Sanden Compressor on a Nailhead

Discussion in ''Da Nailhead' started by Lobucrod, Dec 7, 2019.

  1. Lobucrod

    Lobucrod Well-Known Member

    May not be the prettiest install but definitely the cheapest. I bought a universal u-weld bracket with my Vintage air system and used it to build my own bracket utilizing an extra AC Alt bracket I had laying around. Here are the results. I decided to use two separate belts instead of the pair like factory. Independently adjustable and better belt wrap on the pulleys




  2. bhambulldog

    bhambulldog 1955 76-RoadmasterRiviera

    Nice Work !
  3. bigcat

    bigcat Member

    Looks good. I really like the idea of individual belts and better belt wrap.
  4. John Codman

    John Codman Platinum Level Contributor

    A couple of years ago a parts store told me that Sanden had a direct replacement compressor for the big GM A6 compressor. Not true?
  5. I am using a Sanden SD7-H15 on my 64 Riviera and it works extremely well. We removed the factory air system and replaced it with vintage air Gen-4 mounted inside the car up in the dash and eliminated everything in the engine compartment on the passenger side firewall.

    None of these are even close to as large as the Harrison A6.
    The A6 is just a monster and a great compressor as long as the shaft seals never leak and you are ok with the space and weight it consumes in the engine compartment.
    The A6 displaces 207 cc (12.6319 cubic inches)
    This equates to the A6 being 27,000 BTU at 2000 RPM (compressor speed) which is over 1-Ton and @4000 RPM it is 42,000 BTU which is nearly 2-TONs of capacity IE it can cool a small house.

    Most aftermarket Sanden / Vintage air kits etc use the 5 cylinder SD5-H14 compressor which is 138cc displacement (8.42128 cubic inches)
    I used the larger 7 cylinder unit that displaces 154.7cc (9.441 cubic inches) as I wanted more cooling capacity at idle, nothing more annoying that coming down to a light in 100+ temps and having the vent temp rise 10 deg when the compressor slows down.

    The reason most retrofit kits call for the smaller displacement compressor (SH5-H14 or H11) is to help offset the heat load on the condenser created by using R134a. I fit the LARGEST possible parallel flow condenser possible in the front of my 64' Riv to ensure condenser heat soak is never a concern. The main thing is to be certain NOT to use anything other than a modern Parallel flow condenser. The old tube an fin units are simply NOT efficient enough to remove the heat from R134a. Performance will suffer and the compressor life will be shorter. If you live someplace where the ambient temps seldom reach 90 you can get away with it but not here in the southern regions where 115 in the summers is frequent.
    The bottom line is you simply cannot go to large with the condenser. The more surface area you have here the more efficient the system will be. The larger condenser also helps to avoid the need for electric fans to augment idle airflow.

    The A6 has massive capacity which is great IF you have 2 evaporator coils or one really large one with enough airflow not to freeze up. Reality is even in the Texas summers we wont come close to using that much compressor capacity in a passenger car like a Riviera etc. My registers blow 34-36 F on the freeway and 37-39 F idling in 100+ heat.

    My unit is mounted to the A6 bracket using the 2 first bolt holes slightly enlarged to fit the Sanden flange spacing. A single bracket to the back supports the rear. I am using a rear exit head on it (they are interchangeable to find one that clears the hood and preferably keeps the discharge port facing UP at the 12 O' clock position. Sanden units use an oil sump that retains enough oil in the unit to keep it properly lubricated. You do NOT want to allow the discharge side to face downward or lower than a 3 or 9 O' Clock position as it will pump itself dry and the refrigeration oil will collect in the lowest point of the system aka condenser = Bad.

    The stock (rebuilt) alternator and wiring simply does not keep up with the full blower speed load below about 1300 engine RPM. This annoyed me to death as the fan speed would slow at at lights etc when the car is absorbing the MOST heat. I replaced my original factory alternator with a 225 Amp unit from Power Bastards which bolted directly in place of my factory unit without any bracket modifications. This unit is internally regulated so I made all new engine compartment harnesses from the firewall bulkhead connector outward. I am using 4ga charge wire from the Alt to the distribution block at the Horn Relay and 2 ga battery leads from the batt to ground and batt to distribution lug. Nothing like always have 13.8-14.4 v at any speed or any load. 225 AMPs is overkill but the reason is simple, this alt puts out 125 at idle and that is only 50% of its rated capacity so it is never working hard vs the original which could not keep up and was maxed out. Stable clean power = winning.
    300sbb_overkill and philbquick like this.
  6. Lobucrod

    Lobucrod Well-Known Member

  7. philbquick

    philbquick Founders Club Member

    WOW Superstingray you did your homework. A lot of good info, thanks!!
  8. 322bnh

    322bnh Well-Known Member

    The cars these were used on needed that much capacity since they cooled outside air instead of recirculating.
  9. That is a valid point.
    The older cars had a LOT of hot metal to cool and big windows, they also did not have the insulation in the headliners, roofs, etc that cars have today. I know a friend of mine has a 55 4-door with the factory rear deck AC and the A5 compressor, he blocked off the outside air intakes for that very reason. To force it to recirculate the already cooled cabin air 100% of the time. The danger in in doing that is we have to make very certain there is no carbon monoxide buildup inside the car over time on a drive. My vintage air system also is full recirculate only. No outside inlet exists. I can always open the Cowl vents if I want some outside air to come in without opening my windows.
  10. I will say another friends 60 Electra Flat Roof 4 door we have blowing 34 deg at the registers using the original system with the sealed (non rebuildable A5) compressor. The A5 is a 5 cylinder smaller version of the A6. What I find is that we never hit the compressor capacity limits but we could certainly use double the airflow from the registers on 100+ days. The older cars simply did not have a lot of blower capacity compared to say my 2016 Denali HD 2500 Truck. The fan/ducts/plenum/evap they are using in that thing is a MONSTER.

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