Case through bolts - what's the original finish?

[Jameel]

I've seen the threads where folks are doing yellow zinc on them. Or sometimes just on the acorn nuts and washers. Others I've seen where the heads are dark, like black oxide. Others I've seen are bright (perhaps clear zinc?) The ones in Wayne's rebuild book just look like he cleaned them a little and reused them. They certainly don't look replated.
Obviously they can be plated, and I've read some of the threads about yellow zinc and cad.

Question #1 How did they come from the factory? The heads on mine ('83 SC--believed to have never been apart) had a dark surface with very light rust, with the nuts and washers a sort of dull gray, with a hint of yellow on the nuts.

Question #2 If I don't send them out for zinc plating, what's another good option?

[Shaun @ Tru6]

We've done customer's sets in both black phosphate and yellow zinc.

First is black phosphate with yellow cadmium acorns and second set is all yellow zinc.

[juanbenae]

[Jameel]

Nice looking parts Shaun. We do some parkerizing on some of our products. Have you ever parkerized the washers and nuts as well? Any reason not to other than aesthetics?

[Tippy]

Good job guys of NOT answering the OP's question...

[bigel]

OP doesn't seem to mind...don't be a Ricardo...

[Jameel]

Originally Posted by bigel

OP doesn't seem to mind...don't be a Ricardo...

Well, I'm not going to complain about the response from Shaun, since I found it useful, even though it was a bit off topic. The other response I'm still trying to figure out. Yellow zinc parts on a bench? Unless those are NOS parts, doesn't tell me much.

But yes, I'm still interested in finding answers to my two questions.

So, anyone know what the original finish was?

[db_cooper]

Originally Posted by Jameel

I've seen the threads where folks are doing yellow zinc on them. Or sometimes just on the acorn nuts and washers. Others I've seen where the heads are dark, like black oxide. Others I've seen are bright (perhaps clear zinc?) The ones in Wayne's rebuild book just look like he cleaned them a little and reused them. They certainly don't look replated.
Obviously they can be plated, and I've read some of the threads about yellow zinc and cad.

Question #1 How did they come from the factory? The heads on mine ('83 SC--believed to have never been apart) had a dark surface with very light rust, with the nuts and washers a sort of dull gray, with a hint of yellow on the nuts.

Question #2 If I don't send them out for zinc plating, what's another good option?

#1..As I recall the hardware OEM was parkerized..it was better than nothing but would rust in a few decades. yellow dichromate was used too on nuts and washers.

[Shaun @ Tru6]

Jameel, I can't say with 100% certainty, but I think the original case bolts were simply black oxide, early ones anyway. I say this because I've never seen any evidence of any type of plating on motors I've pulled apart. Or on customer bolts sent in to be redone. We use black zinc phosphate because it lasts longer though isn't close to zinc chromate.

If you wanted a factory look that would last a very long time, I would opt for black zinc chromate.

I know that SWB fan straps, early front torsion bar adjusters and brake line holders were black zinc phosphate as well as early lock, wave and Schnorr washers. We always buy new and replate for customers...I consider them one-time-use only items, no sense in putting your car back together with worn out washers. Front hub bearing caps and shift rods are grey zinc phosphate.

Washers and nuts were yellow zinc so that's what we do, or yellow cad.

[winders]

I'll add more to thread....

I had a case thru bolt break on my 964 3.6L race motor. It happened to be one that kept oil in the case. What a mess considering I had over 4 gallons of oil in the oil system. Anyway, the engine builder and I discussed it and decided to replace the broken case thru bolt with an ARP thru bolt. When the engine was rebuilt, the rest of the engine's thru bolts were replaced with ARP.

Problem solved....

[yelcab1]

Originally Posted by winders

I'll add more to thread....

I had a case thru bolt break on my 964 3.6L race motor. It happened to be one that kept oil in the case. What a mess considering I had over 4 gallons of oil in the oil system. Anyway, the engine builder and I discussed it and decided to replace the broken case thru bolt with an ARP thru bolt. When the engine was rebuilt, the rest of the engine's thru bolts were replaced with ARP.

Problem solved....

that must have been quite a bill !!!

[winders]

Originally Posted by yelcab1

that must have been quite a bill !!!

Which part?

[Jameel]

Thanks for the further info Shaun. Good to know.