AC fitment problems

Beck · April 21, 2008, 12:11:03 PM

I am having problems fitting an AC evaporator to my 62 Chevy truck. I was intending to use one of the retro under dash units. All of them I have looked are to deep. There is a heat/defrost diverter that comes from my factory heater in the way. My next option was to use one of the "Sure Fit" setups since this replaces the factory heater. This won't work either because I have boost not vac from my motor. The "Sure Fit" has vac control valves. There are other units that have electric control valves (Gen II) but none that are easy to install.
Didn't some cars come factory with vac pumps? Are they common? Do they work and last? How big are they? Are they noisy? Would I be able to find a unit in the salvage yard?
Should I just spend the extra time and trouble to put one of the electric control valve units in and forget the vac pump?

Thanks

enjenjo · April 21, 2008, 12:21:42 PM

Most diesel cars came with a vacuum pump, diesel Escorts, VW, and others.

papastoyss · April 21, 2008, 12:23:47 PM

80,s VWs that had cruise control had a small electric pump for the cruise control. It's about the only part of the system thay didn't give trouble.

WZ JUNK · April 21, 2008, 12:59:48 PM

I think it was Vintage Air that sold a little electric vacuum pump to use with the air conditioning controls. I believe it was to be used when one of their units was installed on a diesel truck. I have a new one on the shelf and I kept it to use on something someday but I never have found a use for it.

John

Fat Cat · April 21, 2008, 06:56:13 PM

Most newer(post 2000) Class A motorhomes with Gas motors in them have a electric vacuum pump that mounts right below the brake booster on them. GM P-30 series chassis is where I see them most. I also see them on some of the small International trucks.

On the motorhomes they use them to supply vacuum power to the brakes in the event of an engine shutdown or failure. They are usually supplied with 12v power even with the key off.

wayne petty · April 21, 2008, 09:13:26 PM

most gm cars in the 80's had electric vacuum pumps up under the front drivers side fender... in front of the tire...

here is a link that shows how to hook up the pump for brake booster assist...

http://www.victorylibrary.com/mopar/pump-tech-c.htm

there are 2 differnt types... one with the vacuum switch built in one with a remote switch... usually mounted on the front of the brake booster...

these were not designed for full time running.. to use this for a/c control.. you will need a check valve and a vacuum tank...

wayne...

Ed ke6bnl · April 22, 2008, 03:15:44 AM

Quote from: "enjenjo"Most diesel cars came with a vacuum pump, diesel Escorts, VW, and others.

my dodge diesel has a chevy style hydroboost system and the p/s pump looks like my chevy dually has but has a rear mounted vacuum pump. The p/s pump itself may be gear driven though.

Leon · April 22, 2008, 11:15:23 AM

If the Gen-II unit is too big, try looking at the Gen-II Mini, it's 7.3" deep, 9" high, 19" wide.

Beck · April 22, 2008, 05:36:18 PM

Ed ke6bnl - This is going on a truck with hydroboost, but my pump does not have a vac pump.

Wayne - I think you have hit the most available unit in the salvage yards. Where do I dump the vac pump exhaust if I have 30 psi in the intake manifold?

Leon - The Gen II Compac will fit, but puts the floor heat outlets both on the passanger side.

The U-pick-it place I go have no big units (motor homes, or diesels). I am pretty stupid about VW parts, but I will look.
I don't know if I am better off adding the vac pump and using the "made to fit" ac/heat unit or not adding the vac pump and spending extra time installing a universal electric controlled ac/heat unit. With the electric controlled unit once I have the installation done I don't have to worry about the vac pump failing. I ahve to make up my mind and get it ordered. It is going to be the holdup on the project soon. It will take at least a week to arrive.

Thanks guys!

wayne petty · April 22, 2008, 08:31:51 PM

Quote from: "Beck"Ed ke6bnl - This is going on a truck with hydroboost, but my pump does not have a vac pump.

Wayne - I think you have hit the most available unit in the salvage yards. Where do I dump the vac pump exhaust if I have 30 psi in the intake manifold?

vent it to atmosphere... maybe through a brake booster inline check valve... and thats a lot of boost....

i seem to recall when my auto shop instructor turned up the boost past 28 psi on his class c streamliner he blew the copper head gaskets out and dented the frame rail... he had a twin turbo big block chevy in a top fuel frame running alcohol...

UGLY OLDS · April 22, 2008, 09:11:57 PM

What are you using to make "boost" ? I may have an idea..

Bob....

Beck · April 22, 2008, 10:20:04 PM

I am powering with a 4bt, which is a 3.9 liter Cummins 4 cylinder. It is just like the motor in the Dodge diesel trucks but missing 2 cyl. It has a Holset H1C turbo on it that I have put a smaller exhaust housing on. The fuel pump will be tweeked slightly.

UGLY OLDS · April 23, 2008, 08:11:29 PM

Quote
Quote from: "Beck"I am powering with a 4bt, which is a 3.9 liter Cummins 4 cylinder. It is just like the motor in the Dodge diesel trucks but missing 2 cyl. It has a Holset H1C turbo on it that I have put a smaller exhaust housing on. The fuel pump will be tweeked slightly.

Whoops :!: So much for THAT great idea... :oops: :oops:

( Sorry.... I missed the diesel part ...... :oops: )

Bob...