My quest for better ports has begun



Well I just ordered myself a Xmas present. I ordered a electric die grinder off Ebay. A couple of guys on Stangnet bought the same grinder to port their 4 banger heads.

So Im gonna give it a try on my 80 I6 head. After I clean up the pockets and portmatch the exhaust and clean up the log I will take it to have bigger exhaust valves seats cut.
Always: Look after your eyes. Especially if you get tempted to use a carbide cutter (they munch cast iron compared to a stone).

I have a $70 grinder, and the burrs cost from $50 to $75 each - there's six of them: Round-ended 1" barrels in 1/2" and 3/8" sizes, ball ends in 3/8", 1/2" and 5/8", and a "christmas tree" shape that goes from a point to 5/8". Mine are "Garryson" brand; English.

From inspection, the most obstructive things to flow are the valve guide bosses, and the short side radius. The SA guide is a good general starting point, but bear in mind it also is designed to make you feel good about the way their product works...

It's not hard to open up the exhaust around the flange, but to feather the results in as far as possible, is what takes the time and sweat. I took mine to 32mm at the flange, with a 1/4" corner radius. The blend finishes almost at the boss for the valve guide.

I also recommend the head be stripped and sandblasted (nice to work on a clean piece), and that the welsh plugs are pulled before blasting, to get the accretion out of the water jacket.

You can really hook into the valve guide bosses if you're going full roller rockers, as the side loads on the valve stem are minimal.

Compressed air is good to clean up with; note that the filings will rust stain concrete if left... Heck, I'm gonna redo the driveway anyhow!

Regards, Adam.
get a good selection of burrs and a porting kit (cheap source for alot of sanding rolls) remember to go slow as high speed will just bounce around and dull the burrs. I do my grinding in the yard on a couple saw horses. just let it fall in teh grass and after a couple rains most of it will break down and all. get a face shield!!!!

8) not only look after your eyes but your lungs as well. wear safety glasses, or better a safety shield, and at the very least a filter over your mouth and nose. one of my college instructors had a lung removed many years ago because he was constantly breathing iron and aluminum dust when he was doing head porting.
8) Thanks for the tips. I will definately take them to heart.

I am going to disassemble the head and get it hot tanked and new valve guides put in and cut the exhaust seats for bigger valves. Then the proting will begin. I was thinking of ducting my shopvac to combustion chamber so debris will be pulled into vac instead of getting it all over everywhere.
Just a quick suggestion, do the porting before you do the exhaust valves, just in case you nick the seat with the grinder. Easier to clean up if you do hit it. Also, everyones suggestions for shield and dust mask are right on, I had a small piece of filing just hit my eyelid a couple of weeks ago while porting my head and I stopped until I could get goggles and a mask. Good Safety sense.