. I didn't remove much material, just focused on cleaning up the crap left over from casting. I got the bump near the exhaust valve guides, the seams on the walls, knife edged the center joint, and removed most of the dimple at the top and bottom of the exhaust port right near the outlet. I still need to do a final cleaning, then I'll polish. I used my finger as much as my eyes to feel where the imperfections were and try to keep everything as close to equal as possible between the each cylinder.

The intake side looked pretty good, so I didn't touch them other than one of the seams on the front most valve for cyl one...that one was pretty nasty.

I checked port size with new gaskets, and the exhaust side is pretty damn close to matched, but the intake side has quite a bit of room to grow. Any thoughts on this? Seeing as I don't have a flow bench I'm leaning towards not messing with them, but am open to suggestions. The runners on a spare intake mani that I have are even smaller than the ports in the head, so I don't know if it would do much good to try to open them up...I can't reach all the way up in there with any of the tools I have.

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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sat Apr 09, 2011 8:58 pm 
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this my first time messing around with porting and polishing, didnt actually remove all that much material, just a couple of spots and then smooth it out.


Attachments:
File comment: after cleaning,
exhaust port1.jpg
exhaust port1.jpg [ 23.23 KiB | Viewed 13494 times ]
File comment: after polishing
exhaustport2.jpg
exhaustport2.jpg [ 25.16 KiB | Viewed 13494 times ]

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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sat Dec 10, 2011 9:03 am 
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Resurrecting an old thread(not the done thing i know usually) and being a newbie here at the same time with some pics from heads ive done for others.

Done a fair bit of work on the 20 valve motors for various people and the same thing always crops up with them; theyre a pain to get more flow out of. :)

Stock intakes look a bit messy with a rough surface finish and guide bosses that are quite wide.

Image

As you can see here theyre quite rough which creates a viscous drag loss.
This ones on test to determine the flow across the lift range.
You can also test to see if lifting the valves higher gains any more flow.

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Exhaust ports similarly messy but can be easily improved, unlike the intakes.

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Doing a lift test here on a 7A head.

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Blocking off one side of the port whilst making incremental mods to see what results.
Usually you find you can get a certain flow figure i dunno, say 125cfm@28" depression down that one side, yet when you make identical mods to the other side the total flow dosent equal what you had if you summed up both sides individually.
I would think thatd be turbulence or flows colliding as they exit the port creating a restriction that you cant get rid of.....

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I usually aim for an 80 to 120 grit surface finish on the intakes, anything finers pointless and may even flow worse.

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Quick look back up the ports from the chamber.

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Arty photo done with an led torch...comes out blue looking.

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Since i bought a professional valve seat cutter it makes the job of doing valve seats at home a snap.
This ones a Mira seat cutter from switzerland, really lovely to use, hand driven but highly accurate.
Where i live (central uk) theres really no one i can trust to do this job, so i went and got equipped to do my stuff myself along with the usual valve guide replacement and flow tests.
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The business end- uses "formtools" to cut any angle combo you could want.
I tend to stick to 45 seatX2.0mm with a 70 degree bottom cut.
I usually belnd the top out into the chamber by hand as its not very easy to get a fully formed top cut in the available chamber space and impossible on the intake sides as you have that godawful step thats there from the factory.

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Finished items generally take on this appearance, almost too nice to put on a block. :)

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Exhaust ports end up finished at 120grit just to try and keep them from gaining too much carbon buildup.

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That head came from this tired old 7A which i rebuilt for a friend.

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It was running a very badly screwed on set of triumph bike throttle bodies which i had to totally re-engineer.

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Couldnt really reuse any of the original setup as it was a mess and didnt fit right.
Intake trumpets i couldnt buy so i made them myself one rainy saturday afternoon along with the rest of the throttle body setup.

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Motor came out ok as well after i got it all put back in one piece. :)

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Ive done a fair few other heads, not only 20 valvers ( they have such a lot of work in them!) but also.....

8 valve "DX" head for Golfs.

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Intakes are easier to work on than the multivalve heads!

What ive done here is to open out the valve seat to the maximum diameter of the intake valves.
That little step you can see gets blended in after im finished,

Image

Hope i didnt bore ya all too much on this one! :)

Tony.


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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sat Dec 10, 2011 9:40 am 
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Well done Tony, very nice. May I ask how much was the valve seat cutter?
Ive just watched recently this Basic Engine Building DVD by boxwrench and i learned a lot.
Keep us posted.

Chris

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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sat Dec 10, 2011 10:09 am 
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Hiya Chris thanks for your comments.

It was rather expensive,~2400 uk pounds more than my quattro cost me. :)
Before that i had a PEG 10 valve grinder that was an awesome piece of kit but i just couldnt settle with it.
It ran at something like 10k rpm and scared me silly so i parted it out for the Mira kit which just suits me fine.

Edited to add, if youre really into engines, flowtesting and improvements i can recommend a book by ex F1 race engine builder Guy Croft, deals mainly with Fiat motors but the material is just as relevant to any engine.


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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sat Dec 10, 2011 10:43 am 
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Thank you Tony for the info.
Im not really into engines (yet) but I just started to rebuild my 3B and I want to do many things with it.
Im not on the hurry, still collecting parts whoever I got few good bits already.
I just want to learn few things in theory before i take my engine to a machine shop (not much good around here) so i know what to look for, what they are talking about etc.

Chris

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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sat Dec 10, 2011 12:09 pm 
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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sat Dec 10, 2011 12:56 pm 
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That 20v is gonna scream.. I would love to hear that running

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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sat Dec 10, 2011 1:08 pm 
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Me too! Its currently being wired in to an 80 quattro for a friend of mine so im sure i can get some footage of it running ....or blowing up. :)


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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sat Dec 10, 2011 4:40 pm 
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Really nice work. Thanks for sharing the pics and info

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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sat Dec 10, 2011 6:35 pm 
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Good show, Tony!
Can you speak a little bit or post some pics regarding unshrouding the valves (7a) and streamlining the part of the valve guide that protrudes into the port?

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Last edited by rathergoodaudis on Sat Dec 10, 2011 8:23 pm, edited 1 time in total.

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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sat Dec 10, 2011 7:06 pm 
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Hell of a first post, man! Wish I had the patience/time/skill to do something like that...

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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sun Dec 11, 2011 9:03 am 
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Thanks for all the comments fellas, very much appreciated, hope i can answer some of the queries tho! :)

Streamlining the intake guides isnt something ive put much effort into mainly as the material on these 20 valve heads is pretty tough, well, quite a bit tougher than that of other heads ive worked on like Toyota and Mazda, even the 10 valvers seem a lot softer and they cut a lot quicker and easier.

Access is a bit of a pain also and trying to get them all the same is one of those jobs that takes an age so as of yet ive not really experimented with that streamlining aspect.

I tend to lower the height and reduce the width which gets a gain, the only downside ive found is that when the guides go back in you can sometimes get a skewing effect ( its miniscule) that kicks the guide over to the side unsupported.
Although its very minor it can happen.
Having said that though, they always and i do mean always, go back in on the skew anyways, just they tend to aim in other directions, they never line up as previously and you notice it when you cut the seat with it being a tad offcentre.

One of the main problems i found that also causes that skew-over, is the interference fit between the guide and its bore in the head.
Every single time ive removed the oem guides ive measured them and found them to be 12.04-12.05mm.
But the aftermarket stuff seems to vary wildly, 12.08mm not being uncommon, meaning obviously that theyre way too tight, and it shows when you try to install them as the pressure gauge starts to rise too high.
Ive also found wide differences between the internal sizes of aftermarket guides such that the on set had more slop between the stem as a new item than the old worn out guide exhibited.
Incidentally i always press them out and in cold, using copper anti seize compound as a lubricant, i dont use any other lube like moly or motor oil as it dosnt work as well.
Cold pressing means you can get a feel for how much pressure its taking to push them in, you dont get that if you warm the head up or cool the guides down and in extreme cases if the interference fit is too much you can crack the head, plus you cant get the guide stuck if its at room temps along with the head.

Aftermarket 20 valve guide...this ones from febi. This is 12.08mm, not the oem size of 12.04/5 mm.
Means i have to hone each one down to size so with 20 guides, it takes a while!
Image

I nearly always reduce the guide height fractionally also, i never shave them to the surface of the port, itd compromise reliability too much.
They get a "bullet" nose applied to them also which reduces their intrusion into the airstream.

Image

Heres the aftermarket one as they come to me on the far left, the others are as removed from the head.

Image

Some almost finished ones.
Resized, shortened a fraction and bullet nosed.
Note: since this photo was taken ive refined the shape further, its all subtle stuff, but it does work.

Image

Guide bosses arent entirely removed as id be scared of a breakthough into a water jacket for one thing and for another itd probably skew the guide even further offcentre than usual.

Image

With the guides in you can how much less of an impact that whole area has in terms of restriction and its measurable too.

Image

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I did do some tests with "infilling" as on other heads ive found you can get an apparent ( not to my mind proven yet) flow increase by adding in material at a specific point just before the short side radius on these heads.
I was a little worried about adding in an epoxy resin filler to a clients property to have it dislodge later on so ive not investigated it further although it did show an apparent worthwhile increase of a few cfm.

Image

Exhaust port bosses can be simply flushed to the surrounding area as its small anyway and is a carbon trap.

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My old PEG10 valve grinder used a solid pilot that fits inside the guides and is tightened with a small screw at the base.

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The actual grinding head with the integral motor sits over the pilot and is adjusted downwards until it starts to contact the seat.
The whole machine does an oscillation, both round the seat and in an orbit.
Seriously cool to watch but also somewhat frightening as it goes a fair speed.

Image

Regarding the deshrouding aspect.
I did do a little work on that but i didnt seem to find any extra flow.
I suppose my testing regime could have been a little more rigorous really and maybe something would have become apparent.
Since ive got an AAN motor in my own quattro (unfinished as yet) there will doubtless come a time for the head to be removed for some work to be done on it, ill see what i can find out about deshrouding on these heads from that as and when.

Something else just sprung to mind, and this applies to any head, the manifolds need to outflow the ports.
I did some tests on an ABY and found they just about matched the bare port flows of the head when they were unmodified.
You tend to get some natural inherent flow bias due to the design with all these things anyway which you cant do anything about, but getting the runners of the manifold to outflow the ports is pretty vital or else all the work you put into the ports gets strangled by the manifold....
Making it larger than the ports and tapering it down internally is one way out of that.

Image

This particular head came with a brand new AAN exhaust manifold that the client wanted matched to the ports.
With any exhaust you want to have the manifold at the face larger than the port so you have a step that discourages backflowing during overlap, pity the stock item is the wrong way around!

Image

Looking out the exhaust port and a nice (or rather nasty) step presents itself.
Has to go.

Image

Not only that, imagine youve just spent XXX$ on a new turbo and this breaks off inside and shatters the turbine...
Gave me a nice cut as well, teach me to stick my fingers down unauthorised holes...

Image

Very hard to get any kind of grinding tool in there so i used an extended carbide burr on a small flexi to remove it all.

Image

Anyways, i think ive drifted slightly off the thread topic.... hope this helps someone out.

OOps! Forgot the flowtest result.
Typical result, test carried out at 10" depression converted to 28".
Note: Ignore the apparent drop in flow at 7mm lift on the modified (top line obviously), thats a lifting error, and my fault.
Also dosnt show bare port flow on here.
Stock was-190cfm.
Modified- 215cfm max.
Flows dont quite intersect at max lift but thats not always possible to do anyway.

Image


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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sun Dec 11, 2011 9:25 am 
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Very nice, if that is a pic of the "new aan manifold" thats actually an RS2 manifold.

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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sun Dec 11, 2011 1:21 pm 
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Wow. I must say that, compared to the lot of we flailing louts, you are quite an asset to the community.

I'm glad you touched on the subject of anti-reversionary exhaust ports - this is important for turbo and N/A alike.

One thing I had heard from professionals in the VW 16v arena is that the greatest and easiest gains in power come from unshrouding the valves aggressively - even despite the compression loss.

I'd heard it from more than one source, so I wonder if it's something that can't be quantified using the constant, one-way flow of a test rig. For instance, as a wild guess, it could contribute to better charge stratification instead of gross flow... dunno.

Your lucid documention is much appreciated.

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 Post subject: Re: Lets See some Pics of Ported 20V heads!
PostPosted: Sun Dec 11, 2011 1:56 pm 
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crappyoldaudis wrote:
Wow. I must say that, compared to the lot of we flailing louts, you are quite an asset to the community.

I'm glad you touched on the subject of anti-reversionary exhaust ports - this is important for turbo and N/A alike.

One thing I had heard from professionals in the VW 16v arena is that the greatest and easiest gains in power come from unshrouding the valves aggressively - even despite the compression loss.

I'd heard it from more than one source, so I wonder if it's something that can't be quantified using the constant, one-way flow of a test rig. For instance, as a wild guess, it could contribute to better charge stratification instead of gross flow... dunno.

Your lucid documention is much appreciated.


Ha ha, i tend to do a fair bit of flailing and have often been described as a lout in various quarters. :)

Ive only seen photos of the Vw 16 valvers and they do look almost the same but ive no idea if thats the case.
If that report regarding aggressive deshrouding is accurate then im not too worried about a little compression loss on a turbo unit and ill trade a little of that for lots more flow any day of the week.
Ill see if i can get a hold of an unserviceable head and experiment on that, for sure its something id like to investigate, especially if it gets rid of some of the myths surrounding what does and dosnt work....frustrating to not actually "know".

Pretty sure the test rig should show it up, after all, the flows coming in as it usually does, impacts on all the same surfaces, just does it quicker, will see.

Thanks for your remarks, appreciated.


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PostPosted: Sun Dec 11, 2011 8:53 pm 
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Good stuff. Thanks for the posting! Keep it coming! 8-)

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