Tuning issue on a 440
How did you determine that the jets were installed backwards?
You know that on that carb,
the bigger ones go under the metering rods..... right?
Thank you for that information. When I said "bigger" I meant the taller jets. Furthermore, I have a pin gauge set and measured them out and placed them in their respective areas according to the FSM. And the carb I did that jet swap on is no longer on the car.
Unplug the vacum advance. Set the timing to 36 total. Use premium fuel (91+) and test drive it. LEt us know what happens.
NOte: to set total timing you have to rev it until the light line stops moving, which can be 3,500+
Pull the vacum advance and see what it does.
10 degrees of advance at 4400 should run fine even if you set the base to 24 degrees or more, IF the vacuum advance is disconnected.
I think your VA is coming in too much, too soon or yielding too much total timing.
For testing purposes I did just like you described. I set the initial to 16 BTC with an idle rpm of 750 with 18.5 inHg going from the port on the intake that the power brakes feeds from. I set it at 16 since I have determined with my Sun machine that the distributor puts in 20 degrees of mechanical advance. I disconnected the vacuum pod and plugged that port on the carb.
Off idle is good. it is hard to tell if the off idle was better than the 12 BTC setting, but was better than what it was just at. Under moderate acceleration I did not hear pinging, but under spirited acceleration there was. I did not hear any pinging at steady state cruise at various speeds (20, 30, 40, 50). I did a couple WOT in first and second and I did hear pinging through out the rpm range during that test.
As mentioned above I verified the carb is set up to the FSM (jets and rods) with the exception of the rod springs , since the book does not specify spring rate. A member on cbodiesonly said that when jetting the car to the FSM one should account for the E10 fuels by 1.05 times. Is this sound thinking?
I did not do the rod spring test at idle yet, I wanted to get some springs before I do that. I should have them ordered today.
I am trying not to just change everything at once. I am trying to change one thing at a time to see how it reacts. Ideas on next steps?
