# CNC porting of cyl. head on 3 axis + 3d scanning of ports



## spaceman_spiff (Oct 27, 2014)

My goal is to CNC port the cylinder head for the 2.2/2.5 Chrysler 4 cylinder k-car from the 80's and 90's.

I have broken this down into a few steps:

Step 1. Make silicone mold of ports and combustion chamber (silicone off ebay for about $40)
Step 2. Scan molds using laser scanner (DAVID scanner + barcode laser line generator)
Step 3. Create 3D model of mold scans using Geomagic and Solidworks 
Step 4. Use 3D model as a guide to create a custom combustion chamber and intake/exhaust runners
Step 5. Use Camworks to create toolpaths and machine cylinder head runners and CC on 3 axis using a few fixed setups.

So far I've gotten to step 5, but only for a small part of the combustion chamber.

I believe that using all the CAD and CAM software tools, you could reach all required internal geometry on the head using just a 3 axis mill with a couple fixed setups.

The CAD and CAM software do their job and help you figure out how to get to all the surfaces on a 3 axis with minimal setups.

If you take your average cylinder head, and say a 3/8" rod, you can see that most of the surfaces are visible from one perspective. Now add a few more vantage points and a tool that can undercut like a spherical ball mill or just a ball mill with a reduced shank, and you can get to 100% of them, at least on this head. 

So I think this can be done on a 3 axis with minimal additional setups.

Keep in mind that the scans of the head only function as guides. Whatever design you want for the CC and runners gets drawn up in Solidworks from scratch, and you can use the existing stock surfaces to help you figure out how far you are straying from existing geometry. The only critical scanned locations are things like the valve seat centers, valve guide, planes at the head gasket and intake manifold gasket surfaces, etc..in other words, things that are machined can act as datums. You cant use the cast surfaces as datums because of core shift. Besides, we arent here to keep the existing surfaces, we're here to destroy them MUHAHAHAH

Heres what I've done so far:


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## JimDawson (Oct 27, 2014)

spaceman_spiff said:


> Now add a few more vantage points and a tool that can undercut like a spherical ball mill or just a *ball mill with a reduced shank*, and you can get to 100% of them, at least on this head.



Google ''Lollipop cutter''

This is very cool.  Please keep us posted on your progress.

I am going to be looking at DAVID Laser Scanner, I need that because I don't have it.:whistle:


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## spaceman_spiff (Oct 27, 2014)

JimDawson said:


> Google ''Lollipop cutter''
> 
> This is very cool.  Please keep us posted on your progress.
> 
> I am going to be looking at DAVID Laser Scanner, I need that because I don't have it.:whistle:



The lollipop/spherical cutters only come up on ebay once in awhile and they are $$$...theres one now for $65 that I've had on my watch list for months, http://www.ebay.com/itm/190717798779?_trksid=p2055119.m1438.l2648&ssPageName=STRK:MEBIDX:IT

I'm not actually sure if I need it or not. Hopefully not. Since you get to design the new surfaces and almost certainly everything gets bigger in one direction at least until the bowl, I'm hoping that I can just use standard tools or possible just end mills with reduced shanks. 

DAVID scanner is very important, or some kind of 3D scanner software which does a great job of stitching the scans together. I tried using makerscanner, but you cant get the laser at multiple angles and you cant stitch the scans in it. With DAVID scanner its pretty easy and its stitcher works great.  Plus you can angle the laser anywhere and get all the nooks in crannies. I think I needed about 5 different scans, flipping/rotating the casting, to generate that intake runner.


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## mattthemuppet2 (Oct 27, 2014)

that's really cool, especially the scanning part. I didn't catch the "why" though - are you trying to increase squish volume (if that's the right phrase) to turbocharge the engine? In other words to lower the compression ratio? I'm not well up on the design of 2 valve heads like that, so I don't know if there have been improvements to how the flame front and combustion mix swirl is managed since then. I was always under the impression that most tuners worked on opening up and profiling the ports/ runners to improve hp, but then again, what I know about tuning engines could be written on the back of a stamp


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## cjtoombs (Oct 27, 2014)

This is interesting, and something that I had thought about doing, but never got around to it.  A rotary 4th axis would go a long way to reducing the number of setups needed.  One thing that you will likely need to do is come up with several port designs and test them on a flowbench, if you want to get optimum performance.  If you can get some heads that are basically scrap (cracked, has a combustion chamber pounded out by a dropped valve, etc.) you can run each port with a different program, then test them.  I don't see why you couldn't use the rotary cutters normally used for hand porting to reach those hard to get areas.  You would have to do light cuts, due to the springiness of the shank.  You could also fabricate your own cutter, similar to a fly cutter, to reach the most onerous areas.  Good luck.


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## spaceman_spiff (Oct 27, 2014)

mattthemuppet said:


> that's really cool, especially the scanning part. I didn't catch the "why" though - are you trying to increase squish volume (if that's the right phrase) to turbocharge the engine? In other words to lower the compression ratio? I'm not well up on the design of 2 valve heads like that, so I don't know if there have been improvements to how the flame front and combustion mix swirl is managed since then. I was always under the impression that most tuners worked on opening up and profiling the ports/ runners to improve hp, but then again, what I know about tuning engines could be written on the back of a stamp



The engine is already turbocharged. Im not an experienced racer or engine builder by any means. I have a general idea what needs to get done here but mostly I am doing what the crowd on the TD/TM forums want. From what I can tell, its pretty standard stuff:

-deshroud the valves
-make the runners much larger and smooth entry into the bowls
-transition the surfaces going up to the valve guide so a splitter is made
-make the bowl a spherical shape instead of the mass produced conical shape

And the usual smooth and other things.

This head was probably designed in the late 70's..


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## spaceman_spiff (Oct 27, 2014)

cjtoombs said:


> This is interesting, and something that I had thought about doing, but never got around to it.  A rotary 4th axis would go a long way to reducing the number of setups needed.  One thing that you will likely need to do is come up with several port designs and test them on a flowbench, if you want to get optimum performance.  If you can get some heads that are basically scrap (cracked, has a combustion chamber pounded out by a dropped valve, etc.) you can run each port with a different program, then test them.  I don't see why you couldn't use the rotary cutters normally used for hand porting to reach those hard to get areas.  You would have to do light cuts, due to the springiness of the shank.  You could also fabricate your own cutter, similar to a fly cutter, to reach the most onerous areas.  Good luck.



Yes I will probably cheat and use the 4th axis I'm working on instead of manual angled setups. But I really do think it could be done on a few fixed setups. Probably get the entire bowl from one side. Then the runner done in maybe 3 setups..straight on, and maybe two more at 15 degree angles. Even a manual rotary table would make it cake.


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## spaceman_spiff (Oct 27, 2014)

Heres a modern chevy LS3 head with a CNC ported CC..basically exactly what I am shooting for. Deshrouded valves and everything smoothed out. The runner and bowl are alot more complicated.

And below that you can see the same head I'm working on, but hand ported by someone with alot of hard work.


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## visenfile (Oct 27, 2014)

So this is mostly a project to demonstrate CNC capabilities?  Because with forced induction seems like you will only realize marginal HP gain.  And I don't think I read any warnings about "hitting water?"


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## Fabrickator (Oct 27, 2014)

Interesting to me where modern innovation and technology has come.  I ported by "hand" thousands of heads for Top Fuel and Alcohol Chrysler Hemi's in the 80's for all of the top pros on the racing circuits when I worked for Keith Black Racing, as well as a zillion 2 stroke dirt bikes.  Never thought it would come to this.


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## spaceman_spiff (Oct 27, 2014)

Fabrickator said:


> Interesting to me where modern innovation and technology has come.  I ported by "hand" thousands of heads for Top Fuel and Alcohol Chrysler Hemi's in the 80's for all of the top pros on the racing circuits when I worked for Keith Black Racing, as well as a zillion 2 stroke dirt bikes.  Never thought it would come to this.



Those are amazing. Wish I was working with valves that big lol.


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## spaceman_spiff (Oct 27, 2014)

visenfile said:


> So this is mostly a project to demonstrate CNC capabilities?  Because with forced induction seems like you will only realize marginal HP gain.  And I don't think I read any warnings about "hitting water?"



Right now the only ported heads at this level available for the turbo dodge guys are about $1300, and those are all ported by hand, which is a ton of labor on these particular heads, as opposed to some others which are much easier to just clean up. I'm going to try and lower that price quite a bit but provide the same performance. The turbo dodge crowd supplies all the ideas, I'm just machining what they come up with. Seems like around 400hp, modifying the head starts making bigger and bigger differences, perhaps 50hp to 120hp at nearly the same boost levels.


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## nickmckinney (Oct 27, 2014)

I still hand port 2 sets of heads a week for my other gig. In aluminum I could port that head in about 3-4 hours total once I know the desired shape, but I am one of the faster ones. You need to bandsaw one into pieces to find the average wall thickness. It needs the roof raised as much as possible and the short side reworked before anything else and should be flowed with the intake manifold in place as that is usually the choke point.

I would not touch the chamber on that head, what you are doing won't help the flow much if any. A good valve blade profile will clear the chamber for max flow and that is usually the first ~0.1" from the valve edge.

Also the CNC will not be able to get the short side very well if at all.

I would bet a $3 bill most gains will be found with the valve job only once you have it on the flow bench...........


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## spaceman_spiff (Oct 27, 2014)

nickmckinney said:


> I still hand port 2 sets of heads a week for my other gig. In aluminum I could port that head in about 3-4 hours total once I know the desired shape, but I am one of the faster ones. You need to bandsaw one into pieces to find the average wall thickness. It needs the roof raised as much as possible and the short side reworked before anything else and should be flowed with the intake manifold in place as that is usually the choke point.
> 
> I would not touch the chamber on that head, what you are doing won't help the flow much if any. A good valve blade profile will clear the chamber for max flow and that is usually the first ~0.1" from the valve edge.
> 
> ...



Wow armchair machining and armchair flow testing in one post. The modifications I'm going to do were designed by people who have already done the flow testing. Multi angle valve jobs on these heads does pretty much nothing, unless the head is modified as shown. 

This shows how two 1/2" ball mills can reach the same point on a typical short side radius.


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## mattthemuppet2 (Oct 28, 2014)

if the boost is staying the same are the gains you're talking about just from that squish work? Or from intake profiling too? I wonder if it's better flow into the chamber or better swirl/ combustion once its in there, as I presume the compression ratio has dropped from that work? Or is the deck skimmed too? Interesting stuff!

Out of curiosity, why this engine at all? Cheap and available? Just because?


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## nickmckinney (Oct 28, 2014)

spaceman_spiff said:


> Wow armchair machining and armchair flow testing in one post. The modifications I'm going to do were designed by people who have already done the flow testing. Multi angle valve jobs on these heads does pretty much nothing, unless the head is modified as shown.
> 
> This shows how two 1/2" ball mills can reach the same point on a typical short side radius.




As someone who owns a cylinder head performance shop with both a seat and guide and a flowbench and a constant volume of heads to rework I will drop out of this with a final observation. I would probably be doing a radius valve job on that head instead of multi-angle. You need to be on a flowbench with the gazzilion different multiangle/radius profiles available. You can change the flow gain 20-30CFM from just a different angle/radius profile but it will happen in a different lift range, and some profiles want a smaller bowl and throat and that will change your CNC program. As for CNC on a tight SSR good luck, been there done that.


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## nickmckinney (Oct 28, 2014)

mattthemuppet said:


> if the boost is staying the same...



With a properly ported head the boost level will actually drop with no other changes.


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## spaceman_spiff (Oct 28, 2014)

nickmckinney said:


> As someone who owns a cylinder head performance shop with both a seat and guide and a flowbench and a constant volume of heads to rework I will drop out of this with a final observation. I would probably be doing a radius valve job on that head instead of multi-angle. You need to be on a flowbench with the gazzilion different multiangle/radius profiles available. You can change the flow gain 20-30CFM from just a different angle/radius profile but it will happen in a different lift range, and some profiles want a smaller bowl and throat and that will change your CNC program. As for CNC on a tight SSR good luck, been there done that.



The reason there are so many cylinder head performance shops is that the only real test comes at the racetrack, and by that time, there are plenty of other things to blame. So buy yourself a flowbench, a valve and seat grinder, and some burs, and now you too can join the fantasy world where opinions rule. Like I said, I'm not designing these changes, I'm machining them. They were designed by racers and engine builders and have been proven on the racetrack. But thanks for your after-the-fact pontificating about what won't work, when it already has. 

I don't know where you are getting your ideas about CNC. CNC + cylinder heads go together like white on rice. Looks like you are ignoring the diagram I put up showing two 1/2 tools reaching the tightest spot in the runner, even without undercut shanks, and with plenty of room even in the stock geometry. But hey facts don't matter when you own a cylinder head performance shop. Tell me more about how whats already been proven is wrong. 

Thank you SO much for your contributions to my project, I've really enjoyed your comments telling me what wont work and what I shouldn't do. Its truly in the spirit of a hobby forum.


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## nickmckinney (Oct 28, 2014)

Wow - seems like you already have alllllllllllll the answers, nope I have never seen a CNC head much less hundreds hahaha. Good luck and enjoy!


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## Micke S (Oct 28, 2014)

CNC porting, based on flow bench and track tested shapes and dimensions, is how reputed tuners works since long. No need to discredit this attempt. Once the process is optimized, it will give a lot more power than good a valve and seat job only.

Keep up the creative work Spaceman !


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## lcvette (Nov 23, 2015)

Spaceman_spiff, did you ever finish this project?  Very cool work you were doing, would love to hear about any updates! 

Sent from my XT1080 using Tapatalk


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## Bill Gruby (Nov 23, 2015)

Sorry, Spaceman_spiff  has not been here since 11/14/2014.

 "Billy G"


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