many thanks for all the responses on and off list.
in answer to the various queries:
1) the difficulty cranking i referred to was after hard driving with (i'd
guess) hot oil. the starter would not be able to turn the engine over
unless i waited 5 minutes or so. its a brand new gear reduction high torque
starter. my old 5.0 starter was just the same. the wiring is good. the
battery is a fully charged optima. i tried cooling the starter with cold
water and that didn't help.
2) the oil i changed was about 2500 miles old (older than i'd normally
allow) and with those temps maybe it had degraded somewhat. its possible
that new oil was all that was required to help the hot cranking and the
weight change did nothing. if this is the case i'd prefer to switch back to
a 40 weight. however, when cold the 5w is noticeably thinner than the 10w.
same brand, mobil semi syn. there is absolutely no sign of the cranking
issue anymore since the oil change. i assumed (never a good idea, i know)
that the thinner oil created less resistance.
3) i've never autocrossed the car but i race it sometimes, run it on track
days and drive it very hard on the road (prolonged periods with rpm between
4 and 6k). i'm also rallying to morocco next month which is 5000km (and
hopefully another 2000km back again!). hence, the engine needs a little
more care than an average daily driver and gets proportionately more abuse.
4) i'd like to change the thermostat to a 180 which tends to run at about
190 but fear it would drive the oil even higher.
5) my mechanical water temp is calibrated. my electrical oil temp is taken
at the remote filter block adapter (should be the highest reading) and is
calibrated.
if possible i'd prefer not to running 30 weight oil in morocco.
6) i have a thermostatic oil flow valve rated to open at 180F which i could
run a small oil cooler off. i have a few sizes of earls coolers lying
around. would prefer if it was not visible though as contrary to popular
opinion, i don't think it looks cool! hopefully with a small enough
cooler, the oil will never reach 180 but stay about 212.
7) my reading around tends to agree that between 210 and 230 is a good
range, with higher being possible with more frequent changes. if what i
read is true, it seems having 170 water temp is worse for the engine than
260 oil if the oil is fresh.
8) how does a/f ratio affect cranking ability? (its bang on according the
innovate LM1 incidentally)
9) my oil pressure is ~ 50 psi idle, 75 psi above idle.
On Mon, Sep 28, 2009 at 7:35 PM, Dave Munroe <dave@munroe.ca> wrote:
> Maybe this time?
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