Re: [Amc-list] trip to Santa Fe

[Tom Jennings <tomj@xxxxxxx>]

On Wed, 2007-07-18 at 19:16 +0000, Wrambler242@xxxxxxxxxxx wrote:
> You may find a slight increase in economy with higher engine temps, but with high timing it may not work.
> I've never been scared of letting the temps run in the 210-225 range on the 4.0L's. Any ping is usually very light, even on low octane crud. Which is all my RM will let me buy....
>    The 258 may not like higher temps at all. Different head and bore could change everything.

Yeah, there's a complicated interaction between temperature and ignition
timing and pinging. The general drift is simple: high temp == more ping;
more advance == more ping. Getting max. advance without "much" pinging
can be tough.

My current dash temp gauge is badly calibrated; I have a new one, but
it's not in yet (I bench calibrated it!). I have to run outside. lift
the hood and measure, and I haven't done that.

Mine too now seems to run fine at high-normal temps now that I got the
timing CURVE right. The essence of the change was, more, and sooner,
mechanical advance, and less static; it means the PEAK advance with
vaccum advance is a few degrees lower at cruise, but at all other times
it's MUCH higher than stock. That solved the always-pinging problem.
It's paradoxically a lot less sensitive to temperature now.

83 258, stock, with an 81 aluminum water-cooled manifold, and a
32/36DGEV Weber, 2.5" exhaust w/turbo muffler, 2.73 axle. 75MPH = 2750
rpm or so.



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