So I was left with the grinder, a variable speed plug, and three carbide bits for aluminum.
My mission? To rough out the inside of the runners with an aggressive tooth.
There were a few annoying bumps inside the runners, they had to be ground down.
The yellow arrows indicate what disrupted flow due to excess aluminum, imperfect bends.
These areas were thicker due to the mounting bolt allowances.
I had to take great care not to remove any more than necessary in these spots.
Removing too much would make the manifold weak and prone to failure.
There was an outline of carbon deposits to follow for the general shape of the porting.
It matched the gasket shape, and will still need some fine tuning to get it as good as possible..
I am an artist and a sculptor, and I made my way through the opening.
Down the Rabbit hole I went, twisting and turning, the sights stranger all the while.
Checking constantly with my touch, I made sure the runners open up as balanced as possible.
A little progress one tube at a time keeps it consistent.
It was a little difficult as each tube bends a different angle, I had to carefully observe and maintain the equal balance of all while trying to remove material in fattest spots.
So due to global warming it is mid October and there is sunshine and grass.
Here in Canada, Igloo season is postponed for now.
It is cold; it won't be long now...
To be completely honest, I was terrified of doing this modification, and it has delayed me.
I just had to educate myself as best I could, and just dive in and get a feel for it.
It did not take long to understand the best angle for the cutter to slice nice.
Firmly locked body held the tool in a grip less prone to chatter. Movements were very deliberate.
Emery cloth or sandpaper will smooth out and further shape the runner walls, but will not polish;
It is coarse enough to leave a good scratch on the walls.
Good thing too, it's getting pretty rough.The bit I used to get way in deep was scary.
It runs at 25,000 rpm and when it starts, it bends out into a cone then runs straight again.
I really had to hold on with a white knuckle grip. What a monster!
The new valve guides have been installed, and are sitting pretty.
![]()


























































































