Re: 1950 327 with Ultramatic - Idle Speed

Posted by HH56 On 2023/2/3 20:12:18

Don't have an answer to why the idle is increasing so much but 650-700 is a bit too fast. Was the adjustment made when engine is warm and the carb fast idle is not in play? Is the linkage spring strong enough to move the linkage and close the throttle plate or could anything be interfering with the accelerator linkage? 49-50 Ultras with the two piece throttle valve linkage had a bellcrank on the side of the trans. That bellcrank did cause some drag issues if it started to stick and was eliminated in the 51s when Packard went to a one piece rod.

For what it's worth, the adjustment procedure you mentioned remained the same on all Ultramatic versions thru 56 but the recommended RPM varied from 375-400. Some have found the recommendation a bit low causing some engine stalls. You can increase it some -- but try to stay around 450 and not go above 500. If you go much higher than 500 the centrifugal advance in the distributor can start to interact and interfere with setting the timing as well as the car will want to creep excessively when stopped at a light.