There seems to be a lot of talk and questions around the forums regarding oil. A lot of you seem to use a variety of oils and weights with a variety of engines.
I am curious to find out why you use the oil you do, AND if you know what the numbers mean in the choice of your oil, specially the multi grade users.
Did you pick your oil?
Did your manual suggest your oil?
Did your engine builder suggest your oil?
What year, make & size is your engine?
Do you know what the numbers mean in your oil?
[This message has been edited by gnarley (edited April 29, 2002).]
The manual in my Marine Power 454 mag recommends strait 40W oil. I used that for about 100 hours. Then I switched to Syn Oil (specifically Mobil 1). The heaviest they offer is 15W50 hence what I use. I have also used Valvoline full Syn in 20W-50 and it works good also.
The things I notice about Syn versus conventional oil is the oil pressure stays higher when hot. To me that says the oil is generally running cooler or not thinning as much with heat.
I run Mobil 1 5-30.
I selected this oil based upon
a) machined tolerances of this particular engine, (e.g. automotive = tight)
b) oil temp while hot is still relatively cool (145F). Oil pan has it's own temp sending unit, and boat runs an oil cooler.
It is a mildly built 460ci Chevrolet.
As to what it means; it's a viscosity rating, 5 weight while the engine is cold, for easy wear on the bearings during startups, http://free.***boat.net/ubb/wink.gif 30 weight at operating temperature.
Did I pass? http://free.***boat.net/ubb/biggrin.gif
Originally posted by Costello:
Did I pass? http://free.***boat.net/ubb/biggrin.gif
I'll tell you later. I want to see what a lot of others think as well then I will post info regarding the topic of multi-weights that might open a few eyes.
1 - I did pick my oil, straight 40 weight.
2 - The boat is a 1975 there is no manual.
3 - Had no engine builder, bought the boat used.
4 - Block 71 ford 460, heads 70 cobra jet, don't know when it was put together.
5 - The numbers on a multi-weight oil means, at cold temps the oil will flow like the weight of the low number, and at 212 degrees F the oil is only as thin as the higher number. Polymers are what is used as a viscosity thickening agent.
Dang I need a spell checker!!
[This message has been edited by INFINITEJJ (edited April 29, 2002).]
I actually just started running Straight 30 wt and an oil cooler. I was pulling 60 to 75 pounds of pressure. I don't have the faintest idea about the heads or bottom end of my motor, cause when pops and I bought it 11 years ago, we said we'd rebuild when she started to stumble. I bought Dad out a few years ago, and it still runs good. Next trip, I'm gonna give 20-50 a try. http://free.***boat.net/ubb/wink.gif
I just use plain old merCruiser 25-40w in my 350/260hp. That way when things break I'll just blame them....Ok gnarly, whats your choice....Mike.
The first number represents the low temp at which the oil will still flo freely.The second number represents the strength of the oil film.15w50 Mobil 1 is what I use because I have proven to my self that my engines hold better hot oil pressure and lower oil temps which means synthetic doesn't break down as fast and reduces friction in your engine.Less friction and heat = a very happy engine which = a very happy me. http://free.***boat.net/ubb/smile.gif Bum
OK, what i would suggest to use for oil would be a low winter number (in 20W50 the "W" means winter not weight) and then use a higher warmed up number (50) The reason the "w" stands for winter is because in the winter (cold) time the oil wont go lower then a 10 weight when it is cold...(0 weight equals water) then when the engine warms up it wont go past 50 weight unless it is overheated, contaminated, or old and breaks down... this is what i have learned from my shop teacher and specs from oil company's... it seams like the oil should get thinner when hotter but it is the petroleum in the oil that counter acts this affect i believe...So it is better to use oil that has a low winter weight and a high warmed up weight so the oil weight can change steadily while the engine warms up.... hope this was help!
Logan
The "W" means the oil meets specifications for viscosity at 0 degrees F and is therfore suitable for winter use.The greater the differance between the low and the high number the more polymers or thickening agents that must be used to make the oil do the job.
[This message has been edited by INFINITEJJ (edited April 29, 2002).]
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