Classic Car Blog- Spitfire Cylinder Head Polish and Porting and Clean!
24th Feb 08 Cylinder head port and polish! It has taken a long time to get to this stage and I am still not completely finished. I started out as a quick de coke of the cylinder head but ended up being a small exercise in polishing and porting. This was because the more I cleaned the better it looked so I kept going and decided to do a really good job and slightly modify the head as I went. As I want to get the Spitfire back on the road as soon as possible I resisted the temptation of going to stage 2 or 3 by adding bigger valves and opening out the combustion chambers to their limit, I will do this on another engine once the car is back on the road and I can rebuild one to fast road spec.
With all the carbon removed the chambers were polished using a grinding stone in a drill but not removing too much metal from the chambers just making sure they were nice and clean and shiny. The valves were cleaned by putting them in a drill (protecting the stems with tape) and then clamping the drill in a workmate. The drill was then run and wet and dry sand paper was used to remove the carbon and get them to a nice state of polish.
The inlet and exhaust ports were cleaned up again using a grinding stone in the dill. As can be seen in the first photo above the round ports were enlarged as there is a lip just after entrance to the port. The old gasket mark was still seen on the side of the casting and you can take it out this far but in my case I just made it parallel down the port. After it was done with a grinding stone it was finished off by hand.
After the ports were done the valves needed to be lapped back in. I borrowed a Gunsen valve lapper from a friend and it certainly made it easier on the hands rather than the good old fashioned sucker on a stick..
The final picture shows the head completed and ready to be cleaned and painted.