I want to heat a set of roller bearings in Synthetic 10w30 motor oil. I will use a thermometer. I do no want to ignite the oil in doing so. What would be the safest max temperature before ignition. Would it be better to use conventional SAE 30 oil for this task?

Consider http://www.amsoil.com/storefront/ase.aspx?zo=1181889. Full chemical synthetic, SAE 30and 10w30, flash point ASTM D-92 457F, API SL for high zinc metal protection, and corrosion inhibitors.

Here is the MSDS for health and safety info http://www.amsoil.com/msds/ase.pdf?zo=1181889 .

230 degrees C is a fairly regular number for PAO synthetic base oils. That number fluctuates a bit from brand to brand. Don't exceed 200 degrees C on PAO your experiment should be safe. Curious-what are you trying to accomplish with this demonstration?

I am going to heat a set of crankshaft roller bearings to slip on an iced down crankshaft. Old school, backyard method. It is a crank out of an old industrial antique DeVilbiss air compressor that I am restoring.

Thanks for the info. Much appreciated

I really enjoyed reading this Thread, we have a member who wants to heat some roller bearings in Synthetic 10W-30 motor oil. From reading the title, I am guessing he already has a quart of Mobil 1 10W-30 Synthetic Oil. He is asking about the safest max temp before ignition.

Tim Vipond, the Amsoil Salesman, does not even answer the OP's question, he puts up an Amsoil Link, breaking Forum Rules.

JMorgan, who is a Schaeffer's Rep, actually answered the OP's question, and he did not even put up a Schaeffer's Link, he did not try and sell him Schaeffer's Oil.

The OP thanks JMorgan

Ha! I used Castrol 10W-30. Heated the oil and bearing in an extra heavy cast iron container to 375F. Pulled the crank shaft out of the chest freezer and the bearing out of the container; using a large pair of pliers to drop the bearing on the shaft. It slid right into place as expected. Thanks for your help. J.D.
The compressor should be back in service by the weekend.

Thanks for the update. I love hearing about those restoration projects.

Tarhill: Thanks for the encouragement.

Every engine oil manufacturer will have a specification sheet on the website. If that sheet doesn't tell you the flash point, the Material Safety Data Sheet will, and they are required by law to offer that document to you.

From Mobil 1's website:
Mobil 1 10W-30
Flash Point, ºC, ASTM D 92 =224 [degrees C; = 435.2F]

Mobil 1 EP 10W-30
Flash Point, ºC, ASTM D 92 =230 [degrees C; = 446F]

You must not confuse flash point with self ignition point. As long as you are careful to keep sources of ignition away, it is safe to heat liquids above their flash point.

Also, It is difficult not to introduce dirt when you heat a bearing in oil. If fitting to a shaft, use dry heat, an oven or hot plate. if you do a lot of such work, pick one up at a garage sale for the shop.