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"What is a
decent oil temperature for take off. The viscosity changes by roughly 2
orders of magnitude between start up and steady state cruise. Is there
some viscosity/temperature threshold that should be observed to prevent damage
at take off power? Also, is there a particular reason for not mixing
brands/viscosity? I tend to run multi weight in the winter and straight
weight the rest of the year(same brand). There is obviously be some mixing
during the change over. Chris Zavatson"
Decent oil temp
for take off? Chris, I think it is important on this site to say "I don't know"
when it is so. Here's what I do know. In our IMSA road race car we ran 50W oil
for a while. We wanted the oil temp at 150 deg F on the pace lap. This was
impossible on cool days. The concern is two-fold. One, oil to the valve train
and two, oil to the connecting rods at high (8500) RPM. The other concern is
actually blowing up the oil filter if oil pressure gets too high. I've seen this
happen. This obviously would be very bad on take off. I would think that over
100 deg F should be OK with 50W oil, but I don't know for sure. The reason I
don't mix oil brands is due to its negative affect on oil consumption. Changing
from straight 50W to 20W50 is not nearly as big of a concern, in my
opinion. However my experience says you will get better oil consumption while
running the 50W oil as well as better lubrication and therefore less engine
wear. You know, I used to get in a big hurry during run-up, I'm not sure why,
just seemed like I should get the engine back to idle. Now I do the run-up lean
and let the engine warm up a little...no big hurry. I know the question was,
when do you pull the throttle back and request clearance for departure...hope
this helps.
Craig
Berland
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