A/C converted car - questions

I have a Mach 1 that did not come with A/C from factory (per Marti). Therefore A/C was added at sometime before I purchased it. I have a few questions out of curiosity:

-There is a "cup" looking feature sticking out of the car on the passenger side fender that when I look from the inside is empty. Is this were the blower is placed in non-A/C cars? If so, in an A/C car the blower location is replaced to behind the dash and this blower serves as the A/C fan and heater fan, correct? Is this cup protrusion in original A/C cars as well? When empty looks like a good place where to hide stuff

-In the drivers side I have a vent that I can open/close with a knob. Is this feature available in original A/C cars as well? Is this feature supposed to exist on the passenger side?

Mine was a non-A/C car, and I have the bump. I also have the fresh air ducts (on both sides) that you referenced. The cable controls a flapper to close off the blower vents, and allow air in through the "hats" in the cowl. The A/C cars had the "hats" blocked off, I believe. I know the Classic Auto Air kit I installed had me block off the driver side "hat" and remove all of the original ducting. I tried to come up with a way to use the original fresh air ducts, but it was going to be too much of a hassle to fabricate pieces/parts, and I was under the gun to get the car out of the shop - so I blocked 'em both.

I still have all the original duct work with those flappers (one is seized & a bit rusty), but the other works fine. Both are restorable, IMHO, and the rest of the ducting is in 'not so bad' condition.

Mine was a non-A/C car, and I have the bump. I also have the fresh air ducts (on both sides) that you referenced. The cable controls a flapper to close off the blower vents, and allow air in through the "hats" in the cowl. The A/C cars had the "hats" blocked off, I believe. I know the Classic Auto Air kit I installed had me block off the driver side "hat" and remove all of the original ducting. I tried to come up with a way to use the original fresh air ducts, but it was going to be too much of a hassle to fabricate pieces/parts, and I was under the gun to get the car out of the shop - so I blocked 'em both.

I still have all the original duct work with those flappers (one is seized & a bit rusty), but the other works fine. Both are restorable, IMHO, and the rest of the ducting is in 'not so bad' condition.

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Interesting. My car has a working flapper, but only in the driver's side plus the A/C system.

Edit: I just saw in the Illustration Manual that once the vent is open air would come through the dashboard duct and through the bottom to your feet. I think in mine when I open the vent I get air only to my feet. I will have to investigate the whole setup, once I unwrap the dashboard, which is protected right now due to the floor work.

The non a/c cars had two vents, they are dual position, floor or dash. A/C cars did not come with them at all and the driver side cowl would not have a vent hat.

I have a different computer so cannot get to the pictures.

It is easier to put air on one or our cars than to take it off. The bubbled helmet shape on the firewall on the passenger side is only on NON air cars. NON air cars have the dual vents into the cowl and a hat section that will eventually leak on both sides.

If you are putting air on you will need to block off the one on the drivers side and you have to cut the key shaped hole in the firewall to clear the AIR conditioner hookups. Along with getting all the air components off a donor car. Compressor, brackets, condenser, evaporator, hoses, inside controls and full heater air box. Along with all the ducts and the center dash section. Sounds like a lot but not really.

If you are taking air off you will need to add the helmet to firewall to clear the blower motor and block off the key shaped opening in the firewall and put the hat on the passenger side which is a pain without opening up the cowl. You will have to have a donor car for the fresh air vents, heater box and all the controls and ducts.

Keeps one busy always someone taking air off or putting air on.

David

My '71 vert that I am just disassembling has the driver side cowl blocked off and the passenger side cowl is open to the A/C box. How do I know this? I just cleaned out a 4" deep mouse nest that was tucked just below the open cowl and resting up against the A/C evaporator in the box. The opening/closing of the cowl is controlled by a vacuum operator damper that can allow fresh air or block off completely. Unfortunately for me, it appears that when there is no vacuum applied, the flapper is in the normally open position, should have been the other way from the factory around to prevent unwanted entry...

My '71 vert that I am just disassembling has the driver side cowl blocked off and the passenger side cowl is open to the A/C box. How do I know this? I just cleaned out a 4" deep mouse nest that was tucked just below the open cowl and resting up against the A/C evaporator in the box. The opening/closing of the cowl is controlled by a vacuum operator damper that can allow fresh air or block off completely. Unfortunately for me, it appears that when there is no vacuum applied, the flapper is in the normally open position, should have been the other way from the factory around to prevent unwanted entry...

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Just a little tip on keeping the critters out of there. I take 1/4" galvanized box wire that you can get at any hardware. Some sell small sheets some rolls. I take the cowl vent plastic grills off and cut a piece that fits the bottom side that will go into the cowl. I use small wire ties to attach to the plastic grill. This keeps most critters out. Spray the wire mess with flat black paint and you have too look for it to see it.

I also cut a round piece an put it over where the heater box goes to the hole in the cowl as a second barrier. There are two drains one on each side of the cowl and if you have the fenders off you can put a piece there also but it might catch trash and clog up so I leave open.

I had a pretty good sized black snake living in my Mach 1, skins inside and under hood, which kept the mice away but don't really like snakes either. I do not think there is another entry point unless you have a rust hole somewhere that any mice can get in.

David

I have a different computer so cannot get to the pictures.

It is easier to put air on one or our cars than to take it off. The bubbled helmet shape on the firewall on the passenger side is only on NON air cars. NON air cars have the dual vents into the cowl and a hat section that will eventually leak on both sides.

If you are putting air on you will need to block off the one on the drivers side and you have to cut the key shaped hole in the firewall to clear the AIR conditioner hookups. Along with getting all the air components off a donor car. Compressor, brackets, condenser, evaporator, hoses, inside controls and full heater air box. Along with all the ducts and the center dash section. Sounds like a lot but not really.

If you are taking air off you will need to add the helmet to firewall to clear the blower motor and block off the key shaped opening in the firewall and put the hat on the passenger side which is a pain without opening up the cowl. You will have to have a donor car for the fresh air vents, heater box and all the controls and ducts.

Keeps one busy always someone taking air off or putting air on.

David

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Thank you David. My car was non-air, but had the A/C installed when I bought. I also have a functional venting flap on the driver's side. Curiosity is killing me so I will unwrap my dash and dive under it to investigate what did they do.

NON air cars have the dual vents into the cowl and a hat section that will eventually leak on both sides.

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My car has these two cowl openings. Can you please expand on how these typically leak and what can I do to make sure they don't leak? What do you mean with "hat" section that leaks?

In my case I don't know if they leak because I have not had the car wet yet. The PO said he "never" had it out in the rain since the car was restored 12 years ago. My cowl has no signs of rust as far as I could see.

I have attached a picture of the upper and lower cowl as separate pieces. The Hat section is not attached but goes around the two large diameter holes on each side. It was a round sheet metal piece that had a flange formed up about an inch or little higher. The flange kept the water from just running into the two large holes that are where the fresh air vents are on cars without air. If you have air there is only one hole on the passenger side. When they assembled these at the factory they depended on the manual operator to properly apply the seam sealer under the Hat ring around the big hole. They spot welded the parts in with the sealer in between. Then smeared more sealer around the outer edge. As you know when a human does things they do not always do a good job and some leaked right from the factory. You will see rust stains inside on cowl and firewall if leaking. Since none of the steel in our cars is galvanized it rusts easily. These cars were not dipped into a vat of primer like they are today so the inside of the cowl did not get primed or painted.

To tryed to slow down the rust in my vert I took POR 15 and taped an extension on the handle of a paint brush and went inside the cowl and brushed it on the top of the cowl and bottom and went up through the vent holes and put around the Hat. I had also removed the wiper arms and wiper motor to give more room. Of course I cleaned it the best I could before applying the POR. I actually poured some in and let it run out both sides of the drain holes in the cowl that are under the front fenders. Just trying to seal up any cracks I could. I then sprayed some undercoat inside the cowl similar to what Ford did during the assembly.

If you are replacing the cowl on a car you can do a much better job sealing and painting and coating everything than the factory did.

I personally never wash my cars with a garden hose or pressure washer. I just use micro fiber and water and wipe it clean. If I ever get caught in rain and it really gets dirty then I might rinse it off with hose. These cars have some sealer applied inside the doors, cowl, quarters, trunk but not a very good job. When water gets in there either from rain or washing you are going to feed the rust. What sealer is in there cracks with age and if you have ever pulled the front fenders off you will see some good examples of how it cracks and just peels off. A good example of the water getting trapped and causing rust is the tail light panel. The design of the seal was bad in my opinion. It was done for looks not function. The seal is on the inside of the metal so water gets around the tail lights and seeps into the trunk. The water sitting there between the rubber and steel causes rust. When you wash with a hose you fill that area with water and feed the rust. I have a California vert always garaged and the only rust is around the tail lights because of washing the car.

When you wash with a hose the water runs down into the cowl and gets into all the cracks and feeds the rust.

Just my opinions on how to make these cars last a little longer.

David

Here's what happens when it rusts (as David said) - mine had tons of pecan shells and leaves jammed in the cowl side drain vents, so the moisture just collected and rusted through everything. I wound up cutting the whole front clip off another car from the junkyard, and went back for the cowl after I opened up mine up and found this:

Driver Side



Passenger Side



Repaired







This was all done before those new cowl pieces David showed were available - otherwise, I would've just gone with the new sheet metal.

While I had it opened up, I coated everything with Rust Bullet Black Shell, sealed everything, and painted on more Rust Bullet Black Shell (similar to POR-15).



After all that work, Classic Auto Air had me close off the "hats" - neat, huh?

Here's what happens when it rusts (as David said) - mine had tons of pecan shells and leaves jammed in the cowl side drain vents, so the moisture just collected and rusted through everything. I wound up cutting the whole front clip off another car from the junkyard, and went back for the cowl after I opened up mine up and found this:

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Thank you Eric. Awesome pictorial. Pictures are worth a thousand words. I think I get a good idea of what would happen. I inspected my cowl, as much as I could without disassembling too much, and it looks good. I will also check the areas of the hat for sealant as recommended by David. I think I was lucky that the PO didn't get the car wet so that has kept rust largely under control.... except for the floors.....

If your floors are rusted close to the firewall, you might have some leaks that you might not be able to get to unless you pull up the cowl like I did. The water came in from somewhere, and firewall/front floor rust issues are typically caused by cowl leaks. The windshield seal could've also allowed moisture in to rust out that area (if it is rusted out, that is).

If you can get some kind of a fiber-optic "snake" camera in there, or toss in a drop-light and look for any light leakage from under the dash, that should help ease your mind.

Of course, if your rusty areas are further back, it's probably because the windows (passenger and quarter) weren't sealed up, and moisture got in through there.

Glad to share the follies of my project - one of the reasons I took so many pictures. Some of them might actually serve as 'what not to do' kind of things.

If your floors are rusted close to the firewall, you might have some leaks that you might not be able to get to unless you pull up the cowl like I did. The water came in from somewhere, and firewall/front floor rust issues are typically caused by cowl leaks. The windshield seal could've also allowed moisture in to rust out that area (if it is rusted out, that is).

If you can get some kind of a fiber-optic "snake" camera in there, or toss in a drop-light and look for any light leakage from under the dash, that should help ease your mind.

Of course, if your rusty areas are further back, it's probably because the windows (passenger and quarter) weren't sealed up, and moisture got in through there.

Glad to share the follies of my project - one of the reasons I took so many pictures. Some of them might actually serve as 'what not to do' kind of things.

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Now that was one rusty cowl for sure. I guess the critters feel safe in there and love to store stuff for hard times.

You did a lot of work on that car. I am parting out a 72 vert that has less rust than that, lol.

Looks like you did all you could to prevent again.

So the aftermarket air does not take in any fresh air?

David

Nope. In fact, they pretty much replace ALL the factory ducting with round or rectangular flex hoses. Kind of like the "Max A/C" setting - recirculates everything. I guess they are more old school than the factory - if you want fresh air, open the windows. LOL

The cowl replacement was one of the "small" rust-fix products on my car, actually.

That's also one reason why I'm referring to that laundry list of things I'll be doing tomorrow (replacing the power steering pump, wiper motor, speedometer cable, etc.) as "small stuff."

So yesterday I was able to investigate under the dash. Since I have all the instruments out it was not that hard. I can't see any rust from underneath the cowl. From the outside there may be some on the protruding hat, but it is hard to see how much. I will have to use a flexible camera.

Also, I found out that my car has a "hybrid" system. The A/C air inlet is, as expected, through the passenger cowl hole. However, they left the driver's cowl hole with a working flapper, but they disconnected the fresh air dash duct. The A/C duct is in place in the driver's side so you get A/C air through the vent as it should be. What's interesting is that they blocked off the fresh air outlet to the dash but left the fresh air outlet to your feet.

Prior owner had smelly feet.

To get a look inside the cowl you can use your camera phone on a selfie stick or get a kid with small hands to help.

Prior owner had smelly feet.

To get a look inside the cowl you can use your camera phone on a selfie stick or get a kid with small hands to help.

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It wil be fun to drop the phone down in the cowl hole....[emoji1]

1971 M-code Mach 1

I am in the process of converting my '71 convertible from non-air to air. As noted, there are differences in the cowl between the two - the dome for the heater blower motor (the AC cars have the blower in the center of the cowl below the radio speaker), the holes for the heater core are in a different place in non-AC cars, and the ductwork behind the dash is somewhat different. The drivers side cowl does not have the vent hole and there are also different mounting holes for the heater/evaporator housing, a vacuum hose boss passthrough, as well as some additional brackets at the center-top of the cowl for hanging the AC blower motor. I didn't figure all of this out until I got the car back from the body shop and eagerly started putting the AC system in the car. Rats. The car is now back at the body shop getting the firewall holes patched/cut, the driver's side vent hole filled in the cowl, and the brackets added for the blower motor. I am leaving the dome for the heater blower motor, as it is pretty well hidden from view unless you are really looking. Pretty stupid on my part because I had everything for the conversion before the car went in for paint. An expensive oops...

Be advised that the new replacement cowl and firewall parts are for non-air cars. They will need some work before they can be used for an AC system. Unfortunately I haven't seen any conversion instructions to show what needs to be filled and what needs to be opened up. I suppose now I have this experience, I should be able to provide some documentation.

We all live and learn each day and that is good. Just bad that you had the car back from paint. At least is doesn't affect any of the parts of the car that are color.

There was a time that the cowl lower only came for the air conditioner and did not have the hole in the driver side. I guess more wanted it than did not.

It is amazing how many parts come into play for something like air. The Buck Tag is part of the control on the line to make sure that all the brackets and holes are in place for the options chosen.

Winter is here in the mountains of N.C. had first frost last night and building a fire tonight OMG. No more fresh tomatoes.

David