Unknown item threaded into exhaust manifold

[Bill3747]

Trying to identify this item that is screwed directly into the exhaust manifold.  This is on a 1947 Buick Special straight-8.  I saw one of these in pictures of what if I recall correctly was a 1940 Buick coupe a year or two ago.  It was for sale on Craigslist I think in either Findlay or Lima OH.   I have no idea if this is unique to Buick, but I listed it on the Buick club forum and have had no luck.  The larger diameter tube is threaded into the manifold and the smaller diameter tube is solidly attached to it at its lower end and clamped at the top.  The round cap like piece at the top doesn't remove with a fair amount of pressure and I didn't want to risk breaking it without identifying it.  There are no external attachments to this and don't appear to even be any places where something would be attached.  It was suggested that it could be some kind of exhaust whistle, but it seemed kind of odd to me that it would be screwed right into the manifold and if that was true how would it operate.  Also, I am not able to see any type of identification markings on it.  Thanks for any help you can offer.

Bill

 

[lump]

Stumped me. 

 

When I first read the headline, I expected to find a photo of a whistle or other sound-making device. Don't recognize this as that, though. Then I suspected some kind of device for transferring engine heat to the passenger compartment. But that doesn't look right either. I'll be interested to learn what this is. 

[jimkf]

The device pictured was supposed to allow into the exhaust manifold thru a butterfly valve under the cap as the exhaust pulse went by. This was supposed to improve mileage by reducing the fuel pulled out of the cylinder during cam overlap.

 

Did they work? Who knows...some folks swore by them...other at them as being snake oil.

 

I saw one for sale on ebay a while back and it was made by Clear-Ex.

[billorn]

1 hour ago, jimkf said:

The device pictured was supposed to allow into the exhaust manifold thru a butterfly valve under the cap as the exhaust pulse went by.

 

 

Allowed what into the exhaust manifold? Birds? Rainbows? Fairy dust? Dont keep us in suspence I am dying to know!

 

[Guest]

 Yes, the critical word seems to be missing!

[Bill3747]

Thanks jimkf for the info.  I have to say though that I'm having a hard time understanding the concept.  I might be making a wrong assumption but it appears that air would be drawn in through the valve by vacuum.  How that would actually reduce fuel consumption is unclear to me.  Hopefully I'll eventually find more information on this thing. I'd like to know if the top cap is removable and if it could be disabled if I wanted to.  I really don't want to risk breaking it and I'd prefer not to remove it.  As prone as straight-8 manifolds seem to be to cracking I'd just as soon not remove it and try to install a plug.  

 

 

 

 

 

[jimkf]

Yes, I did miss a critical word...air. As the exhaust valve cycled, it drew air into the manifold which was supposed to reduce the amount of unburned fuel being sucked out of the combustion chamber. I have no idea if they really worked.