Pmb performance

[jk356]

I am excited to finally have my s calipers back from pmb performance
They look exquisite.
I especially want to acknowledge the hard work of Marquis Burgess for seeing this project thru until it’s completion.
Jeff k
1971 911s

[Jim Morris]

When did the plating color change from #2 (gold iridescent) to #1 (clear zinc)? I remember a technical comment from Eric at PMB stating that from the very beginning the calipers made for Porsche were gold (split the halves to prove it, if the caliper finish has degraded (sacrificed) from gold to silver from loss of the yellow chromate). So, was there a year where the factory color was changed?

[davep]

When did the plating color change from #2 (gold iridescent) to #1 (clear zinc)? I remember a technical comment from Eric at PMB stating that from the very beginning the calipers made for Porsche were gold (split the halves to prove it, if the caliper finish has degraded (sacrificed) from gold to silver from loss of the yellow chromate). So, was there a year where the factory color was changed?

Not applicable to these S calipers which are anodized aluminium. I have two NOS S calipers, early & late, and both are natural aluminium color.

[jk356]

And installed

[jk356]

Installed again

[Jim Morris]

Ah yes. Aluminum of course would be anodized, not zinc plated, and apparently they went with a silver anodize rather than a gold version. My mistake missing that they were aluminum, not cast iron. Thanks for setting this right. Car is going to be extraordinary.

[jk356]

also thanks to tru6 for the beautiful plating

[Neunelfer]

Thanks Jeff, glad you’re happy with the calipers and more importantly Marquis. She works hard to keep people happy.

Here’s a quick rundown on S-Caliper history:

1969 - Basic 908 style casting. “Clear Anodizing”. No forged circles in the top. Notches cut for pins.
1970 - Same as above without the pin notches. Forged circles came along later with no “X” in them.
1971 - Same as 1970 with “X” stamped in the forged circles.
1972 - Same as 1971. Dichromate finish showed up in the later 2/2 of the year.
1973 Onward - Remainder of 72 models used up and the new “beefier” forging was used.

We can only theorize that the dichromate finish was added to aid in small part to potential corrosion issues and a demand to make the calipers a more uniform color front to back. It is my thought that the same dichromate was used for the anodized calipers as the one they used on the steel. Original steel calipers were “not” a shiny deep gold finish you see in most platers work these days. As an industrial process it was rather quick and rudimental.

Hope that helps.

E.

[ejboyd5]

I know the monotony of a production line (even Porsche) would not have suited me, but I often think how nice it must have been to work with new parts, with nuts and bolts that had not yet had their edges rounded over, and with fastenings that had not become recalcitrant through corrosion. Nice pictures.

[Alan.uk]

Hi, here is what we do for the 72 on S front calipers.
Before that we anodise them.

https://www.instagram.com/p/B_SuvqGF...=1lvef0eopsaqp

Sorry I can’t post a direct pic.
Thanks
Alan