Idling RPM Issue 67 327-300 w AC & PG

[Al R.]

Re: Idling RPM Issue 67 327-300 w AC & PG

Tim, I had threaded plugs installed in the 2 holes as many have done. Has anyone to your knowledge, ever tried putting some type of insulation down into the slot prior to carb & gasket installation to help out on the heat transfer? just curious

[Timothy B.]

Re: Idling RPM Issue 67 327-300 w AC & PG

No insulation, just plugs.

[Al R.]

Re: Idling RPM Issue 67 327-300 w AC & PG

Tim, I removed the gasket between the carb and the SS plate today. Also used a vacuum pump connected to the distributor can, which BTW is a B26. At approx. 14 in. the advance arm is fully pulled in (total advance). I then plugged the vacuum line going to the can from the carb and rechecked the timing 6*BTDC (has a little wavering movement) and then started the engine, set the RPMs to 600 (has a waver of approx. 20RPMs either way now), adjusted the air bleeder screws on the carb to try to achieve the best vacuum and then used the vacuum pump to see where the total advance occurred at 600RPM. This is what I found--timing is all in at 23.8* with a vacuum of 13" at 600RPM. However, with vacuum line from carb to the can connected, the timing and vacuum are 34.7* & 19.5" at 1400RPM--23.8* & 13" at 600RPM

[Timothy B.]

Re: Idling RPM Issue 67 327-300 w AC & PG

It seems to me that from the vacuum readings in post #9 the camshaft may have been changed. If that is so the engine idle should be increased to approx 7-800 to provide a stable 14" vacuum for the B-26 control which should be pulled full at 12".