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

[spaceman_spiff]

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.

 

[spaceman_spiff]

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.

 

[nickmckinney]

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...........

 

[spaceman_spiff]

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...........

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.

 

[mattthemuppet2]

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?

 

[nickmckinney]

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.

 

[nickmckinney]

if the boost is staying the same...

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

 

[spaceman_spiff]

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.

 

[nickmckinney]

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!

 

[Micke S]

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 !