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Exhausting questions
https://www.slantsix.org/forum/viewtopic.php?t=66461
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Author:  and739 [ Mon Feb 14, 2022 11:16 am ]
Post subject:  Exhausting questions

I have a couple of question pertaining to stock, cast iron exhaust manifolds.
First, what's the purpose of the tiny spring on the rear side of the heat riser valve? I'm not talking about the one behind the counter-weight that closes the flapper valve, I mean the one on the opposite side that rides on the flapper valve shaft and the small pin that runs parallel to the shaft. I've seen one on every slant six exhaust manifold I've had my hands on, it just seems that this little spring doesn't really do anything, it's just along for the ride.
Second question, exhaust manifold outlet flange to exhaust head pipe mounting studs, I'm familiar with the 7/16" studs that screw in to accept a gasket, the head pipe flange and nut. Is there another fastening option for this connection? I have one exhaust manifold with smooth, drilled holes that are larger; a 7/16" thread tap slides right in. I wasn't sure it there was a through-bolt mount on some applications, or if maybe this one may have been drilled out sometime during its existence.
Thanks for sharing your thoughts and experiences.

Author:  volaredon [ Mon Feb 14, 2022 3:31 pm ]
Post subject:  Re: Exhausting questions

either way works, thru bolt or stud and nut. I wouldn't lose any sleep over it. The thru bolt/nut is more forgiving, if it breaks off when taking apart, "so what". if the stud snaps (or strips) it would be more of a pain to fix, especially from under the car.

Author:  and739 [ Tue Feb 15, 2022 7:26 am ]
Post subject:  Re: Exhausting questions

Thanks Don. That's what I was thinking too, just never seen another one like that and am curious about it's origin.
Have you got any ideas about that little spring?

Author:  Killer6 [ Tue Feb 15, 2022 9:07 am ]
Post subject:  Re: Exhausting questions

It's there to prevent the shaft from rattling/ticking once there is no tension from the clockspring to dampen it.

Author:  SlantSixDan [ Tue Feb 15, 2022 9:25 am ]
Post subject:  Re: Exhausting questions

Quote:
I have a couple of question pertaining to stock, cast iron exhaust manifolds.
First, what's the purpose of the tiny spring on the rear side of the heat riser valve?
Anti-rattle.

Author:  and739 [ Tue Feb 15, 2022 11:08 am ]
Post subject:  Re: Exhausting questions

And now I know.
Thanks, everybody for your responses!

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