Are there any external engine components that are not meant to be plated, other than the obvious tin that gets painted? I'm preparing to send of my pile-O-parts to Van Nuys. Most are nuts, bolts and washers that I plan to have done in clear zinc (i.e. silver). There are a few items that are question marks to me, and I'm not seeing a coating noted in the parts catalog:
Oil sump cover plate with magnet
Oil drain plug
Fuel lines
Fuel pump fittings
Crankshaft pulley
Case studs
Head studs
On a related note, is there a recommended thickness that I should communicate to the plater? I understand that tolerances are relatively tight, and too much coating could affect torquing.
Thank you.
1960 356 S90 Sunroof Coupe
1970 914-6
2014 Carrera S
Dennis: With zinc plating I doubt you will have tolerance problems. The old zinc plating is not clear, it is called "white zinc" and is a bit more opaque and less blue than "clear" zinc. If in doubt, run a die over the threads before install.
When you paint over zinc plating, you need to scuff it well with something, either fine sandpaper or Scotchbrite pad. I am not sure about the oil sump plate, but the rest of the parts would rate zinc plating, in my humble opinion.
I would not plate the sump cove unless you are going to R&R the magnet.
Nor would I plate (torqued) studs; there's always the chance of H-embrittlement unless they are baked.
I am not sure that Hydrogen embrittlement is a factor with zinc plating, as it is with chrome. Zinc plating is softer than the parent material. A a safeguard, one could bake the new parts in the wife's oven for 4 hours at 350 like I would.
"During Zinc Plating and Cadmium Plating, Hydrogen can diffuse into base metals making them more brittle. Some engineering specifications on particular metallic components demand a stress relieving process as a step in the electroplating service." https://heplating.com/plating-process-toronto/
Erik Thomas wrote: ↑Wed Jun 26, 2019 5:51 pm
The old zinc plating is not clear, it is called "white zinc" and is a bit more opaque and less blue than "clear" zinc.
Thanks for the heads up on this. I have read a lot of plating threads, and they all seem to use "clear" and "silver" interchangeably. Now that I look at the Van Nuys Plating site, I see they list clear, blue, yellow, black Zinc chromate.
I continue to be overwhelmed by the subtleties, inconsistency, and choice of plating. Analysis paralysis on my part at this stage.
1960 356 S90 Sunroof Coupe
1970 914-6
2014 Carrera S
Use new wave washers and use the old washers for crankcase thru bolts and head nuts. Don’t plate any of these. I plated as
I didn’t know the valve cover springs and they are fine.
Check very carefully #40 and #46. Thesee are drilled thru and also have holes in the side. If these have been tightened too much, they can break. See if the holes in the side are perfectly round. If elongated, buy new parts.