Anyone ever disassemble a distributor - need help
The 1970 Hamtramck Registry Library Page (1970 - 1974)
As far as the distributor advance and initial timing, those specs are in the back of the electrical section. I have paper copies for 67 and 68, and digital copies of some others that I just need a few pages from as reference. Many of these are available as free downloads from mymopar.com
Timing tape, tachometer and timing light is how I usually figure out what the advance is doing.
Also I've had had access to a distributor machine.
But if there's a larger cam, then compression and temperature of the fuel/air inside the chamber at idle is going to be poor. So more timing is needed for the flame to develop.
But if the mixture is leaner than best power at idle, that's another reason an engine will want more timing. Flame front takes a little longer to grow with lean mixtures.
So if we compare the non-emmision 273 Hi-Po 4 bbl to the 360 2bbl with emmissions
Initial timing: 0-5* initial timing may have been because the 360 had more effiicent burn at idle than the 4 bbl. But we know from Chrysler's tech booklets that the initial timing was reduced to insure increase the heat in the cylinder walls and exhaust gas. This reduced left over CO and hydrocarbons. They also ran the idle mix leaner. So this combination reduced power at idle, hence the higher idle rpms (750 vs 600 or 650)
Advance to 1600 rpm: This is long and quick to get timing up to where it ought to be for the 360 to have max power.
Advance above 1600 rpm: The engine is in the range where combustion speed is increasing with rpm
Advance above 2400 rpm: The 360 2bbl engine, probably due to the cam, is less efficent at WOT than the 273. So it need more lead time for the burn.
360 was introduced as a truck engine. That's in the Mopar Performance manual and the Taylor smallblock rebuilding book which are both pretty reliable. But thanks to Barry, we can see for ourselves what was available for each of those years. Check out the dealership data books here
The 1970 Hamtramck Registry Library Page (1970 - 1974)
As far as the distributor advance and initial timing, those specs are in the back of the electrical section. I have paper copies for 67 and 68, and digital copies of some others that I just need a few pages from as reference. Many of these are available as free downloads from mymopar.com
Timing tape, tachometer and timing light is how I usually figure out what the advance is doing.
Also I've had had access to a distributor machine.
Like Trailbeast wrote, we can only make general statements.
But if there's a larger cam, then compression and temperature of the fuel/air inside the chamber at idle is going to be poor. So more timing is needed for the flame to develop.
But if the mixture is leaner than best power at idle, that's another reason an engine will want more timing. Flame front takes a little longer to grow with lean mixtures.
So if we compare the non-emmision 273 Hi-Po 4 bbl to the 360 2bbl with emmissions
Initial timing: 0-5* initial timing may have been because the 360 had more effiicent burn at idle than the 4 bbl. But we know from Chrysler's tech booklets that the initial timing was reduced to insure increase the heat in the cylinder walls and exhaust gas. This reduced left over CO and hydrocarbons. They also ran the idle mix leaner. So this combination reduced power at idle, hence the higher idle rpms (750 vs 600 or 650)
Advance to 1600 rpm: This is long and quick to get timing up to where it ought to be for the 360 to have max power.
Advance above 1600 rpm: The engine is in the range where combustion speed is increasing with rpm
Advance above 2400 rpm: The 360 2bbl engine, probably due to the cam, is less efficent at WOT than the 273. So it need more lead time for the burn.
