Quote:
Originally Posted by DarkMx-6
how do you make sure that all the exhaust ports are closed before you start porting and polishing? And what did you do it with?
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You have two choices:
The better way: remove the valve cover, the rocker assembly off, on the exhaust side, put the valve cover back on.
The way I do it: Only one exhaust valve is opened at a time, leave the car in neutral and use a 21mm socket on a ratchet to turn the crank (bolt is in the center of the utility pulley, there is a rubber plug in the passenger wheel well guard you pull out to get to it). Turn the crank until the valve farthest from where you are working is opened, then stick a rag in the opened valves port so no aluminum gets in. If you want to be safe, after fulling out the rag, pull the spark plug out for that cylinder and blast air in the plug hole.
I use a carbide non ferrous metal porting bit, usually I use air powered or electric die grinders but because of the fact I am only doing the exhaust and the valves are still in the head I don't want to take much off so I prefer
a drill and 41" drill extension with 1/4" chuck (like the ones for a dremel but bigger).
If you simply clean away the carbon and take off the porous surface aluminum evenly on each valve port you can keep things pretty even (Don't try to clean all the casting seem away with this tool or you'll cut grooves).
Then I use die grinders and sanding cartridges :
to sand and smooth out the surface, if you are counting the passes and trying to match them that way, then use a fresh cartridge on every port (they will still be good to use on many other jobs), If you where consistent with the metal porting bit then it's easy to keep things even with the sanding cartridges.
To shine it a bit I really slacked and just used a small sand paper flap wheel :
Normally after that I would use a cross buff kit and then felt polishing bobs and wax to put on a mirrored finish (people say it's just for show) but carbon doesn't build up on the mirrored finish like it does normally, just a very thin black film you can wipe off with you finger after 20 000km's of driving.
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If you haven't used a metal porting bit then you might not want to try it on your head, there pretty unforgiving.
Go right to the sand paper cartridge rolls (take more time/less chance for error). then use the flap wheel or :
Cleaning the exhaust ports for dummy's:
Behold the cross buff kit:
These come in different sizes and grits, the coarse ones are agressive enough to port with (if you have enough of them), they will clear the carbon , take away the rough aluminum and open the valve ports up a bit with no chance of nicks and grooves in the aluminum (almost fool proof, almost.)
Remember to lube the buffs up with some type of oil or they will burn out quickly.