synthetic oil?

[Franz]

Greg back in the 70s I could have introduced you to an HD-21 Allis I would have been more than willing to shove a 55 gallon drum fire under, and preyed the damn machine would burn.
Of course, the way my luck runs, the idiots running that company sent a couple nitwitt operators out who ran the HD-11 out onto a burning landfill, and sank it right next to where they had just sunk a twin engine Terex, in the middle of the damn fire.
A small fire under a dozer wasn't that uncommon around here in cold winters to get them running again.
I even made up a couple heat exchanger rigs for people with 450 Deers so they could connect the Deer to their pickup in the morning and warm the block up from the truck's cooling system.

Franz
Most of the service rigs out here now use a self contained system to preheat them, heard of some trucks using them too. They're a diesel fired boiler that circulates the coolant. 15 or 20 minutes brings the block up to operating temp when its 40 below.
Greg

[Markopolo]

Originally Posted by Sberry27

down there new modern fuel inj engines should use the right oil too, they start so fast that it needs 5W 30 to build oil press fast. I would use what is recommended, no place to do amateur engineering.

Sberry....I appreciate that.....but someone told me a long time ago that 10W30, or 10W40 or 15W40 (or whatever)....that's just 10wt. oil with "viscosity improvers" added. Once the additive package in the oil breaks down, all you have left is a 10wt. oil

[Shade Tree Welder]

Originally Posted by Markopolo

Sberry....I appreciate that.....but someone told me a long time ago that 10W30, or 10W40 or 15W40 (or whatever)....that's just 10wt. oil with "viscosity improvers" added. Once the additive package in the oil breaks down, all you have left is a 10wt. oil

You would be correct!

[Markopolo]

Thanks Shade !

Using just a little "Thomas Edison" common sense......I think there are at least 2 reasons that multi-grade oils are specified:

#1: They want their engine to deliver maximum fuel economy, and
#2: They DON'T want their engines to last "forever" ! (think about it) !

As far as start-up....I would think a heavier grade oil would have a tendency to "cling" to moving parts better during shut-down

[Jim314]

This thread has been very enlightening guys. Thanks for all the posts.

[SlimJim]

Once again, thanks for class Shade. I have learned more about oil here in twenty minutes than I had in my whole life.

[Shade Tree Welder]

Originally Posted by Markopolo

Thanks Shade !

Using just a little "Thomas Edison" common sense......I think there are at least 2 reasons that multi-grade oils are specified:

#1: They want their engine to deliver maximum fuel economy, and
#2: They DON'T want their engines to last "forever" ! (think about it) !

As far as start-up....I would think a heavier grade oil would have a tendency to "cling" to moving parts better during shut-down

I think I wrote this before but it is worth going over again.

Multigrade oils have a low temp specification (0W, 5W, 10W, 15W and 20W) and a high temp spec. (212F), SAE 10, 20, 30 ,40, 50. FYI 10W and SAE 10 are not the same! Same goes for 20W and 20.

A multigrade is designed to supply a pumpable oil at low (winter) temps. During summer multigrades are not needed. I use the rule of thumb if there is a chance of frost during the oil change period use multigrade oil if not use a single grade oil.

The viscosity index (VI) improvers used in multigrade oils (and yes synthetics use them too only they can use a little less) The formulator starts with a base oil that can pass the low temp spec SAE 10W let's say. Okay he got that done then he has to add enough VI improver to meet the high temp spec. SAE 30. You see because the base oil that passes the 10W will be way too thin at the 212F temp to meet the SAE 30 spec. the VI improver (polymethacrylate) is a temperature activated sponge. As it heats up is expands and thickens the oil.

Now alittle more info. By the Lemke definition; (which differs from the legal/marketing definition and yes there was a federal court case over this.) Mobil 1 is a true synthetic, they use PAO's and esters as their basestock. Amsoil, Castrol and most of the "synthetic" motor (crankcase) oils are now made from Group III basestock which is pumped out of the ground and is refined in a oil refinery. It is isocracked and isodewaxed and has some properties closed to true synthetic base stock such as PAO. The main difference you still have a broad range of molecular weights whereas, with true synthetics you have only one molecular weight range. Just another case of the lawyers and marketing geeks making up what they want to be true.

If you have a stock engine in a stock piece of equipment and the manufacturer does not require the use of synthetic oil, don't waste you money! Change it when recommended and always change the filter.

If you are a guy who runs hi perf engine, strokes crank runs closed head with open pistons and has to run 103 octane to eliminate knocking or dieseling (yes i have friends that do this) then you may want to consider Mobil 1. Otherwise don't waste you money.

When I was in the Navy the only synthetic oil we used in the engineering plant was for the LM2500 main engines (basically your average DC10 engine) I was on gas turbine (Jet engine) Spruance class destroyer. The engine, if I remember correctly idled at 4000 RPM. A synthetic had to be used due to the stress and temperature of the engine. Everything else was group one out of the ground oil.

Okay I am tired of typing.

[Franz]

Originally Posted by Markopolo

As far as start-up....I would think a heavier grade oil would have a tendency to "cling" to moving parts better during shut-down

While heavy oil, such as 30 weight has more cling factor short term, if the engine isn't restarted within a couple days, especially in cold conditions, the cling factor will be of little importance compared to the time it takes the oil pump to pickup from the sump and really lubricate the engine wear surfaces.

A simple way of determining what oil will do in an engine is a cast iron pan and heat source. Straight weight oils become very viscous at 300°, and that is an easily reachable temperature in an engine.

[Shade Tree Welder]

Originally Posted by Franz

While heavy oil, such as 30 weight has more cling factor short term, if the engine isn't restarted within a couple days, especially in cold conditions, the cling factor will be of little importance compared to the time it takes the oil pump to pickup from the sump and really lubricate the engine wear surfaces.

A simple way of determining what oil will do in an engine is a cast iron pan and heat source. Straight weight oils become very viscous at 300°, and that is an easily reachable temperature in an engine.

The base stocks used in crankcase oils have flash points in the low 300's F. If you put an oil in a cast iron pan and heat it to 300F the thickening is called oxidation. I would say the temp of a stock engine is not likely to get near 300F. Low 200's is more realistic.