Finish on inspection door machine screws

[AZ-240z]

Need some verification of originality trivia. The two inspection doors on the 240z are secured by 5MM machine screws. I believe the car came from the factory with these machine screws unpainted and in clear zinc or cad. and were mounted to the car after paint was applied to the doors.

Can anyone with an unmolested 240z substantiate that these inspection door machine screws were unpainted? The same thing is true for the rear deck hatch, which is fastened to the hatch hinges with four unpainted flat head phillips machine screws, since the hatch was painted separately and assembled to the car after the finish was applied.

Thanks for checking.

Dan

Original Owner/hls30-20419

[Arne]

Dan, the inspection cover screws were painted body color on mine. As best my painter and I can determine, it was original paint until I had it painted a couple months ago. Build date 7/71, 905 red.

[Zak's Z]

When i stripped all the PO's previous paint on mine, my inspection lid screws were also the original orange color of the car. I clearly remember it was awkward trying to get all the paint off of that area.

[AZ-240z]

Arne, Zak,

Thanks for your speedy replies. My car had been repainted maybe 20 years ago, and, as I wasn't into totally correct at that time, couldn't remember if these little machine screws had factory paint when new.

Thanks, again, for helping to clarify this.

Dan

[26th-Z]

Dan,

It took me forever to find this thread again! I took your question to Cleveland this past week and looked at several "original" cars. The inspection lid screws were painted and the tapered screws used to attach the hatch to the hinge is unpainted - finished in a super light cad yelow finish, almost silver zink.

Chris

[AZ-240z]

Chris,

Thanks for taking this to Cleveland to verify the finish on these screws. Wish I could have been there to pour over probably some very nice and original cars.

In one of my earlier inquiries, Carl was good enough to tell me why the hatch to hinge machine screws were unpainted, and now, due to your diligent efforts, this has, once again, been verified. The screws for the hatch that I got from Nissan were not tapered, though, just flat, countersunk, phillips headed screws with no noticable yellow in the finish, just silver.

It is interesting that you noted that the cad finish was a super light yellow finish. My Nissan parts supplier, ( and he pays attention to these early 240z parts), had mentioned to me that the original yellow cad finish on the correct parts numbered hardware for our 240z cars is being supplied by Nissan, now, with a clear, or silver cad finish. In fact, when I bought a box of machine screws with the correct part number to fasten the center and two corner front valence panels together and to the front fenders with those clip-on capture nuts that Kats profiled on his web site, the machine screws, also, had a verrrry light yellow cad finish instead of the more yellow finish used on the original capture nut clips used with those screws.

Trivial, maybe, but VERRRRRRRRRRY interesting.

Dan

[26th-Z]

Dan,

Cleveland was my first "digital" automotive outing. I bought a little Canon powershot A590 and didn't lug the film camera equipment this year. I wasn't real sure how to use the buttons and features completely. Sorry I didn't take any pictures of the fasteners.

I did manage to take some shots during a conversation we were having about original finishes and I think they turned out nicely. These two unruley characters were examining the paint and chrome finish on the 1973 240Z. Notice the very faint orange peel finish and the plating quality of the chrome bumper. These "as original" finishes are not so common. Re-chrome work today is highly polished with few, if any, undersurface blemishes. In comparison to the blue paint on this example, there was a black 240Z at the show that had the most remarkable mirror quality paint finish.

[AZ-240z]

Dan,

I did manage to take some shots during a conversation we were having about original finishes and I think they turned out nicely. These two unruley characters were examining the paint and chrome finish on the 1973 240Z. Notice the very faint orange peel finish and the plating quality of the chrome bumper. These "as original" finishes are not so common. Re-chrome work today is highly polished with few, if any, undersurface blemishes. In comparison to the blue paint on this example, there was a black 240Z at the show that had the most remarkable mirror quality paint finish.

Well, I'll cut these characters, along with you, Chris, a little slack and assume they may know a little something about these early car's subtle nuances.

I've seen some NOS bumpers, and, as has been observed in past threads, the chrome has what appears to be brush wheel marks under the chrome and not nearly the depth or luster as new, three strike chrome.

But, they are NOS perfect inside and out and I am thinking for total originality, they would be more highly prized by the restorer, as would be the single stage paint with the factory orange peel appearance.

Any thoughts on original vs. restored on NOS parts and finishes as seen through the eyes of a collector's or restorer's preferance? I am thinking of hanging all NOS chrome bumpers and overriders and would like opinions.

Thanks for the great pics, Chris. More, please, with all the little details.

Dan

[26th-Z]

I took a couple of pictures of the early fuel door knob. The plastic one. I'm goingto look for the thread on fuel door knobs and post the pictures there.

[Carl Beck]

Chris,

It is interesting that you noted that the cad finish was a super light yellow finish. My Nissan parts supplier, ( and he pays attention to these early 240z parts), had mentioned to me that the original yellow cad finish on the correct parts numbered hardware for our 240z cars is being supplied by Nissan, now, with a clear, or silver cad finish. In fact, when I bought a box of machine screws with the correct part number to fasten the center and two corner front valence panels together and to the front fenders with those clip-on capture nuts that Kats profiled on his web site, the machine screws, also, had a verrrry light yellow cad finish instead of the more yellow finish used on the original capture nut clips used with those screws.

Trivial, maybe, but VERRRRRRRRRRY interesting.

Dan

Hi Dan:

Bare steel parts, when electroplated with either Cadmium or Zinc have a dull gray to dull silver appearance. Cadmium offers about three times the durability of Zinc in terms of corrosion protection. Both Cadmium and Zinc are sacrificial coatings.. that give themselves up to protect the steel from corrosion and thus prolong the life cycle of the original part.

So why use Zinc? Cadmium is a heavy metal, and listed on most of the worlds "Restricted Substances Lists" by the various environmental protection agencies around the world today. About the only plating companies that can supply actual Cad. plating services - are MilSpec. vendors and they are usually far more expensive to deal with. All the government controls/regulations etc on the handling of the Cad. plating solutions add a lot of cost to the process, as well as liability to the vendor in terms of physical harm to their employees from exposure to heavy metals.

To either Cadmium or Zinc plated parts, a farther protective finish can be applied to forestall oxidation of the Cad. or Zinc ( oxidized zinc plating will turn an unsightly, sticky, white salts appearance). This is done by dipping them in a chromate/dichromate bath. The chromate/dichromate (either are the same to the platter - as the process and result are the same, although there are very slight differences in the chemical make up).

Chromate coating can be clear or a number of different colors. In the case of the original parts produced back in the 60's and early 70's for our 240-Z's, the bright yellow or gold appearing parts were bathed in a Yellow Chromate bath. That yellow chromate bath was a Hexavalent Chromium. That (hexavalent) chromium is today also being banned by most EPA's around the world... and instead a trivalent chromium is being used (that is what was always used for clear chromate coatings). The bad news is that the hexavalent chromates are far more durable than the trivalent chromiums, or other modern substitutes.

So... the bright yellow/golden parts that you used to see on the 240-Z's when they were produced.. the one's that look like they have a bit of oil on them, that reflect the deeper blue, yellow, gold, red hues.. were most likely Cadmium plated then bathed in a Yellow Chromate bath. All done to very high quality controls over the process and chemicals. That can still be done - but very few platters offer the service, and it is expensive relative to Zinc with the newer trivalent (or other newer chemical processing) yellow chromate.

Yellow Zinc as it is commonly called - can be made to look very much like the original Yellow Cad... but only with strict attention by the platter to the chemical mix and process used. Most of the time Yellow Zinc plating lacks that original rich luster found on the original parts... it's close and most likely close enough for most .... but many of us noticed the subtile difference upon close examination or in the sun light.

The original Zinc plated parts - that look gray/silver were also bathed in a clear chromate solution.. they still look gray/silver, but after several years you can see a slight yellowing of the original clear coating. The guys in the materials lab tell me that is a sign that the original chromate coating is reaching the end of its lifecycle.. They also tell me that one can not stress highly enough how important quality control of the chemical solutions and the entire plating process is - to the end result, in terms of finish and durability. Likewise the quality of the part you start with...

FWIW,

Carl B.

[Zulaytr]

AZ240 wrote:

Any thoughts on original vs. restored on NOS parts and finishes as seen through the eyes of a collector's or restorer's preferance? I am thinking of hanging all NOS chrome bumpers and overriders and would like opinions.

Dan,

I recently had a chance to through the Auburn, Cord and Duesenberg Museum in Indiana and I found the attached poster asking that same question about which is better. I hope you can read it but if not it basically says that you only have original once and that in many cases a restored car is really "over" restored as compared to how it came out of the factory. The comments about the bumper finish are correct in that the originals do have waves and a less deep chrome finish than what you get with a re-plated one. I know a chrome plater in CA that would ask, especially if you are a Corvette owner showing in the NCRS, how do you want it finished?

Take care and I hope you are enjoying your fine Z.

Regards,

Bob

[AZ-240z]

Dan,

I recently had a chance to through the Auburn, Cord and Duesenberg Museum in Indiana and I found the attached poster asking that same question about which is better. I hope you can read it but if not it basically says that you only have original once and that in many cases a restored car is really "over" restored as compared to how it came out of the factory. The comments about the bumper finish are correct in that the originals do have waves and a less deep chrome finish than what you get with a re-plated one. I know a chrome plater in CA that would ask, especially if you are a Corvette owner showing in the NCRS, how do you want it finished?

Take care and I hope you are enjoying your fine Z.

Regards,

Bob

Bob,

Thanks for taking the time to offering your resource information and observations. This has been my feeling about authentic value. You can never duplicate the real thing, even though the original finish may be inferior to todays standards.

I'm am enjoying the car and process of making it more original, piece by piece.

Always enjoy hearing your thoughts, Bob.

Dan