Decided it was a good time to do some prep work on the carbs. They had been painted with Eastwood carburetor paint for over 20 years and actually looked OK, but decided they needed to be finished correctly. Stripped the paint and now they're down to bare zinc edit... make that aluminum. Always thought these were a zinc alloy but looks like they're actually aluminum.
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So, started looking for pics of IDAs, and found many that looked like zinc with no passivation, some were a deep golden dichromate, and some were a lighter shade. Does anyone know how these would look as new from the late 60s, early 70s?

Dan

Here's a link to a YouTube video showing an over the top restoration of triple barrel Webers. Hope this helps. https://www.youtube.com/watch?v=UXRW_9-DyAY

Mack

Alodine is the correct method. Used primarily in aviation

Very nice video Mack. Thanks for sharing the link. I'm more interested in the "correct" metal plating the carbs would have came with. Looks like in the video it's left bare. Maybe he said, but I didn't listen to it all, just skimmed to see if he did any type of plating.



Ben, from the bit of plating research, I thought alodine was mainly used on aluminum? I thought the Webers would be a zinc based alloy, maybe containing some aluminum, like zamak. Most zinc based carbs seem like are plated using blends of dichromates, at least from what I've researched. Are you sure specifically about these carbs? I'd love some references to find out exactly what I'm dealing with.

Thanks,
Dan

You may want to watch Klassik auto training school on YouTube. Kurt goes over the finish. I can't remember his process on redoing them. You could also ask Paul Abbott from performance oriented.

Thanks for that! Unfortunately in the Klassik vid on carbs, looks like he is only cleaning, not performing actual plating, and sounds like he'll likely use cerokote from what I heard. Talks like he'd send parts out for plating, or did until prices became too high. He also refers to the carbs as being aluminum, but I'm about 80% sure these things are a zinc alloy, not just aluminum. Oh well.

Dan

I think there are some references to them being die cast aluminum in Haynes or The bird - saw that somewhere. But like you, I’ve assumed they have some zinc content since they often get chromate coating by various restoration outfits. Die cast parts with Al / Zn alloy are not uncommon.

I’ve never had a new set of NOS IDAs in my hands but I’m sure my new Italian made Weber IDFs were not yellow chromate. To me it seems the castings were probably left raw. If anything was in there it was very light / clear and didn’t resist the casting turning a dark gray over about a year time. Can’t imagine they were doing anything radically different for IDA3C’s. Almost any picture I see of them is a silver / gray body.

Thanks for the help Superhawk. Yes, I also see some references saying they're aluminum and some saying they're zinc allow. I wish there was an easy test, but I don't want to file any part off just to do an acid dip test, and I can't really use weight as a means either since I'd be guessing. Starting to wish I'd just left them painted with that tacky looking carb paint from Eastwood.

Dan

Noooooo! They look great right now - raw. I’m 1000 % sure they weren’t painted - LOL

Was going to suggest this but everyone is against paintClick to view attachment

I may just do that. Agree they do look good bare. Even though this is only a planned six conversion in a '74, just kinda wanted the carbs to be, well, correct. Hey, all this talk about fuel injection lately has be thinking I need to go with some ITBs and a megasquirt or something anyway, so probably just overthinking it.

Dan

The good stuff! and it is lacquer so should be fairly fuel resistant.

Dan

I just picked up a pair of bare idtp bodies and will probably just try soda blasting them on the outside to bring back the cast finish. Theyll probably oxidize again over time but at least theyll be clean during the rebuild.

Finished my last two sets with Gibbs... I've had NOS Webers for both BMW and Porsche, and as far as I could tell there was nothing on them but maybe Cosmoline. That will go amber over time.

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This is kinda like fan finishes... dozens of opinions on what's correct, but the simplest answer is probably the right one.


YMMV

Sounds like the consensus is for bare finish. Thanks for the input.



Russ, always impressed to see your work and appreciate your input. At work I was a big believer in the KISS principle, and thanks for the reminder it applies here as well. And thanks for the reminder my Gibbs supply is running low, time to order some more.

Dan

here are images from the Abbott site.
seems like a guy who tries to get things really nice
many more photos of each on his site

http://www.performanceoriented.com/index#/...c-for-1970-9146

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Yes positive. Paul abbott and I discussed it extensively. I bought some from aircraft spruce but just never used it.

Thanks, Dan... FWIW, the top image is of the engine from my '67S, original matching carbs rebuilt by Paul. Bottom is of my old 6, built by Bruce Ellsworth. Gibbs on both.

Also agree with Ben, Alodine is correct.

Thanks for that. These illustrate why I'm confused in the first place. Some look bare and some obviously passivated. The IDAs they show look bare, so yet another example to keep them unfinished.



Thanks Ben. I was really thinking these things were a zinc alloy, but guess I was wrong. It helps make the decision to leave them unfinished easier. I've had enough fun getting up to speed with zinc plating and don't feel like diving into aluminum with zincate, alodine and all that stuff just yet.



Beautiful engines Russ. And it sounds more and more like the carbs are aluminum after all.

Dan

Just had these restored …

Beautiful! These definitely look like a light touch with a coating process. Look really nice like that. Thanks for showing.

Dan