What oil for your engine

[rgv500]

Good Mobil site giving details of what oil for what engine.

Click on the lube recommendation button in the centre of the screen

http://www.mobil.co.nz/startframe.html

[kiwimex]

i guess they dont have lexus engines in their boats

[wildrj]

More on oils- from Popular Mechanics.
Interesting to note recommended oil change intervals the same between mineral and synthetic.
My Kodiak manual states 50hrs for mineral, 100 hrs for synthetic.
Might have to re-investigate this. Also interesting that race oil has a much shorter lifespan.

http://www.popularmechanics.com/automotive/how_to/4232672.html

[Matthewf/Norbert/TuiDog]

oil should always be changed out frequently to remove wear debris, this is often well before the oil has lost any of its properties, so whether it be mineral or synthetic does not make any difference to oil change out interval. what the oil companies are bragging about is how long the oil can run and not lose its spec, they don't care how much your engine wears due to wear debris though.

if you are running high hp, high rpm and high temp then a synthetic is a good idea to ensure a stable oil film thickness/strength, but you will still need to change it out say every 50 hours, less if you can afford it.
I have found castrol edge 10w-60 synth to be the most stable/consistent oil pressure wise.. they also do a mineral oil that is cheaper (25w-50)

[Husky]

I have a 350 chev (mercuiser) engine on which I'm looking to improve the oil pressure when hot.  Have been running 20w 50 till now.  I saw some Penrite products the other day which I'm considering.  I think the grades were:
15w 60
20w 60
25w 70

All were semi synthetic at $43 / 5 Litre pack.

Any thoughts as to what proportionate pressure increase going from 50 to 60 or 70 might be?  eg I guess in my mind going from 50 to 70 is an increase of 2/5 so if oil pressure was 50psi would it increase to 70psi (not the real no's just an easy example).  The oil pressure presently drops to around 35psi when hot (and it is fresh oil) - and yes I know I should check out the bearings and oil pump...