yes Dr. evil, the way the whole body operates is a bit of a chemical reaction in a way, thus anything that casues death would be a disruption in the normal (life) chemical reaction, thus using the websters definition of poison, any cause of death is poisoning. i would not support this postion however.

However this might lead one to argue what is life? are we all just chemical reacitons/ does man have a soul, what is the miricle of life, etc... Very deep questions indeed.

Bottom line, is we want to make sure our 914 heaters are functioning well to prevent carbon monoxide poisoning.

the fascinating thing is that simple elements, with out which we could not survive, when placed int he right combinatin, turn deadly poison. We need oxygen,a dn we have alot of carbon in us, yet combined as CO, it is poison, same for CN (cyanide) we have alot of carbon in us, and nitrogen is constantly inhaled, and without nitrogen, most life giving plants would die, yet combined as CN, we have a deadly poison.

Uh, N is not just inhaled but a major inherent part of proteins, so, just about everyting in the body

I am a med stoodent ya know.

I was poking fun at the rediculous nature of your arguments. Both are right. Both fit the definition. BUT, it is the definition that saves ones ass that has the most merrit.

Back on topic and on a serious note, when ducting and powering your heater system it is wise to make sure you are forcing air through it (forces bad stuff out of the crack) rather than sucking from the end (sucking all bad stuff in as well). However, I know Jim, and his car and considerations are impecable so if he says that he considered these things I would feel safe riding in his car with the heat on any time.

Just a minute guys! Truth is, both CO & CN are deadly! Call it poison or not, you can dies from these.

I've been subjected to both & believe me, I'd far rather die from CO exposure than CN. With CO, I merely began to doze off. With CN, I saw my nails turn blue instantly ( and i mean INSTANTLY), thereafter could not draw oxygen to breath - very painful. With CO, I just became lethargic & sleepy - no pain.

Both ocurred in my early life as a chemist for K___k. Labs were not very safe in the late 60's. That's why I became an accountant thereafter - true stories. Wouldn't wish the CN on anyone - barely survived!

Point is - "poison" or not - they're potentially lethal. Don't pit yourself in the position to find out how tough you are - avoid at all costs.

Werent you guys called alchemists back inthe 60s?

my poison of choice was phosphine, PH3, damn near killed me, fatal in ppm levels. My company failed to properly purge an inline gas filter.

lot of really nasty stuff used to build computer chips, PH3 is one of them. made me sick for years.

it like CO is listed as toxic/poison, but it is much much more dangerous.

i saw another post regarding gas heaters in the car. Got toobe careful with them too. If you pick up an old used one check them out carefully, a corroded heat exchanger in them can also lead to CO poisoning. we had one in my old VW bus. would get the Bus almost too hot, in freezing weather, really cranks out the heat


back to medical stuff, it is amazing how such small quantities of the wrong chemicals can do one in. Nerve gas is very scary stuff Then we got al the more seeminly benign chemicals that over years of expose can cause cancer and other probelms. automotive paints, gasoline, parts cleaners and such.

Got to minimize exposure to these things. The more we learn, the more we go"oh my, we used to use that stuff all the time, without a care!!"

How dare me! I read to the end of this thread hoping to learn more about heating systems.

On the original subject,

What if the fans were installed on the inlet side of the "J" tubes? The entire system would be under positive pressure (lessening CO concerns), the fans would be subjected to a lower temperature environment (longer life), if the airflow was sufficient you could eliminate the stock fan (does anyone know the stock fan cfm rating?).

You would need to include some type of backdraft damper in line with each fan. If the fans are light enough, a very short piece of tubing clamped to the "J" tube and the outlet of the fan should be adequate to support the fan.

Just thinking (very rare for me)

yeah, that would be the way to go, basically add fans in the engine bay much like the stock electric fan is. You could go too two fans int eh engine bay, one for each heat exchanger. a source of fans would be the wrecker, maybe out of an air cooled late model VW bus. You definatly want a one way valve, so when the fans are not in use, you don,t suck up hot air into the engine bay via the engine cooling fan.

The fan on the front of the motor is a lot more powerful and will force the air back through the electric fan. The electric fan really helps mostly at idle and low rpm's. The check valve will let more air in the passenger compartment at higher speeds by precenting this back flow from happening. There are also 2 small ones at the outlet of the fan housing. These do the opposite. They let the electric fan force air into the heater plumbing instead of exiting through the front fan housing at low enging rpm's.

Nice. So, what's the proper way to say "tomato"?

Back on topic, a properly buttoned-up system dumps a lot of heat. Speaking from experience. Tight connections, even insulation around joints (which helps reduce leaks, too), helps quite a bit.

The 914 heat exchangers are waaay longer than any air-cooled VW's I've seen!!! I have a stock squirl-cage blower with a Y-splitter so air gets diverted to both exchangers (when the blower turns on). Works very well. Yes, blow-in is safer than draw-in. Yes, the comment about cracking a window open DOES help get more heating air in...assuming your air-cooler still has good seals

Using fans in the rear compartments is a good idea: I picked upa couple of Detmar Brake Duct Fans at Pomona a while back. They have a nice SS mesh over the opening and the base will set over the intake tube, gonna hook it up to the rear fan wiring ans see how it goes.

A close look at these says the fan unit is almost identical to the ones I mounted up front....

Pics...

I'll be real curious to hear how these work out. I've got plenty of heat for my 914, but my son's 1975 VW Bus could probably benefit from a pair of these pushing air through the HEs. Part numbers would be a real benefit.

yeah, busses are much harder to heat, much more volume and smaller heat exchangers to boot.

I have seen vendors sell boosters for VW's Busses in cold areas often have the auxilary heater (gas heater) expensive, but they really heat that big cabin toosty hot, even inthe snow.

the front of the bus can get really cold driving down teh road, all the cold air,a dn only a thin bit of metal, and if your luck a little bit of foam to keep teh heat in, make sure your heater duct under the floor is sealed form leaks,and insulated, that can help.

what year bus is it??? split window? bay window? vanagon? as they got newer, they made better heating systems. my 63 was always cold (until I turned ont eh gas heater)

The Results are in: I hooked up one of the brake duct fans in the engine compartment Sunday. I leave at 4:15 am and it's pretty chilly. Monday I used the rear push fan only, Tuesday the front pull fan only, Wednesday tried both.

The front fans behind the speakers are superior.

Well now that I know way more than I wanted to about CO.............

Back to the original topic. I had a similar fan in my bilge. It was pretty noisy. Do these fans add a lot of noise inside the cabin? 914's are already pretty noisy. Eddy

Sorry for the hijack. But there is more....

Andy it is the imprecise English (American) language again.

IIRC, in my NIOSH handbook CO2 is listed as SIMPLE asphyxiant

CO is listed as a CHEMICAL asphyxiant. Both kill you by asphyxiation (suffocation).

CO2 simply displaces oxygen. So you are fine as long as oxygen stays above 12% IIRC. No real concerns about chronic (long term) exposure. And if exposed, exposure to air (21% oxygen IIRC) is sufficient for recovery assuming you are still breathing and have no other injuries.

CO chemically bonds with your hemoglobin. CO even bonds preferentially with your hemoglobin. Small concentrations, even in an environment with more than adequate oxygen can result in asphyxiation overtime. Once exposed to CO a person can still asphyxiate after being removed from the environment with CO. High concentrations of oxygen may be required to displace CO in the bloodstream. Yes Andy is right it suffocates you from within. CO exposure is very bad.

Is CO a poison? That probably depends on which definition you are using. If CO is listed as a poison on the MSDS, then legally it is a poison, but that does not make it technically so. Carbon Monoxide poisoning is commonly used in English to describe CO exposure.

I now return you to your regular scheduled thread.

Back on topic: I have no heat in my 914.

I have a three speed switch. On low it's very qute, medium speed it's barely noticeable, on high it's louder. I usually run it on low, and it pulls plenty of toast air.

"poison" is pretty precise, and we are dealing with english here. Now is a chemical asphyxiant considered a poison? inquiring minds need to know. here we go again.

I doubt the fans will add much noise, the aircooled 914 is noisey such that you probably won't hear the fans at all when driving. I can't hear the stock fan over the engine noise.

Since I drive my car daily and run the heater / fan regularly, why not have a blood sample analyzed ??
Paging Dr Evil..

Next time the good Doctor is in Huntington Beach, we'll take a sample and send it to the lab ?

Good one Jim

You could always get one of those CO detectors from Home depot. Cheap and it will keep you from being slowly drowned, asphyxiated, deoxygenated, de-anionated, etc

While you take the blood, we could finish the electric window install....
Just kidden. Decided to remove the hidden door speakers and move the elec window in their place.

1975 Bay Window. So are there any part numbers on those things? Since you got them at Pomona you probably don't have a catalog number from a store type source, but with a part number we might be able to track down a commercial source.

English is not very precise. In biology a "biological toxin" is a venom and by definition is not a poison. BUT

Per ask.com a poison is anything that causes death or illness. So water is a poision. Carbon Monoxide is actually listed under the definition. DOT requires a shipment of CO to be labeled with a "poison gas" plaquard. So I vote poison.

And the good I mean evil Dr. should have quoted Paracelsus: "Alle Ding' sind Gift und nichts ohn' Gift; allein die Dosis macht, dass ein Ding kein Gift ist."

But I am helping everyone to miss the point:

CO is undetectable and a problem at very low levels. Your system may be sucking in air from leaks in the heat exchangers. It would be best to pressurize the exchangers by placing the fan before them as the factory system.

The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned carbon monoxide a threshold limit value (TLV) of 25 ppm (29 mg/m(3))

The IDLH (immediately dangerous to life and health) is 1,200 ppm

I think 12% where oxygen displacement starts becoming a problem is like 12,000 ppm.

Just want you to be safe.


BTW for everyone but Andy, Paracelsus was German and translated his quote is:

"All things are poison and nothing is without poison, only the dose permits something not to be poisonous."

Get on The Samba website, and do a search of gas heaters in the topic forums, also get out the classified sections. there were several manufacturers of these gas heaters. They were more common in places like north canada and such, and are a popular item in the bus campers. if you buy an used one, check it carefully thant the burn can is not corroded with holes, else CO can leak into the cabin, and we should all know what that does by now. i fin good condiotn, and with a properly located exhaust, there should be no problem with CO, however a potable tester, or test indicators (as sold for private planes) would be a wise thing to use.
i believe tehy were also fairly popular options on VW Things, the Thing, unlike the convertable Bug, or Ghia did not have a heavely paded top, just thin vinyl for the top, hence there did not hold heat well at all.


the Samba is a great VW site on the web. it is like this club, free to join, and post questions, just ask on the bus forum, and you should get plenty of replies on specifics fo teh Bus.
good luck!

Does that mean it sucks in her farts and disburses them in your car?