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Hot Rods Covering For A/C Lines To The Trunk

Discussion in 'The Hokey Ass Message Board' started by Carl Hungness, Feb 23, 2024.

  1. Carl Hungness
    Joined: Jul 16, 2018
    Posts: 149

    Carl Hungness

    I am installing a Vintage Air unit in the trunk of my '37 LaSalle and seeking some advice on covering for the lines that run through the frame. I'm not getting TOO close to a muffler, but a tad closer that what I'd like, so seeking some knowledge on insulating the lines.
    The attached photos are from five years ago, the car has now been just about totally
    restored. It sports a 500" Cadillac and turbo 400. This is the same car I drove through
    college from 1964-68 when it had a flat head in it. She should be a stump puller now.

    Attached Files:

    Budget36 likes this.
  2. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 12,344

    Bandit Billy

    I'd call Vintage Air and ask them. They have a great tech line. Anyway, I always got help when I asked for it.
  3. Onemansjunk
    Joined: Nov 30, 2008
    Posts: 318

    from Modesto,CA

    Contact your local home Heating and Air Conditioning Company. They install Line-Sets all the time in new houses. My old ass can't remember the name brand off the top of my head.
  4. Ziggster
    Joined: Aug 27, 2018
    Posts: 1,737


    Assuming the compressor and condenser are mounted up front, it is super critical to insulate the complete length of the low pressure or suction line from the evaporator outlet to the compressor inlet. For every degree the suction temp increases, there is a corresponding increase in suction pressure which equates to an increase in compressor discharge pressure. The higher the discharge pressure, the lower the compressor performance/capacity. There are closed cell foam tubes designed specifically for this purpose. Also, you’ll also have to adjust the refrigerant charge accordingly to ensure there is sufficient charge to ensure liquid refrigerant fills the entire high pressure line from the condenser outlet to the expansion valve. When I worked in mobile HVAC design, we used this stuff.
    loudbang likes this.

  5. Joe H
    Joined: Feb 10, 2008
    Posts: 1,542

    Joe H

    I have installed a lot of A/C hoses on school buses, dual units on the roof, dual units under the bus, dual compressors, short buses and long ones. We never insulated any hoses, the only time we ever wrapped a hose was for protection from abrasion or going around a sharp corner. For a hard line, run it through a length of heater hose or proper A/C line insulation. Use the soft dense foam type, not the hard open cell type, keep it loose, and keep the two lines seperate. If you compress it, it doesn't insulate.
  6. Ziggster
    Joined: Aug 27, 2018
    Posts: 1,737


    The school bus manufacturers are not the best yardstick to use when considering best design/performance criteria. We could never supply anything to the school bus manufacturers because they were only interested in the absolute lowest cost equipment.
    Sure, you don’t have to insulate the lines to save money, but the system will suffer in terms of cooling performance (i.e. higher vent temps). It all comes down to what is more important to oneself.
    loudbang and jimmy six like this.
  7. jimmy six
    Joined: Mar 21, 2006
    Posts: 14,872

    jimmy six

    McMaster Carr has insulation coverings. I bought some for my oil filter lines. I had to slide them over before I put on the fittings. They were very close to the headers on our LSR roadster.
    loudbang likes this.
  8. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 4,255


    Is there any kind of self contained unit like the old window ACs that could be mounted in the trunk and run off electricity ?
  9. What about the newer style ac hose. Small in dia. has a strong cover on it. VA sells it. Uses a different type fitting
  10. brando1956
    Joined: Jun 25, 2017
    Posts: 203


    My ol' buddy Chuck was a lifetime GM employee. He said that the workers in his shop referred to A/C line insulation as "donkey dick." Strangely, that name does not appear in GM parts catalogs. Warning: A Google search for this part could show results that may make one feel inadequate.
    SS327, loudbang and Budget36 like this.
  11. mohr hp
    Joined: Nov 18, 2009
    Posts: 936

    mohr hp
    from Georgia

    Go to a boneyard and crawl under a few conversion vans and Suburbans with rear air. See what they used.
  12. BJR
    Joined: Mar 11, 2005
    Posts: 9,877


    Just get the same stuff that they use to insulate the air conditioner lines for your house central air. Any heating and air conditioner dealer should have the stuff.
  13. Ziggster
    Joined: Aug 27, 2018
    Posts: 1,737


    I worked for General Motors Diesel Division back in the early 90s (now General Dynamics Land Systems) developing the AC system for Light Armoured Vehicle or better known now as the Stryker. We used all GM automotive components but drove the compressors via hydraulic motors. We had a huge problem of hot air coming off of the radiator heating up the A/C plenum as all the AC components were hung off of the radiator cooling stack. We tried reflective paint, insulation, etc. with little effect. Packing the proverbial “10 lbs of $hit into a 5 lb bag” was never so true in my career.
    Ultimately, to solve the issue we reversed the airflow as it went through the evaporators. Originally we pulled the air through the evaporators where that cooled air flowed next to the plenum with the hot air exiting the radiator. The cooled air from the evaporators was dramatically heated by the radiant heat from the radiator plenum. Again we tried everything to insulate the two plenums from one another, but nothing really worked that made a significant difference. It was only when we reversed the airflow, bringing in the hot interior air next to the radiator plenum and then into the evaporator that we saw better air temps coming off of the evaporators. This was because there was less of a difference between the two temperatures (e.g. 40F vs 140F - testing was done at 120F with full solar loading). All to say, is that you want to keep the cool parts (suction line piping and cooled air coming off of the evap) insulated as much as possible from heat.
    In fact, on many GM systems /vehicles using suction line accumulators (big aluminum can acting as a refrigerant reservoir of sorts), had a foam insulation “sock/sleeve ” to keep them cool from the heat in the engine compartment.


    TrailerTrashToo likes this.
  14. PotvinV8
    Joined: Mar 30, 2009
    Posts: 418



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