Re: heat riser valve on exhaust manifold on 1934 1103
Posted by Owen_Dyneto On 2009/7/2 7:48:06
Somekind of control cable or other mechanism may have been attached to the heat riser to allow controlling it from inside of the car. Look for any extra holes in the dash or evidence of a bowden cable set up.
No cable or control mechanism. Do you see the two protruding threaded studs? A circular stamped steel cover with vent holes for the heat flow mounted over the circular spring and retained the end, and nuts and washers on the two threaded studs retained the cover. When the nuts and washers were loose, the cover could be rotated to adjust the tension on the bimetallic spring.
I believe this was essentially the same on the 320 and 385 engines from when they went to downdraft carburetion in 1933 thru 1939 perhaps. Here's a sketch I made of my 34 heat riser many moons ago, the cover/spring retainer detail is in the lower corner.
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No cable or control mechanism. Do you see the two protruding threaded studs? A circular stamped steel cover with vent holes for the heat flow mounted over the circular spring and retained the end, and nuts and washers on the two threaded studs retained the cover. When the nuts and washers were loose, the cover could be rotated to adjust the tension on the bimetallic spring.
I believe this was essentially the same on the 320 and 385 engines from when they went to downdraft carburetion in 1933 thru 1939 perhaps. Here's a sketch I made of my 34 heat riser many moons ago, the cover/spring retainer detail is in the lower corner.
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