DIY Headers

I'll skip finishing the welding on the rad core, and drop the engine in for dimensions. Its seems our warm weather forecast doesn't go past today (High of 18C), to dip down to below freezing until April 9. At least I'll make some headway on the header.

I've already de-rusted and refinished the new K-Member (engine support) and Trans cross-member, but the original is in place to hold things together enough for the header measurements. It all comes out anyway, since I've got all new springs, brakes and struts to go in.

Should have some pics and dimensions by this evening. I'll leave the block in to confirm as I go. The old rule - "Measure TWICE, cut ONCE" really applies here.

 

Engine Bay Proofing

Its been on and off Cloudy all afternoon with winds up to 60KPH, and we never hit the 18C forecast. So I stopped at 6:30 PM. I just hung the 2-in-1 collector to get a general idea and line up things, sort of. With the standard trans, I won't have that kick-down bracket over Port 5 and 6. It interferes with the header exhaust flange. I modified the one from the Zephyr, so I could use the engine lift bracket feature.

This engine is in nice condition, with less than 8,000 Kms (5K Miles) on it, since it was rebuilt. I'll run it while the other is being rebuilt.

I'll install the starter tomorrow for positioning, and secure the above collector properly. But from what I can see, I've got a clear 'line-of-sight' for the first 4 ports. Looking at the pics that you sent me, Mike, at the beginning of this thread, although the tubes are bent, they don't look like they are equal length. If the floor tiles are 10" tiles, the last 3 look a few inches shy of the first 3 ports. How critical is equal length for an inline six?

Anyway, I do get a straight run of 29 inches (add 5.75 inches for the mitered stub, I calculated that it needed only 32.25")) at 45 degrees, from my Port 1 stub to below the frame of the car. It and Port 6 would go into the closest entry on the block side, into the 3-in-1 collector, with the others would be located on the fender side, with each 3-in-1 vertically aligned to feed into the 2-in-1 collector.

Here's the pics from today's outside adventure:

 

Have you tried it with the starter in there?
#6 looks a little short.

 

Only on my mockup in the basement. I made the real SS piece longer to allow 3/4" clearance above and at the end of the starter. The pic is a couple posts further up.

I just remembered this morning that I can't install the starter, because the alignment pins for the bellhousing haven't been changed to the right locations. I'll take it out there, and block it up to better locate everything.

 

One of those high-torque mini-starters could give you a bit more clearance in there too.

 

Good point. I'll keep that in mind.

 

On Equal Length header tubes

On V8s, V6s and V12s, everybody agrees that Equal Length is the only thing to do, but on I6s, its a different story. Now, I understand why you said 18" to 24" tubes. They should be equal length on the farthest 3 ports and equal length on the closer ports, but don't have to be all the same length. Duh...

Here's Burn's Stainless tech article on it:
http://www.burnsstainless.com/v-12exhaustdesign.aspx

Here's Headers by Ed's comments on Equal Length tubes:
http://www.headersbyed.com/hc_buildbetter.htm

So for I6s, I could make them equal on 6 or by front 3 and rear 3 cylinders, but Ed makes a good point of the tuning issues, which would get complicated with a tri-power carb intake.

So, instead of reinventing the wheel, I'll go for equal length on all six, mainly by pushing the collectors further under the firewall, and closer to the transmission mount. I don't want all those curved bends shrinking the space for both AC and Heater coolant hoses.

On your pics, Mike, the rear cylinder tubes do look shorter than the front tubes:



This set seems to have handled it by offsetting the tube length at the 3-in-1 collectors:


If I compensated the difference in rear tube length and front 3 tube length, between the 3-in-1 collectors and final 2-in-1 collector, would that be detrimental to tuning?

 

On another forum, one member wondered why I didn't just extend the AC bracket out, instead of all this work. Its a good question and deserves a decent answer. I replied as follows:

I measured the stock distance between the stock manifold and the AC compressor at 1-1/16 maximum, and 3/4" minimum. The cast iron manifold holds its heat far longer than a thin-wall Stainless tube, and I've got it laid out to leave about 3/4". So with a stock belt pair, and allowing for belt stretch, I'll have enough clearance. The other issue that isn't that apparent is the linkage for the tri-power carb setup. With the AC pushed out further, it could hit the AC directly, at the first carb pivot or the progressive linkage arm running to the central carb.

There's all kinds of work-arounds for this issue on Falcons and Comets:
http://fordsix.com/forum/viewtopic.php?f=1&t=67303

Fox-bodies have less space, and the only one I would use otherwise is the AC bracket or AC/Alternator from a Maverick to put it on the other side of the block, above the PS pump. But those are in the UNOBTAINIUM Parts class up here. We plan on doing a lot of touring during the summer months down in the Southern USA and into Mexico. Getting stock AC V-Belts in most roadside towns is much easier than having a garage owner look for some off-the wall length.

And there's another invisible BONUS. I'm an engineer, 66 years old this year. I do a lot of Imagineering on wooden gadgets and cabinetry, but very little in metal shapes. Doing this has revived my spatial vision/imagining capacity. So now, this type of work is almost like a fountain of youth thing for me. Its a plumbers nightmare, and an ex-engineer's revival! :2_thumbs_up_-_anima

 

Mate firstly you are doing a good job, keep it up.

Here are a couple of things that you may want to consider as you go though. Do not get too lost on trying to keep all of your lengths exactly the same length, and here is why.

Ok when building the lengths into some sort of equation, while the lengths of the first cylinder pipes can inherently be longer because it has so much further to travel than the last cylinder which is a given, often you will also see that the No1 pipe is also very straight with little restrictions. However it is equally not unusual that last few cylinder pipes can be slightly shorter but also often have bends that are in excess of 110 degrees in the middle as well.

What this means is, there will be a slight loss of momentum due to the parasitic component of such a large radius, making the gas pulse itself take a fraction longer to travel the shorter distance of the last pipe than it would through the longer but less complicated pipes up front. So as long as you build enough length to accommodate the volume required for maximum hp from each cylinder, the varying air speed in each pipe will closely match the timing of each other in the collector because the gas flowing through the shorter pipes that have a very large radius bends will be slightly retarded over the gas in the longer but straighter pipes. I hope this makes sense.

If you want to see how much momentum is lost on a large radius bend, look at how much a river gouges out the outside of a bend. Here there is lost energy that is ultimately converted into erosion. The same thing is happening inside the header tube and often in the long term it is the outside of the bend of the largest radius that fails on a header first for this reason. So increasing the radius of a bend not only helps to increase physical length, it also aids to retard the pulse ever so slightly as well.

OK the other consideration when quoting an exact length is, keep in mind that this is generally related to an equation that will be related to a given volume at a certain RPM to maximise the most HP! This information is only good for two things, 1) a drag car for a flat chat launch, and 2) making maximum hp on a chassis dyno for show. It does not factor in any real world driving traveling in top gear at say 60 mph up a slight incline with your A/C on. Too often the big is best scenario will rob you of the necessary bottom end and midrange torque required to make a car drive nice on a day to day basis.

Ok work within a couple of inches of length of each other factoring in the fact that some pipes will ultimately need a greater radius to curl back and meet the cluster that it is intended for.

If you look at the pic of these headers I have put up, you will see these features I have described are designed into this header. All that and I am still clearing a steering box and clutch mechanism at my end as well! Cheers Mike.

 

You're a master in this, huh? When someone can bring a complex engineering issue, like the effects of bends, into the visible realm of real life comparisons, well my hat goes off to you...

Well, in comparison, I have a 4 lane highway for my pipes to scroll down o the collectors, without the RH steering issues, so I'll do a few long curves and have room to spare. Thanks Mike.

 

...Me too, even I followed that!
Normally I start to glaze over at the sight of the word "equation."

 

Mike, I've seen a lot of good videos on welding SS tube, as you can imagine. Some of the nicest and strongest welds on the tubing were chamfered on the outside, regardless of being, MIG, TIG or Gas welded.

I've got 3 options:

1) MIG with 308 wire; http://www.princessauto.com/en/detail/0-030-dia-x-2-lb-stainless-steel-welding-wire/A-p0142430e
2) Propane Gas with MUGGYWELD's SS6 rod and flux; http://muggyweld.com/
3) OXY/MAPP Gas with 308 flux-coated rod. http://www.princessauto.com/en/detail/1-8-x-18-in-flux-coated-nickel-silver-brazing-rods/A-p8471070e

The chamfer makes sense to me, because the welding wire/rod has a larger surface to grab, than if I left the tubing flat at the joint. Since this tubing is just over 1/16" thick, I'll do about a 1/32" chamfer on light inside angles (11 to 30 degrees) and 1/16" outside angles (45 to 60 degrees). If they're gonna split, they'll do it on the outside angles, that point downward.

I'm going to use this afternoon to practice with that, on a couple cut-offs. If you have any recommendations, please do so.

 

Welding SS Tubes

I'll post pictures tomorrow, but I did a few practices with MIG, and the 308 flux coated rod. I didn't try the muggyweld rod yet. I bought it last spring, and the flux comes in a separate 'jar'. Apparently it has a 6 month shelf life, but I've kept it in a cool, dark, dry place, so it may be ok. The issue with the Muggyweld product line, is that we can only get it from one source in all of Canada, and it takes a week to come here, from Toronto, so I'll tinker with it when time is on my side, and our currency value improves.

Anyway, I am thoroughly impressed with the 308 rod with OXY/MAPP gas! It flows nice, you don't have to overheat anything, and it flows into the seam, right into the interior of the tube, without any dripping. It just penetrates, and binds the entire thickness nicely.

I'll be welding/brazing on the mitre caps in the morning (already cut and ready to do) and grind it smooth and buff it up. Not gonna get fancy with buffing, since I need to braze it into the flanges, after I get the second port done. Gotta fit the first tube in the engine compartment, first.

Anyway, the braze is strong, and the seams are solid. Very happy with it.

 

I haven't died or anything.

I've been hunting down the Trac-Lok differential for mine. Since its a Mexican built Fairmont, it came stock with a DANA 44 8.5" differential. Taken a lot of research, phone calls to DANA's own Tech service, and helping them with old files I found on DANA's own Forgotten sites in Venezuela, Columbia and Brazil. Good thing I can handle Spanish.

I'll be back on the Header, sometime next week, after I reinstall the axle, and new rear suspension (Lower and Upper control Arms, shocks, new coil springs and upper and lower isolator pads (got the last 2 NOS in the US), rear sway bar, etc.

 

Nice to see you are working your rear end off!I've been reading all about it here and there.