Today I pulled out both a ’58 QD carcass and a running ’58 QD to see what’s going on. Just like I expected, not much.
The ’58 midsection is designed a bit differently than the earlier ones. The web in the middle separating the two chambres is only 5/8" or so deep while the earlier ones are closer to 5" deep. This allows the hot gases to immediately flow into the shifter area after leaving the cylinder. Some of the exhaust gases travel to the bottom of the housing before coming back up the rear chambre thru a small triangular hole near the bottom. The plate at the top seals off this part of the housing forcing the gases to discharge thru a hole about the size of a nickel into the rear water exit passage and out thru the idle relief port.
After running the motor at both idle and top barrel speed for several minutes, the housing temperature in the shifter area never changed more than ten or fifteen degrees. The shift handle itself never got much more than ninety F which was about the same for everything else in the direct sun today. In other words, the housing and the shift handle were both at good operating temperatures and I wouldn’t have been able to boil water or fry eggs on either of them.
