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driverinmyhead Samba Member
Joined: June 20, 2012 Posts: 122 Location: PacNW
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Posted: Mon Mar 30, 2015 9:27 am Post subject: 1978 Heating System Mystery |
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Currently working on the exhaust. While under there, I noticed this:
Something missing?
My heat exchanger is 2 pieces (exhaust manifold bolted to the exchanger). Just wondering if someone swapped a different year on there.
Trying get the heater working good. The smell of burning oil was overwhelming.... found a duct disconnected. Hope that helps.
Now to solve is mystery! |
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northernbus77 Samba Member
Joined: November 17, 2008 Posts: 196 Location: Yukon
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Posted: Mon Mar 30, 2015 11:20 am Post subject: |
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Looks like you are missing the heat dump tubes. Try a quick search and you will find plenty of info on them.
Example: http://www.thesamba.com/vw/forum/viewtopic.php?t=329288&highlight=dump+tubes
I would think having them blocked off would cause your heat exchanges to get hot (no air flow when the heat is off) could partly explain the smell. |
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aerosurfer Samba Member
Joined: March 25, 2012 Posts: 1602 Location: Indianapolis, IN
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Posted: Mon Mar 30, 2015 11:23 am Post subject: |
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Those should not be blocked. Test the functionality of the heat dump valves and go from there. The parts missing, while nice are more circumstancial that anything. _________________ Rebuild your own FI Harness..My Harness
77 Westy 2.0L Rockin and Rolling Resto!
72 Sportsmobile (sold)
79 Tran$porter... Parts car money machine (gone) |
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Randy in Maine Samba Member
Joined: August 03, 2003 Posts: 34890 Location: The Beach
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Posted: Mon Mar 30, 2015 11:30 am Post subject: |
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They just dump heat from the heads when the heat is not headed into the car. |
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driverinmyhead Samba Member
Joined: June 20, 2012 Posts: 122 Location: PacNW
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Posted: Mon Mar 30, 2015 11:59 am Post subject: |
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Thanks!
Back in the 90s I didn't care what was missing or why. These days I am trying to understand WHY the engineers did what they did and get everything working properly.
BTW: that exploded view of the exhaust system is giving me nightmares! Lots of changes between years, smog no smog and OP modifications.... Aaaagggghhrrrr *. Tearing my hair out. |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50260
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Posted: Mon Mar 30, 2015 12:56 pm Post subject: |
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Remember that engineers are a bit obsessed with how they do thing. It is debated what the dump tubes actually did, but likely they were there to keep heat away from the fuel tank for emission purposes. If you just go back and add a short down pipe off the valve they will probably do 95% of what the full OEM system did.
As other said, blocking the dump valve off is not what you want to do though. |
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Bleyseng Samba Member
Joined: July 03, 2005 Posts: 4752 Location: Seattle
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Posted: Mon Mar 30, 2015 2:19 pm Post subject: |
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Just as long as the Flapper valves are working so heat can be directed into the bus or dumped you should be fine. The 78-79 Buses are the only ones with the Dump tubes so as long as the hot air can be dumped if not going into the bus you're fine. Air flow thru the heat exhangers is important as it keeps them cool even if you aren't needing heat. Oil smell can be from oil leaking into the heat exchangers so clean them out and fix all oil leaks (i.e. pushrod tube O rings, valve cover gaskets, oil filter seal and oil cooler seals.) _________________ 70 Ghia Black convert-9/69 build date-stock w/133k 1600 SP-barn find now with a rebuilt tranny and engine
77 Westy 2.0L w/Ljet, Camper Special engine-95hp and with LSD!(sold)
76 Porsche 914 2.1L L20c, 120hp Djet (sold)
87 Syncro Westy Titan Red 2.1L 2 knob 100k miles |
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my59 Samba Member
Joined: August 13, 2003 Posts: 3781 Location: connecting the dots
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Posted: Mon Mar 30, 2015 5:02 pm Post subject: |
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The odd thing about the dump tubes is that they are not just pipes to dump heat out to the side of the engine; they have a flute in each one with a hole before the open end. Were the engineers trying to suck cooler air in right before the opening to lower temp further?
Can normal heater valves be adapted for dump tubes? My dump tubes are in fine shape hanging in the barn; the 79 heater valve boxes are rotted out and I have oval heads and a 78 exhaust /heater valves with the mushroom covers that dump heat just fine.
Just wondering if I would see better head temps with dump tubes. _________________ my59: Well son, my grandfather died before I got to drive it, so does that answer your question?
our79: sunroof bus w/camper interior and 2.0 FI
Other:'12 Jetta, '77 Benz 300D, and a 74 MG Midget. |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50260
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Posted: Mon Mar 30, 2015 7:31 pm Post subject: |
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All I have done to clean out my heater boxes is to fix the leaks and then remove the accordion tubes along with blocking off the pipes heading forward into the cab for the summer months. A couple of long trips through the mountains effectively burns the heater boxes clean. |
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driverinmyhead Samba Member
Joined: June 20, 2012 Posts: 122 Location: PacNW
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Posted: Mon Mar 30, 2015 9:30 pm Post subject: |
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Hmmm.... I guess I better start looking for some dump tubes (or fabricate some).
Fighting with my header pipe seals right now. |
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airschooled Air-Schooled
Joined: April 04, 2012 Posts: 12688 Location: on a bike ride somewhere
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Posted: Mon Mar 30, 2015 9:33 pm Post subject: |
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driverinmyhead wrote: |
Hmmm.... I guess I better start looking for some dump tubes (or fabricate some).
Fighting with my header pipe seals right now. |
You MIGHT be able to use T1 fresh air heat hose. Bailing wire will hold them in place at the rear, and hose clamp in the front will work until you find the right parts. I've always contemplated doing this to a T1 engine actually. I think they help more in stop and go summer traffic in the heat; on the highway there is quite a bit of airflow happening down there anyway. _________________ Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
www.airschooled.com |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50260
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Posted: Mon Mar 30, 2015 9:41 pm Post subject: |
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driverinmyhead wrote: |
Hmmm.... I guess I better start looking for some dump tubes (or fabricate some).
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The dump tubes are the least of your worries when it comes to the heating system. As others noted they were only used for the last two years of the US spec Bay. They were then eliminated when VW used essentially the same engine in the air cooled Vanagons. |
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driverinmyhead Samba Member
Joined: June 20, 2012 Posts: 122 Location: PacNW
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Posted: Tue Mar 31, 2015 9:59 pm Post subject: |
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My heat works. Kinda.
It stinks like burning oil, one of the levers on the dash was rigged up and the "heat" (yes HEAT in parenthesis), isn't very heat.
Especially since I fixed the exhaust manifold leak, it's oil stink city.
I plan to pull the center "hose" that runs down the middle of the belly off, and degrease the bottom of the engine after I replace some gaskets and seals.
Anyone have a decent pair of heat dumps they are willing to part with reasonably? |
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my59 Samba Member
Joined: August 13, 2003 Posts: 3781 Location: connecting the dots
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Posted: Wed Apr 01, 2015 2:55 am Post subject: |
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I went through the heating system last year and after removing the mouse nest made from seat stuffing found that the top of the Y junction in the rear and the front t junction (basically both ends of the main pipe) were rusted out on top.
Not being able to remove them I cleaned them up best as I could and got busy with metal duct tape. Made a huge difference in hot air flow.
The heat exchangers were scrubbed during the engine rebuild so they are not oil infused. _________________ my59: Well son, my grandfather died before I got to drive it, so does that answer your question?
our79: sunroof bus w/camper interior and 2.0 FI
Other:'12 Jetta, '77 Benz 300D, and a 74 MG Midget. |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51057 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Wed Apr 01, 2015 7:04 am Post subject: |
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my59 wrote: |
Can normal heater valves be adapted for dump tubes? My dump tubes are in fine shape hanging in the barn; the 79 heater valve boxes are rotted out and I have oval heads and a 78 exhaust /heater valves with the mushroom covers that dump heat just fine.
Just wondering if I would see better head temps with dump tubes. |
The dump style valves look like mushroom ones except with a splitty aircleaner elbow in place of the mushroom, not sure how plentiful split bus aircleaner parts are though.
Wildthings wrote: |
The dump tubes are the least of your worries when it comes to the heating system. As others noted they were only used for the last two years of the US spec Bay. They were then eliminated when VW used essentially the same engine in the air cooled Vanagons. |
The fuel tank also moved to the front at that time, I still suspect the purpose of the dumps is to prevent or lessen fuel vapor production by keeping the tank cool, they also added that insulation under the tank when the dumps came along.
driverinmyhead wrote: |
It stinks like burning oil |
Remove that foil and let the air flow through them all the time like it was designed to do, betcha the oil stank goes way down _________________ Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50260
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Posted: Wed Apr 01, 2015 7:23 am Post subject: |
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busdaddy wrote: |
Wildthings wrote: |
The dump tubes are the least of your worries when it comes to the heating system. As others noted they were only used for the last two years of the US spec Bay. They were then eliminated when VW used essentially the same engine in the air cooled Vanagons. |
The fuel tank also moved to the front at that time, I still suspect the purpose of the dumps is to prevent or lessen fuel vapor production by keeping the tank cool, they also added that insulation under the tank when the dumps came along. |
Even without the tubes in place the dump valves are already pointing the waste heater air away from the fuel tank. While a simple down pipe might help a little, the tubes that run all the way to the rear of the engine add little and are a liability as they tend to be rock and stick magnets.
If someone has a system in good shape and drives only on paved roads then I wouldn't suggest that they remove it, but if you don't have it and/or drive in more interesting places I sure wouldn't waste my time to go out and find all the various parts and pieces to put the dump system back on. I one lives in California, now that would be a different story.
I might be interesting for someone to record the temperature of the fuel in the tank after a long run both with and without the dump tubes to see how much difference there is. |
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