Parking Heater - Final

In March, I posted a series about installing one of those inexpensive Chinese Diesel Heaters into Hapy, the TDI-powered microbus (See Parking Heater 1, 2, 3, 4, and 5). I have completed the little things that I had left undone, so today's post takes a break from the oil temperature and pressure stuff and wraps up the heater.

Power Switch

I had left off with a power switch wired between the main (drive) battery and the heater. It was dangling around in the cabinet behind the old refrigerator-turned-cabinet. I added a wire to the luxury battery housed under the rock-n-roll bed through the fuse box I have controlling circuits to that battery. I also bored a hole into the wood support I have in that rear cabinet holding the old westy battery maintenance panel. I don't really use that panel, mostly because I haven't finished wiring up shore power to charge the luxury battery. Anyway, I punched a 5/8" hole through and fed the switch through, nutting it down. It looks fairly finished now; it just needs a label.

Cabinet a Cabinet Again

floor back in.

The heater sits on the floor of the old refer cabinet. I only need about 7 inches of clearance, but I gave it 8-1/2 so I could add a layer of insulation later. At the 8-1/2 inch point, I attached 2 wood supports running along the front and rear walls. On top of these, I put a thin run of foam to reduce any noise or rattling, and then settled a rectangular board for a cabinet floor. In the future, I will probably attach some kind of insulation to the bottom of that floor. For now, it is just a bare piece of wood.

The smaller cabinet can still hold quite a bit of stuff. I re-stowed the zombie-apocalypse Red Cross first aid duffel, some paper products, and a few other fairly important yet random things (playing cards and a cribbage board, for example).

Afterburner

Afterburner installed

Afterburner unpacked

The Australian guy (Ray Jones) who makes the Afterburner appears relatively unaffected by the CoVid-19 lockdown, so he was able to process my order and sent it to me. Bear in mind, he is a one-man operation, so the waiting list can be rather long. I let the package sit for a few days in quarantine (on concrete garage floor) before digging into it. The included install instructions are easy to follow, and all of the parts are easy to identify. I had it installed, complete with wire routing and final wall mounting in a couple of hours. I have only scratched the surface of what this thing can do, but I am very impressed with it so far. In my opinion, the white case and grey buttons looks great. Like so many other improvements, this shows me how much I can raise the aesthetic simply by adding carpeting to the wall cards. All of the scratches in the picture on the right, here, highlights how overdue this is.

Afterburner operating

Okay, today's post was a little light, but all combined, those short passages took me hours to complete. More important, the heater is complete. Once I have the Afterburner figured out, I'll be able to pre-heat the bus in the winter time, have the heater turn on based on a schedule, shut off based on temperature, etc. Basically, it will have the same capabilities as a home thermostat... but in a 50 year old VW bus. This heater install was originally so we could get warm during the summer solstice music festival in Bend (4Peaks) which would have been next month had the CoViD pandemic not happened. Assuming everything is back to normal in June 2021, we will use it there. Maybe, just maybe, next winter I will be able to achieve my old dream of taking Hapy to the mountains for some fun in the snow.... now that we have a way to get the cabin warm. Hmm.. maybe I need to figure out how to add a defroster first.

Thanks again for following along. More next time-

Oil Pressure and Temperature (Part 5)

When I left off last time, I had a Porche combination gauge fitted to to the bus dashpod in the previously blank third-hole. I had wrangled the stock oil pressure sensor out of the oil filter housing and back into a VDO "T". Into the other side of that "T" I threaded the big dual-pole oil pressure sensor. Last, I removed a M10x1 plug near the oil pressure sensor spot and threaded in a sensor designed to capture water temperatures, topping at 150* (250*F). Today's post continues this saga with a detour into swapping out the temperature gauge innards with new guts from a new VDO gauge.

Wiring Rear

I started with the next obvious thing: wiring up the sensors in the engine bay. First was estimating where to cut the cable. I threaded it through the cable holder on the oil filter and then gave myself about a foot more. With a knife, I whittled the cable casing back to the cable holder. Then, I followed the color chart, starting with the black wire to the temperature sensor. This sensor is less than 4 inches from the cable holder, so while this was easy on the brain, it required some stretching and finger dexterity to cut, strip, attach a disconnect and heat-seal the connection. Once done, I cut the housing on the dis-connect so it could slip onto the stud on the end of the sensor. For the oil pressure related wires, I did not have ring disconnects. So, I will revisit those later, after the CoVid lockdown ends. In the meantime, I simply placed the stripped wires (red and blue for the warning light and gauge respectively) and threaded the cap down on the posts. This will work for testing purposes, but with the shaking that comes from a diesel plus the shaking of driving, one or both will fall off eventually, so I will need to apply the ring terminals.

I left the rest of the cable alone. Back when I was still suffering temperature issues, I removed the engine cover. I decided this was a great time to re-install it. So, with a couple M6 bolts and washers, the cover went back on.

More Gauge Fun

cut line on new gauge

temp gauge removed

The longer I thought about the suitability of the oil-temperature gauge in the combination cluster, the less enthusiastic I became about installing it without trying to do something about it. So, I decided I would hack-up a water temperature gauge and swap the innards with the innards of the combo gauge. My plan was for it to continue to look like the original gauge, but the top of the range would be 250*F, aligning with the sensor. This might have the opposite effect of giving me an "in the red zone" appearance when we're still down in the 230*F range. I think I can live with that, so long as the gauge gives shows a clear difference between 210*F (normal) and 235*F (my believed top end of normal).

So, how do we swap the innards? It starts with removing the temperature section from the combination gauge. It is held on with small slotted screws. Once removed, the unit pops right out. I had an extra new-old-stock (NOS), new-in-box (NIB) temperature unit I got off eBay before I got the combination gauge. I figured I would use that as my transplant target so I can revert back to the original later. I found a few differences between the original gauge innards and the new ones. I will highlight those differences as I work through this.

New VDO Gauge Destruction

old innards top
new innards bottom

At a high level, I followed the Dave Barton PDF process where you cut the housing in half to get to the inner workings of the new gauge. I found that a standard screwdriver was 1/4" thick, so I used that to mark where to cut. I threaded the collar up to that point and then traced around the gauge housing, using the collar as a guide. I taped over the gauge lens with blue painters tape and the cut the line with my hacksaw. As directed in the instructions, I cut just enough to break through and then rotate the gauge housing to extend the gap around it. The top part lifted off right where the gauge face meets the housing. Perfect instructions; nice job Mr. Barton. I also used the salad-fork method to remove the needle, using sparing force so the needle slowly lifted off the little pin. I encourage taking great care on this step.

With the needle off, I removed the small slotted screws on either side and then removed the gauge face. Then, I moved to the flip-side. With a 7mm socket, I removed the nut on the post. The tabs hold the gauge innards in by friction. So, I put the mounting collar on backwards, so I could stand the gauge on its (now missing) face, with the tabs pointing upwards. With a framing hammer, I gently encouraged the gauge innards down by tapping on the tabs and the bolt-post. If you do this take care that the pin the needle sits in does not get crushed or bent or in anyway really touched. It did not take much force to get the innards to move. I held the hammer about 4 inches from the head and tapped.

Old VDO Gauge Mount Destruction

gauge mounting plate

I started with the same process as I had done with the new VDO: salad fork on the needle. This was not as clean a process as it was with the new one. In fact, I would discourage anyone from trying to remove the needle this way if you intend to reuse the needle or the innards. In my case, the needle was damaged, and I was unable to tell how the original needle was connected to the pin. I resolved to using the new VDO needle and kept going. I removed the 2 slotted screws holding the gauge meter / face on. Underneath was a thin piece of dried up wax paper. I carefully separated that from the gauge innards.

With the gauge face torn down, I switched to the mounting side. The old gauge separates from the metal plate fairly easily. With a 7mm socket, remove the nut from the central post/bolt. With a slotted screwdriver, encourage the innards to pull away from the metal plate. It is held purely by friction.

Re-Assembly Preparation

testing old and new together

Now, we have a small pile of parts. From the new VDO innards, the tabs need to be removed from the rest of it. These simply slide out. Now, look at the 2 innards. They look very similar in some ways, but have one major difference on the not-gauge-face side. The inputs are 90* offset. If you look at the old metal mounting plate, you will see that the 4 holes around the central-post/bolt hole are 2 different sizes. The old gauge innards' holes line up with the smaller set and the new gauge innards line up with the larger set. The plastic thing that holds the tabs for the older model has 2 plastic nubs that line up with the larger holes. Those nubs hold the plastic holder and the innards stationary. If you were to cut them off, the gauge would not sit still, and could ground against the metal plate. I hadn't pieced this together when I cut them off in an attempt to get the new innards to mount. I would recommend instead that you expand the smaller set of holes so they are the same diameter as the larger set: so all 4 are the same size. Then, the plastic holder can go in in either orientation. If you hastily cut off the plastic nubs, like I did, you can solve by locating a pair on small plastic finishing tabs from one of those assemble-at-home pieces of furniture. With a little whittling, it can be formed to hold the innards in place. I suggest altering the mounting plate instead.

Re-Assembly

approximately 175*F

comparing top temp
modified on the right

However you solved for the attachment of the plastic bit to the metal plate, slide the new VDO innards onto the 2 posts. There are 2 ways the gauge innards can fit, but only one that actually works. So, when you do this, consider the orientation of the gauge so that the gauge sweep will be on the correct side. Press together firmly. Making sure the ground tab is on the bolt, thread on the 7mm nut and tighten with the socket. I considered the orientation of the new innards on the old plate and marked which side was for the signal (S) and with was for power (+) before I moved on.

If you intended to create your own gauge face, or paste on an aftermarket one, now is the time to do that. I would really like to have markings to show where important temperatures are, but I also like the simplicity of the stock gauge, so I left it alone.

To the gauge face side, I set the wax paper and then the old gauge face. I used the 2 slotted bolts from the new gauge to attach. Last, carefully press on the needle. Once it is all together, it fits back into the combination gauge housing just as easily as it was removed. If you are using the needle from the new gauge, you will need to insert a small washer between the mounting plate and the combo-gauge for each mounting bolt or the needle will hang-up on the contoured plastic near the rear (front is front) of the gauge housing. Using the 4 slotted bolts it was held on with before, mount the plate to the cluster threading each bolt through a small washer. Re-attach the wires.

Setting the Gauge Range

gauge re-installed into dashpod

As you can see from the pictures, I took the opportunity to test the new and old innards with various temperatures. First, I applied an open flame to the sensor to determine the top temperature. I then checked to see where the needles of the 2 different gauges sit when I put the sensor in boiling water. This took some doing since the "kitchen" table is 10 steps or so from kitchen-proper. I would boil some water in a small cup in the microwave and then dash over to test it. As a result, I think the picture on the above right is for around 175*F. If you consider how much gauge is left above the needle for the new innards, and that the top temp is 250*F, I will have a wide band for the temperatures we care about: 190*F to 230*F.

Well, that's an awful lot for this week. All that's left is installing it into the bus. I have to do some wire disconnects, but I don't expect it will be terribly dramatic. Now that I see the gauge in it's final form, I would absolutely recommend bus-pilots who still have their original air-cooled engine to think about installing one of these combo gauges. The original temp range is designed for the air-cooled hot oil, and it looks really good, in my humble opinion. Knowing that the new gauge innards can be swapped in eases my old concerns about long-term support as well. Just get a new VDO gauge (less than $40US today) when one of these fails, and do what I just did.

Thanks, as always for following along. Not sure what I'll work on, much less post on next. I guess I'll figure it out when I paw through my parts and incomplete projects. Stay safe and be well-

Oil Pressure and Temperature (Part 4)

This really has been a ton of fun. We have a Porsche combination gauge mounted to the rear of my removed-from-bus dashboard. We have tested the VDO sensors against it and everything seems to line up. So, today we shift to installation.

Cable, Not Wires

inside belly pan

Rather than run another whole set of individual wires, increasing the spaghetti under the bus, I went a different route. In the TDI retrospective (See TDI install retrospective: Secondary Electrical), I mentioned a cable company. Shortly after that, I decided that I would do this gauge thing and use a cable to send the signals from the engine bay to the dashboard. I figured that I had the 3 for the oil system (temp, oil pressure gauge and oil pressure idiot light). I also want to know when the coolant is low and when the electrical system is tanking, like a normal car. So, I got a 6-wire cable, leaving one open for future expansion. Similar to most of the other stuff on this project, I ordered the cable in January before things started getting CoVid-interesting.

Snake-y

harness pops out here 

I want this install to be as clean as I can make it. So, I figured I would route the cable along the same route as the original main harness. Finding where it pops out inside the front of the cab of the bus isn't very easy: it is under the windshield-washer tank. This is much more obvious from underneath, hidden inside the center belly-pan between the main rails. I drilled a matching 11/16" hole an inch or so to the driver-side of the main harness pass-through. From inside the center belly-pan section, I pushed it up through that hole, inside the bus. I then took it from the inside, along the same path as the main harness over towards the fuse box, over the ventilation tubes and up behind where the dashpod sits. I gave myself an extra foot of cable so there wouldn't be stress on it later.

Sending the cable rear-ward was the easy part. From the center belly-pan, I threaded the cable from behind the front axle along the same route as the main harness, meeting it where it emerges from the steel pipe it travels to the rear of the bus. It ran along the main harness pipe, through a small pass-through in the rear cross-beam and back towards the starter. It passes right into the engine bay where the fuel does. I coiled the extra cable there. I had ordered 30' so I had more than enough to run it exactly where I wanted it. I cut off the excess, leaving almost 10 feet of cable, so the total need was just over 20 feet. For my future self, here is the wire color -to- purpose mapping:

Circuit	Color	Purpose
1	Black	Oil Temperature Gauge
2	Red	Oil Warning Light
3	Blue	Oil Pressure Gauge
4	Orange	Coolant Warning Light
5	Yellow	Alternator Warning Light
6	Brown	open

Pressure Sensors

splitter and stock sensor in

The TDI computer already has an oil pressure signal. It comes out of the oil filter housing. I decided that if that location was good enough for the computer, it was more than good enough for my gauge. So with a 1" spanner (that was the closest I had to the required), I knocked the stock oil pressure sensor free and applied the splitter (VDO 240 850). In order to get the splitter to point the right direction (away from the oil level tube), I added a washer between the splitter and the oil filter housing. If you do this, you may need to do the same. I put the original pressure sensor into the end and the new dual sensor into the split off the side. The dual sensor has a 17mm nut close to the threads, and tightening it can only be done from below, about 30* at a time. Fun.

Temperature Sensor Stuck?
Between the insertion of the original pressure sensor and the new dual-sensor, I went after the temperature sensor. Why? I realized that once I had the dual pressure sensor in-place, I would have my access and vision blocked by it. The plug in the oil filter housing was on fairly snug, but a pop with a ratchet holding a Torx socket did the trick. I don't remember which size; my apologies for not writing it down. Once free, oil seeped out of the hole, even though I had drained the oil before I started with the pressure sensor. No matter. It just made a mess. I first tried with the longer temp sensor (VDO 323 423), but found that it hung up on something inside the housing. I was barely able to get it back out again, and after looking at the sensor after I removed it I concluded that it was not a good idea to use that sensor here. I put a picture of it down below on the right.

Temperature Sensor, Take 2

temp sensor in

I cleared the hole, and checked for depth with a small screwdriver. It seemed like the sensor should have fit, but there is no doubting the compressed look of that sensor. So, grateful I had the shorter, but lower max temp sensor, I considered the impact. Consider that this is not an air-cooled engine, whereas the Porsche combo-gauge came from one. Also, the oil and coolant exchange temperatures, cooling the hotter oil as they do and that cooler oil is what is passing through this part of the housing on it's way back to the engine. I did a quick survey of posts about oil temperatures of TDI's and even the guys who run 'em hard say their temps don't get above 230*F. In fact, most of the folks out there pose that temps above 250*F would be cooking their engines.... and these folks have a sensor in this location, so the plan is holding, so far.

them bumps aint right

So.... I decided that this sensor is probably fine, especially for the short run, while I figure out if this is the long-term solution. Key to this thinking, is to remember that the gauge is to help identify patterns and trends. Also, to remember that this is the temperature as it is re-entering the engine. So, this will be a delayed signal of a climbing temperature event. In fact, it could be masked if the coolant is effectively pulling heat out of the oil. Concluding that I'd come this far and that there was not a better port to test temperature anyway, I continued. The shorter (250*F / 120*C max) sensor threaded right in with no trouble. I lightly torqued the sensors, filled the engine with oil and called it a day.

Wait a Minute...
One nagging thought I have about this is the numbering, or lack thereof, and the red zone on the Porsche combination gauge are completely out of alignment with what I would be concerned about as I drive a TDI. These numbers ("normal" between 194*F and 248*F) are way to broad. AND, regardless of which sender I use, the red zone starts outside the top end of it (at 302*F?). So, I may need to change that gauge at some point if it is really going to be useful long term. I mean, honestly, if normal is around 210 and getting too hot is 230, I will not easily see the difference on that gauge.

Well, that's it for today. All that remains is everything else. I will work on getting the engine-compartment end of the wiring done next. Then, I'll see about getting the dashpod wired and re-installed. Depending on how exciting and time-consuming those are, it could be one or two more posts before I have oil instrumentation.

Thanks, as always, for following along. Be safe, be patient, and if you can, patronize your favorite restaurants with a go order. Now more than ever, you can vote with your wallet for the businesses you want to survive. Personally, Amazon doesn't need my money; Discount Import Parts (now only on the east side) and the local mom-and-pop grocery do.

Oil Pressure and Temperature (Part 3)

Hapy cinco-de-Mayo. My last post ended with some testing of the Porsche combination gauge with the modern VDO sensors. I'll pick up where I left off.

Where Were We?

Porsche combo gauge

After I wrote all of those posts about the TDI install, I realized that the little UltraGauge does not show my oil temperature or pressure. I can see the coolant temperature, though. When we drive up a long grade, we can see the coolant temp climb, and I wondered if the oil temperature was leading that charge upward, dumping heat into the oil:coolant temperature exchanger. So, I started collecting sensors to compliment the gauges I had lying around from back when I had the original air-cooled engine and thought that having an effectively oil-cooled engine without a gauge about oil was just silly. That's especially true when that engine was 5 meters away. In my usual fashion, I can't just run wires from sensors up to the dash and stick a couple gauges in back of my windscreen and call it good. Oh no. That would just be too easy. Instead, I got this notion that a combination gauge from a 70's-era Porsche could fit into the 3rd hole in a VW bus dashpod. I was right. But, does it work with the new VDO sensors? Why, yes it does.

Simple Initial Testing
I did some very simple tests of the sensor-to-gauge circuit in my last post. All I did was demonstrate that the gauge would respond to 12V, and if I had a sensor hooked up, the gauge would lift slightly off the bottom post. This is no casual "who cares" moment, in my opinion. Most important, this indicated to me that the big circular thing that I had shipped halfway around the world had operational gauges. But, would they respond correctly to real-world input from modern VDO sensors?

Temperature

water still steaming, needle at 9:00

Testing the viability of the oil temperature circuit was fairly easy, once I had the circuits set up again. While Boo loves me, I still had to tear down the tests for dinner. So, things needed to be set up again. This time, I included a small glass cup and a meat thermometer. Into the cup I set the sensor, wrapped with a grounding wire with a sender wire on the end. With the circuits powered by a big auto battery, I poured boiling water into the cup. The gauge moved from pointing down to 9 o'clock (correct for water boiling-point) which should be around 210*F. I thought I could confirm the test with the meat thermometer, but instead I found that the meat thermometer was not correct. How fun! In subsequent tests, I discovered that the probe on the meat thermometer needed far more surface area to reach the correct temperature reading. So, rather than triangulate on the proof that 9 o'clock means 210*F, I learned that my meat thermometer reads cool unless at least an inch of it is inside the target. Good to know for future baking. Anyway, this test passed.

Pressure

decoding the no-number gauge

Testing the pressure was not as fulfilling as testing temperature. For temp, we know the boiling point of water so if the gauge doesn't rise to halfway, then we would know that the sensor is on a different resistance gradient than the gauge. That would have been a real bummer. For pressure, I needed to depend on my Mity-Vac. The Mity-Vac has already proven its worth of the years as I have tried to bleed brakes and pull fuel through lines after running the tank empty (I know; bad owner). It also has a pressure setting though. With the circuits wired up, I set to it. I keep a short stretch of fuel line in my Mity-Vac kit, and that fuel line is the perfect size for the threads of the pressure sensor. I threaded one end onto the sensor and put a basic auto-adapter from the Mity-Vac kit in the other end. To that, I connected one of the short clear lines and then the Mity-Vac. This set up allowed me to send a pressure signal to the sensor. I jammed the grounding wire between the end of the fuel line and the sensor housing on the threads (establishing a viable ground) using that friction to hold the wire in place.

around 15 psi and around 1 BAR

Once everything was powered, I simply applied pressure with the Mity-Vac and watched the needle rise off the post. Translating "Druck Pressure" to PSI is a brief exercise in understanding German. Druck is effectively barometric or BAR and 1 bar = 14.7 pounds per square inch. So, to confirm the gauge is operating correctly, I needed to get "Druck" = 1 when I had just shy of 15 pound of pressure on the Mity-Vac. That succeeded: the needle on the gauge climbed to 1 and then slowly dropped as the pressure was slowly released, matching the needle drop on the Mity-Vac. I would have liked to have proven the mid-range of the gauge, but the Mity-Vac and my cobbled-together plumbing couldn't handle more than 15 pounds of pressure. I thought about getting my air compressor involved, but concluded that the test was already successful.

Conclusions
So, what did this tell us? That sensors bought today will correctly align with a gauge pulled from an old Porsche. We demonstrated earlier that the gauge would fit in the spare or "third" hole. I think we have a winner and I'm beside myself with excitement about it. I will clean everything up, replace some bulbs, run a wire bundle, and road-test everything, etc. when I have some time outside with Hapy. You can see in the pictures on this post taken during the tests that the gauge now sits nicely centered in the hole. I think it looks fantastic, but it's my bus, so its my choice. Knowing that I will have visibility into the lubrication system, and can start analyzing whether the oil temps are leading the temperature increases on long climbs is pretty exciting.. for me anyway. If my theory is proven, I can start looking into improving oil temperature management so climbing hills or mountains eventually have a much reduced impact on engine temperature. First, we need to see the data.

Thanks, as always, for following along. More next time-