Something Everyone Should Know About Head Porting

[crazybill]

I drill and tap mine also......The main reason I dont weld them which
i used to do was because of the heat....Any time you put heat like that in a head you have seats and guides as well as the cam journals start to move around........Aluminum is funny stuff when you put heat to it...........

 you dont have to put that much heat into the head . I can pick a head up and carry it around the shop immediatly after welding . literally hundreds of welded busa heads and not a single one had a problem .
They dont get nearly as hot as one thats gets a bridge rebuilt . not to mention the heat you have to put into one to install new guides . The head on my personal bike had come from a crashed bike and had the upper right motor mount boss badly cracked but we welded it right up then milled off the outter spigots and moved the outter ports inward 5mm each ,welded on new outter spigots and its got almost 10k street miles , over 130 documented dyno pulls(R&D BABY !) plus was on my big stroker all last summer .
Simple little thing like welding the emissions ports doesnt move a thing... I have a good welder though too....

[LE05BUSA]

What do you want for the 110? I know somebody that might be interested.

[enginetuna]

We have a new Centroid 5 axis machine dedicated for head porting. The head fixtures are made by Centroid.
All other head work is done on other machines.  The 5 axis could do surface milling, valvejobs, guide work, just about anything actually but its designed for head porting and thats all we use it for.

Roughly what sort of money does one of those machines run at?

[crazybill]

 was quoted 125k for the cheaper one . 20k of that was for the mastercam software though . I prefer solidworks or surfcam....

[enginetuna]

That's not so bad then.
Does anyone with one use ot for other jobs like machining crankcases/bellmouths/general one-off parts?

[Competition CNC]

Yea $135-150,000 will get you set up. 
You will need some plates tools other misc stuff.  Not too bad.

When we get our second machine it will be for digitizing, piston domes, and oddball stuff.
Anytime you digitize you arnt making chips. And making chips makes the money.
Thats the drawback of this machine, you digitize right on the machine in 5 axis with the probe in the spindle so it ties up thae machine.
I have a 25 degree rotary tilt table for sale also if you wanted to set up your own.

I'll ask my partner what he wants for the flow bench. Its actually his.

[enginetuna]

What is the kind of time to digitise a head and then again to machine it?
Like you said things have to make money.  Profit is key, not turnover

[Competition CNC]

Well, digitizing depends on port complexity and size. That applies to cutting as well.
Four valve heads are treated as two separate intake ports for each cylinder so a Busa head would have 6 ports to digitize and 16 to cut.
The actual probing time is several hours. But you need to set up an initial digitizing tool path and then start the 5 axis digitizing.  When I’m digitizing I’m not making chips. So you can see why I need a second machine!!!

For example I can digitize a SBC intake port and exhaust port in a day or so. Four valve heads take twice as long or even 4 times longer if you need to digitize two intake ports because they are different.   Then it takes a day or so to bring the data into MasterCam and work with the splines and create a surface and have the ports ready to cut.  Then you have to transform or copy, mirror etc. all the ports to the right places.  It’s usually 2-3 days but can be 3-4 days.    All in all it can be 4-5 days before you are happy with the port and actually are ready to cut.  So you can do the MasterCam work while you are making chips.  Time management is key.


When I cut a Busa head I use a .020" tool path step over to give the port the desired surface texture. That takes three times longer to cut than a typical .060" stepover used on many automotive heads. So you tie up the machine 3 times longer.  I make a lot less money on Busa heads than a typical pair of race V8 heads.  But I personally love the bike stuff and want to bring engineered cylinder heads to the bike world.
The stage 1 head was designed for street 1397's with mild aftermarket cams. That combo isn’t that far from the factory performance envelope of a stock Busa.  Watch what an engineered stage 2 head on a 1500+cc busa and then the stage 3 on a 1650+ cc engine will do.  Hang on boys, I cant wait till spring!!!

[Competition CNC]

You don’t have to put that much heat into the head. I can pick a head up and carry it around the shop immediately after welding.

I agree its very localized spot welding and there isn’t enough heat or time to heat soak the head.

But over heating the head and loosing the heat treatment is a very real danger.   But it’s not going to happen from welding the air injection holes.

We sent out a set of VERY expensive heads to get a ceramic coating on the combustion chambers several years back and they came back SOFT as SOFT can be.  I forget the Rockwell number now, but they were ruined, the heat treatment was gone!!!  We never used that company again.

When any of you guys are heating heads you should either do it in an oil bath or use an oven. Never use any kind of direct flame.
A head should be heated between 250 deg. F and 300 deg F. for guide work.  If you get to 400deg F the head starts to relax and its gets worse the hotter it gets until you have a soft head.  At that point you throw it out, its scrap. It will usually cost more to fix it than to buy another one.

[spdingtkts]

I remember the guy that does my aluminum welding telling me about the first time he welded an aluminum head.

He did it for a dealer and it needed a lot of work all over the head. When the guy from shop came to get it all the seats fell right out of it.

Lesson learned that day.

[whtrthanu]

im not saying you guys are wrong by welding the emission ports, i was just stating that I dont  prefer to do it that way........
As far as you welding the spigots on the other head, you bet there was alot heat put in that one...
I do alot of welding.......alot of aluminum....I actually do welding for UL .........under writers labs.....So I think im pretty ok at what i do, and so do they..........
i did an oil cooled head years ago Like that with spigots and skull caps.........There wasnt a straight piece left on it.............You can leave it alone, and run it......or you can go over it and see how bad it moved.....i actually re machine the cam journals because they definetly move.....but everyone does things different....im not saying your wrong or im wrong just givin you my opinion...........

[enginetuna]

Well, digitizing depends on port complexity and size. That applies to cutting as well.
Four valve heads are treated as two separate intake ports for each cylinder so a Busa head would have 6 ports to digitize and 16 to cut.
The actual probing time is several hours. But you need to set up an initial digitizing tool path and then start the 5 axis digitizing.  When I’m digitizing I’m not making chips. So you can see why I need a second machine!!!

For example I can digitize a SBC intake port and exhaust port in a day or so. Four valve heads take twice as long or even 4 times longer if you need to digitize two intake ports because they are different.   Then it takes a day or so to bring the data into MasterCam and work with the splines and create a surface and have the ports ready to cut.  Then you have to transform or copy, mirror etc. all the ports to the right places.  It’s usually 2-3 days but can be 3-4 days.    All in all it can be 4-5 days before you are happy with the port and actually are ready to cut.  So you can do the MasterCam work while you are making chips.  Time management is key.


When I cut a Busa head I use a .020" tool path step over to give the port the desired surface texture. That takes three times longer to cut than a typical .060" stepover used on many automotive heads. So you tie up the machine 3 times longer.  I make a lot less money on Busa heads than a typical pair of race V8 heads.  But I personally love the bike stuff and want to bring engineered cylinder heads to the bike world.
The stage 1 head was designed for street 1397's with mild aftermarket cams. That combo isn’t that far from the factory performance envelope of a stock Busa.  Watch what an engineered stage 2 head on a 1500+cc busa and then the stage 3 on a 1650+ cc engine will do.  Hang on boys, I cant wait till spring!!!

Ok thanks for the answer on that.
Seems like a lot of time.  May have to rethink that idea because there wouldn't be the volume to pay for it over here.  Even copying their best heads for people, the labour cost with up to 5 days would render the price out of all but a handful of peoples budgets.

[Competition CNC]

Ok thanks for the answer on that.
Seems like a lot of time.  May have to rethink that idea because there wouldn't be the volume to pay for it over here.  Even copying their best heads for people, the labour cost with up to 5 days would render the price out of all but a handful of peoples budgets.
[/quote]

Yea you have to do your digitizing, in between production cutting, and manage your time well to keep the cost to the customer down.  Most of the custom digitizing I do Is for the high end of the market. But I'm getting the speed down now, each one I do now its a little quicker.
These guys http://www.vhmotorsports.com/home.html just bought the same machine. I think they might be using it by now.

[enginetuna]

These guys http://www.vhmotorsports.com/home.html just bought the same machine. I think they might be using it by now.

Rumour has it they already have a good share of the AMA superbike paddock as far as head porting goes.  So i guess they are up to speed now.  Nice to know that is the machine they have though, thanks again.

[chavcat]

Any truth to the rumour that the ZX14 head is inferior to both the Busa an ZX12 heads even after modifications?

[gnd111]

Any truth to the rumour that the ZX14 head is inferior to both the Busa an ZX12 heads even after modifications?

www.dragbike.com lists the results for the total amount of flow but it mentions nothing of velocity which is a big deciding factor in power/mph/etc...

[crazybill]

Any truth to the rumour that the ZX14 head is inferior to both the Busa an ZX12 heads even after modifications?

www.dragbike.com lists the results for the total amount of flow but it mentions nothing of velocity which is a big deciding factor in power/mph/etc...

velocity was measured but not conventionally.... so it wasnt posted . I have all the flowcharts for that head and a couple other port designs for the 14 .