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Discussion Starter #1
Hello together,

the big manifold of my 1300 GT optically seems to be broken from the outside, but from the inside it looks ok.
What do think. Is it broken?

WP_20141022_047.jpg

WP_20141022_048.jpg

Antoher question. What kind of manifolds are these, because the have those screws on it?

WP_20141022_052.jpg

Thanks in advance and kind regards,
Tom
 

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Tom, very difficult to tell from the photo's. It could be just a simple casting flaw, or the beginnings of a crack, that hasn't yet gone all the way through.
Suggest you give it a very good clean up , inside and out around the said area with a rotary wire brush, and see if it shows anything else up.
Steve
 

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I had a similar situation with my manifold.
It was the beginning of a crack.
What I did was to use a file to deepen the crack and welded it with special cast iron electrode.
This happened 5 years ago and manifold is stil strong and solid.
 

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Discussion Starter #4
Thank you both!
I was also asking me the question if this is a casting flaw!?
But as you both say, it could also be a beginning crack.
I think at first I will clean it and then try to grind the location a bit down, in order to see how deep the crack goes.

Best regards!
Tom
 

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That's a crack. The metal here is quite thin so they often break just there. It's on No. 4 where the pipe is relieved to allow a spanner in onto the nut isn't it?

The screws are present on some manifolds and not others. Suggestion is that they're ports to fit a "sniffer" in to check exhaust mixture on individual cylinders but I suspect that these thing may pre-date that technology!
 

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Tom:

Alas, I concur with Mound Dawg; it's a crack. The good news is that you may have caught it early enough for it to be repairable. The correct procedure is, as Stephen states, to file (or Dremel grind) the crack away before welding. The edge of the crack creates a stress concentration. If you don't remove it before welding the crack will probably come back.

It's been a long time since I've seen one, but my (very dim) recollection is that some cars had heat shields attached with those mystery screws.

Good luck with it!
Bob Stewart
73 GTV
 

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Discussion Starter #7
Mound Dawg, Stooie, thank you both for your estimation!

Concerning the screws, I also think they seem to provide a "port" for getting access to the exhaust gas flow.
They are the reason why I´m thinking about repairing them. On the other the hand I could get some used ones in good condition for around 70€.
 

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Regarding the plugs, looks like the ports for the air injection manifold from the air pump on a mid-seventies US car. I have the same exhaust manifold on my '77 Spider.
 
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