Exhaust heat abatement on mid year

[Mark E.]

Re: Exhaust heat abatement on mid year

Here's a lesson I learned about cabin heat. There's a lot of threads in the archives about cabin heat, with some great advice including: check for missing or worn grommets in the firewall and console, check for torn lower shifter boot, check tunnel insulation, check operation of plenum air doors, check hood to cowl seal in the firewall and console, and check for body seam gaps in the AC/heater plenum.

But there's one more thing I did that really reduced radiant heat along the bottom of my '70's console: I rerouted the exhaust pipes that were within 1/2" of the fiberglass floor near the tunnel- good for ground clearance, not so much for cabin heat. The exhaust is not original and I believe was installed closer to the floor than OEM. Increasing the exhaust-floor clearance (in my case, by 1/2" - 3/4") reduced radiant heat significantly.

Is there a factory spec/tolerance for exhaust-floor clearance? Nothing in Section 8 of AIM (for 1970).

[Ray G.]

Re: Exhaust heat abatement on mid year

Hello;
Air flow is the main tool in reducing underhood and cabin temperature. The best tool is an electric fan. Puller fans work the best.
The only part of the transmission producing heat is the torque converter. As previously mentioned by another poster to your thread. Not all converters are created equal.
We mount electric fans on separate cross bars, not on the radiator. We don't think the fans vibrations are good for radiators long life.
Good luck.
Ray

[Ken A.]

Re: Exhaust heat abatement on mid year

Having worked on this back in the day I suggest:
40 degrees is too hot, adjust for 38.
Check to make sure the evaporator drain nipple is intact, this is critical to keep from sucking in engine heat
Add more insulation to the discharge pipe
Make sure your thermostat is a 160 degree
Check shifter boot as already mentioned.
The Corvette system should freeze your ass off, as it's cabin is 1/2 the size of a car

[Mark E.]

Re: Exhaust heat abatement on mid year

Ken,

Good tips. The evap drain nipple is one of those over looked parts that are often just missing.

"Add more insulation to the discharge pipe"- Are you referring to the low pressure line between the evap box and POA (very short length), and/or between the POA and compressor? Since this is downstream of the evaporator, will this have much effect?

Any benefit with insulating the line between the dryer - expansion valve - evaporator?