Timing Advancement; How Far?

[beaufort-fj60]

Um, you get no vacuum advance

Couldn't resist. Why would you do that? You would not have much power to spare (like we do anyway)

ha ha

I was just wondering if there are any detrimental effects to the engine by not advancing the dizzy through the rpm range. I'm at sea level, well about 10' actually.

 

[kevinmrowland]

I don't think it would do anything detrimental, just wont have as much power available. I see no benefit of not utilizing the vacuum advance.

 

[cando john]

my 83 fj60 with stock motor dui dizzy runs @ about 12 deg @ idle and full advance it will push up to 40 deg. ..... i like the power

 

[kevinmrowland]

Sounds about just like mine.

But the thing is, since I can manually switch on the HAC I can push it another 6 degrees under load, still runs good, if not better.

So I think I will advance the base timing 6 degrees, then push the button under load until it results in pinging.

I'll post what I end up with as a total.

 

[lathrop]

Think this thread gives me a clue. I was getting 15 to 16 mpg before a tune up and replacing vac hoses and disconnecting the hac which was TU. Seems possible that the hac which was sucking at sea level may have advanced the timeing. Its now between 11 and a bare 15 mpg. runs and Idles smoother with better power. I have been procrastinating on advanceing the timeing anyway. So I guess I should try 11* or so advance.
As to octane Before the tune, I tryed boosting it and the mpg went down. ? 1 tank is not all that meaningfull. too many variables. But I need to get the best I can.

 

[BackFromTheDead]

On my '85 FJ60, I advanced the timing 14 degrees BTDC. I thought this was gonna be too much, especially since I'm at sea level, but I haven't heard any pinging yet. Anyone else advance it this far with any luck?

 

[kevinmrowland]

Way to bring a thread "BackFromTheDead"

14 was about the maximum I was able to advance the timing, 15 was doable but did not feel right and 16 was pinging or sure.

Be sure that your vacuum advance is working to its full potential and push the timing a bit further if you want to tinker.

 

[rmcquet]

FWIW, I learned that the max you can do in Calif and pass smog is 10 deg. (of course, you can just set it for the smog test and then advance it again after).

the tech didn't unhook any vac lines when he took the reading (at idle), so maybe that had an impact on the reading? I still don't understand how the vac advance works. . . . . .

 

[CruisinFJ60]

push it forward and play with it.

i did mine to get the best throttle response the "hottrodded" it round the block to see if i had any pinging then bumped it just a tad more drove it again and called it good. helped give me some torque thats for sure. but i also like to tinker.

 

[BackFromTheDead]

Haha...just like my truck, I like bringing threads back from the dead

I like to tinker a lot too...probably too much. And I wanted to get the best possible fuel economy from this ol rig as well, so have been playing around with the timing advance, in addition to tire pressure, doing a lean idle drop on the carb, etc. etc. I also installed an in-cab vacuum gauge, and try to keep it at 15 inches or higher when driving, and definitely above 10 when cruising.

Since the lean idle drop on the carb, the vaccum has gone from a ~15 and fluctuating slightly to a steady, glued-in-place 19, which hopefully will help MPGs.

I also advanced the timing up to 14 degrees, after which I had to turn the idle speed down a bit to get it back to 650. I haven't heard any pinging yet, and get a lot more torque ( maybe in my head), so hopefully this will work out.

Anyone have any advice on hearing pinging? Jim C. mentioned that often it is hard to hear ping at high RPMs, and I never ever tow anything, and there aren't many hills along the shore here in Jersey. Any tips on how to find out if it's pinging, or methods you've used in the past?