Topic: AC Delete sealant - Butyl Rubber or Seam Sealer?

[Angelo]

I have my AC Delete from www.acdelete.com ready to install. I used #8 screws with nuts everywhere except for the resister. I installed the screws with the thread pointing out for the blower motor, screw head seemed better suited for the confines in that area plus that way I can use the studs to attach a ground wire to easily. I got a plan to extend the hose that attaches to the blower motor, I am aware it's not connected yet.



My question, I was originally going to snake 3/8" thick butyl rubber around the delete cover to form a gasket, but now I'm thinking seam sealer may be better. What is recommended?

I plan on cutting a gasket to size for the resister, the AC delete surface is not completely flat where I mounted it so there's a slight gap on either side. Everything else is pretty snug and air tight.

I'm going to paint the inside. The outside has a nice finish, but the inside is rough fiberglass. It was not fun drilling and handling the dust fibers afterward, so my thought is to throw a few coats of paint on the backside to help prevent future fiberglass fibers from going into the ventilation.

[NOT A TA]

dum-dum to seal it.

[Angelo]

The roll of 3/8" thick butyl rubber I got I believe is the same as dum-dum. What I got is a cheaper alternative to 3M strip-calk.

[ponchonutty]

I would have used dum dum because it never hardens which is what you want since it's in an extreme area with heat and vibrations.  Now I wouldn't have used rubber because it has a tendancy to break down quickly from too much heat.

[Angelo]

I'm pretty sure we're talking about the same thing. The one I got is called "Glass Setting Butyl Tape". Butyl rubber is not like normal rubber, it will not harden. I'm pretty sure Dum Dum was a brand name.

[Elz]

I am going to be doing this as well. The others I have seen don't keep the wire terminals on the outside like you have. I thought those were actually used by the AC system. What do they run? I ask because mine was all cobbled up when I took it apart, so I don't know what was hooked up to what.

[Angelo]

You mean the resisters (orange/red plate) and the relay (chrome item below resisters)? If you are keeping the AC Fan and AC controls in the dash then you want to hook all of those items up. The resisters control how fast the fan spins from the 4 click fan switch in the dash. When you set the fan speed to hi, the relay then takes over the resisters job and sends power from the alternator/battery directly to the fan motor. The AC fan is extra strong when on hi because it's getting powered directly.

If you plan on using a non-ac fan and use a non-ac heater controls, then you don't need this stuff. At that point you could use the AC Delete sold by all the catalog stores. The reverse does not work, you can't use the catalog store AC deletes with an AC fan, the squirrel cage will not fit in them.

This thread has some good pictures of both AC Delete's available: http://www.78ta.com/HTAF/index.php?topic=31177.0

[Elz]

Thank you for that info.

[Elz]

Silly question. Why could't the terminal and resistor be used on the inside to hide it and give it a cleaner look?

[Angelo]

You could do that, you could mount them on the inside of the dash and run the wiring inside the dash as much as possible, just have one wire come out to go to the fan, and that could be hidden by the passenger fender. That be very Boyd Coddington. I did this approach that way I could service the resister and relay without taking the dash apart, just as the factory intended. Maybe I should say that would be very Chip Foose, Boyd would completely rework the firewall so it was flat with nothing mounted to it except maybe the brake booster.

[ponchonutty]

This is what I use.  I can take multiple strips and twist them together for wider areas that I need to close.  I am sure it comes in different sizes and such.  My inlaws use simular stuff to make gaskets for swimming pools but his stuff is white in color.

http://shop.advanceautoparts.com/buy/products/103130-3m-strip-calk-black-60-1-ft-strips-per-box-part-mmm8578-engine-gaskets.html?cm_mmc=ACQ-_-Google-_-National-_-Keywordless--StoreKeywordless--Ad#utm_source=acq&utm_medium=google&utm_campaign=national&utm_content=keywordless--storekeywordless--ad

[Angelo]

The MMM8578 is the same part number, Napa must relabel 3m stuff.

[78w72]

angelo, your a/c delete plate looks nice.  however you are not required to use the a/c resistors or relay if you retain the a/c switches & motor.  you can simply remove the resistor & relay & wire the a/c fan just like a non a/c set up.  granted you will lose the high speed direct to alt current, but you dont need that if you dont have a/c.  that is just for the high speed when the a/c is on.  if you remove all that & jjust have the speeds a non a/c car has it will work fine. you dont need direct alt current for a non a/c car.  also the a/c blower motor can be used with all delete covers, just need to change the squirrel cage to a non a/c one.  $7 at rock auto.   also changing the resistor to a non a/c one & mounting it inside the car like the facxtory did in the heater core box is an easy way  to "chip foose" it.    & does NOT require dash removal to service.   i got the abs plastic cover from the parts place after reading some reviews on the fiberglass one, guys said it fit poorly & was larger than needed.  that would eexplain why the a/c motor & cage fit on that plate,  its alot thicker. 

also,  the a/c blower motors already have a ground terminal, so the backward screws were not needed if you retained that.  but again, the cover looks nice the way you did it too.  just putting some other ideas or alternatives out there. 

[Angelo]

Thanks 78w72!

I actually wanted the Hi Speed fan option so that's all good. The AC fan will need a ground, it only has one flat blade terminal on it and everything it's bolted to now is fiberglass. The main reason the screws are reversed is because of the curvature of the fiberglass where it bolts to underneath, I didn't want a hex nut in that situation. I was not aware the squirrel cages could be swapped, that would save someone a lot of money doing the swap with the other AC delete!

The other AC delete looks a lot cleaner in appearance, and I like how it snakes in between the heater core lines. With today's knowledge and knowing the other AC delete is made of plastic rather than fiberglass I would buy the plastic one and get a squirrel cage from RockAuto.

[78w72]

what do you want the high speed fan for,  are you driving the car in winter or  below freezing?  i have a 78 non a/c t/a & even on low & med the fan blows so much hot air i have to turn the temp selector down a bit.  but its not 10 degrees out either.  my cars are driven untill the 1st snowfall & salting of roads usually above freezing.   but if you want the high speed thats fine, just be sure you need it.  yes the fan needs a ground, on a/c motors there is a ground terminal next to the power.  on non a/c cars the motor mounts to a metal firewall cover & doesnt need a seperate ground. 

heres a few pics of what im doing for my current 72 firebird project. im using a caulk type sealer that stays flexible & will seal better than the rope or dum dum stuff on these thin delete covers.  they are too flimsy IMO to get a good seal on the rope stuff.  you can see the one area on the cover, above the motor that needed modified on my 72, it didnt line up with the stud in the firewall so i just removed it & reused the screw from the factory a/c box. a few other minor mods on the predrilled holes that didnt line up perfectly & that was about it.   i also cut the top heater core hose so it didnt stick out soo far on this cover.  & you can see the resistor inside, because i removed all the a/c ducts it should be easy to get to, maybe removing the glove box liner to do it while sitting down.  & i also have the flap for heat/defrost controlled by a simple cable setup so i can move it to defrost should i ever really need to defrost the windshield. otherwise its always on heat.   & i forced the main a/c door closed so it bypasses feeding the missing a/c ducts.  hopefully it all works as good as when i tested it on the bench!