Long time coming

I have waited a long time for some parts. I've sweated and strained the grey mush in my skull to come up with a coolant layout that would work for my Bus and importantly, work for others as well. 

While scratching my own itch, I've been down two failed paths. The first (VolksarU-0.1) was placing scirocco style radiators in-bay only to discover that 'prior-art' examples were more the product of P.T. Barnum than Earnest the Engineer. The second failed path (-0.2) was a feasibility study on emulating the Fellows Speed Shop design, only to discover that FSS hang their coolant tubing even lower than their radiator! That one was abandoned without spending anything more than my time. (Which without money is all I have had much of this winter.) So much for the dead ends that VolksarU ran down so you don't have to.

The third shot (VolksarU-0.3) looks the most promising, and like most good work, it comes from a mashup of the best works of others, and lessons learned from all of those dead ends.

• The engine compartment coolant piping from the engine outlet / inlet to the heater wye hole in the rear transverse frame member is designed and fabricated by Rocky Mountain Westy.
• The low profile scoop and underbelly radiator concept from Fellows Speed Shop, redesigned with my own break-away scoop and the Champion Cooling EC281 radiator standing in for their custom radiator (at 1/8 the cost and made of the same materials.)
• My coolant piping design to bridge the gap between the connection to the engine bay via the heater wye hole to the radiator itself. The design's chief features are:


• Durable: Built from 304 Stainless Steel, the same material used in the replacement coolant tubing provided by companies like GoWesty, and Rocky Mountain Westy as replacement coolant tubing for the plastic factory tubing in the Vanagon. The Bus may rust down to a pile of brown goo, but this coolant tubing will still be there.
• Compact: Mashing Gates Greenstripe flex hose in the confines of the central box space of the frame is simply a no-go: They're not rigid enough, and they're so fat they won't fit down that narrow space between the radiator and the inside of the frame rail. You can't run them outside the frame rail without putting them at risk of road debris, and looking like an extra from Mad Max. Hose will want to follow its own internal desire to turn itself back into a straight line and puts stress on its end couplers because of it. In short, a hose with an ID of 1-1/2" (the size of the output and input of the EJ22 engine) will have an OD of about 2". Which is too pudgy to fit down that narrow corridor inside the frame rail. So you've got to go thin and rigid, both to fit in the space and to retain unlikely shapes without stressing the couplers, which can cause leaks.Ergo, tubing. Not hose.
• Thermally Conductive: As mentioned in a previous post, hose is an insulator. (It may not seem like it if you've ever grabbed a hot coolant hose, but compared to touching a metal radiator tank at running temperature...hose is an insulator.) Since our cooling ability is already compromised by the orientation of the radiator, best to be throwing off as much heat as possible as fast as possible before, during and after your coolant passes through the radiator. Also, any portion of coolant tubing in the engine compartment is also being cooled by the air scooped into the engine compartment from intakes at the rear corners of the Bus.
• Protected: All of the coolant tubing and radiator is above the frame of the vehicle. You would have to tear the scoop off and run aground first and the chances for your radiator and coolant tubing's survival are better than 50/50, even if you lost the scoop. Keeping all of the coolant tubing above the level of the frame leaves them especially well protected. Short of an in-bay solution, this combination should produce the best of all worlds without bankruptcy as a side-effect of success.

With my six pieces of mandrel bent SS from Columbia River Mandrel Bends in Saint Helens, Oregon, I'm ready to have the radiator modified to move the inlet / outlet, then have the tubing TIG stitched into three assemblies. 

Assembly #1 allows it to jog from the original heater wye hole into the left hand frame rail and forward to the front (previously top) of the radiator where a hose coupler attaches it to a U-bend (Assembly #2) and into the radiator via a hose coupler at the front left.

On the output side of the radiator, we exit at the right rear through a hose coupler and into Assembly #3 which is two 90° elbows cut and stitched into a jog that takes us back to the heater wye hole. 

That's the circuit for the most vulnerable part of the cooling system.

The final piece of fab is the scoop which will be fabricated of steel panels, two angle brackets and a reinforcing strap, any shop should be able to knock this out in under an hour. Between the TIG work for the tubing assemblies and the MIG work for the scoop the price should stay reasonable.

Remember the VolksarU policy on bespoke fabricated parts: Avoid when possible, but if necessary, work from plans. I'm hoping to lure someone with a CNC mandrel bender into fabricating all of the tubing assemblies from single lengths of tubing instead of doing TIG work to put them together.

A Ten Dollar Helmet

In the early 1970's when motorcycles were losing some of their outlaw image, Bell Helmets ran an ad that has become synonymous with risk analysis: "If you have a $10 head, buy a $10 helmet. If your head is worth more, buy a Bell." The helmets were expensive: About $640 in today's dollars, or 15% of the cost of a brand new 1970 Honda CB750, the first mass production 'superbike.' While the "Easy Rider" bad-boys were wearing defiant German Stahlhelm half-helmets, the Bell owners often lived to tell about a terrible crash and the Stahlhelm crowd...not so much.

Coincidental to this story, when I was young and dumb (and not too long ago) I was in a terrible rush to do some maintenance on my 1971 Super Beetle. I really, really wanted to 'git-r-done' and in my haste I finished on time, drove off and almost killed my dumb self.

Half of the problem was cheapness. The other half was laziness. The third half (!) was the internal stampede which causes teenagers to optimistically engineer according to appearance instead of heft. "I looks like it will hold. Let's go," has been the sad opening lines to many tragedies and near misses. The details of my personal idiocy are too mortifying to repeat: Suffice it to say, the fact that I didn't fetch up injured, dismembered, dead (or all three) was a miracle of Providence.

In my experience, some people outgrow this adolescent recklessness, and others make it a way of life.
The Vintage VW clan is infamous for its brand of tin-can patches and 'paint the dirt' solutions. Maybe it's the brand's reputation as an inexpensive novelty. Maybe it is because it attracts cheap dreamers. Unfortunately, there's a difference between frugality (don't waste your money on the bling; just wash it and wax it and keep it in good running repair) and cheapness. (Wherein every possible corner is cut to avoid paying for a correct product, yet still be able to to say 'it runs.')

Those of us who have been left holding the bag of someone else's half-assed work scream in frustration when these kinds of corner cuts bite us. The high ampere cable, spliced together with wire nuts and electrical tape that bear the weight of the hanging cable. The steering tie-rod ends with zip-ties standing in for cotter pins. Even fuel hose doing double duty as brake reservoir hose. They're all symptoms of what a former supervisor (and still close friend) refers to as the "It's Miller Time!" mentality: If it holds together until I'm out of sight, I'm home free.

While I've experienced all sorts of mechanics and tradesmen who produce rip-offs like this, doing this consciously to your own ride, or your own house is not just self defeating, it could qualify you for your own Darwin Award. Worse, you might wind up grieving and in the State Pen. for manslaughter when your daughter makes a left turn in that car you used the zip tie on...which suddenly heads uncontrolled into oncoming traffic when the steering tie-rod lets go...

What brought these terrible ideas to mind lately was listening to some very good people discussing (proudly!) some very bad engineering for vehicle conversion. Instead of selecting the right part for the job, they discuss the work in terms of "what I've got lyin' around." This isn't the same as the hoarder who has the entire McMaster-Carr back catalog in his shop. This is what my father (a mechanical engineer, welding inspector and specialist in nuclear safety systems) refers to as "kick into place at assembly, file sharp edges, and paint to match." It is placing a dubiously high value on having saved a nickel every time you have to replace that $20 part...because you have to replace it so often.

Living in the shadow of dear old dad caused me to develop this mantra for my Bus conversion:

"No part shall go on my ride that is of lesser quality than would be expected in modern automobile manufacturing."

This doesn't mean that a part needs to be made using the same methods: manual plug welding stands in fine for arc-spot welding. An anticipated 20 year life span is reasonable for any modern manufactured part. If a fastener is going to take a beating, use stainless instead of zinc coated fasteners. If you can't get stainless, prefer zinc plated over plain galvanized. Always uprate by one tier over what is require to merely 'make it work.'

There are times when a part must be fabricated to equal or better than factory standards. Obviously, most of us aren't skilled or tooled up to that. There are lots of fabricators out there who are, and if you plan to play in this hobby, it costs money to have their help.

I'll admit my own cut-corner temptations: I had originally thought to use pre-cut pieces of tubing and couplers for my coolant loop. I've had a 'Gates log' (36" length of straight hose) recommended to me to snake my way down to the radiator from my engine with lengths of hose unsupported and sagging like grandma's panty-hose. I was reminded by one of the other thermodynamic engineer wing-nuts I hang out with that 'Hose is a wonderful insulator. Are you trying to insulate the hot coolant to the radiator?' He suggested 16g Stainless Steel tube because, in addition to having a smaller OD and easier to route, it will be radiating heat for its entire length. You must take this into account when you're routing all of the other components, but you'll be throwing off heat efficiently all the way to the radiator and back.

The second half of this example is equally telling: All those pre-cut hoses and elbows and tubes...every time you transition, you have a potential site for a leak. You can't (and shouldn't) plumb the whole thing end to end with metal tubing even if you could, because you're going to have to take pieces out for maintenance so there must be some couplers in the loop. Just minimize them and you minimize the opportunities for leaks. For every part you put in, ask, "How many parts am I going to have to remove to replace this if it conks out?"

When Boeing (a former employer of mine) built the 777, it was the first plane that had been wholly designed (every panel and rivet) in a computer first, not only to make sure it would go together correctly, but also so that it could be engineered in advance for ease of assembly by humans (reach, component weight, arm turning radius) and also so it could be maintained without having to gut a whole section of the plane to get to a $100 part that had gone bad. That's why it is the most popular wide-body airliner in the world: It is easy to maintain and repair, which leads to more time in the sky, making money for its owner.

Therefore, the three cardinal rules for sane adaptation:


1. Use the right materials for the job: Nothing less than what you'll expect on a new car. If you have a part already, that doesn't mean its the right one for THIS job. Match the right part to the project, not the other way around.

2. Fabrication is part of the deal. Either ruin a few nice classics and become an expert yourself, or pay someone else to exercise their specialty on your behalf. DIY what you can, but know your limits. You'll be on the road that much sooner.

3. Pre-visualize assembly. Your clever idea will bite you if a $10 part requires a 200 mile tow and two days in a modern garage because you can't R&R it without removing the engine AND transmission.

Have you been a "Miller Time!" man? It's never to late to change your ways and start thinking like a mortal in a 50 year old VW, instead of approaching cruel reality with a "Ten Dollar Head."

Rubicon

    ru·bi·con

noun
A river in northern Italy

metaphor
The point of no return. Refers to Julius Caesar's march on Rome in 49 BC: It was considered treason to bring an army closer to Rome than the banks of the Rubicon River. If his campaign was successful, he would rule; if it failed he would be executed for insurrection. 

idiom "Crossing the Rubicon"

---

I have committed the unpardonable act of removing a component that can only be taken out in pieces. The rear main heater wye that routes hot air from the air-cooled engine heat exchangers, combines them into a single 4.75" tube that travels forward to a multi-way splitter and eventually produces a whisp of heat at the dash, or at vents on the floor. The whole affair never was very well insulated which is why the heat exchanger, producing an incredible 400°F, was under-appreciated: it never got a chance to do its job because of leaks, busted fittings, and incredibly poor airflow.

That wye pipe that joined the two exchangers on their way forward is a real stinker. It is welded into place before the decking is welded over top of it. Cutting it out with a Sawz-All (reciprocating saw) or an angle grinder is extremely nervous work since the tight quarters can cause you to cut something that you possibly don't want to.

Like the accelerator cable tube. The clutch cable tube. Nothing important. (Yikes!)

Obviously, this begs the question "Why did you take the heater wye out?" From those in the Bus biz (especially the über-purists) that phrase is essentially screamed because it means that for all intents and purposes, there no way back to an air-cooled engine. It is as one-way as losing your virginity.


The longer I've stared at the Fellows Speed Shop design, the less happy I've been with how low swingin' those coolant pipes are. One good shot and you're bleeding out coolant all over the road. The primary criticism of an underbelly radiator has been the proximity of the radiator to road debris. I had managed to get the radiator up and out of harm's way through a combination of skull sweat and smartly sourcing my components. Now I wanted to get the coolant tubing up above the level of the frame rails as well so all of the compromises for the conversion were removed.


The Fellows Speed Show design requires you to either drill through the side of the right hand frame rail like it was a bulkhead to return coolant to the engine, as well as drilling through the rear main transverse crossmember for the inlet side of the radiator from the engine. While both of these structural insults can be reinforced again...why are we drilling through rear and side of the frame again? To move coolant. The coolant travels through tubing 1.5" Outside Diameter (OD). That's not large....would it fit if ...? Remember what I said about that heater wye? The place where it already passes through the rear main crossmember is 4.5" wide and 3.75" tall. Remove the wye, and there's your way into the 'box' at the center of the frame where your radiator lives. Nothing hangs lower than the frame rail, and the whole run of coolant tubing (alternating with hose) is now very safe.


But if you're consuming the whole width between the frame rails with your radiator...how are you going to route coolant from the radiator outlet back to the engine? Won't you have to go outside of the frame rail and transverse crossmember box?


I spent serious time during the last two weeks freezing my tail-feathers off in that chilly garage staring up and visualizing how the hell I was going to run that coolant return without chopping holes in the frame.


First I noted that you could go OVER the frame rails. There is 1.6" of clearance between the top of the longitudinal frame rails and the decking. That's about an extra 3.5mm. That's close, but doable if I could route the coolant from the radiator tank up and over the frame rail. I ran into one of the major challenges everyone doing these kinds of conversions does: The reason the Bus is so big on the inside is that they really mashed everything together outside. The unfloor area I needed to navigate was as crowded as the bottom of a ladies purse.

Even assuming I could get over the rail, I would then have to run to the rear, and then jump BACK INSIDE the rail to catch the return fitting at the wye. That's too much jumping around, too many corners, too many fittings, and too many chances to spring a leak. No. I blew a week working that idea and concluded the only way it was better was that it didn't put a hole in my frame rail. Otherwise, just as bad.

But this failure did lead me in the right direction: I started thinking vertically and that turned out to be just the thing: I wondered about going over the top of the radiator. Nope: Fans there.

Maybe I could sneak around the edge of the fan? 1.5" isn't much. Nope. I'll be so occluded up there that I won't have a straight shot 1.5" in diameter to the rear.

Then it hit me like a pile of bricks: The radiator (with tanks at the front and back) is about 24.5" wide at the body. It has brackets TIG welded on which takes the total width to 28". The brackets hold the radiator to the bottom of the 'C' shaped frame rails. The bottom edges of the frame rails are 26" apart. The radiator shown below sits above the level of the frame rail and the long, serpentine coolant tubing snake *inside* the frame rail.(Not shown especially well by this overlay. Imagine the front to rear span above that frame rail.)

Ridiculous how I've had to composite together multiple pieces to show the layout accurately. The background is from a 1970 low-light Bus, but the principle is the same. The patch in at the rear generally shows the coolant tubing from the engine and how it all mates up at the rear crossbar. This is it: no drilling big holes through frame rails, or saggy coolant tubing running unprotected to the rear. Everything tucked up. Even the scoop (not shown) protrudes only 2-1/2 inches below the frame rails, higher than the lowest parts of the front suspension. 

So what's the distance, when the radiator is centered in the space, between the outside of the radiator body and the inside surface of the left frame rail? I tested it with the best object I had for the job:a piece of 1.5" diameter steel tube. Holy smokes. It fits, and with about that same 3.5mm 'expansion' space as was to be had by going over the frame rail.

There was some occlusion of the steel emergency brake cable conduit on the left hand side. So...close. I got my jack and carefully applying pressure with a rounded piece of wood in the cup of the jack, put a trivial new bend in that tube without kinking it. I checked the occlusion at the rear. Damme. This will work.

All we need now is a single piece of mandrel bent tubing to chase from the outlet at the front right, make a tight turn to the rear, into the space between radiator and frame rail, then emerge at the back and make another 90° turn to be facing right. The space is so tight that there's no way to do it with straight-pipes and elbows and hose fittings. It has to be done with one piece of 1.5"OD pipe.

And where am I going to get that for less than a king's ransom?

I found a fabricator. What you see shown above is the initial cut. Unfortunately, my draftsman (and consulting mechanical engineer with a lifetime of experience in high criticality cooing systems) is bugging out for the warmer climates of Florida for a month. I'm not going to lay around and wait for him to get back, but I'm going to have to put this on the back burner until he comes back and work other aspects of the design.