[383494]

Extrude-Hone

I have used this process a couple of times and while I don't have a dyno, it is a proven reliable and relatively reasonable technology originally developed by GE Aerospace.

Your head, manifold(s) are mounted on a an extruding abrasive polymer pump. As this flows it naturally follows the hydraulic pathway and removes material in a fashion similar to airflow. The results are impressive. The process mates manifold flanges to engine gas inlets/outlets. As it follows physics as opposed to what a manual porter may think is the best mechanical means to enlarge and reshape ports, the results follow the laws of fluid/gas flow dynamics.

OEM manufacturers are now using this tech.

Cheers, S

 

[ghnl]

What is the approximate cost?

 

[383494]

They offer free quotes but with my projects it was within reasonable parameters compared to other means.

 

[iachella]

I have heard of this for cast iron manifolds and wanted to do that, but I was put off by the cost. I can't remember exactly, but a new set of headers was cheaper. I wanted to keep the Alfa manifolds and improve them because I don't like the sound SS headers make. I decided to leave the Alfa manifolds alone.

I did not realize the use in the porting of the head though. It should be cheaper than head work, as you set it up and let the machine do the work pumping the slurry. I hope someone tries it out. Actually, I have a spare 155 head for a future project. Maybe I should inquire. Do you leave the valve seats in place?

 

[Alfar7]

I would not spend my $$ on it. Period.

 

[383494]

Your opinion. Just putting it out there isn't that what this forum is about?

 

[classicalfas]

I’ve heard of this is the early ‘90’s, extrude hone technology, didn’t seem to take off though.

 

[PSk]

This is not going to take into account size changes (reductions) used to increase velocity, it will just bore out to suit the volume of stuff being pumped through it. There is more to porting than just making everything bigger. Yes it will help align ports ... and maybe improve internal casting quality, but that is not porting IMO

Okay I read the link. This is for blueprinting, not porting for extensive modifications. Apologies, when I think of porting I think of the porting modifications to say take a Sud engine from 105hp to 200hp. This won't do that, but it might tidy up the by-hand created ports afterwards
Pete

 

[383494]

I have heard of this for cast iron manifolds and wanted to do that, but I was put off by the cost. I can't remember exactly, but a new set of headers was cheaper. I wanted to keep the Alfa manifolds and improve them because I don't like the sound SS headers make. I decided to leave the Alfa manifolds alone.

I did not realize the use in the porting of the head though. It should be cheaper than head work, as you set it up and let the machine do the work pumping the slurry. I hope someone tries it out. Actually, I have a spare 155 head for a future project. Maybe I should inquire. Do you leave the valve seats in place?

Iachella, the cost is significant but my Ducati head came out beautifully. The slurry matched my manifold and the ports perfectly. It's an interesting and IMO a logical method for porting if that is necessary for the application. Many engines crossflow or not seem to be designed inefficiently at best. Alfas are gorgeous, but I think there would be room for improvement with flow. For the street proper carbs/inj. and tuned exhaust would suffice. I agree with you on headers, sometimes they don't sound great. The cross section of the Alfa head shows a difficult exhaust path when fitted in the car; always a compromise. Regardless they are fantastic little motors capable of great things, stock or full race.

Cheers, S

 

[PSk]

I just watched their video and I do not understand why they never showed the result of this process. Nobody is interested in watching worms move about, we want to see the internal result. I also noticed that for one manifold (not car related) where the goo did not even come out the right end port, and that is because it had found an easier way to go and that was through the middle ports. So consider a single carb manifold for a 4 cylinder or v8, the central ports will be oversized compared to the end ports.

They need to introduce a way of restricting the "this is easy I'll always go this way" process to equate the end result. Would not be a problem for a Nord engine with twin side draught carbs though, or a v2 Ducati
Pete

 

[383494]

This is not going to take into account size changes (reductions) used to increase velocity, it will just bore out to suit the volume of stuff being pumped through it. There is more to porting than just making everything bigger. Yes it will help align ports ... and maybe improve internal casting quality, but that is not porting IMO

Okay I read the link. This is for blueprinting, not porting for extensive modifications. Apologies, when I think of porting I think of the porting modifications to say take a Sud engine from 105hp to 200hp. This won't do that, but it might tidy up the by-hand created ports afterwards
Pete

I look at these forums as exactly that, forums. To initiate conversation, so I appreciate you looked at the link. That's why I posted it, interesting approach. I never suggested that this was an all out hail mary port job, I like the elegance of fluid dynamics expressed by the technique. Inevitably on forums someone has to just shoot someone trying to benefit from the collective's experience down. I am here to learn, and offer up what I have found interesting and or effective. Appreciate your response.

S

 

[PSk]

Quite a few modern inlet manifolds are S shaped, so this would clean those internal passages up well, I think ... as long as individual ports.

I think for manifolds where 1 carb hole goes to 4+ ports, they need to introduce restrictions so the pressure is even in each port to get even work done to each port, otherwise as I said in the earlier post, the easiest path will get the most 'blueprinting'
Pete

 

[iachella]

I noticed that fifth hole too. The first hold was going pretty slow too. Maybe for cylinder heads they can do one at a time. I was also waiting for them to show the shiny new ports.

They do mention this does not increase the volume per se, but will increase velocity due to a smoother path. Proper porting should be accomplished by the professional knowing where to remove aluminum and then this could be a final polish to remove machine marks and groves. Expensive polish though.

 

[383494]

Well, it's accomplished conversation. Hand porting is a science if not a "black art"...from Flathead Ford V-8's in the '40's and 50's to every tuner tearing into a Honda VTEC. The Ducati 250cc I have built, going in a late '50's F3 replica was a perfect candidate and I was pleased. Removing metal with a precious old narrowcase Duc head can have your "oh ****" moments but this did the trick. After NikaSil'ing the cylinder, a Carillo rod, Ross piston, hot street cam, oversize valves, fully balanced electropolished crank and rotating assembly the Duc is 9,500 rpm plus, hoping for 30 HP. Basically a vintage Italian 4-stroke chainsaw motor. I find great pleasure in investigating interesting technologies. Hope everyone else might too or change the channel.

Cheers, S

 

[Jim G]

I noticed that fifth hole too. The first hold was going pretty slow too. Maybe for cylinder heads they can do one at a time. I was also waiting for them to show the shiny new ports.

They do mention this does not increase the volume per se, but will increase velocity due to a smoother path. Proper porting should be accomplished by the professional knowing where to remove aluminum and then this could be a final polish to remove machine marks and groves. Expensive polish though.

Ther eis a page of before and after pictures. Showing the typical semi smooth casting. Then the perfectly polished casting after they are done.

 

[PSk]

So there is! Thanks

Pete

 

[Alfar7]

A reminder. Polished ports are old school with modern air and fuel flow data as a fuel adheres to a slick surface finish and remains in the charge over an irregular surface.
Modern manifolds retain the porting marks from CNC machining and casting finishes for this reason.

A surface smoothed but leaving the sanding disk finish works well. You don`t polish them to a shine as being suggested.

Again Extrude honing isn`t porting just a surface finish with edges matched. Not worth the cost as it doesn`t modify port shape that does improve flow.

 

[horsewidower]

The "polish" in "port and polish" is passe'. At least on the intake side where fuel has been introduced.

I have thought about using it on stock V6 exhaust manifolds, as a way to clean up the interior prior to coating.

I certainly appreciate the original poster's sharing of the information. Part of any conversation is the back and forth exchange of ideas, both pro and con. It's simply a part of the process.

 

[iachella]

Maybe just exhaust ports and manifold? I wonder if they can set it up at the exhaust port in the combustion chamber and force it out and through the manifold. Sounds like a complicated setup, though.

 

[4sfed]

The ports in your cast Alfa manifold (exhaust or intake) are created by a core. If that core is cracked when the manifold is cast, metal will flow into the crack and create a fin that can obstruct flow. Extrude honing is very effective at removing that obstruction ... and was used in the '80's by Buick on the GNX exhaust manifolds, as some of the fins were breaking off and destroying the turbochargers.

Extrude honing the intake of a carbureted or Spica injected Alfa is likely much less effective than just cleaning up the sharp corners around the short port with a cartridge roll ... a 15 minute job. On engines with a single throttle body, it might provide a noticeable improvement.

For a significant improvement, the ports need to be reduced in cross section to increase velocity, and the floor raised to create a larger radius on the short side. When results are measured on the dyno, improvements to the intake are several times more effective than anything done to the exhaust port.

My method is to install inserts in the bottom of the intake port and weld the floor of the exhaust port ... I don't think an insert would survive the exhaust long term. The ports are roughed in on a CNC mill and hand finished. Formula GT in Germany also reduces port dimensions but uses a different method.