I'm just now getting to the inspecting the underside of the 76 2+2 I bought a couple of weeks ago and it seems to have been sprayed many many years ago with some sort of undercoating, especially in the rear wheel wells. Was this standard practice from the company or did a prior owner have this done?

In places where its fallen off, its seem to have worked because there doesn't look to be any rust on the metal underneath.

I guess my next consideration will be how to get it all off so I can clean everything up real well and paint it. Anyone have any suggestions? I do want to be careful scrapping it so I don't scratch-up the metal under it. I'm not sure if there is any kind of solvent that would remove this stuff.

Thanks

Gary.

The early Z's did not come from the factory with any kind of undercoating.

  Gary in NJ said:

The early Z's did not come from the factory with any kind of undercoating.

I've owned two '72 Z's and both had a similar mud sprayed on them, about 3/16". I always thought it was factory since it was under the brake lines and other hard to reach spots which would have required a total disassembly. Another Series I, Series II difference?

  Gary in NJ said:

The early Z's did not come from the factory with any kind of undercoating.

I disagree and we have had this conversation ad-nauseum. Look this up in the archives.

Having said that. Recognize that undercoating by the dealer was common in the 70's. Dealer applied undercoating when removed with mineral spirits will reveal the original paint. Nissan factory in Japan undercoating was very subtle and painted over when the car was produced. It looks more like a stone guard texture and is not uniform throughout the underside of the chassis.

It took me a week to get all the undercoating off my early 260Z this year while it was on the rotisserie. I used elbow grease and a scraper similar to an excessively flattened screw driver (from Harbor Freight) to remove it. The only paint underneath was a very thin coat of light yellow protective paint, not the original color of the car which was silver. This yellow paint must be a corrosion prohibitor similar to the green phos-coating used to protect the sheet metal on new airplanes while they are being built. In this photo, nearly all the undercoating is removed. I used some brake cleaner to completely remove all the residue from a portion of the spare tire well just for fun...

I found the same yellow paint under the tar insulation mat used in the interior.. Notice the areas under the tar mat have the same light yellow paint and the surrounding area is covered by the stock silver.

Just relaying my experience....

Rainman, what you describe (pale yellow paint under the splatered rough undercoating) is pretty much the same as what I'm seeing on mine. And wow, looks like you did a great job. It really looks like it turned out awesome! Well worth all the hard work.

Thanks Healeyalt... Didn't mean to hijack your thread, just wanted to show you what I found..

I might have discovered the original paint color under there somewhere had I been more careful but it's a job that isn't terribly enjoyable as you're now aware!! The car was going in for media blasting after the undercoating removal so I wasn't worried about scratching up the metal.

The fun part has begun in earnest.... Putting it all back together... You're right though, it is very much worth the hard work.. Thanks again!!

Tom

  Rainman said:

It took me a week to get all the undercoating off my early 260Z this year while it was on the rotisserie. I used elbow grease and a scraper similar to an excessively flattened screw driver (from Harbor Freight) to remove it. The only paint underneath was a very thin coat of light yellow protective paint, not the original color of the car which was silver. This yellow paint must be a corrosion prohibitor similar to the green phos-coating used to protect the sheet metal on new airplanes while they are being built. In this photo, nearly all the undercoating is removed. I used some brake cleaner to completely remove all the residue from a portion of the spare tire well just for fun...

Mine had a tough as nails red/rust colored primer. The undercoating underneath and layers of green paint on top came off like butter under a soda blaster. The primer took some time under the gun of the soda blast. Mine is a '72

http://www.classiczcars.com/photopost/showphoto.php?photo=33694&title=soda-blasted-21&cat=500

http://www.classiczcars.com/photopost/showphoto.php?photo=33710&title=soda-blasted-21&cat=500

I experimented with a number of different techniques when removing the undercoating from my early 260. Here is what worked the BEST. First, I would "freeze" an area about 6 inches square with the "canned air" they sell for cleaning computer keyboards. It turns out, if you spray it with the can inverted, it gets cold as hell! After I froze the area, I used a needle scaler (Harbor Freight, 30 bucks), and the stuff pops off like chocolate off of an ice cream bar! I did the first half of the car with scrapers, wire brush, etc in about 15-20 hours. I did the second half using the "freeze and pop," technique in about 4 hours.

Z Greek, how many can of compressed air did you use for the second half?

HEALYALT

I had an old knife lying around in the garage somewhat like a fillet knife approx 12 to 13 inches long. I used the end of it to break the top layer of undercoat and then it was just a matter of using it somewhat like a paint scraper. I went from fron to back underneath in sections. There is a slightly tacky residue that is left which is easily removed using napthlalene (aka charcoal starter). It cleans it down to the anti-corrosive that the factory applied and then it was just a matter of sandblasting. I didn't worry about the time consuming factor because I planned to spend as much time as it takes to have no rust issues ever again.

  jimbob_racing said:

Z Greek, how many can of compressed air did you use for the second half?

I used five or six, no more than six. It was about 5 bucks a can at Walmart.