Re: Bowtie builds are fun..
Whats that old saying? When in doubt, mill it out.
I called up a buddy who had similar problems with his intake on his SBC blower motor (pic here:
http://i67.photobucket.com/albums/h307/syclone1713/100_0949.gif )We looked it over and said let's give it a shot. Took the block, heads, intake and valve covers over to another friends shop, where he just so happened to have a few Bridgeport milling machines lying around.:tup: I'll describe what I did/had to do to make this all work out. Some of it was pretty straight forward and rather easy, and some of it was difficult only because I didn't know if I wanted to go this far. But I said let's go for it.
I forgot to bring my dig camera with me while doing this.
I'm kicking myself in the ass because I wanted some nice clear and clean pics of this build. So these pictures were taken with my 4 year old black berry pearl which has been through hell and back. So forgive the quality of pictures. I didn't get pictures of test fitting, because I only have two hands and for the most part this is pretty self explanatory.
Above I mentioned how the lip of the head where the intake bolts onto it caused a clearance problem with the intake runner flange. And that the bottom deck of the intake needed to be cut to lower the intake onto the heads.
We had some small flat sheets of alum lying around in the shop and put them onto the heads. Nothing we could mock up as spacers made this look any better, and in fact made it look like it would be harder to pull off. I'll explain more further down.
1.) Put the intake on the mill, and cleaned up the bottom deck side of the intake where it makes contact with the china walls. Really didn't take much off these areas, but did take off some material to lower the intake and create an even gap around all flanges. Started with the front of the intake, and then matched the height to the rear. Positioned the intake to where it would only take off the metal at the deck area, and not touch the runner flange when cutting:
2.) After cutting the deck down some, we were still left with the runner flange making contact and hanging over the intake surface lip on the head. Back to the mill, this time vertically cutting the runner flange so it will clear that lip, started with a rough bit for the first cut and then switched over to a cleaner bit for the rest:
3.) Test fit the intake, still didn't clear the lip on the heads. At this point I made a decision. The intake cost almost as much as the heads. But is harder to get now a days, let alone un-milled. So I did not want to screw up the intake.
Pulled the heads off, slapped them on the mill and took some of that lip off. The way the heads were cast from the factory, it looks like they didn't put to much care into the levelness of the casting around the lip, and onto the valve cover rail. The factory mill of this lip, or the intake flange on the head almost looks crooked, its not. But the way the cast and it was milled makes it look like it:
The lip:
Milling time:
Now there is a hairline ride there where the bit was taking out material, only because we didn't mill the angle of the intake mating surface. But its extremely low.
4.) Put the heads back on the block, test fit everything again. The intake fit, but was very tight. No problem, back on them mill for both the heads and intake. This time taking just a hair off of the both of them:
The valve covers are the next thing in line to make fit. While the intake now sits on the heads perfectly. The valve covers still make contact on the runner flange on the intake. Thankfully RPM leaves a good amount of material on the flange on their sheet metal covers. I'm going to have to belt sand on a angle, the flange peak a little to clear the rest of the intake. No big problem. Doesn't need a lot.
One of the valve cover bolt holes that are in the lip that we milled on are peaking through. Only on ONE bolt hole though. When I said they didn't put care into the casting, or final milling of that flange. Maybe it was the location of the holes they really didn't make perfect. The hole is drilled through that part of the head, so it should have enough threads left to hold the bolt. If not, I'll drill it out some, and helicoil it.
Only real screw up was, and I'm not sure if it was our fault, or the machine. Because it was lined up good when it started milling. On the last vertical mill on the intake, we really didnt have a good idea of how much material it was taking off(yes, we started it, took about a half inch off and backed it up and looked it over.). It looked great at the line it was taking, only needed a small amount(compared to what we had already taken off of everything at this point) to make it work. When the mill got to the first runner port we could see it took a different line. Not sure how, but it cut a little closer to one port then the others. We stopped it, moved it out more and finished the mill. So on the side of the intake, where it meets that lip on the head it was sort of a wave in it near the port. You probably will never be able to see it, or tell so its no big deal. Just odd if you look at the intake by its self.
Now the intake ports match up side to side, but top and bottom they are still off from the head ports when the intake is sitting on the heads. You can see this if you look down inside the intake. There is a small air gap on the top of the ports. I'm going to have another buddy put some filler weld inside the upper portion of the ports, and then port match to the heads. This will bring the ports down, or in other words bend the flow more into the head and not more into the flange surface of the head. You'll never see it, and it won't be alot. The bottom side of the ports I have plenty of material on the intake flange to port match to the heads. Which is nice.
When I get the intake back I'll take more pictures of how it fits now on the heads, as well as some better pictures of the milling.
The distributor. I figured I might want to check how it fits and see if I'll have to take the factory cast collar off the stock dist before I go to far as well. So considering I have a bare block I'm doing this all on. I stuck a stock cam back in the block, put the intake (this was before any milling happened.) on the heads and put a stock dist back in. To my surprise, it actually sits pretty well in there.
It mesh's with the cam gear very well, sits a tad high, but like I said this was before milling. I haven't checked it again after milling:
So for the most part the intake to head problem is now finished. I just have to figure out if I'm going to go towards the drivers side, or forward with the plenum. The intake is only drilled for forward. I have both plenums for both styles. Just comes to personal preference and how other things play into it to factor how I go with it.
Going to file my taxes here in a few days, and hopefully use some of it to send the block off to the machine shop finally, and get this thing going faster.
Next project. Diy single turbo headers to clear the AC.
Not sure yet if I'm going to keep the x-over in the factory location or if I'm going to try and bring it around the back side of the motor similar to the turbo buicks. :tup:
