Heater box Quandry

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Bert
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Heater box Quandry

Post by Bert » Sat Dec 21, 2002 9:24 pm

I've been looking for some heater boxes for my '79 bus I think I may have some from an '80 vanagon the only thing is that the Vanagon ones don't have the inlets from the fan shroud the rectangular ones. So if I put these in will I have to cut holes to allow some air from the engine fan to enter the boxes? Does anyone know what the purpose of these inlets is ? I'm thinking if I plug the square outlets from the fan shroud this will free up more air for engine cooling ?? Any thoughts guys?

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amskeptic
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Post by amskeptic » Sat Dec 21, 2002 10:55 pm

As the factory designed it, those heater boxes were part of the engine cooling system.
Notice that the heater control valves never were designed to merely shut off the airflow going to the cabin, they maintained airflow through the heater boxes at all times and shunted the air out around those collars at the control valves. The vanagon has constant airflow through the heater boxes courtesy of that squirrel cage blower mounted on the alternator. Your '79 Bus had constant airflow courtesy of the engine fan. I think you might want to ensure constant airflow through the heater boxes somehow. YMMV
Colin

germansupplyscott
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Heater box Quandry

Post by germansupplyscott » Sun Dec 22, 2002 10:30 am

volks,

amskeptic has a very good point. bert, you don't want vanagon heater boxes, they are too far different from '79, they just won't work without a hack job of some sort.

as i recall, you also wanted to change to federal spec from CA? you have two options, as i see it:

1/ replace with '79 fed spec heater boxes. your '79 cal spec already will have the correct one on the right side, but the left in different. fed spec allows using the simpler exhaust, i.e. a 72-74 muffler. you need to allow for the o2 sensor if you remove the stock exhaust.

2/ switch heads with earlier oval port version. this allows using the cheper and more available 72-74 heater boxes and exhaust. bus depot still has original vw heater boxes for 140.00 $US, which is the best deal anywhere. i have seen 72-74 boxes on ebay for way less in good used shape as well. changing heads means pulling the motor. in other words, you would only do this route if you need to rebuild your motor anyhow.

there are pros and cons to either route.

i do not have a digital camera, but i might be able to borrow one so i can photograph my exhaust. my van started as '79 cal spec, but i have made some changes, which i feel make the system better, simpler, and cheaper to keep up.

if you want to maintain the factory setup, the original parts may still be available in good used condition from bustedbus.com.

scott lyons

Bert
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Heater box Quandry

Post by Bert » Sun Dec 22, 2002 10:39 am

Yes I want to maintain stock heat etc. Both of my stock boxes have been repaired numerous times , I plan on taking out my engine soon and just giving it a reseal ,pushrod tubes,cooler ,installing coling flaps and t-stat, I didn't really want to pull the heads and get too involved but I may have to unless I can find some '79 boxes I guess, I know the Vanagon ones are stainless which is another nice feature. Send me some pics Scott if you get a chance ,

Jay Brown
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Heater box Quandry

Post by Jay Brown » Fri Dec 27, 2002 3:06 pm

There is a set on ebay now. Here's the link: http://cgi.ebay.com/ebaymotors/ws/eBayI ... 1875733071
I beleive the seller is a regular poster on the engine rebuild forum.
Good luck.

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Bert
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Heater box Quandry

Post by Bert » Mon Dec 30, 2002 7:12 pm

Thanks for the info ! I think I've got a set just have to wait for Canada Post to deliver could be spring !!!!

alsehendo
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Heater box Quandry

Post by alsehendo » Thu Jan 02, 2003 2:00 am

Not that he should get the Vanagon heater boxs- however what do you think air through them cools besides your feet.

I ran summer only 80 van and 412 for years with any warm air blower and inlets on exchangeres blocked of with no increase in head or oil temps. I could not use air inlets on Vanagon because the chepo muffler I used wouldn't allow it.

Heat exchangers are not part of the engine cooling system.

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amskeptic
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Post by amskeptic » Thu Jan 02, 2003 10:48 pm

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by alsehendo:
<B>Heat exchangers are not part of the engine cooling system.
</B><HR></BLOCKQUOTE>

I think what I was offering was, not a personal anecdote to what I have gotten away with, but rather a question, why would the factory ensure constant airflow through the exchangers? The answer has come up several times in the air-cooled cyberspace. I have no hot leads, but there was a 911 forum where someone thought to insulate the j-tubes with NASA insulation and found serious heat-soak issues between the exhaust pipes and ports causing the common crack at the lower edge up towards the seats. The conclusion was that the lower you could keep the temperature of the "heat-sink" exchanger, the more readily it drew off heat at shut-down, something you would not see as you walked away from your just-shut off engine with the cherry red exhaust valves and pipes hidden up under your cooling tin. I have seen with my own eyes the glow of those j-tubes.
Colin

alsehendo
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Post by alsehendo » Fri Jan 03, 2003 1:28 am

Cheep aftermarket J tubes glow because they are thin and won't dissipate heat. Goodones like those sold by aircooled.net or 411 412 exchanger cores don't.

I guess what your are say is--use of a heat exchanger itself causes an increase in exhaust valve temps and that air through them is needed to compinsate for this. I'm not sure I can buy this concept for the warm air fan relay in a 79 is not on unless you call for heat--so were dose this so called extra air flow come from not the blower.

Heat tape on headers is used to get the heat out from under the hood away from the radiator on water cooled motor, not to heat up cool the exhaust valves. Don't know how a 911 is set up, but why would you want to do this on a VW when engine fan is already isolated from exhaust via bay tin.

Anyway I think the statement that the heat echangers is an intragal part of cooling anything is just not true. My opinion it is just used to heat up your feet. Maybe others can chime in.

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amskeptic
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Post by amskeptic » Fri Jan 03, 2003 10:57 pm

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by alsehendo:
<B>Cheep aftermarket J tubes glow because they are thin and won't dissipate heat. Good ones like those sold by aircooled.net or 411 412 exchanger cores don't.

>I think my OEM ones do because I have the >dreaded airpump afterburner system with 10 >degrees retard timing

I guess what your are say is--use of a heat exchanger itself causes an increase in exhaust valve temps and that air through them is needed to compinsate for this. I'm not sure I can buy this concept for the warm air fan relay in a 79 is not on unless you call for heat--so were dose this so called extra air flow come from not the blower.

>Every OEM Type 4 engine has the air coming >from the fan housing outlets through the >exchangers and exhausted either into the >car or out around those collars at the >heater valves. Even the Vanagons made sure >to blow air through the exchangers from the >alternator squirrel cage blower. If the j->tubes are 800F and the exchangers are 250->300F there is a huge draw-off of heat from >the head. My guess is, without the factory >designed airflow through the exchangers any >time the engine is running, the exchangers >would be closer to 500-600F, the heat would >not draw off from the head nearly as well.

Anyway I think the statement that the heat echangers is an integral part of cooling anything is just not true. My opinion it is just used to heat up your feet. Maybe others can chime in.</B><HR></BLOCKQUOTE>

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vdubsinjensen
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Heater box Quandry

Post by vdubsinjensen » Sat Jan 04, 2003 8:00 am

I've still got the 79' heater boxes for sale.I've also got others for other years.Sorry,no Vanagons.Paul

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