How I refinished the horns in my '73 240Z

[kenz240z]

I have methodically been "refreshing" my '73 240Z a bit at a time. I've repainted the car, rebuilt the front & rear suspension, installed new carpets, a headliner and a dash cap, refinished the engine bay and just recently had the engine rebuilt. :knockedou One of the last detail items I had left to tackle was the horns. They were pretty cruddy looking after 30 plus years of service. :sick:

First of all, here is a list of items that I used to refinish the horns:

Phillips screw driver

5/16" nut driver

1 Scotchbrite pad

#0000 Steel wool

3M rubbing compound

PPG wax & grease remover

Satin black enamel paint

Wire brush

Barkeepers friend

an old tooth brush

an few old socks

Here are the steps I followed:

1. Use the screw driver and nut driver to remove the six screws that hold the horn together. Notice that the two screws that secure the mounting bracket to the horn are longer than the rest. Also, note that there is a lock washer sandwiched between the horn and the mounting bracket, as well as another lockwasher between the mounting bracket and the nut. Also, there are two little metal spacers that fit in the mounting bracket. Don't lose any of these small items! Once all six screws are removed the horn can be separated into the front cover, diaphragm, and rear cover.

2. Clean the screw heads with the Scotchbrite pad. Place the pad on a hard surface, such as a workbench, and grip a screw by the threads. Rub the screw over the Scotchbrite pad until it is nice and clean. Repeat this process with the remaining screws. Once all the screw heads are clean polish them up with the steel wool. It should make them fairly shiny. :knockedou

3. Use a wire brush to clean the nuts. I used a cup brush on an angle grinder. A bench grinder with a wire wheel could be used, or you could use a hand held wire brush. If you use a wire brush on a power tool, BE VERY CAREFUL! WEAR EYE PROTECTION! WEAR GLOVES! A wire brush on a power tool can easily launch the nut into space. If that happens, consider yourself lucky if it doesn't hit you :hurt: , hit & nick something around you (like your Z! ), or end up lost .

4. Clean and polish the black metal disc on the front of the diaphragm. Use an old sock, or other cotton cloth, damp it with water, and apply a bit of the rubbing compound to the sock. Use small, circular motions to polish the disc. Wipe clean with a clean, dry portion of the sock.

5. Clean the front cover with warm soap and water. Dry thoroughly. Clean the surface with a bit of wax & grease remover on another old (clean, please!) sock. Scuff the surface with the Scotchbrite pad (note - be sure all heavy dirt, oil & grime deposits are removed BEFORE scuffing the surface with the Scotchbrite pad!). Wipe the surface clean with a bit of wax & grease remover in preparation for painting. Allow the cover to dry thoroughly.

6. In a well ventilated area, spray a couple of light coats of the satin-black enamel on the front cover. I placed the cover on a block of wood, up on a box on top a small, portable work bench in my garage. Once the cover has been painted, hang it up with a bit of wire and let it dry.

7. Clean the back cover with Barkeepers friend, or similar cleaner. Be careful when cleaning the back cover, as it contains the coil & other electrical parts. DO NOT SUBMERGE IT IN WATER! I used another old sock, damped it with water, and then applied a bit of the cleaner to the sock. Then, I used it to clean the larger areas of the back cover. For the nooks & crannies I used the toothbrush. I damped the bristles with a little water, applied a small amount of the cleaner to the tooth brush, then cleaned the tight spots. I used a damp rag to wipe the surface clean. Don't tell my wife, I cleaned the back cover at the kitchen sink while she was away at work! :paranoid:

8. Clean the mounting bracket using the same method as for the back cover.

9. When the paint on the front cover has dried, reassemble the horn. Notice that there are 2 dimples on the perimeter of the back cover, located 180 degrees apart. Also notice that the diaphragm has 2 small holes (conveniently located 180 degrees apart, see the connection here?), in addition to the 6 mounting holes. These 2 small holes fit over the dimples, insuring that the diaphragm lines up correctly with the coil in the back cover. The front cover has 2 slots around the perimeter, located 180 degrees apart. Place the front cover over the diaphragm and align the bolt holes so that one slot is at the top of the horn, and the other is at the bottom.

10. Install the mounting bracket to the bottom 2 mounting holes using the 2 longer screws. Don't forget to install the lockwashers! Each of these screws should have a lockwasher between the rear cover and the mounting bracket, and another lockwasher between the bracket and the nut. Install the 4 short screws in the remaining holes, put a nut on the back of each screw and tighten them all down. Use the screw driver and nut driver to complete this step.

11. Reinstall your "new" horns back on your Z!

They may not be show quality, they may not be totally authentic in appearance, but they sure as heck look a lot better that they used to! :classic:

This post has been promoted to an article

[Careless]

Is the front cover of the horn supposed to be black, and the bolts & nuts silver (clear) zinc or yellow zinc?

Also, is the rear cover supposed to be "natural" finish?

I am just getting around to the horns on the resto I'm doing and they're all "gunmetal" gray in their entirety. 

[AZ-240z]

Is the front cover of the horn supposed to be black, and the bolts & nuts silver (clear) zinc or yellow zinc?

Also, is the rear cover supposed to be "natural" finish?

I am just getting around to the horns on the resto I'm doing and they're all "gunmetal" gray in their entirety. 

There have been many thoughts on what is factory correct for refinishing our horns. 

 

I have attached a picture of an early 1970 Z horn to support what I feel is correct

when talking about "how it came from the factory"/

 

1.  Front cover is olive drab.

2,  Center diaphragm is satin black 

3.  Center bolt and nut clear zinc.

4.  outer mounting screws, front side, olive drab.

5.  rear cover and nuts are natural finish.

6.  mounting brackets are natural finish.

7.  4 large mounting machine screws and washers are yellow zinc.

 

 

I may know of someone who offers a kit of gaskets and screws, nuts, and washers for rebuilds. 

 

Dan

Edited October 7, 2015 by AZ-240z

[AZ-240z]

 

Here is another picture that shows the back of the horn.  Granted, it is difficult to tell if

the finish is natural, but I have seen many other survivors that had a natural rear

cover.

[wheee!]

Dan's Pictures 027.JPG

There have been many thoughts on what is factory correct for refinishing our horns. 

 

I have attached a picture of an early 1970 Z horn to support what I feel is correct

when talking about "how it came from the factory"/

 

1.  Front cover is olive drab.

2,  Center diaphragm is satin black 

3.  Center bolt and nut clear zinc.

4.  outer mounting screws, front side, olive drab.

5.  rear cover and nuts are natural finish.

6.  mounting brackets are natural finish.

7.  4 large mounting machine screws and washers are yellow zinc.

 

Dan's Pictures 027.JPG

 

I may know of someone who offers a kit of gaskets and screws, nuts, and washers for rebuilds. 

 

Dan

 

 

Would be interested to know if the gaskets fit my 76 horns....

[Careless]

Dan's Pictures 027.JPG

There have been many thoughts on what is factory correct for refinishing our horns. 

 

I have attached a picture of an early 1970 Z horn to support what I feel is correct

when talking about "how it came from the factory"/

 

1.  Front cover is olive drab.

2,  Center diaphragm is satin black 

3.  Center bolt and nut clear zinc.

4.  outer mounting screws, front side, olive drab.

5.  rear cover and nuts are natural finish.

6.  mounting brackets are natural finish.

7.  4 large mounting machine screws and washers are yellow zinc.

 

Dan's Pictures 027.JPG

 

I may know of someone who offers a kit of gaskets and screws, nuts, and washers for rebuilds. 

 

Dan

 

Hi Dan,

 

Thanks for the breakdown- that's what I was looking for.

Do you mind reuploading the picture of the front? It seems like classiczcar won't load that one properly when clicked, but the rear shot seems to be ok.

 

Thanks again.

[Careless]

has anyone had luck with making their own gaskets?

Dan, do you have the contact for the person with the rebuild kit? I saw a website online where someone offered rebuilt ones. Maybe I can cash these in as cores.

 

They're sprayed gunmetal, and it looks like someone tried to take one apart before because I see one screw missing on the face.

[AZ-240z]

Hi Dan,

 

Thanks for the breakdown- that's what I was looking for.

Do you mind reuploading the picture of the front? It seems like classiczcar won't load that one properly when clicked, but the rear shot seems to be ok.

 

Thanks again.

These were the two pictures that I had used. 

 

Dan

[Careless]

Thanks! They're both working now. I can enlarge and see more detail.

 

[Careless]

I have a gasket punch set, and some of the same type of gasket paper used in the horns at a friends shop. So I think I can safely tumble these items back to regular finish, and have the front covers and bolts Olive Drab plated (if my plater does that). I'll let you guys know how it turns out!

 

The inside of the rear cover looks as though it was clear zinc plated. I'll have to inspect further and post my results!

[Zup]

Careless--

Here's a little more discussion on the horns.

The first post contains a link to an additional earlier discussion regarding them. Seller "nikkibid 1972"  on E-Bay has sold gasket and screw sets in the past. Contacting him may be helpful if you don't make your own. (Rob is another Canadian and a really fine fellow---very helpful to me when I was sourcing small original bits )

 

http://www.classiczcars.com/topic/51388-early-horn-differences/

 

I am really enjoying your documentation of the restorative process. You are doing a fantastic job of it---the way a true restoration should be done---and it is a testament to the ongoing legacy of these fine cars.

I would love to see this car in person when it is finished---will it be shown at ZCON 2016 in Toronto??

 

Jim D.

"Zup"

[AZ-240z]

Careless--

Here's a little more discussion on the horns.

The first post contains a link to an additional earlier discussion regarding them. Seller "nikkibid 1972"  on E-Bay has sold gasket and screw sets in the past. Contacting him may be helpful if you don't make your own. (Rob is another Canadian and a really fine fellow---very helpful to me when I was sourcing small original bits )

 

http://www.classiczcars.com/topic/51388-early-horn-differences/

 

I am really enjoying your documentation of the restorative process. You are doing a fantastic job of it---the way a true restoration should be done---and it is a testament to the ongoing legacy of these fine cars.

I would love to see this car in person when it is finished---will it be shown at ZCON 2016 in Toronto??

 

Jim D.

"Zup"

Jim, I have contacted Nikkibid on behalf of this discussion as I had previously purchased

this horn kit from him. He said he no longer offers this hardware and gasket kit.

He frequently offers products on eBay and I highly recommend him and whatever he sells.

Dan