Porting Porn

Some ALH pics...
This first is roughed in.

Pics 2, 5, and 8 are downright sexy!

Very nice

Frank, very nice pictures and a nice looking work. But it does cause me to wonder who has published before and after air flow numbers on the 1Z/AHU/ALH. Seem to remember Alex22 publishing some work about 4 years ago. But do not recall seeing any other published before and after flow data. Can you point me to any published data? Thanks,

Heh... data. What I can tell you is we worked out the kinks, as there are several. More than anything, it's a matter of removing what's totally WRONG! We know that you can remove too much, but in this head, the angles are structured by water jacketing. We straightened out the exhaust path for improved flow. If we could do more, we would. As it stands, we get responses of 200 degree EGT drops with the same performance setup. THAT was a great outcome and goal.

We have been told we have gotten it about 90% right, but then I ask,"90% of WHAT??" There is no 100% that will cover every situation. Example, a full race port would eliminate the swirl chamber and improve full-bore fueling. We are not interested in doing that. We like efficiency when we are cruising.

The starting point is to port-match to the exhaust manifold, as that can be as much as 1/4" miss. This eliminates turbulence to the manifold. The turn from the exhaust seat going out to the manifold is not easily pictured, but there is a molding mark that is just about a right angle that we radius nicely. The biggest trick is getting a good floor of the exhaust runner, while maintaining the support for the guides. I think this design is how I want it.

If you notice, the #7 picture is something I should show a before/after pic. The inside peak of the swirl chamber used to be a right-angle, which we correct for a radius. That avoids the potential for the head to crack at the juncture.

You got some porting porn? I showed you mine. Show me yours...

I see all kinds of bumps in your exhaust ports on the bottom side. Not a very smooth transition. You don't do anything to your intake bowls?

Franko6 said:

Heh... data. <snip>

As it stands, we get responses of 200 degree EGT drops with the same performance setup. THAT was a great outcome and goal.

<snip>

You got some porting porn? I showed you mine. Show me yours...

Click to expand...

Frank,

Just so I understand correctly you ran the same engine configuration with the stock head. Then installed the ported head (with no other changes??) and got a 200 degree drop in EGT? I "assume" you are talking about a drop in peak EGT, correct?

Any before and after dyno runs? If so that would be great to see you share. Realize this is likely a customer car and you simply don't have the car for testing.

Can you share any information on how the engine was set up? What turbo, what cam, peak boost, tuned ecu, etc? Anything you can share would be great.

Lastly, can you share the extra cost for the port job. Think I saw you post something like $330 to redo a stock head last year as a base cost. If you want to take this discussion to p.m., I am fine with that. Just drop me a P.M.

Thanks,

Damn it Frank, I was hoping to bust some newbie's chops over a ridiculous post. Not the case. Is there anything in the works for the BRM?

As usual, your posts are pretty close to gospel...........

shiny = gospel?

JFettig said:

shiny = gospel?

Click to expand...

Are you new at this? Shiny is ALWAYS better.

I want to see the intake and turbo reworking that go along with this head.

BuzzKen said:

Are you new at this? Shiny is ALWAYS better.
.

Click to expand...

Maybe with headers, not with heads.

They look nice but there is no bowl work done?
Most of the true power gain will be in the valve seat work and the bowl reworking for the max flow.

It comes down to flow bench numbers not just at the high lift tests. As soon as we lift the valve off the seat we need to flow as much air as we can. We need for the air to make a smooth turn in too and out of the cylinder from the moment the valve lifts off the seat. Think of it as the valve is at 0% lift to 70% of lift for 80% of the over all cam lobe shape.

Franko6 said:

We have been told we have gotten it about 90% right, but then I ask,"90% of WHAT??" There is no 100% that will cover every situation. Example, a full race port would eliminate the swirl chamber and improve full-bore fueling. We are not interested in doing that. We like efficiency when we are cruising.

Click to expand...

CNGVW said:

They look nice but there is no bowl work done?
Most of the true power gain will be in the valve seat work and the bowl reworking for the max flow.

It comes down to flow bench numbers not just at the high lift tests. As soon as we lift the valve off the seat we need to flow as much air as we can. We need for the air to make a smooth turn in too and out of the cylinder from the moment the valve lifts off the seat. Think of it as the valve is at 0% lift to 70% of lift for 80% of the over all cam lobe shape.

Click to expand...

You missed a paragraph when you were reading, methinks.

As a pragmatist, I realize is set myself up with this sticky question of porting porn. People who know enough to speak critically find what is wrong with little or no substantiation. It's just like the great but unintended famous quote by Supreme Court Justice Potter Stewart, who best said it:

"I shall not today attempt further to define the kinds of material I understand to be embraced within that shorthand description [hard-core pornography]; and perhaps I could never succeed in intelligibly doing so. But I know it when I see it..."

I chose the word "PORN" specifically. Defining an excellent porting job is opinionated as deciding what in the Supreme Courts' famous decision, is obscene. It is easy to spout an opinion, but hard to prove your point. If you are going to criticize, please provide something to back your belief. I will not accept, "I know it when I see it."
Don't spout opinion without to supporting your ideology.

I am more than willing to accept constructive criticism. I invite all those who find whatever fault with my porting, including (OMG!) too shiny, to offer up any suggestions, and better yet, stop armchair quarterbacking, put down the popcorn and SHOW YOUR PORTING PORN. Don't tell me. SHOW ME! That's as Missouri as I can get.

As for too shiny, do you think in a couple of months of real-time exposure, that shine is still there? I think a nice coating of soot will take that shine's place. Maybe dirty is good and clean becomes bad. (reference, Shelley Berman's 'Cleans and Dirtys') Or, "your dirty ports are actually an improvement over the shiny ones." That is, if shiny is really a problem. Is it really? Prove your point...

For those who pick on imperfections, some of these pics are actually larger than life, and these photographs are unretouched. Even the smallest imperfections stand out. WYSIWYG.

Rattler,

There is always room for improvement, me included. We have often ported the PD heads. It is a challenge to machine-cut the PD, as the head does not sit well. We use a right angle bolt plate to rough the head in.

In spite of the critique about bowl shape, we are not attempting to maximize effect for flow, as that would mean no swirl chamber and we want to maintain the efficiency of the swirl. But to say we are not moving the shape or size is one who has not had the head in his hands.

There are those who build with stacked turbos and there are a lot more who want the engine to last more than a few passes. We are more interested in staying within the limits of the engine's long-term reliability, not maximum effect. A max-flow ported head is for people with a lot of money to spend and something to prove. For that group, head lift is a killer.

JJ, I am sorry that I've not gotten back with you. Stupid busy and the wife is on a short hiatus. Batching it this week...

You have my number below. Call when convenient.

Frank I said it looked good. I bring up the bowel work because you are giving up some power there.

My father Dick Mann had the first SuperFlow bench in the North East in the early 70s.
I was chained to it for over 10 years. We invented and sold a small swirl meter for that machine in the 70s.

If some one is going to go down this path on cylinder head work. I would fine a good used bench and play and learn.

Grind baby grind baby grind, then dyno baby dyno baby dyno, then track test.
Then start over again.

Bob,

I thank you for your input and can appreciate the 'required bench-time'.

Anyone who has ever been to my shop knows there is a modicum of space, crammed with tools, machinery and parts. I am going to make space for vertical CNC machine, which is next on the list, but I would love to play with a flow bench. I will keep watch for a flow bench.

Thank you for your advice.

It appears that the images for all the photos has a glitch. I hope that gets fixed soon.

Frank sent me a quick P.M. Sunday night in response to my comments/questions. Since questions have come up about the high polish on the ports, I am taking the liberty of sharing what Frank told me in the P.M.:

The polish was done for show on the pictures. Frank told me the polish does not improve performance. He was right up front with out me even asking the question.

Hey guys, the thread title says it is "PORN". It makes sense to me if you are posting PORN, you are going to "pimp" the heck out of the pictures. RIGHT??

If anyone wants to see a 1980 article on porting a VW water cooled head by David Vizard, let me know and I will send/post a link I found on the IDI VWdiesel.net forums. Lots of basic information with step by step flow bench results.

In for more learning!

john.jackson9213 said:

Hey guys, the thread title says it is "PORN". It makes sense to me if you are posting PORN, you are going to "pimp" the heck out of the pictures. RIGHT??

If anyone wants to see a 1980 article on porting a VW water cooled head by David Vizard, let me know and I will send/post a link I found on the IDI VWdiesel.net forums. Lots of basic information with step by step flow bench results.

Click to expand...

The whole *item* PORN title thing has been around on forums a while. it typically means "pretty things". Well, maybe I spend a lot of time on forums, so I'm used to seeing that type of title and expecting 0 actual pornography there.

Also, yes, please! I'd like to go through that article. I'm considering getting a spare head to get work done on it and maybe one more to practice on for kicks.

I have Vizard's book... but I would LOVE to see the bench testing stuff.. let me at it!

And as I said, when I am referring to 'porn', it's hard to give a proper definition, "..But I know it when I see it!"

Since I was drawn in by the title and entirely satisfied with the shiny things, I'll pitch in with a couple of questions

I always understood (probably from David Vizards book iirc) that the port wall should still be slightly rough in order to promote turbulence and keep the atomised fuel in suspension in the air charge. A polished wall would allow the fuel to condense on the surface and so not work as well. This is obviously carburetted or port-injected gasoline engine theory. Would this be relevant in any way to a diesel engine? Or, would a nice smooth port promote better airflow and the swirl nub sort out the turbulence?

Also, Frank - you mentioned taking the swirl nub out for maximum airflow on a race engine. I've been unable to find anything useful on the Googles for what effect this would actually have on the engine, only that its not desirable on a road engine. As I'm building a race car with a TDI I'm curious to know what characteristics a max-airflow no-swirl head might create if you (or any of the experts) would care to elaborate please?

Over the years in the forums I've seen someone take out the swirl features once or twice. It doesn't have much negative impact at high RPMs (there's tons of airflow moving at high speed at that point) but it does seem to cause problems with cold engines and at low RPM, at least on VE engines. If the air isn't swirling and tumbling there's nothing to mix the fuel and air together.

It's part of the same reason using a think head gasket to reduce compression is a bad idea - quite a bit of that turbulence is caused by the air getting squished from the perimeter of the piston in to the bowl at TDC.

On a race engine which is presumably going to spend most of its life in the upper end of its RPM range you're going to have air entering the cylinder at high speed meaning it will have plenty of movement. Total airflow is probably more of a concern than cold weather low RPM smoke characteristics.

Mikkijayne said:

Since I was drawn in by the title and entirely satisfied with the shiny things, I'll pitch in with a couple of questions

I always understood (probably from David Vizards book iirc) that the port wall should still be slightly rough in order to promote turbulence and keep the atomised fuel in suspension in the air charge. A polished wall would allow the fuel to condense on the surface and so not work as well. This is obviously carburetted or port-injected gasoline engine theory. Would this be relevant in any way to a diesel engine? Or, would a nice smooth port promote better airflow and the swirl nub sort out the turbulence?

Also, Frank - you mentioned taking the swirl nub out for maximum airflow on a race engine. I've been unable to find anything useful on the Googles for what effect this would actually have on the engine, only that its not desirable on a road engine. As I'm building a race car with a TDI I'm curious to know what characteristics a max-airflow no-swirl head might create if you (or any of the experts) would care to elaborate please?

Click to expand...

Your question about the swirl nub got me thinking about Alex22's posts on the subject. He posted some very specific flow and swirl test data, then made changes and reposted fresh data.
Here is the link to his old thread:

http://forums.tdiclub.com/showthread.php?t=307098

I will need a bit of time to locate the link to the old David Vizard article. Should have it tomorrow.

Frank, Please repost the pictures!!!

Aw, man! Those were BEAUTIFUL! Please put them back up!

Google is my friend!

A quick Google search turned up the link for the David Vizard VW porting article.

Here it is:

http://www.vwdiesel.net/forum/index.php?topic=15782.0

What I like is the step by step with measured results after each step. 35 years old but still instructional.

Also found the same article pictures posted on VWVortex, but without original source credit. Oh well.

I have no control over the posted pictures. The links are still there in my photos gallery, but without thumbnails. Unfortunately, it appears that the Club has has a major glitch in that area. I hope it is recoverable. I think the moderators know about it.

Unlike a gasoline cylinder head, particularly those that depends on carburetion to mix the air and fuel prior to entering the combustion chamber, I think that quite the opposite is true for the diesel engine. Smooth is Good. The more lanier the flow, the more that can be crammed into the combustion chamber. So, I do not think the smoothness of the porting is particularly detrimental. There are problematic porting designs that cause the vortices to become smaller and closer to the surface of the port wall. I have enough problem getting the shape I desire, let alone the funky finish some flow charting is going to show as an improvement in flow.

As I have pointed out already, it isn't going to much matter how smooth I make the walls as the tendency is for a diesel engine to soot. Of course,the intakes of a non-EGR engine will stay cleaner longer, but the exhaust is going to blacken immediately. That would cause an RA hard to measure, but certainly not mirror-smooth.

Thank you for your compliments. Please vote your approval.

Frank, try using photobucket for your pic hosting. I find it much more reliable.

Hey! Pictures are back! Thanks Frank. Did you move the pictures to Photobucket?

I have ported heads and removed the bump in the port and also used thicker head gaskets to reduce CR, the results were satisfactory and without detrimental effect in start up or smoke levels, however i left the ports rough... Some 1.9 Tdi engines did feel a lot better than similar cars with same engines non ported !

I can tell you that there were some flow reports from Visard that showed improved porting if certain areas of the port were rough. Then again, that is on a flow bench, which sometimes is thwarted by the reality of the track. I really don't know. It would take a lot of testing to find a solution. Sometimes I think I'd follow instead of lead on that. Again, whether or not I make a smooth port is strictly temporary, as carbon deposits will take care of a smooth porting job all by itself.

How about some of the new sexy helix-cut swirls? The idea that air volume moves better as it spins is a very popular idea. A little tornadic activity, anyone?