I am rebuilding my SU HD8s right now and fully dismantling them to have the hardware plated. I don’t ever plan to have my car judged but I still try to be accurate where I can be unless it’s a modern equivalent or better product… I was planning to do a clear zinc for the carb hardware and nickel for the fuel delivery and linkages. What were the original plating for these parts? Can I plate the small brass linkage/arms on the carbs with nickel or zinc? I don’t have much knowledge plating brass and was just curious. I’m guessing the original brass finish was cad plated, linkages were painted and small screws/hardware were nickel or cad?
Also, there is a “skid washer” in the exploded view that is missing from my set. It sits under the large spring that returns the piston. I figure it was either lost in the history of the car or my 1967 model year HD8 is a different rev carb. Is this part needed- it isn’t available from SNG barratt.
Every SU I have worked with had that washer (easy to lose when you dump the oil out of the dashpot) but I do not know how important it is. If I needed one I suppose I would be looking to a carb parts supplier such as Burlen or Curto.
Hey Ben,
I’m pretty sure that if you do a word search on the Judging Guide for Etypes on the JCNA website, you will only get a hit on cadmium and not on zinc or nickel. So what I am doing with my current restoration is getting everything done in clear zinc, as the non-concours economical alternative to cadmium. Mostly so everything will look consistent. Also, nickel will dull over time unless you keep after it with polishing. Which is why they plate polished nickel with chrome!
So you may already know but Industrial Plating in Gastonia, NC is the best deal in the world for clear zinc plating. I got everything in the engine compartment (90+ items) plated for $150. There’s a picture in my most recent blog post. To get that price, everything needs to be bead blasted in advance and in good condition, since they basically take all your parts and plate them, regardless of condition. They did reject the door strikes since they are “pot metal” and would have been chemically attacked by the zinc plating process.
I’m pretty sure brass can be plated no problem. That said, I’ve seen restorations where the brass on the SUs was left as-is, polished, and it is a nice look IMHO.
I did the linkage arms and rods and fuel rail and fittings in nickel. Most of the original plating was worn off the brass arms so I brushed off the remaining and polished them. I decided to leave them plain brass and they look surprisingly nice still 18 years later. But yes you can do them in zinc. They were cad plated originally. I would not do them in nickel as it’s a comparatively thick coating and would cause things like the choke rod to not fit in the carb.
I asked about that skid washer when I was rebuilding mine and no one knew what it was. I suspect that it’s a mistake in the drawing as no one described such a part. IIRC it didn’t appear on the list of parts on the Burlen UK site.
I think that the skid washer is fitted to carbs with tapered piston springs. The parallel springs don’t use them. The tapered springs tended to twist–therefore the need to let them skid on the piston top. IMHO.
Erica. It is not a phantom part. Years ago I bought a set of triples from a 3.8 mark 10 and lo and behold there were 3 brass? Skid washers under the springs. I put them in my 3.8 fhc just because they seemed so cool. Don,t think they serve any purpose but they may provide slightly increased spring pressure by taking up a small amount of space. They did make the car go much faster:grinning:
You can do them in Electroless Nickel. I have a solution which I use for doing a quick plate on small stuff like carb brackets and fasteners. After cleaning they only need about 15 minutes in the bath. This adds only a thin layer, so fit isn’t affected.
I have in front of me a drawing from the S.U.Carburetter Co. Ltd that covers the setup on the 150S that states finish-all exterior brass and steel parts( except throttle spindles & accel needle) to be cadmium coated. The above is from the archive of George Camp who was ,in all likelihood, the person most knowledgable about Jaguar related subjects that was ever a member of this forum!
Thanks for the incite everyone! I think I have a game plan now and I’ll tune the carbs without the skid washer unless the spring is digging into the body.
