Skip--I'd have to be a serious engine designer to have these numbers roll
off the top of my head. Only once early in my mechanical engineering career
did I come within shouting distance of such a job; but the company went
belly up way to quickly. Anyway I'd like to take a little time to visit the
numbers.
A quick look at some of my fluid flow and oil viscosity charts from
Worthington tell me that there is a good chance that we can and often see
transition flow Reynolds numbers in the 2000 to 5000 range under very hot
oil temperatures in a race engine. Depends a lot on how hot the oil gets
and what the grade is. So my first comment about strictly laminar flow in
the 1000 range is probably more applicable to light duty average road car or
race car warm up conditions. I'd like to take some time and look at this
more closely.
To that end I'd can any of the active or past racers on the list, especially
guys running the long course, can give me some approximate data points.
1. If you have an oil temp gauge and remember any readings tell me what they
were.
2. Also I'll need to know what the grade of oil you were using
3. And whether you experience any degree of oil dilution from the fuel in
those runs. (this can have a big effect on oil viscosity)
Also nice to know is:
4. Type of engine, make, displacement, oiling system details
5. Approximate full power RPM
6. How far out you were on which course
7. Peak speed. (which will enable me to calculate about how long the engine
was running under power)
8. Type of car and class (this doesn't enter into the calculations, just
makes the data more interesting)
I'll do some calculations and share the essential results in some tabular
form with a summary.
Ed Weldon
----- Original Message -----
From: "Higginbotham Land Speed Racing" <saltrat@lubricationdynamics.com>
To: "Ed Weldon" <23.weldon@comcast.net>; <land-speed@autox.team.net>
Sent: Wednesday, October 18, 2006 11:33 AM
Subject: Re: Internal Engine Block Painting
> Ed,
> Thanks for the good advice. What is a typical Reynolds number for
> engine oil flow? Are we talking 1000 or 2000?
> Skip
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