Fixing Hapy Furnace (part 2)

Picking up where I left off the last post, Hapy has an operational furnace again.

Fuel Pump Swap

As I mentioned in my last post, the fuel pump which originally delivered with the heater/furnace would not work when I tried to bring things back to life. I splurged and bought a more expensive "quiet" model for $50US rather than another standard pump for $20US. I figured quieter or not, the more expensive pump may have better parts in it, and it may last longer whether it is quieter or not. Or it was just a marketing gimmick and I got took. Let's chalk it up to the cost of an experiment.

The old fuel line path was relatively simple. The "hard" (clear but firm plastic) lines that delivered with the furnace had short (50mm / 2-inch) stretches of fuel hose between them and the pump. The pump was suspended from a cross beam by the included rubber mount held in place by a single sheet metal screw. After a few turns with a screwdriver, the pump was on the ground. A few more and the fuel lines were removed from it. The supply fuel line started dripping fuel after a few seconds, so I caught it with a pan. The line on the pressurized side was completely empty, so no drips. I simply reversed the removal: added the rubber mount from the supply end of the pump, added the supply fuel line, suspended the pump from the cross beam and then added the pressurized-side line.

Prime and Fire Up

The Afterburner has a control page where you can direct only the fuel pump to fire up. This allows you to get fuel all the way to the furnace without the glow plug turning on (drawing the battery and maybe burning out the glow plug). I had not connected the pressure line to the furnace, but I wanted to clear the lines of any bad fuel, so I moved the pan under the dangling hardline and triggered the Afterburner to prime. Within a minute of the prime starting, fuel started spurting out the end of the line. It took longer than I expected it to, but perhaps that is an indication of how little fuel these units actually consume. Once the fuel leaving the pressure line looked like the fuel supplied at a filling station, I stopped the prime function and connected the hardline to the fuel hose dangling from the furnace.

While the pump was slightly larger than the original, it did not seem much quieter during the prime. Of course, I hadn't heard it pump in a couple of years, and memory is a funny thing. I do recall that when the furnace was running, I could hear the tick-tick-tick of the fuel pump over the whoosh of the furnace. With this in mind, I set the furnace to start. I did not want to consider the experiment with the new thicker, dedicated wiring yet, so I left the battery tender hooked up. At no point did the battery fall below 13.5V so either the tender was working hard, or the new wiring is a hit.

Regardless, the glow plug got lit, the fan started spinning and after 2 or 3 minutes the furnace ignited. This felt like a considerably longer period of time than before. Perhaps the priming was incomplete and I needed to prime again after connecting the hose to the furnace. Perhaps it took time to ignite simply because it had been so long. Once it ignited, a huge plume of smoke poured out of the little muffler. There was virtually no wind, so the cloud grew and sat slowly obscuring first the rear end of the bus and slowly 2/3 of the bus before a light breeze broke it up. After a few minutes, the cloud dissipated and the exhaust emission was reduced to nothing. All that remained was a light smokey haze inside the bus. I regret not taking a picture of that.

Noise Observations

While the temperature inside the bus slowly crept up from 55*F (13*C), I noted the noises. I could only hear the fuel pump ticking inside the cabinet where the furnace is located and even then, only when I stuck my head into the cabinet. I think the pressurized line is transmitting it. I stuck my head into the rock-n-roll cabinet above the spot where pump is actually installed and could not hear it. Maybe this new pump is quieter. Then, I moved outside where in the past I could clearly hear the pump from several feet away, even from the passenger-door side. I could not hear it, but I could hear the furnace whoosh. Of course, my muffler-ing of the furnace is different this time, having removed the second small rectangular muffler and the motorbike muffler. Perhaps the pump is no quieter, but the furnace is that much louder. To determine if the muffler configuration is a variable, I decided I will conduct another test at a different time, after re-attaching the other muffler bits. I had thought about bringing them along for while-parked use, and maybe I will need to, out of respect for our festival-going neighbors. In the past, I took decibel readings, but they were for while the furnace held a temperature, not during temp catch-up (full blast).

I will continue to experiment with noise readings and post if I find any readings are different than they were 4 years ago. I expect that once I put the extra rectangular and motorbike mufflers on, the readings will be what they were before. The only real mystery to me is whether the fuel pump can be heard over it. At this point, though, the pump seems significantly quieter.

Thanks, as always, for following along-

Fixing Hapy Furnace (part 1)

Having finally arrived at a place where we have some heat while we're moving, I felt motivated to fix the heat for when we are standing still. Today's post covers most of the saga of getting a Chinese diesel heater operational again. Spoiler alert: the heater isn't running by the end of this post.

Brief History

Back in the early days of CoViD, I installed one of those Chinese diesel parking heaters into Hapy (See Parking Heater 1, 2, 3, 4, 5 and Final for deep detail). While I was able to run it a few times, I found that the heater pulled the voltage way down on whichever battery was connected to it. I tried to solve by providing multiple batteries to source from: one to start, one to run, but switching from battery to battery seemed like a bad practice. I had other priorities, so I just let the furnace sit unused. When I did the sound deadening effort and the luxury electrical re-wire, I dismantled the cabinet which housed the furnace so I could get sound deadener underneath it and electrical cables through it. This meant dismantling part of the furnace too. Later, when the band wanted to use Hapy for the album cover, I removed the furnace exhaust so it would not appear in pictures. So, I had a furnace without an exhaust, and would draw way too much juice.

Electrical

Over time, and with more learning about electrical stuff, I have concluded that the wire used to convey electricity but perhaps more importantly the wire for a ground were far too thin. It was due to these thin wires that the voltage would drop so badly as the furnace attempted to compensate. Wires which would have been barely up to the job had the battery been sitting right on top of the heater will definitely NOT be up to the task once you move the battery a few feet away. This is exacerbated by running the ground to the body of the bus instead of back to the battery. The ground location should not matter as much, but I'm citing it as a participant cause anyway. So, addressing the electrical came first after removing the furnace from the bus.

A small harness of wires leaves the furnace body and enters a black plug (see picture on the right). The harness that ships with the furnace includes a pigtail that clicks into the furnace black plug. To my eye, the red and black wires in the pigtail are not nearly as thick as the wires leaving the furnace. This probably saved the manufacturer a few pennies, but the amp draw issue starts right there (and in my case got worse). So, I cut the main power and main ground wires from the furnace black plug and put male/female wire ends on them (12V/ground respectively). I made them different so I couldn't accidentally plug it in backwards. I then prepped a thick 2-wire black/red cable with matching wire ends, and routed it over to the luxury battery. At the battery end, I added a ring terminal for the ground and added a 20Amp fuse into the positive side before adding a ring terminal on that end. I left things detached as I switched to preparing for the exhaust.

Exhaust

From under the bus, it was clear that I had not made the hole(s) large enough for the exhaust, intake and fuel to be easily maintained. Quite the contrary, I had installed it such that once it was all together, it would have to all come apart to fix anything. Frowny-face. So, I started by cutting a 4-inch square hole into the lower belly pan. Many buses do not have these, but I got lucky. Anyway, with the hole cut I could see where the furnace sat, and noticed that the exhaust was getting pinched by the too-small hole in the floor as the exhaust left the furnace. So, I went topside and expanded the upper hole both in the floor of the cabinet and the steel floor of the bus. With the larger hole, the exhaust easily fits and things could be maintained from below. Still, I did what I could on the furnace itself before lowering it in: Connect a 6" long stretch of fuel line, attach a small circle of window screen to the intake (so bugs and pebbles don't get in) and then attach maybe a foot of heat-wrapped exhaust. I set the furnace in place and attached a small subset of the muffler arrangement I had used before: just one rectangular muffler. I may bring the expanded muffler set up for use when we are in tighter camping spots (like festivals), so we can bolt-on some extra quiet. I mounted the muffler to the underside of the frame rail, with the outlet pointing rearward and slightly away from center (picture on the right).

A keen eye can see some fresh Rustoleum primer + paint above the muffler where I discovered some rust had eaten all the way through the body. When I was working on the other stuff I ground the metal down, removing the rust, but exposing the holes. Sadness. That rust traces back to when this bus had a small vent window directly above this spot. That vent window was badly leaking and the rust had already been forming to the point of marring the paint when I bought this bus over 20 years ago. I eliminated the vent window in 2015 (See Calling "glass") with a window I purchased from BusBoys in Redding, CA in 2009. Some things move slower than others.

Fuel

I shifted over to fueling at this point. The fuel line that had been between the included "hard" line and the furnace had breeched, probably when I did the sound deadening. The fuel in the line looked dark, so I dropped the line into an empty pail, and figured I would prime the fuel system, and purge the bad fuel at the same time. Unfortunately, the fuel pump is no longer functional, so I am waiting on a replacement to finish this job.

Afterburner

Back when I first did this job, I bought an Afterburner from the guy who hand builds them in Australia. Apparently, there are people building knock-offs, eating into his business, since they basically have cloned his work. So, if you are looking at getting the much nicer controller for your parking heater, please connect with Mr. Jones in Australia and get the real deal. Anyway, with the Afterburner, I tried to prime the fuel system, but the fuel pump wouldn't respond. When I unplugged the pump, I got a code; I concluded the wiring to the pump was good but pump was bad. So I ordered a new, supposedly quieter, one. We'll see. While I was clowning around with the Afterburner, I got it onto my home network, downloaded the newest firmware and wandered around the new-to-me website that the Afterburner hosts. It's really cool. I am looking forward to triggering the furnace to warm the bus from inside. For reference, here is a link to the user manual.

This is as far as I've gotten. I am waiting for a new fuel pump to arrive. I need to purge the old lines of nasty fuel, and install that new pump. I expect there will be other discoveries, and I need to rebuild the cabinet innards. There's always opportunities to improve things. Anyway, thanks, as always, for following along-

Diesel Dumping Discontinued

In my last post, I discovered that the injection pump was leaking fairly badly. Today's brief post covers my replacing the 2 top seals.

Symptoms

If you don't open your hood very often, especially while the engine is running, any leak may not be obvious. With the engine under the rear deck, and the rear deck often having stuff on it, I hadn't seen the leaks evolve. On my last few drives, I had smelled diesel fuel, and I had made a mental note of it. Honestly, I thought it was related to the now-not-operational furnace which still had a diesel line filled with diesel running to it. I suspect I fueled with something which was not B20 and that caused the seals to shrink. Recall, I wanted to run the air out of the new heater so I popped open the rear-deck engine lid (I cut in years ago) and fired up the engine. I walked to the back of the bus and could see fuel dumping down the sides of the injection pump. I dashed to the driver seat and turned off the engine. Returning to the engine bay, I added coolant, but tried to figure out where the fuel was coming from. It looked like it was coming from the black plug on the side, and maybe out of the edge along the top on the opposite side. The top seals had finally shrunk to the point of being compromised.

DieselGeek

There are lots of sources for seals and seal kits, but IMHO, the best is from DieselGeek (like here). The operator is a TDI owner and only sells things he actually uses. His opinions are highly regarded on Fred's TDICLub forum too. The kit is complete; and you will want to include an anti-tamper socket (here) to get that one fastener removed. His product page contains a link to a complete how-to (also linked here) that will take you through the process. Since it is so well documented, I will not repeat it here. I will only highlight things that I discovered that either differ or underscore that documentation.

Clean and Mark Pump Location

After ordering the kit, I went out to Hapy and cleaned outer case of the Injecion Pump with degreaser. I paid special attention to the seams where the seals would be replaced. Once clean and dry, I applied the JB Weld (as instructed) on 2 corners of the pump covering the lower seals both above and below. This will allow for a more precise re-location of the pump after the lower seal has been replaced. I also took a chisel and made a clear mark that crossed the seam. For good measure, I added lines with a Sharpie. Although diesel fuel can remove Sharpie lines, I did not suffer that fate.

Top Seal

Following the instructions, I replaced the top seal first. Before I started, I wrapped the Injection Pump below the lower seal with a ratty old towel to capture spilling diesel fuel. This turned out to be an unnecessary precaution, but when I need to replace these seals again, I will do the towel wrap again anyway. Better to be safe. I left the return fuel line attached and tilted the cover far enough so I could reach the old seal. With a watch-repair slotted screwdriver, I picked out the seal. It looked fine, but I did notice that it was practically flat with the edge of the cap, so I could imagine how it could be leaking. Once removed, the groove was perfectly clean. I gave it a cursory pass with a paper towel anyway and the new seal slid in perfectly. Before returning the cap to the pump, I noticed some gunk buildup on the black-plug side so I carefully scraped it off with a razor blade and then wiped it clean with a paper towel. It is little things like that which can prevent a complete seal.

Bottom Seal

The lower seal is a little tricky, but, again, the instructions were spot-on with only one exception: The Torx bolt holding the corner directly below the fuel return may not be easily addressed, depending on your tools. The picture below-right illustrates the issue. My Torx socket fits a 1/2" ratchet so it's rather thick. It is also kind of stubby, so the socket itself needs to occupy the space where the fuel return is. So, either have longer throw Torx sockets or do what I did: Remove the cap to remove and install that once fastener. Yes, that's a pain in the butt, but I found no alternative other than loosening the banjo bolt, and after the power steering debacle with Flash all those years ago, I want nothing to do with a banjo bolt if I can avoid it. I just went looking for the post and I can't find one. I can't believe I didn't post on the saga of replacing Flash's steering rack, like, 10 years ago. The banjo bolt was nearly the death of me; my thumb swelled up from applying pressure to get things bolted together... it was a nightmare.

Similar to the upper seal, once the unit was unbolted, the TDIClub documented process was spot-on. Even the "smack it with a bit of wood to crack the JB Weld worked as written. I did not remove the hose from the fuel return line, however. I just tipped the unit back far enough to remove the seal without fear of something dropping into the top of the pump. I also found some gunk build up along one side on this piece, like I did on the cover. So, I did the same thing: slowly scraping it clear and then cleaning the metal with a paper towel. With the seal in place, I again followed the instruction to make sure the little drive stick entered the hole on the piston (you can feel it locate) and set the unit in place, using the fracture lines in the JB Weld to position. Because of how thick the new seal is compared to the old one, there was some wiggle space in the fractures, so the extra marks, bot the chisel and the Sharpie, were necessary to get the unit in the right spot.

Because of the Torx socket challenge, I got 2 of the fasteners on, then removed the cover, put the other Torx fastener in place. At this point, I re-set the location of the top unit comparing the lines again. Then, I tightened down the 3 Torx bolts hand-tight. Since these are brass bolts going into aluminum, the threads can strip, so mind your torque settings (less than 8 ft-pounds). Content, I put the cover back on, added the anti-tamper bolt and the cover Torx bolts.

Testing

At this point, it is recommended to prime the system with a MityVac. I read some comments by users who did not need to do so. I thought I would try starting before getting into the hand-vac, and Hapy fired right up. I walked around to the back and there were no leaks, and he idled nicely around 903 rpm like always. The test for whether the little drive-stick is in place is simply to try the accelerator. If the engine RPM's change, it's in there. Success. So, we took a quick drive around the usual test loop. Hapy was responsive and slowly warmed up. As part of my test drive, I tried the heater.. that worked too! I could feel warm air blowing up through the defroster.

When I got home, I noticed that Hapy was having a harder time maintaining a consistent idle. He would drop down around 875 and go up around 950. I vaguely remember this being a thing for him and a quick tap on the accelerator settled him down. I don't know why this is a dynamic for him, but with the seals replaced he is acting exactly how he used to... without dumping fuel.

That's it for today. I hope to get after the furnace next. We'll see what the future holds. Thanks, as always, for following along-

Hapy Heat Repeat (Part 2)

Continuing the efforts on creating some cabin heat in the old microbus, today's post covers sourcing the air for the heater from inside the bus.

Grounding

air sourcing from inside

In the last post on this topic, I mentioned that the prior attempts, and the original heat, for that matter, all pulled in air from the outside. The original heat pulled from the engine bay, sent it through heater-boxes (insulated boxes around the exhaust manifolds) and then up to the front of the bus. There was even a booster fan to push air when the engine speed was too low to push air. Years ago, I added a bilge-blower fan mid-stream to help get the air forward, and replaced large sections of pipe with insulated hose. In the end, the original system at-best, delivered warm moist air when it was raining (again, it's Oregon so that's 8 months of the year). When not-best, we got cold moist air that smelled like oil or exhaust.

When I did the ALH-TDI engine swap, I removed the original system rear of the front frame, setting a Vanagon rear-seat heater against that frame crossmember. While it didn't leak for a while, it started leaking again this past year. The unit was really never up to the task, and since it was only designed to heat the rear of a Vanagon cabin, I was probably asking too much of it. Still, it was a significant improvement over the original and bilge-blower-enhanced systems. The air was warmer more often, and exhaust-smelled less often. Overall, though, it was not "warm" in Hapy from the use of the heater, and the issue with moist air remained.

Fast forward to the Maradyne heater I just installed. Unlike the Vanagon rear-seat heater, the Maradyne is a 3-row heater core and it is almost twice the width. The core alone could provide considerably more heat. The fan is way more powerful too, so moving that heat into the cabin will be that much more  effective. What remained, however, is the air is still sourced from below the bus, so the wet roads will provide an endless supply of moist air to fling onto the inside of the windscreen. I hope I resolved that with the changes below.

Maradyne Heater Prep

purists love this

In the last post on this topic, I described how the heater was installed on an angle to minimize the ground clearance impact and so the outlets point more directly at the original air pipe. This orientation, however, meant that the brackets were hanging into the space where air intake hoses would go. So, first order of business was cutting those brackets down with the death-wheel (angle grinder). Once cleared, I could easily see that the coolant outlet jutted too far into the same air-hose space so I cut it down as well. Last, I changed the hose from the outlet from a straight hose to a 45* angled hose, routing the coolant above and away from the air inlet. While the inlet is not completely exposed now, it is considerably better. The inlets are 3" diameter and have a lip that's maybe 3/8" for a hose to fit onto. I had intended to add something more substantial for the hose to attach to, but once I got into it, I concluded that the original fan housing could hold a hose and clamp. Time will tell, and I am retaining the extensions I bought for this purpose in case I need to add them in later.

Holy Bus

Well, more like holey bus. In order to send air from inside the bus to the air intake on a fan system that is outside the bus, I need to add a hole or 2 for the air to pass through. I did not want to put air intakes in places where I would accidentally spill water (or other beverages), or get dirt and the like into it. I also did not want the air intakes to be so close to the front that the fan was effectively pulling the warm air right out of the outlet vents. I applied some cold-air-return thinking and chose to put one intake inside the rock-n-roll bed base cabinet. This cabinet is probably the coldest space in the bus (second only to my feet) and the vacuum created by the fan will draw air from the front to the back, creating room for the warmer air to enter the bus more freely. Of course, it's not like a 50+ year old microbus is sealed, but my 70+ year old house isn't either and once I tied the cold air intake into the house system, the house grew measurably warmer.

From underneath, I considered where there was a space without structure nor pipes to interfere with the air intake plumbing. With the radiator, wiring, original stuff and everything else, it is quite busy under there, but there is a space just behind the rear cross-frame (think: rear jack-point) but in front of the rear wheel well that is inside the cabinet, nearest the front outer edge. I tested a few spots with a drill to make sure that I could fit a 3-1/2" circle without hitting something neither underneath nor inside the cabinet and found a good spot. I cored a 3-1/2" hole with a hole saw. Why 3-1/2"? The inner diameter of these hoses is 3", and I felt that leaving a little extra room for wiggling was better than having it tight as would have been with a 3-1/4" hole. This turned out to be a wise decision. Once the hole was cut, I shot it and the support brackets with paint to delay (can it really be stopped when it rains 9 months of the year?) rust.

Fitting

cabin air intake

Once the hole was cut, I was on the home stretch. I found what look like air outlets with metal grills that fit a 3" hose to act as an air intake screen. I a-fixed one end of the hose to the grill, cable-tied it to be double-sure and passed the hose through the hole from above. The hose barely fit. It was so tight, I had to cut off the cable-tie because the cable tie end prevented the grill from sitting flat on the floor. Anyway, I chose an orientation that pointed the grill away from the center of the cabinet so things don't accidentally fall in or over it and then screwed it down to the wood floor of the cabinet. From underneath, I stretched out the compressed hose, stretching it along the side of the radiator, and turning it towards the fan.

I had initially planned to have 2 air intakes, one per fan intake, but after cutting the passenger-side hole, decided that I had 3" of outlet, so having only 3" of inlet was actually a fair balance. So, rather than run 2, I added a 3" wye along the passenger-side frame rail. I sent the stretched and then cut hose into the base of the wye and shifted to the fan inlet on the driver side, knowing it would be the harder of the two. I can always choose to add a driver-side inlet, but with the furnace on that side, there will be additional complexities.

The driver-side was definitely harder, but simply because the coolant outlet hose still ran across the air flow path. I twisted and bent the air hose and jammed it onto the inlet lip. I added a hose clamp while pressing the hose onto the lip, threading the clamp until it was quite secure. Content, I stretched out the hose, threading it behind the fan housing, but in front of the radiator intake to the passenger side. I added a cable-tie on the driver-side to hold the air hose in place. I cut and then sent the other end of the hose into the wye. It got another cable-tie up to the underside of the bus before it entered the wye.

The section from the passenger side air intake to the wye was a little over a foot, and was the easiest part of the install. I attached to the fan intake first, adding a hose clamp, of course. Once stretched and cut into the wye, I cable-tied the wye up near the floor of the bus, mostly out of sight. I cable-tied the passenger-side hose as well so there would be minimal pressure on the hose clamp. At this point, the air intake for the cabin "climate control" sourced from the inside of the bus.

Testing

ground clearance mostly unchanged

All that remained was testing the system, both for air flow as well as coolant. I started with the air flow, accepting that I could confirm that without running the engine. As expected, the fan blows hard, and draws through the inlet. Because the inlet is inside cabinet, it make less noise than it might have had it been placed elsewhere. Still, I will need to be aware of it when we pack things so it is not even remotely blocked.

Satisfied, I exposed the top of the engine and started it up. I had expected to simply add coolant/water while air bubbles appeared but 2 things interrupted that plan. First and worst, the injector pump started leaking all over the place. Now, to be fair, I had smelled diesel on my last couple of drives, so this was not 100% a surprise, but it still was a little bit. Second, air bubbles did not really appear. I will need to bleed the heater core segment, once I replace a seal or two in the injector pump. A seal set has been ordered, so until the kit arrives and is installed, Hapy will sit.

That's where we are at this point. I may try to bleed the heater while I wait for the seal kit, but it will depend on the weather and my workweek. Thanks, as always, for following along. More next time-