How hot do heat exchangers get?

[Green6]

Backdating the heat system on my '79 sc. I've read many threads on this, and it all seems straight forward. I installed the ducts that come off the sides of the fan housing, and had planned on using the stock pre-existing aluminized tubing from the ducts to the heat exchangers. Problem is they are both 2 1/4" diameter, and the tubing is very tight and difficult to get on the necks. I plan on ordering some new 2 1/2" tubing from Aircraft Spruce [PP only has the stock aluminized tubing]. I've seen where some have recommended SCEET, SCAT, CEET, and CAT type tubing. The orange SCEET and SCAT tubing is rated to 550*F. The black CEET and CAT is rated to 350*F. I prefer the black to orange, and the black tubing is in stock, and the orange is out of stock.

What I'm asking is what is the max temperature of heat exchangers where the tubes attach? I would think somewhere close to 350*F, so the higher temp orange ones would seem to be the better choice.

If someone has experience with using any of these different types and has a recommendation your advice is welcome. TIA

[DRACO A5OG]

You can order from Porterfields in OC, Socal or go to an AirCraft Spruce store, they will have it too.

I'd say the heat exchangers get hotter than 350F but others whom will know will chime in I am sure.

[douglas bray]

Use the orange on the heat exchangers. Pelican has it.

[75 911s]

I bought the black ones off pelican. Something about the orange ones that look like industrial A/C ducting in a building to me.

[RichardNew]

Amazon.com is your friend. I bought this infrared scan tool for around $13.00.



I use it for everything from checking brake temps at the track to checking the HVAC system in my house.

Richard Newton
Techie Stuff

[patz]

Make sure the hose do NOT come in contact with the spinning axle. Wire will pop loose and take out the CV boot. Ask me how I know.

[tobluforu]

Originally Posted by RichardNew

Amazon.com is your friend. I bought this infrared scan tool for around $13.00.



I use it for everything from checking brake temps at the track to checking the HVAC system in my house.

Richard Newton
Techie Stuff

My cat loves this device.

[Quicksilver]

The heat exchangers get way hotter then 350°. Years ago I had the heater blower out of my car to repair it and I taped over the hole where the blower motor went. I went on a drive and the tape sealed area over the hole popped off.
Because there wasn't any cooling air flowing through the exchangers the heat rose up through the air duct and melted the plastic duct completely in two so about 2" was missing. The bottom looked like a candle! Still have it on the "Wall of Shame®". (Right next to the cogged v-belt that is missing 2/3rds of the "cogs" but didn't jump off!)

[Green6]

Thanks for the advice guys. Higher temp rated orange it is. Better safe than burnt. The car already has the orange tubing from the heat exchangers to the flapper boxes. I do have some high temp black spray paint left over from painting my wood stove. Maybe I'll experiment on an inconspicuous area and see how it holds up. I already like the less cluttered open spaces in the engine compartment.

douglas bray~ I asked the Pelican sales guy if they had the orange tubing when I ordered the fan ducts. He said they don't carry it, and suggested the stock aluminized tubing. Maybe he was mistaken.

RichardNew~ Those infrared thermometers look handy. I will get one of those for future use.

Patz~ I will keep that in mind. CV boots are much more important than heaters, and tougher to replace.

[911pcars]

Around 350ºF on a bare exhaust tube. Probably way less at the air path into the heat exchanger. Here's a temp. sensing strip measuring radiated heat about 2" from the collector portion of the heat exchanger.



Do not block air flow into/out of a heat exchanger. No airflow creates a stove-like environment.

Sherwood