Mayf
Synthetics have an inherently flatter viscosity vs temperature curve than
conventional petroleum oils, even multigrade types. This is why a "50W"
synthetic can meet lower temp specs and be classified as a multigrade.
Much of the stuff circulating around in used oil is simply carbon particles.
These are fluffy, soft particles that don't cause bearing wear but they
would plug up a fine oil filter fairly quickly. Fine filters are great but
they need to be changed frequently. In industrial & aerospace applications
it is not unusual to monitor the differential pressure across the filter to
determine when it needs to be changed. The filters are also frequently
monitored to detect metallic particles.
Regards, Neil Tucson, AZ
-----Original Message-----
From: Larry Mayfield
Sent: Tuesday, July 30, 2013 7:47 AM
To: land-speed@autox.team.net ; tigers@autox.team.net
Subject: [Land-speed] Oil and Filters...more questions..
Thanks to everyone, I am a lot more informed on oil and filters. The
plurality of recommendations for oil was Mobile 1. Ok, works for me.
However, within the Mobil 1 oil line up spectrum, there are quite a
number of oils in many different weights. The oil needs to be able to do
its job under a lot of stress: acceleration of teh car and pushing the
air up a steeper and steeper aero hill. It needs to be able to carry
the heat away from the internal rotating and sliding parts. I was once
told by a local Las Vegas NASCAR motor builder that the pump needed
should be a high volume pump, not a high pressure one, so that lots of
oil could be pushed through the bearing clearances. It made sense to
me. However, the replies I got had oil recommendations from a light
weight multi grade oil to heavy single ot at least a very low multi with
hight viscosity upper grade: Such as 0W 30 to 0W 50 weights. Ok, those
are available and some of them are down right expensive. I am still
lacing some information, lol.
My motor specs are basically OEM: stock rod and journal bearing
clearances, rod to rod clearances are OEM, etc. Valves use bronze
guides, etc. I have a high volume pump. But, I am missing the logic and
engineering behind the recommendations for the oil grades (hey, what can
I say, I am an old engineer). Experience plays a large part or the
recommendations, I know. Do the Sprint Cup cars use 0w 50 weight oil?
Or do they use lower viscosity multi grade like 0W 30 or even 0W 20?
Either way, why? Same for light airplane motors; Those puppies are at
work the whole time they are in the air. What oils do they use and
why? These are the kinds of things I would like to know regards oils..
For the filters, Mobil 1, Pure one and WIX were recommended. I cut a WIX
apart and it appeared to be well made and had specs that said it could
remove particle sizes down to approximately (I think I remember) 25
microns. To refresh, a micron is one millionth of a meter. There are
25400 microns per inch or one micron is 0.00003934 inches. So a filter
than CAN remove (doesn't say will!) remove a 25 micron particle size or
so means that it might let one through that is just under 0.001 inches.
Seems to me that that is pretty large given some of the rotating
clearances. A lot of the filters said 60 microns! Now, I am guessing
that there is a balance between the flow capability and particle size so
the sizes are compromises. Seems to me that if the motor is contributing
bits and pieces of that size, that it is or may be not long for the
world. I like the idea of using a screen with a small mesh before great
filter and that between the two it would remove most junk. But is that
over kill? The screen can tell me what or if things are starting to come
apart.
Right now, I am leaning towards Mobil 1, 5W 30 Truck & SUV full
synthetic oil used with a good filter such and the Royal Purple, WIX or
Mobil 1 filters. I know that yo all use as a group the full spectrum of
oil and filter products, so why do you use them? I like technical
responses rather than anecdotal ones however, experience and the
situation under which the experience was gained is important.
Any more replies and responses here? Maybe your comments and thoughts
will save some one's expensive motor...
anyhoo, thanks for listening...
still learning
mayf
--
______________________________
drmayf
Worlds Fastest Sunbeam, period.
204.913 mph flying mile
210.779 mph exit speed
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