Originally Posted by o2man98

Your are correct when you say that 10W and SAE30 are different specs. But so are 20W and SAE20. SAE 20 and SAE 20W are two totally separate monograde classifications. SAE 20 describes the high temperature viscosity of the oil and SAE 20W describes the low temperature cranking capability of the oil. Not all xW ratings are made at 0* F. While the high temp viscosities are rated at 100C or 212F, the "w" ratings use low temperature cranking viscosities at different temperatures.

SAE Viscosity-Cranking (cP)
Grade - Max at temp oC

0W - 6200 at –35
5W - 6600 at –30
10W - 7000 at –25
15W - 7000 at –20
20W - 9500 at –15
25W - 13,000 at –10

An oil can be classified as a multigrade SAE 20W-20 if the oil can meet both the low temperature cranking viscosity of 9500 cP at –15C and the 100C high temperature kinematic viscosity requirement between 5.6 and 9.3 cSt. The AMSOIL motor oils listed above meet both the low temperature requirements of SAE 10W and the high temperature requirements of SAE 30. Thus the products are true SAE 10W-30 and SAE 30 oils.

Ken

Originally Posted by minxguy

What you have stated is true for any multi-viscosity oil, any brand. Hence the term multi-viscosity.
I am using 0 degrees as a reference for Saybolt Seconds. people seem to grasp the concept a little easier.
I realize that the cST/cP is more universaly accepted.
Ken

Originally Posted by o2man98

Saybolt or SUS is measured at 212F and 100F.

Originally Posted by Hydrocruiser

I got a bunch of PM's that expressed discontent with M-1 15W-50 EP allegedly changing over to GRP III.

Am I happy with this decision? Not in the least!

Is 15W-50 still a good product ...yes.

Is there something out there for around $6.00/qt that remains a true Grp IV PAO with excellent ZDDP additives etc?

Yes!!

What is it?

Royal Purple 20W-50 sold in 5 gallon pails and shipped UPS free to your door for $6.25/qt and $6.99 in single quarts. While at it their gearlube is excellent and a PAO product as well.
How do I get it?

http://www.rpmoil.com/index.php?main...b62a8a9bc42262

Is this what I would use if I decided not to use V-Twin @ $9.00/qt. Yes.

I am hence moving my 15W-50 M-1 use over to RP 20W-50 as it is a PAO/ better value and quite comparable to V-twin as well for $6.25/qt in bulk 5 gallon units with free UPS delivery in the 48's..

Originally Posted by Knot 4 Me

Hydro, is this their regular 20w50 that is a PAO or is it their XPR 20W50 that is a PAO? There is $6/quart difference in price bewtween the two oils at Jeg's so it makes me wonder if the XPR is the PAO and not the regular 20W50.

Originally Posted by Knot 4 Me

Hydro, is this their regular 20w50 that is a PAO or is it their XPR 20W50 that is a PAO? There is $6/quart difference in price bewtween the two oils at Jeg's so it makes me wonder if the XPR is the PAO and not the regular 20W50.

Originally Posted by Hydrocruiser

The tech told me they have not gone to Grp III bases and said all RP products are GRP IV or V.

Let me know what you hear.

Originally Posted by Knot 4 Me

Thanks. The XPR line must have a way beefier additive package to justify the upcharge.

Originally Posted by Hydrocruiser

The question becomes do we continue with M-1 15W-50 from a number of you?

My answer is that in an offshore boat you need the best edge you can get if you are to see the most longevity from your engine. I like a Group IV/V synthetic best.

Here are the 2007 2,000lb. synthetic oil gorrillas:

M-1 V-Twin 20W-50/Redline 20W-50/RP 20W-50/Amsoil Severe Service 20W-50/Spectro 20W-50.The list is getting shorter.

Yes...15W-50 M-1 is still a great product and i use it as well. It is NOT on the list above however.