AC Woes at Bob Martins

Discussion in 'Workshop Forum' started by TonyK, Jul 8, 2019.

  1. TonyK

    TonyK True Classic

    Location:
    Grimsby Ont Canada
    I think I know what on the issue is, but here is what we have system is charged I have one can of Dura Cool in the system and topped off with 134a. 80 degrees outside air temperature 30 psi on the low side and 295 psi on the high side and only getting 18 degrees of differential temperature 60 degrees at the vent. The return after the condenser is really hot. Bob has the Vic Texas heat radiator with the slim 80 watt fans. I do not think there is enough air flow over the condenser to lower the high side pressure and get rid of the heat. Bob swears the new fans are better than stock for air flow, I disagree. So latter today we will put the car outside and run the AC and then spray cold water over the condenser. The vent temperature should drop, meaning not enough air flow and or we should upgrade the condenser. Also it appears that the new rad installation that the stock condenser is too far from the rad allowing air to flow around the condenser rather than through it.

    Opinions?

    TonyK.

    At Bob Martin's in Radcliff Kentucky
    IMG_1412.JPG IMG_1407.JPG IMG_1405.JPG
     
  2. Dan Sarandrea (Phila)

    Dan Sarandrea (Phila) Waitin' On Parts...

    Location:
    Philadelphia, PA
    Well if you suspect lack of airflow, I would think getting it out on the road and checking temps at +35MPH should answer that question.

    The Vicks unit can be ordered with 7" fans or 10" fans, which does Bob have?

    Was the A/C system working correctly before the rad replacement?
     
    Last edited: Jul 8, 2019
  3. TonyK

    TonyK True Classic

    Location:
    Grimsby Ont Canada
    10" Fans and had not run in years.

    TonyK

    At Bob Martin's in Radcliff Kentucky
     
  4. Dan Sarandrea (Phila)

    Dan Sarandrea (Phila) Waitin' On Parts...

    Location:
    Philadelphia, PA
    Ah, so we are resurrecting the A/C. Standard procedures are well documented but rarely followed. A/C compressor rebuilders would have you remove most of the components and flush them individually, air-dry for 24 hrs, then re-assemble with new orings throughout, blow out with nitrogen, install new expansion valve/orifice tube and receiver/dryer, vacuum/evacuate for at least 2-3 hours, then see if it holds vacuum for at least an hr.

    Doubtful if any shop anywhere has ever followed that procedure to the letter.
     
  5. kmead

    kmead Old enough to know better

    Location:
    Michigan
    I would tend to agree on the fans, the OE fans do well, better than most aftermarket particularly low cost units. I am also with you on sealing between the condenser and the radiator to ensure that fans can be as effective as possible.

    When was the system changed over to 134a? Do we know the provenance of that changeover?
     
  6. TonyK

    TonyK True Classic

    Location:
    Grimsby Ont Canada
    Well we did install a new drier and new expansion valve purged with 134a and look for leaks/hold pressure. Then added 70ml of PAG with die. Pulled a vacuum for 15 minutes. We did put 3 oz of sealer, 1 can of Dura Cool and topped off with 134a. This morning the car was put outside before loading for FFO 2019 and we ran the AC then ran the garden hose over the condenser. What I noticed is that the heat transfer between the tubes of the condenser and the fins seems to be poor. Running the hose over the fins didn't cool the tubes as much as I though it would. I am kind of thinking that the heat transfer between the tubes and fins is lacking. Bob and I are considering installing the new Fiat 500 Condenser on this car like on his Black car and my car, that condenser is 195% bigger than stock and the return temperature after the condenser is lower. All this being said car outside, fan on low was showing a vent temperature of 52 degrees with an outside air temperature of 79 degrees. It is something.

    TonyK

    At Bob Martin's in Radcliff Kentucky.
     
    Dan Sarandrea (Phila) likes this.
  7. Dan Sarandrea (Phila)

    Dan Sarandrea (Phila) Waitin' On Parts...

    Location:
    Philadelphia, PA
    If there is a chance that Bob could be the first human to utter the sentence, "I think the A/C in my X1/9 is too cold," then I'd go with the 500 condenser, especially since new aftermarket units can be had online for well under $100!!! :)
     
  8. LarryC

    LarryC Curator of #10105275

    I've said it before and I will say it again, I don't think the new high-zoot 10" fans are very good. The stock fans move some serious amounts of air and worked well with the new parallel flow condenser. The aftermarket fans were not up to the task. I would go with the new condenser and fit the biggest that you can fit and re-install the stock fans and see what happens.
     
    kmead likes this.
  9. Cratecruncher

    Cratecruncher True Classic

    Location:
    Austin
    It seems to me spraying the condenser or driving at freeway speed should eliminate the possibility of insufficient heat exchange. I haven't been in the X1/9 system but have rebuilt several others. Don't rule out the possibility of a restriction or blockage somewhere. It's amazing what crusty crud can accumulate in AC systems over the years. There is often a filter screen added at the factory somewhere in the system that is a leading suspect for large pressure differentials. The condenser could also be clogged.
     
  10. There is no way that these thin fans are better than stock. I also ran them briefly (not the Vicks ones, but similar) and they were nowhere near as powerful as the factory ones. They drew a fraction of the current, but there is a reason for that.

    I'd suggest running a pair of factory fans (or even one of each and then you can compare the difference).

    Cheers,
    Dom.
     
    Mike Schofield likes this.
  11. LarryC

    LarryC Curator of #10105275

    Just to respond to this thread, today I drove in 92 degree heat with the AC on. For various reasons, after several years and a very tiny leak on the upper condenser connection, my 134a charge is about ready to be re-charged, I still have not replaced the wimpy fans with my original stock fans yet, and so the cooling is not optimal on city streets. But once I got on the freeway, at 65 mph the cooling was way better. So I am thinking that more air flow via the stock fans will definitely be a good thing.
     
    Cratecruncher and Mike Schofield like this.
  12. Mike Schofield

    Mike Schofield True Classic

    I recently did a Vicks all aluminum rad install and decided I’d replace the loud stock fan. I first started with a duel 7” fan setup but wasn’t happy with them. I then purchased a spal 10” fan and thought I’d test the difference between the 7” fan, the 10” spal and the stock. I was very surprised that the stock fans definitively put out the most air flow followed by the spal fan and in a distant last was the 7” aftermarket. I did not “measure” the output with a meter but it would be very interesting to see the numbers. I ultimately decided to go with the spal fan due to its quiet operation. Although, I find that the spal fan causes a noticeable voltage drop when operating...if you can live with the “loud” stock fans, I’d choose that all day.
     
    kmead likes this.
  13. TonyK

    TonyK True Classic

    Location:
    Grimsby Ont Canada
    Today at FFO we were on a drive and Bob reported that while on the highway he had AC in the car. At stop lights it dropped off. Let's look at the Condenser build, copper tubes with fins that may be steel or copper but not soldered. Over the years corrosion starts between the contact surfaces and affects heat transfer. Newer aluminum condensers have welded fins to the tubes so they have a better heat transfer. We will be changing the condenser in the future. Now as I was driving on the same run, same day my evaporator froze up. So from that happening I know that apart from keeping the fan on low which caused the freeze up, everything is working as it should on the Abarth powered X1/9.

    TonyK.

    At FFO 2019
     
    Mike Schofield and kmead like this.
  14. TonyK

    TonyK True Classic

    Location:
    Grimsby Ont Canada
    This morning Bob and I took the car for the rally drive. This morning it was 85 degrees, humid, with the AC on you can see how cold the air was coming from the vents into the passenger compartment. As long as we were moving this was the case and eventually the return line frosted, so I increased the fan speed to thaw out the evaporator. The AC is working as it should. I have stock fans on the car, but even stock fans do not move the same amount of air as driving down the highway.

    TonyK.

    At FFO2019.
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  15. LarryC

    LarryC Curator of #10105275

    Is this with a tube and fin condenser? Or have you installed a parallel-flow condenser yet?
     
  16. TonyK

    TonyK True Classic

    Location:
    Grimsby Ont Canada
    Fiat 500 Condenser I think it is parallel flow.

    TonyK.

    At FFO 2019
     

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