[10secbird]

This started out as a port match, and then I ended wanting to enlarge the runner opening at the plenum and ended up with a port openings at the plenum that are 1/4 taller and wider than as cast. It has been 20 years since I have put a grinder to a port and I forgot a few things, like technique...got a little anxious, and worked a little to long with the carbide burr before switching to finishing cutters...stone...sand roll...flapper. Also, got anxious and should have worked all ports a little at a time simultaneously; an important proccess I should have employed to acheive more uniform sizing between all runners.

Trying to acheive the enlargement and taper I wanted resulted in a paper thin attachment of the runners to the plenum as can be seen in one photo with the light showing through the holes. A trip to the welder reattached the runners and gave me some room to play with for radiusing the runners at the plenum opening.

So much for a simple port match, I'm only half way done porting now, and the plenum top mating surface needs to be surfaced flat again as the heat moved it around a bit and the top now rocks on the manifold. The head-to-maniold flanges seemed to have weathered the heat as they sit nice and flat on the heads still.

[10secbird]

I put a solid 8 hours grinding in yesterday....Now I just need to touch up a few walls, final measure port dimensions and adjust to get all runners as close as possible in size/volume. I put a few holes in the thing, but only one that I'm really embarrased about, most of the holes were at the runner attachment to the plenum where a big fat weld all the way around the runners patched the holes and gave me the room I needed to radius the openings. The hole I'm embaraased about is through one of the dividers between a pair of runners. Its not reachable with a welder...so I'm going to epoxy it.

[blueghoast]

Major difference from stock, Nice work.

GT.

[10secbird]

Originally Posted by blueghoast

Major difference from stock, Nice work.

GT.

Thanks...it is quite a bit different from stock. Mostly the openings in plenum are opened up max size until breaking through. Welds allow me to then put a nice radius on the openings. Trying to taper true enlarged port size (where the radius ends) down to the smaller opening at the head, running the taper the full length of the port. I'm happy with what I'm trying to do...but not so happy with the way I approached the project from the start and my grinding skills are rusty, having forgot a lot of technique.

The biggest mistake I made from the start was to finish an entire port before starting on the others. I should have worked one small area on all the ports and then move on to the next cut on all the ports, thus improving the likelihood that all ports will end up the same size and shape.

The situation I have now is that the first port I did ended up being very large and now I have try to make all the other ports that size, which makes for some timid grinding, as I fear breaking through attempting to match the size of that first port, which is on the edge.
Porting is so tedious and when you do it in small steps on all ports at a time, it can be a while before you get to see your port come together, and that is one of the reasons people (including me) get anxious and make the mistake of roughing out an entire port before moving on to another port.

I'm already burnt out and this is just a simple straight runner intake manifold. I’ll be glad to get this done and out of the way as it has me stalled getting other areas of my car put back together. I’m ready to move on to the next project and get back out to the track for the first time in 25 years.

I’m motivated…maybe a little too much as a port match turned into full blown port reworking with trips to the welder, and now a trip the machine shop to get the top machined flat again after warping a bit from the welding heat….oh yeah and some epoxy work too. I’m sick of this manifold …lol I don’t want to port anymore! Thank god I’m not porting a set of cylinder heads

I have to hand it to anyone who is a head porter 40 hours a week. I had a best friend who passed away 15 years ago who had that job; he worked as a full-time cylinder head porter for Sacramento's then premier race cylinder head shop; BC Gerolamy. I used to love going to that shop, looking at all the stuff they were working on. The work they did was beautiful, like works of art painted with a grinder.