Well.......2 LIM'* later and I finally got her done. Yeah, that'* right..... I said two. The one I bought from Morad looked like he had it tanked. The casting was beautiful........and I managed to muck her up. My dimension came out to .930 on a couple of ports and I decided that was too much. So I went to the local boneyard and picked another one up. More expensive(30. to be precise) and ALOT uglier than Ed'*. :( Put it this way. It is definitely better to practice on one 1st. By the third port on the first one I had a good system going. Here'* some pics and brief details.
Pics of 2nd LIM ........NASTY!!!
Next I put layout fluid.........er..primer(no layout fluid available) sprayed some primer around the port
Next using the "centroid" of the port I first measured out the widest dimension of the port and made two marks.
I then did the same thing top to bottom. These to steps help you to verify the centroid of the port. IMO.
Next was trying to figure out a square reference port. I decided to use the injector port side "bottom" of the LIM. See the picture and you'll note where the square is held against the LIM. I then scribed a line up the side to side marks I made.
Note here my widest measurement on one bank of the ports was already .910. 10 thou over info I received from Will Wren stating in his experience on that the head ports he measured were 0.9 x 1.900. The other bank were at .900. So keep that in mind when grinding. Will'* measurements were on the cylinder heads, not the LIM ports.
Here is a pic showing the layout marks. Unfortunately it is not so clear because I didn't take these pics for this sequence until I was done
Time to start porting. Using the carbide bit pictured later I started to grind up to the layout marks. STOPPING and MEASURING as I went so as to make sure not to go over the .9 x 1.9 head size. Of course mt layout marks were right on but....measure twice, then cut. DO IT AGAIN and AGAIN!!!! When I was about .007-.010 away , I then filed up to the lines(finished measurement) to keep the ports straight.
One done. Pic2
Most of the material came out of lower left and upper left corners. A note about castings here. The one I got from Morad was "beatifully" poured. The second one had a bump in each port down the lower left that stuck out about 3/16". There was also a "seam" running down the runners that didn't match. Sorry no pics. The LIM I received from MOrad had none of those issues. Just a toss of the dice. Also the ports on one bank (2nd LIM) also seemed to have a nick on each one in the same spot of each port on the profile of the port
. This maked measuring and squaring up the port scary.
I believe it was much more a big PITA to "smooth" out the runners than do the porting. Some pics of finished runners.
Some tools I used.
Note the flexible attachment I had for my dremel. Made control IMO much better. Also had dial calipers, file, gasket cookie w/ rt. angle die grinder. Compressed air and various dremel bits. The pic of these two did 99% of the work though. I like the small radius on the carbide bit I found at my local hardware store. Was good for getting the radius at the corners.
Unfortunately, I won't be able to give a butt dyno of this mod alone. Will be installing this at the same time as my other mods. See General chat http://www.bonnevilleclub.com/forum/...asc&highlight=
Good luck to all that try this. Research all porting posts diligently.