Mercruiser requirements SH,CF/CF-2
- Thread starter JonS
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I want to run a synthetic.
I have several customers who run the Amsoil 15w40 in 5.0L and 7.4L, Mercruiser inboards. The oil is still in good shape after 125 hours. Their 20w-50, high performance synthetic oil (CI-4/CF-2/SJ rated), would also work very well in this application and reduce oil consumption; compared to the Amsoil 15w40. A number of commercial fishing boats with diesel engines run the Amsoil 15w40 or Delvac 1 (typically with bypass filters) - either will hold up fine in this application.
I'd imagine that "Ken2" In Wash State is aware of boats running multigrade synthetic lubes; combined with bypass filters....
Petroleum based, multigrade oils shear very badly in Marine inboard applications, hence the MM recommendation to use a straight weight oil ....
Tooslick
www.lubedealer.com/Dixie_Synthetics
I'd imagine that "Ken2" In Wash State is aware of boats running multigrade synthetic lubes; combined with bypass filters....
Petroleum based, multigrade oils shear very badly in Marine inboard applications, hence the MM recommendation to use a straight weight oil ....
Tooslick
www.lubedealer.com/Dixie_Synthetics
In finding a synthetic replacement for the Mercruiser 25-40 oil, Merc states (bold added):
"To help obtain optimum engine performance and to provide maximum protection, we recommend the use of Mercury Precision 4-Cycle 25W-40 Marine Engine Oil. This oil is a special blend of 25-weight and 40-weight oils for marine engines. If not available, a good grade, straight weight, detergent automotive oil of correct viscosity, with an API service rating of SH,CF/CF-2 may be used. "
In reading up about API levels, I see that the SH is obsolete, so no problem choosing an SJ or SL.
My confusion comes from the diesel CF/CF-2 requirement. If an oil is rated for CF-4 or CI-4, will it meet the requirements of CF/CF-2?
Also, what do you all think of Royal Purple's HDEO 40? It is the only straight 40 weight synthetic oil that I have found so far.
"To help obtain optimum engine performance and to provide maximum protection, we recommend the use of Mercury Precision 4-Cycle 25W-40 Marine Engine Oil. This oil is a special blend of 25-weight and 40-weight oils for marine engines. If not available, a good grade, straight weight, detergent automotive oil of correct viscosity, with an API service rating of SH,CF/CF-2 may be used. "
In reading up about API levels, I see that the SH is obsolete, so no problem choosing an SJ or SL.
My confusion comes from the diesel CF/CF-2 requirement. If an oil is rated for CF-4 or CI-4, will it meet the requirements of CF/CF-2?
Also, what do you all think of Royal Purple's HDEO 40? It is the only straight 40 weight synthetic oil that I have found so far.
Amsoil 15w40 would be perfect.
Amsoil 15w40 Heavy Duty Diesel and Marine oil. Really. No need to look further.
Grease;
CF-2 oils are Detroit Diesel (DD) two stroke single grades.
The new shear stable CI-4s in 10W30 and 15W40 multi-grades, I think, makes Merc's original recomendation of a CF-2 25W40 a little obsolete.
25W40 is a single grade SAE40 that happens to pass SAE's 25W cold crank and flow tests.
Big deal.
Most modern SAE 40 CF-2 HDMOs formulated from group II base oils would likely pass a 20W flow test, but are not marketed as 20W40s.
The better CF-2 SAE 30s are likely 15W30s, but who cares?
The point is CF-2s are alegedly formulated without VI improvers, and are therefore and supposedly shear stable.....
I believe the risk Merc is trying to avoid is owners using cheap dino PCMO multi-grades.
CF-2 oils are Detroit Diesel (DD) two stroke single grades.
The new shear stable CI-4s in 10W30 and 15W40 multi-grades, I think, makes Merc's original recomendation of a CF-2 25W40 a little obsolete.
25W40 is a single grade SAE40 that happens to pass SAE's 25W cold crank and flow tests.
Big deal.
Most modern SAE 40 CF-2 HDMOs formulated from group II base oils would likely pass a 20W flow test, but are not marketed as 20W40s.
The better CF-2 SAE 30s are likely 15W30s, but who cares?
The point is CF-2s are alegedly formulated without VI improvers, and are therefore and supposedly shear stable.....
I believe the risk Merc is trying to avoid is owners using cheap dino PCMO multi-grades.
UF,
Thanks for the help understanding this CF/CF-2 confusion.
Yes, Merc is really behind on oil recommendations.
Now I will have less reservation about using non-Merc oil.
Thanks for the help understanding this CF/CF-2 confusion.
Yes, Merc is really behind on oil recommendations.
Now I will have less reservation about using non-Merc oil.
My owners manual says the same thing on my boat, but it's a '96. I'm sure they've upped their specs on the newer boat maintenance manuals. Anyway, I sure wouldn't run the Mercruiser brand of oil. Now I like their greases and outdrive fluids, but that's it. I started out using a straight wt. 40, but oil pressure was pegging the needle at 60 psi. Didn't like that. Went to pennz. 15w40 and got about 50 psi at WOT and about 30 at immeadiate idle. Plus, I believe the Pennz. 15w40 is their equal to diesel oils.
Mine is a 2001 and it still says this. I know people with newer boats powered by Merc that complain of the same recommendations.
I think if I were to use a dino in this boat (and I may next year), I will use any of the HDEO's from Penn, Mobil, or Chevron.
I think Merc is comfortable with this situation because they make money on their oil AND they don't mind the rebuild dollars due to shorter life.
[ December 14, 2003, 09:56 AM: Message edited by: Grease is the word ]
I wonder if running a SL rated oil in a marine engine is a bad thing these days. Especially the dino's and maybe even some of the synthetics (mobil?). The impression I'm getting from talk in the other subject areas here on BITOG and from noria and other publications is that the SL oils are formulated more for EPA reasons such that there seems to be a trend to less zinc and phosphorus (traditional anti-wears) in them, to help decrease the risk of catalytic converter poisoning I guess and theoretically reduce emissions. Maybe an expert on the subject can add more? But this may be one case where you would not want to go with the latest API rating off the store shelf. I don't remember/know the changes over the past few years from SF on up, but it may be better to find one of those if not going with a heavy duty diesel oil or a non-api synthetic like amsoil, RP, or redline.
Comments?
I had done a used oil analysis on my 2002 bayliner, after running the factory fill oil for the 1st 10hrs. It had sheared into the 30wt region, and analysis showed high magnesium #'s for anti-wear.
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=3;t=000301
[ February 09, 2004, 10:56 PM: Message edited by: 1 FMF ]
Comments?
I had done a used oil analysis on my 2002 bayliner, after running the factory fill oil for the 1st 10hrs. It had sheared into the 30wt region, and analysis showed high magnesium #'s for anti-wear.
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=3;t=000301
[ February 09, 2004, 10:56 PM: Message edited by: 1 FMF ]
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