Topic: 69 evaporator

[mbyers]

Hello collegues
Those of you that own 69 mustangs that have factory air may be aware that FORD manufactured 2 different styles of evaporators?..early 69-69 1/2 and late 69 1/2-70. I?m trying to find out when did Ford transition from early to the late style; specifically what month. I have a car built in Jan 69 and curious if that is month the change was made. Reason For inquiry is PO removed all original factory components and installed retrofit unit. The one reliable way to determine whether one has early or late evap is by orientation of inlet/outlet tubes traversing firewall. Firewall bracket and grommet are also uniquely shaped??I have neither. I am wanting to replace all factory original equipment back in the car and want correct evap core. I have perused many websites but to no avail. Can anyone help?

Thx
Matt

[J_Speegle]

Matt Glad you posted this to the general forum. I know you asked last week about it but searching my pictures it's been very difficult to find clear pictures that will show this detail with the car assembled.  The difference appears to be in the orientation of the both necks that connect the hoses to the evaporator and in turn differences in the seal and the AC/heater case not visible with the case installed in the car.

The two pictures below illustrate the differences in the seal and in turn the cutout in the cases between the two. Pictures borrowed from NPD - THANKS. Upper left the earlier 67-69 style and the lower right the 69-70 style

[Daven]

Thanks Jeff!  I have the one in the top left and I had no idea what it was for!

[J_Speegle]

After looking in to a question I've not heard of before I think its going to be difficult to determine when the change over took place at each plant. What is required is pictures of observations of the AC/heater case from the firewall side and/or clear pictures from a good angle of allot of passenger firewalls.

Looking through my pictures I could only find one that had the outer opening trim removed allowing a pretty clear view of the attachment points and seal on the case

69 Dearborn Mustang built likely the first half of May 1969 with the "late" version. Have the tubes orientation vertical from one another.




Set of pictures showing the AC line attachment points being vertical from one another. Possibly the "earlier" version

Examples from 69 Dearborn built 4/2/69, 9F16089x, 9t19666x 9f13488x





A set of pictures showing the attachment hoses at an angle that appear to match the first picture orientation of the tube ends at the case.

Examples from 9R11107x, 9R14025x, 9R11446x, 9R11485x




Drawing no conclusions at this time. Just offering examples for discussion and observation

[AJ]

Late to this conversation. Photos of heater box from my late feb 69 car.   In one photo can see 428 inked on the box.   In the context of this conversation,  the AC evaporator would be considered a late model.   FWIW 

[mbyers]

Hello Jeff
I would like to apologize for not responding to your response w info regarding evaporator core. I?m just now seeing your response. I always enjoy reading your threads regardless of subject matter. Thx u for material. Regarding early/late cores, I have concluded that late cores started in Jan 69 so I went w late core evaporator design.

I have two other questions if you don?t mind

1. Where is water heater valve placed on 69? Is it secured to firewall like 67-68 model?

2 those that have SMOG system on their cars, do most deactivate the smog so it doesn?t sympathetic draw of HP or is it not safe or illegal to do that?

Thx Jeff

[J_Speegle]

Hello Jeff
I would like to apologize for not responding to your response w info regarding evaporator core. I?m just now seeing your response. I always enjoy reading your threads regardless of subject matter. Thx u for material. Regarding early/late cores, I have concluded that late cores started in Jan 69 so I went w late core evaporator design.

Thanks for the kind comment

Will have to find time to look at my examples to see if I come up with the same answer. Did you happen to focus on one plant in particular?

Kind of left the discussion hanging and didn't look further into the examples back in Jan 2023

I have two other questions if you don?t mind

1. Where is water heater valve placed on 69? Is it secured to firewall like 67-68 model?

No not secured to the firewall like 67-8 but sort of "floated" at the rear passenger side of the engine. Location and landmarks differ depending on which engine car car came from. On V8 cars the hose (preformed rigid S shaped) from the firewall/heater connection held one end and the bulk heater hose held the other.. Valve is pretty much all metal (main body brass) unlike the plastic replacements you often find for sale on the internet


A shot of an original S hose as described above

2 those that have SMOG system on their cars, do most deactivate the smog so it doesn?t sympathetic draw of HP or is it not safe or illegal to do that?

Can't speak for everyone but in the day allot of them got removed completely and plug especially if the engine was removed for repair or rebuilding. Some, especially based on engine type, just removed the pump belt reducing the need to remove all the parts and deal with those ramifications. In some cases I found my cars ran worst without the systems functioning. Today removing or not having is illegal. And of course given our focus here the cars are not restored or like they were built often if not on the car and working.

As mentioned in similar threads some go as far as installing the complete system after they have removed the vanes in the pump so that it does not pump any air. Not really sure why they choose that since it is not really much of a drag on the engine (approx 3% in studies) and you need to plug the tubes and fittings at the heads or the hot gases can burn the paint off the thin small tubing in some examples.

[Big Al]

J -  Not on this subject but I noticed in the first photo of the firewall posted in this thread, that an extra, oblong / slot hole just right of the heater / a/c opening (the low wire appears to either terminate there or goes thru it) is present.  Note the heater box mounts with nuts are still attached.  The hole appears to have a shadow / witness mark of a gasket or plug at one time.  My Aug '69 Dearborn (100871) built car had this same hole.   Pls refer to the replies I received Jan 29, '21, in Extra 70 Dearborn firewall hole.  I filled my hole and made it go away due to the information I received at that time.  There is NO heater mounting point missing or broken off that would use this hole.  Pls note this for future inquiries or information discussed.  Ford obviously put it there. 

I also believe my car came with a firewall ground (to block) as the one I removed was under the deadener/sealer around the heater / AC opening.  I removed, due to comments received and not sure I should have. (yes. I'm aware there is the Neg cable ground to the block  -  which my car came with  -  but some of the first cars could have had both)
thanks for your time
Big Al

[Bob Gaines]

[quote author=J_Speegle link=topic=27826.msg176348#msg176348 date=1696829794


Can't speak for everyone but in the day allot of them got removed completely and plug especially if the engine was removed for repair or rebuilding. Some, especially based on engine type, just removed the pump belt reducing the need to remove all the parts and deal with those ramifications. In some cases I found my cars ran worst without the systems functioning. Today removing or not having is illegal. And of course given our focus here the cars are not restored or like they were built often if not on the car and working.

As mentioned in similar threads some go as far as installing the complete system after they have removed the vanes in the pump so that it does not pump any air. Not really sure why they choose that since it is not really much of a drag on the engine (approx 3% in studies) and you need to plug the tubes and fittings at the heads or the hot gases can burn the paint off the thin small tubing in some examples.
[/quote] Jeff this is not relevant to the evaporator but to address your smog system comment. There are other incentives besides the engine drag on a original but non functioning smog system . There is a substantial lower price advantage on a locked up or dragging while spinning smog pump core at 250.00 or less compared to a restored smog pump that is restored to top operating conditions at 850-1200. A locked up core can typically be made usable as a dummy stand in that looks the part with minimal effort and a little detailed clean up .  Also the non functional smog tubes can be made to look functional but made to be able to be taken out of heads with minimal effort and time (2 minutes maybe for both once rubber smog hoses are disconnected) for better access to spark plugs.

[mbyers]

What a privelage to have two of greatest minds in hobby commenting on my post. I learn so much from you guys and hope you all get rewarded in some way for all that you offer to this great hobby.

Pics that you included Jeff appear to be all late designs. My conclusion of timing of evap conversion period being Jan was based on few observations. Other Gentleman on this thread indicated he had Feb built car and has late design. Even though my car has all the underdash components gone, the evap/heater brackets that attach to firewall is still present. There is also difference in early brackets vs late model brackets. Late model opening is triangular in shape which is consistent w mine so I can assume that Jan used late design but can?t guarantee the switch was not in middle of month. I met guy at car show who had Nov built Dearborn 69 that had early design configuration. Missing link at this time is what happened in December. I know I shouldn?t assume but I?m betting December used early design and Ford made switch in January?? no hard data to substantiate it unfortunately until a Dec built car w a/c is made available. I would imagine concours judges for 69-70 Shelby?s may know the answer bc points would be taken off if wrong evap was in car which is easily visible. bigger question is why did they feel need to change engineering of the core??.. crazy times at Ford back then. I personally feel vertical lines are PIA bc it?s difficult trying to tighten lower hose to evap when 428 block is in car. Horizontal lines would seem easier like 67-68.

Appreciate input from both you Jeff and Bob on SMOG issue. I have 2 KRs and  69 gt500 vert all have original smog equipment and wondering if I needed to have pumps rebuilt. Two of cars pumps spin but no air is expelled from pump during idle. Not sure how long it?s been this way but sounds like I need to either plug holes at the heads or rebuild pumps. Given how difficult it would be trying to loosen ferrules on big block is daunting task. Risk of bending/breaking pipes is too high. It never occurred to me that hot exhaust gases coming up the pipes could destroy them. Sooooo?? I will be rebuilding pumps. Side note, I?m amazed how difficult it?s become to find good original smog equipment and money they are bringing. As always, Thx u both again for your expertise.

Matt