Secrets of the heat exchanger box Mondial T revealed | FerrariChat

Secrets of the heat exchanger box Mondial T revealed

Discussion in 'Mondial' started by porphy, Jul 15, 2015.

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  1. porphy

    porphy Formula 3
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    #1 porphy, Jul 15, 2015
    Last edited by a moderator: Sep 7, 2017
    After a long period of interruptions and other "while i'm in there" delays I have finally today removed the black box under the dash of our "T"'s that is home to the heater heat exchanger, the A/C exchanger, the expansion valve and the fan motor. I have attached pics here so you can hopefully see the layout. The opening of the sealed box requires drilling out several pop rivets and scraping off the thin layer of an elastic black material that they used to seal the box from air leaks. The removal of the dash I will treat either later here or in another post. It's painful and long but not complicated.

    The black box is marked Borletti on the outside and the motor squirrel-cage fans are also marked Borletti. There is nothing marked on the motor but I have not removed the mounting hardware as yet. I have done a quick search but find nothing on line. It seems to be a brush-type DC motor. The axes do not turn easily but do turn, which means that my initial thought that the bearings had worn to the point of seizing may not be true. The armature looks to be very worn. I cannot get a clear picture of the brushes until I remove the mounting hardware which I hope to start tomorrow. It involves drilling rivets. This was not made to be serviced!
    But as Rifledriver said, it can be done.

    The only nice thing about the removal is that all of the tubes leading to the exchangers in the box are on the right-hand side and are reasonably accessible. I will post more as I continue to assess the fan motor. If anyone has a source for Borletti fans let me know. I thought that I could use the SPAL (spal.com) fans but I don't find a suitable model in their on-line catalog. It may only be the brushes because the bearings seem OK or I might need to rebuild this motor if the armatures are worn. Any suggestions of an electric motor rebuilder would be of interest.

    I will post more as the info increases.
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  2. 123howie

    123howie F1 World Champ

    Jul 3, 2014
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    Wow! Is the motor frozen? Did you put 12v to it when its out? Was the motor your only problem here?
     
  3. porphy

    porphy Formula 3
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    The motor stopped with a screech on the trip to Mondipalooza. I thought it was the bearings.because it was making a rattling sound for several months before it screeched to a halt. I found that the bearings seems to be fine but there may be noise coming from the brush area and I can't see where with the mounting bracket in place. I put 12 Volts on it last night and it comes on only when I move the armature and in certain positions it does not move at all. So I need to remove the mounting bracket in order to get to the brushes and the armature.
     
  4. Wade

    Wade Three Time F1 World Champ
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    Randall, you're going to replace the motor, correct? I'm not an Auto Electrician but I recall something about age, amps and resistance regarding the motor itself. And, I suspect, what leads to the "hidden fuse" meltdown on the 348 (and some dash fires) as well.

    As time goes by newer maintenance issues and concerns are revealed, just another "while you're in there.". ;)
     
  5. porphy

    porphy Formula 3
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    #5 porphy, Jul 16, 2015
    Last edited: Jul 16, 2015
    Wade, I would very much like to replace the motor, however, I don't find anything as yet on Borletti fan motors. Also I don't really know if the motor is Borletti even though the fans are clearly marked Borletti. The only mark I can see is the number 808 on the motor. However I must remove the mounting hardware to fully see the motor and it's markings. I will try Italian sites if I don't find anything here. I will consult an auto electric locally tomorrow to see if they can rebuild this motor. It may be as simple as the brushes or a worn commutator where the brushes touch the armature. I tried to find a replacement on the SPAL site (spal.com) but nothing seemed to be correct. I may need to re-look at that site.
     
  6. Wade

    Wade Three Time F1 World Champ
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    Check out this thread beginning at post # 60 and onwards. Although for the 308/328, they are talking about dual fan blower motors. Plus some possible sources as well.

    http://www.ferrarichat.com/forum/308-328/22057-ac-unit-308-328-a-3.html

    Interesting info if you haven't seen it.

    For example:

    https://webstore.spalusa.com/en-us/productlist/0188/products/centrifugal-blowers/double-wheel/blowers+double+wheel.aspx

    BTW, the thread is from 2007 so some of the links might not work (just cut to the host site).
     
  7. jgoodman

    jgoodman F1 Rookie
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    Good to hear that you're finally making progress on this Porph. Are you going to replace the coils while you're in there?
     
  8. Wade

    Wade Three Time F1 World Champ
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    #8 Wade, Jul 16, 2015
    Last edited by a moderator: Sep 7, 2017
  9. porphy

    porphy Formula 3
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    Yes, most likely Jay, but I'm on the ventilator motor situation right now and, as a good male, I cannot multitask!! Hope you and your family are good.
     
  10. porphy

    porphy Formula 3
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  11. porphy

    porphy Formula 3
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    #11 porphy, Jul 17, 2015
    Last edited by a moderator: Sep 7, 2017
  12. porphy

    porphy Formula 3
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    This Motor has been out of production since 2005 and Bosch has no stock.
     
  13. Wade

    Wade Three Time F1 World Champ
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    It shows in stock at Rock Auto for $61.79

    But call to verify
     
  14. porphy

    porphy Formula 3
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    Thanks very much Wade. I would never have thought to look there even though I use them for my other cars. Thanks again very much.

    It is also cross referenced to two other Bosch numbers. I would like to ask about those numbers with Bosch. Based on the numbers, I have ordered. I will post the results.
     
  15. aec

    aec Karting

    Jul 28, 2011
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    Just wondering why the Borletti fan blades are numbered 11, 13, 15, ... ?
     
  16. Wade

    Wade Three Time F1 World Champ
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    I've seen little metal clips on some to correct an unbalanced condition. And determining that can be a trail and error affair so having them pre-marked helps reduce do-overs (my attempts with a ceiling fan comes to mind). But I'm guessing... :)
     
  17. porphy

    porphy Formula 3
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    Yes. Mine have small balancing weight clips on the fins and I assume these numbers are balancing orientation marks.
     
  18. porphy

    porphy Formula 3
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  19. porphy

    porphy Formula 3
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    My understanding is that when one tries to convert from a R-12 system to an R-134a refrigerant there are several potential problems: 1) the R-134a tends to leak out of the R-12 system due to the physical character differences in the two refrigerants, therefore the R-134a systems have o-ring seals at tube connection points; do knowledgeable experts use teflon sealing tape on 134a connecter threads?, 2) the R-134a is reported to lead to higher high side head pressures than R-12; does trying to find an expansion valve with a larger orifice help reduce the head pressure as has been suggested here, and what are the effects of the somewhat reduced head pressure other than reducing potential leaks?, 3) I understand that it is recommended to consider installing a more efficient condenser heat exchanger in order to improve the additional heat generated by the higher high side pressures, is this true? What about the evaporator, does it need modification also? Are these suggested mods worth the trouble? Thanks for your replies.
     
  20. afterburner

    afterburner F1 Rookie
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    My QV got converted to R134a as R12 is not legally available in HK anymore.

    System emptied and flushed.
    Compressor oil changed to R134a compatible product.
    Receiver dryer exchanged.

    6 years ago; no leakages so far, but slightly less cooling power than R12.
     
  21. godabitibi

    godabitibi F1 Veteran
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    I did some 134A recharging over R12 and it worked ok for me. I only replaced compressor oil with PAG and a new dryer, add a bit of oil in the system and fill it to 80% capacity of R12 with R134.
     
  22. afterburner

    afterburner F1 Rookie
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    Yes, same on mine.
     
  23. porphy

    porphy Formula 3
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    OK. Thanks much. Certainly sounds less complicated than considering these things which might compensate for the slightly less cooling capacity of 134a vs R-12. I might, however, put a new expansion valve in "while I'm in there". Already have the new filter/drier and Schrader valve.
     
  24. porphy

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    #24 porphy, Jul 25, 2015
    Last edited by a moderator: Sep 7, 2017
    There are three relays associated with the AC unit. Two are clearly marked as ITALAMEC 4320629 and are available. However, there is a third relay marked only ITA IAMCC and on the side 056-12V and the painted sign "OA" on another side; no other markings. It is a 4 pole relay in contrast to the 5 pole ITALAMEC relays. Since the wiring diagram in my workshop manual on CD is almost impossible to read, I was wondering if anyone knows what the characteristics are for this relay or what the replacement relay would be for this ITA relay.

    The first three photos are of the unknown relay; the fourth is of the ITALAMEC 4320629 relay.
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  25. 308mon

    308mon Karting

    Oct 5, 2014
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    If I remember correctly there should be 2x 4-pin relays (regular pattern NO type) and 1 x 5-pin relay (regular pattern changeover type with 87a pin to break the ground line for the engine bay electromagnetic heater valve controlled thru the Bosch controller located under the foot well plate). The 4-pin are usually rated for 30 amps, although these may be rated at 56 amps (hence the 056).
     

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