Inside the CNC cylinder head program at AMS: The EVO X Head

[AutoMotoSports]

Tim and the guys in the engine shop have been working pretty diligently on an engine program for the EVO X. With the great success we have had with CNC heads on the EVO VIII and IX we knew it was a must to develop a head for the evo X. I wanted to share a bit of the process involved in the CNC porting process




I am going to show you a series of pictures in sequential order of the CNC process. each will be labeled with a corresponding number, 1-4. Below are the descriptions of each stage of porting all the way up to the final product.

1. - As cast by OEM, this the way your stock EVO X cylinder head would look

2. - CNC ported: Note the un-machined areas in both the port and the chamber. These areas will vary from casting to casting. In some castings a port wall or roof may be left un-machined. This is due to the acceptable tolerances for castings, which allows for a greater amount of deviation in port location and shape than the CNC machining process. During CNC machining, an exact copy of the port shape and size is machined into the casting regardless of the variations in the casting.

Of course, you could modify the CNC program to machine the un-machined areas. This approach would result in the CNC "look" in all the ports, on all the surfaces. The drawbacks is the "modified" port would result in a larger than desired port volume and / or a port shape that is not the same as the originally developed port.

With all of the above considerations, it is our approach to cut the developed and tested port shape into a casting along with lightly hand finishing the un-machined areas in. This is not only more aesthetically pleasing, but proven to obtain the exact results our customers expect. The results are verified on our Superflow SF-600 flow bench by comparing each heads flow numbers after machining to the results of the original "master port"

3. - Hand finishing and blending; this step cleans any transition lines left during the machining process and blends in the previously mentioned un-machined areas.

4. - Finished; All surfaces polished along with a valve job and blending



Now onto some pictures showing this.




Lets start with the bowl area on the head.




First is the stock bowl on the EVO X. Again this is what your stock head is like



Here is after the first stage of porting or Step 2 listed above



Here is the bowl after the next stage in porting, step 3 listed above



And finally the finished bowl, this would be step 4 above






Now lets move to the exhaust port on the EVO X head



First is the stock exhaust port, step 1 listed above



Step 2 on the exhaust port



Step 3 on the exhaust port



Finally the finished product WOW!! step 4 listed above






Lastly we move to the intake port on the EVO X head.




What gets me the most about this is the sheer increase in size of the port after we are done.

Step 1 the stock port



Step 2, after the initial CNC work



Step 3, Some more hand finishing



The final product, WOW is that a great deal bigger and smoother!




There you have it! An inside look at the CNC porting program here at AMS for the EVO X

Eric

[derekste]

Awesome stuff. Who did the original hand porting that the CNC is based off of? You guys don't have a CNC machine in house yet, do you?!

Are the valve guides installed in step 4? Do they not protrude into the port, even in stock form? If so, that is badass... wish my VW had that instead of the tapered valve guides I did as part of my P&P.

[uneedthis2]

Looks great, now lets see what kind of numbers this will produce!

[Evil Evolution]

This is a pretty big step towards makin some real power on the X. Do you guys have a HP goal you want to hit by spring?

[AutoMotoSports]

A how its made video

[AutoMotoSports]

[a1091156]

I must say, well done on reducing below 0.250" lift flow numbers. Not many people realise how little the valve open area is around that duration and that it is were reversion occurs.