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oil viscocity what do the numbers mean? #13347
10/03/04 04:53 PM
10/03/04 04:53 PM
Joined: Feb 2004
Posts: 6,257
acworth / N. georgia - south e...
cheapstreetdustr Offline OP
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cheapstreetdustr  Offline OP
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Joined: Feb 2004
Posts: 6,257
acworth / N. georgia - south e...
i know this has been asked before but i am confused. temporarily...
what is the first # and what is the sencond#
higher number is thicker?
first # is warm
second # is cold or w for winter is this
right..?


365" Iron J heads,,3480lbs best 1.39 60ft on SS springs.10.54,124 mph ...6.67 1/8th et.average 60fts 1.46 w/ small cam &.063 no2 pill tagged & insured
[image][/image]
Re: oil viscocity what do the numbers mean? [Re: cheapstreetdustr] #13348
10/03/04 05:53 PM
10/03/04 05:53 PM
Joined: Jan 2003
Posts: 949
Klamath Falls, Oregon
Dartslantsix Offline
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Dartslantsix  Offline
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The higher the number, the thicker it is. The first number is when cold, the second is when it's hot. Now, viscosity is a function of temperature too.
If you had a graph of viscosity vs. Temperature of straigh 30 wt, it would slope down since it gets thinner when hot. Most straight weight oils have the same slope on that graph. But a weight such as a 10w40 has a less steep slope in that when it's cold it acts like cold 10wt, but when hot, acts like a hot 40 wt.
Hope that helps.

Re: oil viscocity what do the numbers mean? [Re: cheapstreetdustr] #13349
10/03/04 07:38 PM
10/03/04 07:38 PM
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MICHIGAN
DynoDave Offline
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Check out this information on the API doughnut.

web page


DynoDave
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Re: oil viscocity what do the numbers mean? [Re: DynoDave] #13350
10/03/04 07:43 PM
10/03/04 07:43 PM

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Re: oil viscocity what do the numbers mean? #13351
10/03/04 09:58 PM
10/03/04 09:58 PM
Joined: Feb 2004
Posts: 6,257
acworth / N. georgia - south e...
cheapstreetdustr Offline OP
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cheapstreetdustr  Offline OP
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Joined: Feb 2004
Posts: 6,257
acworth / N. georgia - south e...
thats why i like this site
thanks


365" Iron J heads,,3480lbs best 1.39 60ft on SS springs.10.54,124 mph ...6.67 1/8th et.average 60fts 1.46 w/ small cam &.063 no2 pill tagged & insured
[image][/image]
Re: oil viscocity what do the numbers mean? [Re: cheapstreetdustr] #13352
10/04/04 02:39 PM
10/04/04 02:39 PM

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The 0W, 5W, 10W number is the SAE viscosity defined by the SAE J300 specifications. The test used here is the cold cank simulator which tests the oils ability to permit a satisfactory cranking speed under severe cold conditions. A 0W is tested -35, 5W at -30, 10W at -25 and so on. The other number is the kenematic viscosity tested under ASTM D445 measured at 100'C.







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