BTW, I flush the oil cooler before installing a freshly rebuilt engine
and also at the first oil change. I don't bother at other times.
Mike
-----Original Message-----
From: Daniel1312@aol.com <Daniel1312@aol.com>
To: mdietsche@yahoo.com <mdietsche@yahoo.com>
Cc: spridgets@autox.team.net <spridgets@autox.team.net>
Date: Tuesday, 16 March 1999 6:15
Subject: Re: Oil and Oil coolers [2]
>In a message dated 15/3/1999 4:52:16PM, mdietsche@yahoo.com writes:
>
><< Sump oil temp above 200 is desirable, with preferred range
> around 220-230 for small engines. The reasoning is that colder temps
> don't fully dissipate the entrained acids and other blowby compounds
> that wind up in the oil, and these compounds are damaging to the
> engine. It's true that conventional oil deteriorates at these temps,
> but that's why you change oil regularly. The newer synthetics and
> blends are much more temp-tolerant and can run hotter with less
> deterioration.
>
> Oil coolers make sense if you are running hotter than this with
> conventional oil, esp. in the summer. This problem might show up as
> low pressure after a long summer drive, with the viscosity of the
> conventional oil not able to hold up to prolonged high temp running.
> Some folks use an oil cooler, but screen it off in the winter to keep
> the oil from running too cold when the weather is cool. Also
> available are oil cooler thermoststs that only send oil to the cooler
> matrix when it's above a preset temp (about 180 or so -- this is
> sensed outside the sump, where it has already cooled down some from
> the sump temp). With the new synthetic oils I don't think an oil
> cooler is such an issue unless you are running VERY hot, and then you
> probably have other problems anyway. >>
>
><< 7,000rpm with 100bhp!!!!>>
>
> I've had excellent luck with the Quaker State blended synthetics in
> all my older vehicles. QS's lubrication engineers steered me away
> from their pure synthetic in any car older than 1980, unless I was
> changing all seals on an engine rebuild (same for tranny and axle).
> But they said their semi-synthetic blend could be run with no seal
> problems, and it is very temperature tolerant. As far as rebuild
> theory, I like to run the first 500-1000 miles on a good conventional
> like Valvoline (it's known for its detergent action), then switch to a
> semi-synthetic blend thereafter.
> >>
>
>At last, a posting I can almost agree with!!!!! The only points I would
add
>are: When the oil gets too hot the film can break down and the damage can
>begin.
>
>High rpm (say 6,500 upwards) especially prolonged for more than a few
minutes
>whether on the road or race track are what pushes up the oil temperature to
a
>critical level and it is this more than ambient air temperatures which
cause
>problems. Problems can be cured with a cooler or synthetic oil or both,
>preferably both.
>
>Never run an engine in with synethetic (it can cause problems).
>
>Most synthetics are fully miscible with mineral oils - no need to flush etc
>and by the way, WHO empties the oil cooler on oil changes.
>
>The 1500 engine needs an oil cooler more than the A - Series.
>
>Some engines (Porsche flat 6, for example) have problems with synthetics in
>certain instances - details on request.
>
>Cheap oil is good for nothing and like most things you get way you pay for.
>
>I've used Mobil Synthetics for years with no problems, including their diff
>oil.
>
>Daniel1312
>
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