So whats it for?

35ragtop

35ragtop

Senior Member
Hi guys,
I took this fitting out of the exhaust system (LHS below the manifold) on my 48 Mercury. I would like to know its correct purpose please. To me it would seem that it is for some cold weather purpose but in our climate it would be of no benefit. The car is ex California in recent times.
I look forward to your opinions. I couldnt find any reference to it in my parts book.
thanks
Dave
 

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That is a heat riser. its function is to cause enough back pressure to force more of the exh. gas through the intake manifold crossover to help heat the fuel during cold weather to help atomize the fuel, so that it ignites easier for cold weather drivability. yours is missing the spring that opens the valve as it heats up and reduces the back pressure. when it is cold, before the engine is run, the valve is normally closed. hope that this explanation makes sense to you.
 
to add to what is written it is missing the spring that fits on the outer portion.they are (were) handy if you live in a humid climate as they helped with warm up and kept (keep) the moisture from freezing in the throat of carb while engine warms up.later years used a pipe from the manifold to do a similar thing.common until F.I. came along
 
54vicky said:
to add to what is written it is missing the spring that fits on the outer portion.they are (were) handy if you live in a humid climate as they helped with warm up and kept (keep) the moisture from freezing in the throat of carb while engine warms up.later years used a pipe from the manifold to do a similar thing.common until F.I. came along
Click to expand...
Obviously in your state of exuberance, you failed to read post #2 above :confused:
 
Thanks fellas,
I knew that the answer would be here on this site.
I definitely dont need to warm anything up in our climate. It will make a nice conversation piece on the bar top.
Merry Christmas
Dave
 
Dave you might want to modify that to help the dist stay warm and run in deep water.LOL
Lawrie
 
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