On the 914-6 a couple intake manifold questions:

1. Would the same manifold be used for Weber IDTP and Zenith 40-TIN? They ones I took off our car had Zenith 40-TIN on them. I'm wondering if I can use the same for correct Webers. One version of the listed part numbers seems to match 1970 911 where Zenith were used. That seems promising.

2. Were they originally black? I've seen some restoration videos where people powder coat them black. Including the inside. Ours appear black. That said, I think they are magnesium. Why would Porsche paint these?

Thank you.

Photo as found on engine.
Click to view attachment

Stock -6 factory engine picture

I had not seen that photo. Thanks. Those intake manifolds appear black to me.

I had thought the upper valve covers were black?! The ones I took off our car were, and given their condition I assumed they were original. Perhaps not.

Dennis - here is a good thread on these for reference, including some part number decoding:

http://forums.pelicanparts.com/porsche-911...-manifolds.html

to your questions:

1) Same manifolds can be used for Zeniths or Webers (40mm). Some variants have vacuum ports drilled so be careful to block those off if not used

2) Check the attached article, but most were coated from the factory with some form of black sealant - presumably to prevent the external surfaces of the magnesium corroding; however, I have never seen the inside runners coated - I would not trust any powder coat exposed to gasoline to NOT flake off and float gently down to the inlet valves....!

Hope this helps,

- Tony

Yes, black.
The Zenith question is interesting. Compare the part numbers of '70-'71 911T
manifolds to 914 6 manifolds
The intake ports on a 2.0 911 T (same as a 914 6 2.0) the same as a 2.2 911 T ?

That's an interesting thread. Thanks Tony. I will check the part numbers on ours.

I did some more checking about the coating. Your logic makes sense to me. That said, Kurt from Classic Kats and Mike from Pierce manifold recommended powder coat. I don't have a better thought other than perhaps leaving them as they are.

For what it’s worth I’ve seen the coating on the inside.

I’ve also heard it was done to keep the side of the runners smooth improving airflow and keeping fuel from coming out of suspension when moving along the walls and better atomized.

I have a pair of manifolds I stated to refurbish. I can say that that coating is tough, very hard. Doesn’t come off easily with Glass bead. I eventually stepped up to Aluminum Oxide, even then, it took me at more time and effort than it should for something like paint.

I read but can’t point to link on the bird that it was some sort of early baked on teflon type coating. Honestly I don’t know what it was but it sure doesn’t come off easily!!! Whatever Porsche had put on there - they spent money on it and I can’t imagine that being done without reason.