930 Manifold Questions - cleaning and plugging vacuum Y

sigchuck · 01-11-2022, 07:51 AM

Hi guys, I have a factory 930 manifold that I'd like to clean up. It's in great, relatively original condition - just has some dust from sitting and carbon buildup. It's still wearing the factory finish (annodized??), and I'm not sure what might be best for cleaning it. Soap and water seems safe, but wasn't sure if anyone had actual experience with carb cleaner, Berryman chem tool, etc.

Also, I don't have any need for the large vacuum Y fitting that is coming off of the front (rear of car) driver side of the manifold. Any idea what might work best for plugging this hole/keeping it air-tight? The fitting is loose but I don't think the hole is threaded. Would JB Weld or some other epoxy adhere to the magnesium - I'd obviously like to avoid the engine ingesting anything that might come loose!

Thanks for the help!

donbecker1234 · 01-11-2022, 10:12 AM

IIRC I used the Simple Green Aircraft in a large tub and let it soak, seemed to clean it pretty well.

T77911S · 01-11-2022, 10:45 AM

I pulled it out and used a carriage bolt (something with a round head) and epoxyed it in.
you can paint it black but I had mine powder coated after.

TurboKraft · 01-11-2022, 03:47 PM

We machine an aluminum plug for that hole when the Y-fitting is removed, epoxy it in.

Or tap it for pipe thread.

reclino · reclino's Garage

I cleaned mine carefully with some fine grey scotch Brite. The manifold is magnesium, your not going to be able to finish it like the factory did. After getting mine as clean as possible I painted. And baked on VHT brake caliper satin black paint. I think I lightly soda blast all the white deposits off before the paint.

Page 12 of my thread I did the manifold.
"Barn find" 1986 911 turbo

pkabush · 01-12-2022, 03:15 PM

I spent countless hours hand sanding out all the casting lines and imperfections.
Can’t recall if I went to 320 or 400 grit and then Gibbs oil. Being magnesium it gets dull pretty quickly. Which I prefer over super bright.
I’d look into a blasting media if you want to keep it factory. Maybe soda?
I couldn’t find a plug in the correct size so I ended up buying a oversized brass plug and chucked it up in my drill press to turn it down to size before epoxying it in.
Chris’s turned aluminum plug would’ve been way easier and it probably has a closer expansion rate to magnesium. Not sure it matters much in this application though.