CB 044 HEADS
42x37x94   Home Port Job

These heads were shipped to South Africa via Germany from the USA. Why, because it cost 10% less than if I got it
direct from CB themselves. Dont worry, I do not understand it either.

Below are a few pics of the heads and manifolds in pretty much the same form as they are now. I used a die grinder, with various size tungsten carbide cutters a few flap wheels and a few (many) sandpaper inserts which look like cups. The flap
wheels were great for unshrouding the valves and polishing the combustion chambers and once they had worn down,
worked brilliantly in the exhaust ports. I used 80 grit Flap wheels throughout, mostly on my die grinder and then on my drill.

The faster a flap wheel spins, the finer its finish. It also works through the aluminium quite quickly at high speed.
All the polishing of the exh port, combustion chamber and final smoothing of the inlet were done with the 80 grit
at 26000 rpm. Then to get the final rougher finish on the inlet ports, I used the same flapper in a drill at 800 rpm.
The final polishing was done with a polishing wheel mounted in the drill at 800 rpm. It makes the finish look bad
simply because it makes everything dirty, but it does smooth it out nicely.

Below the pics, I will give a short description on how I did my porting work.

One of the pics below, you can see an outline. That is my manifold. So I cant really go much bigger at the moment
but for a street car I think it will be enough. Eventually I hope to get the CB "Big Beef" manifolds, and will then do
a bit more porting. 

Inlets manifold side     Inlets manifold side     Inlets manifold side     Inlets manifold side


Inlets         Manifold before and after         Inlets


Inlet combustion chamber side     Inlets combustion chamber side     Exh port, chamber side     044 marking


Inlet Manifold size

The Porting Process


This is something that I cannot overstate:

WEAR EYE PROTECTION!!!!!
If you go blind, you will do a pretty crappy job and not be able to drive your car


The Combustion Chamber

I went off  to a machinist who has on of those 5-axis milling machines. He has a cutter with an 8 mm guide
that fits into the valve guide. He then cut the chamber on both the inlet and exhaust sides up to the cylinder marking.
As the guide is at a slight angle, he has to take smaller cuts as he got closer to the valve seat. The left me with a
"stepped" form of unshrouding job in all my chambers.
I then took the heads home and started with my die grinder. Using tungsten carbide "burrs", I smoothed out
the steps until they were nearly smooth. I then used an old 80 grit flap wheel to finish off the unshrouding and
remove all the casting marks that were still left. I then polished the chamber with a cotton type polishing wheel.

Inlet Ports

Again, I used the die grinder for this job. As can be seen in the pics, I used marking blue to mark out the
port outline I was going to use. To do this, copy a standard manifold gasket and then make a port design that you
think would be applicable to your use. I didn't go too big as I feel my manifolds will not be able to flow to the same
extent as the inlets, so I opted to aim for port velocity instead of big power. When I do eventually upgrade to
the big beef manifolds (as well as Web 86b cam and Scat 1.4 rockers), I will open the ports a bit more to use
the cam to its full extent.

Using the die grinder, I smoothed out the port (again using the tungsten carbide burrs). I used 3 olive shape
burrs and a long straight burr. The bigger olive and straight burrs were used to open the roof and side walls,
while the smaller olive burrs were used to get in where the larger ones couldn't. The straight burr is good at working
the roof of the port and "pointing" the port towards the valve seat.

I then used the 80 grit flapper in a 800 rpm drill to smooth off the port and get the desired finish. To get to the casting
marks and the parts of the port that the flapper cannot reach, there are various small "cup" shaped sandpaper inserts
that are shaped like a burr.

To make the port and the valve seat match perfectly, I used a flap wheel and worked that area until both surfaces were
level. This is very easy to do, but one must be very careful as it is very east to make a total F-up.
The aluminium is a lot softer than the stainless steel valve seats. So put the flapper against the seat and port and polish
until they are smooth. The amount of material you take off the seat is sooooo little it makes no different to the seat itself.
BUT, it is very easy to polish a bit too much and end up with the port being opened up bigger then the seat. You will then
need to get the seat (all 4) machined down by a milling machine and then try again.
A step in the air flow causes a form of resistance - yes, even a step from a small size to a bigger size!!!
however, stepping from small to large  is about 15% the resistance as stepping from large to small (same size step).

Exhaust Ports

Basically, just polish the crap out of them using the same methods as in the inlet ports and combustion chambers.
The sharp 90 degree bend just under the seat is also critical to air flow. BE CAREFUL!!!!
DO NOT remove too much from under the seat, as the seat will break through the port and fall out under operation.
instead of taking material away from the bend, rather smooth it and make it round. That way keeping its strength
and drastically improving the port flow around the bend.