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"Built Dam Strong!"

22 May 2012

DOHC ZC flanges, tri-y headers and some good tips for V-band flanges

I thought I would grab some detail pics of the DOHC ZC flanges I got in!

Here is one on top of the C-channel piece I got to do header fab from:



Laser precision!



Once the header gets made, I will flap wheel those marks out and smooth it up, and given how nice they are, it shouldn't take long at all!

Today I got a lot done, though I had to take a huge step back because of a glaring mistake I made, but I definitely made the best out of the situation and am really stoked about the next few days!

Here's the tubes for the smaller of the two 4-2-1 headers you may have seen in the background of some of my pics:

I had just finished sanding them. I wanted to attempt to get into the "crotch" of the first 2-1 merges, but, as you can see . . . that wasn't gonna happen:


Welp, it's only metal. Time to cut and paste!






I then took the time to wire wheel the whole setup. The pieces came out really good looking!


This is a weld from when I welded the merges into the whole collector:


I love the way brushed steel looks!

This is an process photo of setting up my ghetto rigged welding "table:"


Yes, that is a half a door with a stainless shelf I liberated from a recycle pile. I clamp my ground lead to the shelf and it provides a really decent ground for anything placed on top. I use a wire wheel to break up the oxides on the surface a bit each time I use it, and that really does help make better electrical contact. 

Enough talking, more welding!

Here is the start of welding up the v-band onto the tail of the collector:

You'll want to note that I actually extend the pipe through the collector a bit:


(More on why in a few more pics.)

Best part of the weld on the v-band:

Inside the pipe, yes, that was cleaned up afterward:



Now here's the flange without the other half on.



Welding the v-band flange like that does a few things for you:
1. Self-indexing connections are easier to put together by yourself.
2. The connection will seal better, as there is no split at the joint of the flanges.
3. Welding with the whole v-band assembly together helps prevent warpage. 

Overall, this is a much better way to do things as long as you have the extra space to do so. Just make sure you leave enough of the other side's flange to get a good weld onto the exhaust tube. 

Next, I welded up the "crotches" of the primary merges:


Then, to correct for lack of proper equipment, I welded on slip-fit rings onto the primary merge legs

Mockup:


(Note, the sanded portions of the slip fit rings! ALWAYS clean your metal. ALWAYS)

Getting things started off RIGHT!


Still have a lot to learn about welding this stuff, but I am definitely getting better. 


After the slip fit rings were welded on, it was time to re-weld the primary merges to the rest of the collector. I chose to gap these welds, and used my handy-dandy body panel clams to space everything correctly:



DONE! 


I love the way that thing looks. 
Here's a closeup of the welds in the middle:

A friend of mine who is a very excellent welder told me to try using thinner filler. I will certainly do that. I'll also try a few other techniques for joining this thin tube that he mentioned. (Thanks, Remo!)

Now that the collector is 99% done (there is actually some porosity in one of the welds that I am going to cut out and weld over. I have no idea WTF caused it, but it might just be an odd spot in the metal which happens on occasion), It's mockup time!



The collector is easy to hang by itself, but when you add this stuff:


It gets a lot harder to manage by one's self. 

Another view on the ground:



In place, sort of:


This being my first completely from scratch header build, I have run into some issues. LOL! Since I cut the collector apart, my primary tubes are a bit off, as you can see in the next two pics:




The simple solution for that is to cut and past, again. heh The problem is that I need to get the collector in place first and it needs to be on something solid. I will have to build a fixture for it in order to keep everything where it needs to be. My primary concerns are getting as close to the oil pan as practical to maximize ground clearance, and to make sure that the header ends in a spot that will actually fit in a car.
I oopsed that with Justin's headers, because he wanted it tucked TIGHT to the pan, and I ran it straight back from the corner of the pan instead of the middle of the pan, which lines up better with the center tunnel of the car.

Whew . . . what a long post. It was totally worth it. I really enjoyed cleaning up after today. The next header I build in the coming days and the battery tray and seat pan I am going to fabricate are going to push me to new levels of pickiness. I just want to make sure the people I am doing work for are satisfied with it! I always want to do the best job possible.