HEAD PORTING

My head was returned from the shop i was getting all the machining done at after pressue testing and cleaning. Now was the task of trying to get some flow through the head to support my other modifications.

There is a good site on porting here - http://www.sa-motorsports.com/diyport.aspx. This tells you pretty much everything you need to know. The thing with this is unless you've got a big compressor this is going to take some serious time to get it all done. I took the cheap route and didn't buy the kit. I had a carbide burr and 5 porting rolls. Of which I still have some left. But would recommend the kit if doing it again it would have made life much easier. Especially in those tight places.

I started using high pressure dive cylinders, but as I only had two cylinders got sick of getting them filled or running out of air all the time, naturally half way through what I was doing. These air grinders use a LOT of air.

I then bought a compressor from super cheap auto it was cheap but noisy and i think the constant running has just about killed it. I would run it up from empty use it till empty again wait 5 mins do a bit of vacuuming to clean up the mess and start again.

Set up here now is the key I had a sturdy work bench, an old vacuum cleaner, the compressor, a radio (must have), and a box with a desk lamp on it so you can see clearly what your doing.

With the exhaust ports we matched these up to the exhaust manifold flange before we stated the exhaust manifold. We could easily bolt it on, then grind up to the shape allowing a perfect match.

Exhaust side with matched ports:

The inlet ports were not so easy. I ordered a gasket set and set this up and traced around inside to make my matching lines. I then reversed the gasket and proceeded to do the same to the inlet manifold. There is a big difference here. I ended up grinding away quite a bit of material.

In this particular head there was a lot of rough area around the valve guides. I started using the porting rolls as every thing you read says to not use the burr. Well I have to say i found the burr very effective. It takes less time and provided your careful the finish come up nicely when sanded over later on. Once I'd roughed out the bowls I put the burr away and started on the paper rolls. This took a long time trying to get a tidy shape and uniform finish.

Starting on the bowls exhaust side:

A bit further on:

Now onto the inlet ports:

Matching the inlet ports:

Starting to come together a bit nicer now:

Shiny, those last little bits are real hard to get to:

With this completed I then moved onto the most important area the radius into/out of (depending on side) the cylinder. This is quite tricky to get into and works best once your rolls have worn down a bit. There is a real knack to keeping a nice shape to this and it takes time. A good light is your friend here and your forever moving the head around. I used a roll of tape under the head just to give the back edge some elevation to get a better angle.

Unfortunately I ran out of time so never got to flow the head as I had wanted to to see if I was going in the right direction. However, the workshop I went to does a lot of this work and said that they could tell just by looking at it that what I had done was in the right direction.

Fingers crossed with the 3 angle valve job my efforts will have given me the flow that I need to match the other components of the build.

Final product:

Back after bead blasting ready to install: