Part of my twin-turbo 500cid crewcab project is to build turbo manifolds. Unfortunately my life is such that I don't get to work on this as much as I'd like to, but today dispite the nut-freezing weather I managed to do some cutting and welding.

Here you can see one of my collectors, which is nothing more than a 1/2" thick mild steel flange shaped with a cutting torch, with four sections of "black pipe" sections and welded together, and to the flange. The most difficult part was "chucking" the highly angled pipe sections into the chop saw, and cutting down. Anyway, because of the angles of the pipe coming off the flange, I won't be able to insert a bolt (or a nut it seems), so I chose to enlarge the holes slightly to 27/64" and tap with an ordinary, course thread 1/2"-13 tap.




The next step is to place the collector/flange where I want it to be, and the easiest way I could think of was to make a simple jig. The jig is painted red mostly to prevent it from rusting away while I work on this project over the next few weeks, but it being red also allows you to see the actual jig clearer. Essentially its three pieces of scrap I had lying around, welded together, to place the top of the turbo flange slightly higher than the valve cover top, reasonably parallel to the earth. The jig required a bit of notching where it mounts to the head, so I can move it one port over to make a symetrical turbo manifold for the other side. Anyway, I mounted the collector/flange using threaded rod I hacked up into 1.5" long sections, just because I had one 1/2" bolt lying around and tons of 1/2" threaded rod. Convienence is everything!

The cadmium plated grade 8 bolts are longer than one would think is necessary, but I put mild steel "sleeves" on them which as a final step will be welded to the header plate. The purpose of this is to give me easy access to bolt heads unlike most headers which require allen head bolts and a contortionist with a ratchet to install, and uninstall. Longer bolts means the heads of the bolts clear the tubing, and I, or anyone, can install and remove them with simple tools without skinning my knuckles.




Here I've installed the header plate, which is 7/16" thick flat steel, with holes bored for the mounting studs as well as the exhaust ports. It should be fairly obvious that the exhaust holes in the header plate are round - just because it was convienent to do so. They will be ground to a more rectangular shape afterwards, to match the porting I've already done on the "good" heads.

Here I've tack welded the sections of black pipe together to form the first of four exhaust runners. My photography is terrible, and the pictures make it look "kinky" whereas it's really not that bad. It's definately not a smooth bend however it's not awful either. I have a small tubing bender that's not capable of bending this diameter & thickness, so I chose to hack off little angled sections instead and not worry about it too much.




And here is another picture of the same, single runner, from another angle just to better illustrate what I've done so far.




Some additional comments.

Yes, I know stainless is preferred, however my local steel supplier didn't have the correct diameter in stock, and I didn't have any stainless mig wire handly, nor does my tank have the appropriate gas mix for stainless mig welding. Black pipe is 1/8" wall (at least in this diameter), and I can use some of the vast stock of flux-core wire I have sitting on my workbench, so for me this was fine. The splatter was a bit annoying, but I solved that by spraying the areas I'm not welding with Pam cooking spray. Smells funny but it works fine actually, and is dirt cheap.

A note about "stepped" elbows, to make curves. This is by no means ideal, however I believe (having done worse than this in the past with good results) it will not matter to much for my very heavy crewcab. Each elbow seam to the next elbow, has a ledge on parts of the connection on both the outside, and the inside. I paid special attention to line up the inside "bend" edges the best I could before tacking, so as the exhaust pulse flows down the stepped exhaust tube, it won't see that much of a step. More noticable steps are on the inside curve, where more than likely it won't effect things all that much. I didn't worry about what the outside looks like... only the inside. It's ugly anyway

The first set I made were even uglier, and making them while attached to ahead on an engine block is definately not the way to go. Welding upside down in a garage on your knees is very tiring, bad for your knees, and your back. So this time around I made a simple "holder" out of heavy angle iron I had lying around to attach to my smaller engine stand. This allows me to rotate the head around 360 degrees, generally giving me reasonable access to all the pipe seams.

When completed, as mentioned above I will port match the header plate to the heads and weld up any splits that occur while doing that. I intend to be aggressive with the porting as the heads have been ported quite far.

Then I'll shape the header plate so it fits cleaner, even though it being a 4" wide plate doesn't hurt anything. I think it would look a lot better if I shaped it a little bit, but I'll worry about that later on as that's merely just a finishing touch.

 

Nice work. Are you having as much fun as I would be if I were in your shoes?

That's a cool idea relative to the manifold bolts. I wonder though... With such a long bolt do you run an increased risk of a twist off? Perhaps; however, I'd guess that the remainder would be exposed allowing easy removal as opposed to drilling out.

I swear if I were a billionaire I'd set up a foundation to help folks likes us: those that have the potential but perhaps lack sufficient funding for materials/tooling to reach our idea's ultimate potential.

 

When I built the twin-turbo 75 Dodge truck, I did the same thing regarding the exhaust bolts, except I used round tubing instead of square. I haven't welded them on yet so I can switch them out later. I removed and installed the dodge manifolds multiple times with no problems of them breaking... maybe because I used anti-sieze each time and they weren't on there very long as I was tweaking a variety of things over the life of the project. Grade 8 bolts tend to be okay in exhaust manifolds... though some people prefer stainless. I find stainless galls and can after zillion heat cycles be a paint to remove.

As far as fun... any time I get to play "truck monkey" is happy time. I find it's the one point in the day where my mind can be free from the daily drama called life. Though at this rate I'll have one exhaust tube done every other week LMAO.

BTW, as far as cost... making manifolds this way is dirt cheap. Black pipe (natural gas pipe) is not very expensive. It's essentially an ERW welded, 1/8" wall steel pipe, and it comes in a variety of diameters, and the wall gets thicker as the diameter goes up. Available at any home center. Most of my project time (unlike today) is late at night, and there is something to be said for the convienence of hitting the home depot (or lowes) at 10:45pm to grab another piece of black pipe

The header plates (raw plates) cost me about $6 each, the bi-metal hole saw was another $6-7, the turbo flanges were one piece and the steel supplier gave it to me for a buck, because it was too small to be useful to them.

For a "foundation" I think a defunct aircraft carrier would be perfect... dock it almost anywhere to match the seasons, and everyone who lives onboard splits the costs of the tools, so there are minimal duplicates.

But of course air craft carriers, even defunct ones, are expensive!

 

Lookin' good Frederic. Love the collector mounts. Also, the header bolt sleeves are an excellent idea. Will they pass through the flange and be welded on the inside face or butted and welded to the outer face? I may borrow that idea for my build. Just curious but why not use weld els for all of those small radius sections?

 

Welded on the outer face.

I couldn't find weld-els locally for less than $9 a pop. McMaster was cheaper, but by the time shipping was added for the quantity I needed, it would have been in that ballpark.

So, a $20 section of black pipe, and a $6 metal cutting wheel.... and I'm set

Since I pay myself .000000000001 cents an hour...

 

You are going thru the same basic sequence I'll do when I get around to building manifolds for my twin turbo FE! I figured an old set of headers for flanges, some 180 bends and I'm set. Might spend just a bit more than you initially, but what difference does that make? None to you, right LOL! The pay's the same

I've got a 390 hanging on the stand right now, just need to put the heads back on and start playing. Of course I need to find turbo's also! Luckily I work at a large machine shop so making most of the hardware will be a bit easier for me.

Good luck with it!

 

I hear ya.... I'm thinkin' that extra cash will come in handy with all of the tires you'll be incinerating.

 

Freight - I found it fairly easy just to make the header plates... then at least you can make them thicker which reduces warpage from the heat. My first set of manifolds on the Dodge truck were old van headers that I hacked the tubing off, and they warped and snapped one of the bolt heads. I couldn't tell it was from curving off the head or sheer by expanding left to right. Never had a problem with 1/2" plate or 7/16" plates.

Just a thought... heavier, but you only have to make them once

Twinscrew - I'll be using junkyard/cheap tires at first, as a fuse. I don't want to break the rest of the drivetrain, so until I get things tuned properly and get familiar with controlling this beast, the tires will be the fuse. *then* I'll spring for two sets of rears... one will be for load carrying/towing, one will be for street play and as treadless as DOT permits...

Though I have a dually rear in storage... so I may have twice the tire/contact patch eventually. Haven't decided yet.

 

Picture of the final welding, then "slag cleanup". Looks much better, I think.

 

[QUOTE=frederic]Had some free time today so cut the sections and tack welded another exhaust runner.






Fun fun fun!

 

I'm jealous.

 

Jealous?

Of what, my having an hour or two a day to putter around, or my large supply of rusty black pipe?

LMAO

 

This would be a snap for me & my suite of EDM tooling machines! Anyone wanna trade services for services/parts?

Send me a drawing & I can fabricate most any piece of pipe you need.

In return, I could use someone nearby (SF Bay Area) who can help me out with some sandblasting, or maybe some good parts for my 51/48 Panel Hotrod...

-HP

 

Another day, another hour, another exhaust runner.



I have to say I'm proud of this considering this is made mostly of black pipe, made with a cheap miter saw with a metal cutting blade, a flux-core mig welder (no gas), and electrical tape for "clamps".

 

I lied - it's almost done!

Last (first) runner tacked:


Last (first) runner final welded:


Another view:


Now I have four runners, curved in strange ways but Mr. Tape Measure says
it will fit between the 460 and the inner fender liners with about two
inches of clearance on the passenger side. When I make the driver's side
I'll have to make the runners closer to the head, because the 900lb
steering gearbox is reasonably close and I don't want to have the exhaust
bang on it, or bake it to "medium well".

What is left to do on the completed side, is to chip off the remaining
slag, mig *****, and clean up two small welds that I'm unhappy with. One
I completely missed the joint (???) and the second didn't penetrate
correctly because of the lack of clearance. I was trying to be "clever"
and was trying to weld between two of the exhaust runners with about 8" of
mig wire hanging out the gun nozzle. It sorta worked, but the end of the
wire wobbled too much to make a nice weld, so I'll have to figure
something else out.

Anyway, one side almost done!