31 PA: Exhaust manifold with "heater" ?

[FourDoor]

Just for clarification I think you mean CO poisoning,carbon monoxide. CO2 is carbon dioxide and generally ,in small amounts, isn't dangerous.  I had one of those heaters on a car I had some years back and I removed it because I simply didn't trust the seal between it and the exhaust gases. Carbon monoxide is, by itself, odorless and that's what makes it so dangerous. Although I suppose you would smell the exhaust fumes the same way you would smell them if you stood behind the car's tail pipe. But I didn't smell anything with a garage heating system that tried to kill me. I used to get a headache if I stayed in my shop for a long time when furnace heat was being used. I thought it was paint fumes, thinners, oxy/acet. torch fumes etc. etc. Nope. None of the above. It took some time to finally realize I was being gased by the CO that was being transferred from a six inch long ,1/4" wide crack in the  fire box. The CO was being passed to the hot air plenum and then out into the shop with the blower fan. I have been very cautious ever since because I smelled nothing. I really don't recommend that anyone keep one of these 'fresh air heaters' on their cars. Atleast if you must don't connect the flex pipe to the toe board fitting or plug the flex pipe solid if you still want to keep it for the originality aspect.  :)

[30 Ply 30U]

Here is yet another style of Otwell Health Heater produced for the early Plymouths. Note the long reversible vent on the top of the unit. Stamped into it, it reads "Upside down is right side up for summer driving". The vent dampner inside the car is also stamped "Otwell". You have to keep an eye on these for cracks or you could end up in trouble quick from Co2 poisoning!

[Jim Benjaminson]

The Otwell Manifold Heater was an aftermarket accessory made for the Plymouth.  If you guys want to send me your mailing address, I'll make a copy of the original Otwell brochure and send to you.

[BryanD]

Here's a pic of my manifold for comparison...

[BryanD]

Thanks for the picture :)  That's obviously an original Plymouth item.  I assume that the heater part on top is made as a single cast piece with the exhaust manifold below?  (that's how mine is -- one casting).  Mine doesn't look quite the same bit its the same basic idea.  If I get a chance I'll post a picture later.

[30U sedan]

Try again.....

[30U sedan]

Trying to post picture.......

[30U sedan]

My 30U has the same type of heater......
I'm pretty sure it was an "optional" feature.

[BryanD]

My PA has an exhaust manifold that has the "airflow" style heater built onto the top.? This is the kind where air goes in the front (near the fan), flows thru above the manifold picking up heat, and then enters the car through a vent in the firewall.? This particular manifold has some problems (warpage and cracks) and I've been looking for a replacement.? Well... everyone I've contacted has said that the PA did not come with that style of manifold, and this is backed up by pictures of PA engines that I've been able to find.

SO: Is there any chance this was an "optional" feature?? If not this manifold is either from a different model Plymouth, or maybe even from some different make altogether?

Can anyone shed some light on the "proper" manifold for this car?

Finally: if this is the wrong manifold, is the vent in the firewall for heat still correct?