Setting initial timing
Figured I post this here for those who might have some old jeep experience:
A couple questions as I am setting initial timing and idle for my V6 - it has a new comp cam with the 252 grind (just a bit more lift but not extreme - good for 1000-4000 rpm), so I am kind trying to find new norms. (note: dwell set and reconfirmed multiple times at 30, and using a timing light on #1 wire with carb vac advance line plugged).
1) How much initial timing is too much timing? Here at 5000' I ran 5-8 BTDC with the old stock style cam. ALthough 5 BTDC is FSM direction, given the extra elevation here, and the use of a vac gauge, I went up to 8 BTDC over a few years. I think my vac guage (reading manifold vac) probably suggested I could go higher, but was a bit hesitant. Now with the fresh engine and new cam - figure I should start from scatch. So can I place initial timing where the vac gauge reads maximum? This would put me at 14-16 BTDC - That seems like a lot of advance even for 5000'+ elevation. My ear also tells me this is the range where the rpm smooths out the most as well as reaches max rpm. I am just hesitant to run that much advance. Maybe the new cam likes that? Don't want to burn a valve - will be diligent listening for pre-ignition and keep an eye on temps when idling and for hard starting.
2) What is the expected amount of manifold vac when idling at these high elevations? I am getting about 13 Hg with all the idle mix and speed re-adjusted for the 14 BTDC advance. I think this is pretty much what it used run...but just wondering if any other high elevation jeepers see similar numbers.
maybe...just maybe...getting closer...
2010 Tacoma TRD