Digitally Ported ALH and AHU Cylinder Heads

It's been a long time coming, but we got it. The accuracy and repeatability of our cylinder head porting is not only spot-on to our design, port-to-port, but the bottleneck in the business has always been the time and effort it takes to hand port a cylinder head. On average, we spend 8 1/2 hours per cylinder head to complete the job. The workmanship does not suffer just because it is a job done by hand, but the advantage is with CNC equipment, we have tripled our production and are able to 'let the machine do all the work'.

If you have ever seen a 5-axis cylinder head porting machine at work, it will make you dizzy with the motion to get to every point and access. It will make you even dizzier when you see the price tag. A Centroid 5-axis machine will start around $250,000.

Of course, being a true-blue blooded VW guy, THAT isn't going to happen. We made the purchase of a Hurco KMP3 machine, gutted the old motherboard and screens, installed a 4-axis board, run against a software program from one of the wizards I may have mentioned before, Tom Rathbun, of Grand Rapids, MI. It was actually a team effort of Tom, Gordy Peterson and my buddy Randy Palleson, while I was relegated to the simpler mechanical tasks, I mostly stood back and let the brain trust work. They are all remarkable people.

Eventually, we may apply the fourth axis, but 95% of the porting is able to be accomplished within 3 axes. Watching the machine at work is like watching paint dry. It does it's work slowly and accurately. Our three-position holding jig carries three cylinder heads, which rotate positions; A, B and C. It's a three hour process from each station.

We have some time-lapse photography coming soon. It turns a 3:10 hr job into a 22 second video. You can get the idea...

Because of the comparative speed and self-sufficiency of the machine to produce with only minimal involvement, we can spend more time on the balance of duties required of us. We will be able to increase overall production.

Our first CNC machine is a dedicated Newen Seat and Valve machine, where the Hurco CNC, we will be expanding into other products and processes that are production based; the world that CNC is a wonder at.

There are just a few bugs to get out and we need to tweak speeds and roughness average. Then, we will be offering the digital porting service as a group buy, discounted with complete cylinder head or engine builds.

We were already competitive. Now we can turn out volume.

Sounds good Franko, is my head a candidate for the treatment?
Cheers,
Richard

I've gotta start saving some coin...it's time for a freshened up head

Sent from my Pixel XL using Tapatalk

Good to hear you have that sorted out Frank

What are the tell tale signs of a head needing itself refreshed =~)

Fahrvegnugen said:

What are the tell tale signs of a head needing itself refreshed =~)

Click to expand...

Now there's a good question!

As usual, it's been busy, so excuse the delay.

The most common indication of a cylinder head needing refreshed is worn valve guides and blowby through the guides or valves. A leak-down test will give you an idea if you are losing compression through the rings, valve guides or out the intake or exhaust ports.

The other indicator is a larger-than-average puff of blue smoke at startup. What happens when the engine is turned off, the valve guides will drip a little oil down past the valve guides. Startup burns that oil off and that is your initial 'blue smoke' at start. If it continues for more than 15 seconds, you are getting into a point of wear that the guides (or maybe rings) have become worn enough that some maintenance should be done.

Normal interval for a cylinder head needing guides is around 250,000- 350,000 miles. As always, good maintenance makes longer life.

I hope your video will show how you "zero-out" the machine to begin cuts.

So do you have a price range to get a head done??

Prairieview,

The method of creating the baseline X, Y, Z is the mandate of any digitally programmed function. That always happens in every CNC program or you can't even start. In our jig, there are the three necessary reference points on the jig we use to hold the cylinder head. Y to the back surface, X to the side of the center plate and Z to the top of the center plate. All other reference points are calculated off those points.

Sltlytwkd,

How slightly are you slightly tweaked? That would make a difference on how we would port.

We will alter our porting profile to meet particular needs. For example, if all we are doing is getting a stock engine to not be so asthmatic, we clean up the intake to round out the rectangular 'mistake' toward the combustion bowl and open up the exhaust, leaving a small reversion stop at the exhaust manifold end.

Working our way to larger improvement, the major porting bottleneck is in the exhaust port turn from the valve seat around the corner. The idea is to make the flow as smooth transition as possible, without compressing gasses in the port's turn. Compression of gas creates heat, which is a negative effect.

Finally, our Street/ Race port addresses opening the intake, with the reversion step going the opposite direction... Reversion is not specifically an exhaust problem. It happens both directions, so the better we can control the reversion, in and out, the better the cylinder head will work.

Port size should not be exaggeratedly large, as air speed is generally an asset. Surface roughness, or texture, even to the point of dimpling is less important in the comparatively lumbering TDI than in engines capable of high rpm. We still think minimizing wall vortice size is important. But some of the more exotic vortice reducing methods only work on engines with extreme engine rpm and near hypersonic airspeed.

What is more, ceramic coating treatment of piston head, valves and exhaust port can have more effect for carrying heat out of the engine. Since coating takes away our particular surface texture and with coating consideration, port finish is of less importance. The ability of the coatings to carry heat to the turbo takes precedence over port finish.

A 1Z head differs from an AHU too much for this to be applicable, correct?