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skidemon
08-07-2006, 11:26 AM
Can anyone clarify for me the need for using 15W40 engine oil?
This may be an old bit for most of you, but I have a hard time understanding why the marine version of the GM 5.7L (350cu.in.) would require 15W40 and the automotive application uses 10W30 or 5W30.

:confused:

bigmac
08-07-2006, 11:40 AM
Can anyone clarify for me the need for using 15W40 engine oil?
This may be an old bit for most of you, but I have a hard time understanding why the marine version of the GM 5.7L (350cu.in.) would require 15W40 and the automotive application uses 10W30 or 5W30.

:confused:

A marine engine is far more extreme duty. There's no transmission to keep the engine in its optimum torque range, so you're constantly lugging it, then overrevving it. When's the last time you ran your GM truck at 4000-5000 rpm all day?

Anyway, the issue is not the viscosity of the oil, it's its shear resistance and this is reflected in its API service classification rating. IIRC, your boat calls for CH-4/SJ . CH-4 is called for by commercial-type diesel applications and SJ is an automotive application, indicating the the oil is suitable for either.

skidemon
08-07-2006, 11:47 AM
Thank BigMac. Excellent points, I didn't think about the revs. If I want to run a synthetic oil, Mobil 1 has 15W50. What are the thought's on Mobil1 15W50? Is there a synthetic available ni 15W40?

bigmac
08-07-2006, 12:08 PM
Thank BigMac. Excellent points, I didn't think about the revs. If I want to run a synthetic oil, Mobil 1 has 15W50. What are the thought's on Mobil1 15W50? Is there a synthetic available ni 15W40?
Synthetic won't hurt anything, it's just a waste of money as long as you follow engine mfgr's recommendations regarding oil change. Any oil that meets or exceeds CH-4/SJ, synthetic or not, will work fine in your boat and provide it with all the protection you need.

thijs
08-08-2006, 03:18 PM
Absolutely there are 15w40 synthetic oils. That is all we ran in our diesel ambulances in Hinton. (I agree a waste of money though).

pflcjl
08-15-2006, 07:58 AM
Is it really a waste of money? I change my oil twice during the summer at 35 hours and prior to storage. I was thinking of using amzoil synthetic and changing only once in the fall prior to storage. Based on the belief that synthetic can go longer between change intervals. Thoughts?

bigmac
08-15-2006, 08:40 AM
Is it really a waste of money? I change my oil twice during the summer at 35 hours and prior to storage. I was thinking of using amzoil synthetic and changing only once in the fall prior to storage. Based on the belief that synthetic can go longer between change intervals. Thoughts?

The difference between synthetic oils and group II-based oils is mainly shear resistance. Since catalytic refining, there's not that much difference in the viscosity index of the group II and group III base stocks, therefore much less need for viscosity index improvers (long chain polymers that make multi-viscosity oils like 15W40). VI improvers are what breaks down in multi-viscosity oil, therefore less VI improver = less to break down. Your oil change schedule, or even Indmar's recommended intervals, is such that there is negligible shear breakdown of CH-4/SJ oil, therefore synthetic gets virtually no advantage. Nothing wrong with synthetic oil - it's good stuff. Just unnecessary.

Indmar has no stake in the success of the oil companies, but they do have a huge stake in the longevity of their engines. If they thought synthetic would be better for their engines -- longer engine life, better Indmar reputation, fewer warranty claims -- they'd just recommend it instead of 15W40 - no skin off their nose. Same is true of all the auto manufacturers, especially those with 5 year or longer power train warranties.

That this question keeps coming up indicates the stunning success of the oil companys' marketing.

bret
08-15-2006, 09:10 AM
just a note about Mobil 1. I race Porsches on the weekends sometimes and almost of all the cars, except for some of the newer ones being less than 3 years old, are all OFF Mobil 1 because of thinning concerns, catch cans from crankcase vents being more full, and some seals leaking even after being replaced by new ones. I don't know what changed in the formulation after the merger between Exxon/Mobil but from my use and others - it isn't the oil it used to be.

Amsoil is very expensive and I think it would be overkill in a boat but it's your boat and your $$.

trickskier
08-16-2006, 02:24 PM
Synthetic won't hurt anything, it's just a waste of money as long as you follow engine mfgr's recommendations regarding oil change. Any oil that meets or exceeds CH-4/SJ, synthetic or not, will work fine in your boat and provide it with all the protection you need.

I have a 2 questions Bigmac. I was told by the people at Mobil that synthetic oils run cooler and they do not contain any varnish, so seals remained pliable and did not harden. Can you comment?

bigmac
08-16-2006, 02:32 PM
I have a 2 questions Bigmac. I was told by the people at Mobil that synthetic oils run cooler and they do not contain any varnish, so seals remained pliable and did not harden. Can you comment?

No catalytically-refined base oil has any "varnish" in it (whatever that is). In the "old days" 60 years ago or more, paraffin was a common component of oils. As to running cooler, hogwash -- oil temp is a function of engine temp, heat dissipation is a function of engine design.

trickskier
08-16-2006, 02:40 PM
No catalytically-refined base oil has any "varnish" in it (whatever that is). In the "old days" 60 years ago or more, paraffin was a common component of oils. As to running cooler, hogwash -- oil temp is a function of engine temp, heat dissipation is a function of engine design.

Thanks for clearing that up.....One other question......Is the Mobil 1 oil filter worth the extra money?

bret
08-16-2006, 02:49 PM
Mobil 1 filter is a WIX filter, so is K&N, just like a shirt factory - some go to Wal Mart packaging some go to Dillards - Lord&Taylor, etc.

Get a WIX.

trickskier
08-16-2006, 03:00 PM
Mobil 1 filter is a WIX filter, so is K&N, just like a shirt factory - some go to Wal Mart packaging some go to Dillards - Lord&Taylor, etc.

Get a WIX.

Do you have a cross over number for a Mobil M1-302 to a Wix?

bigmac
08-16-2006, 03:14 PM
Wix makes very good filters, Fram makes very BAD filters, and they make them for several companies, including Pennzoil. The PZ-3 that MC recommends for the MCX is a bad, bad filter.

The WIX filter is 51069 . The AC PF-25 has been replaced by the PF-454. You can buy the PF-454 at any GM dealer (and elsewhere, I'm sure). IIRC, I bought the WIX at NAPA.

BrianM
08-16-2006, 03:20 PM
I'l chime in here with save your money and just buy dino oil and change at regular 50 hour intervals.

From my reading the Napa Gold filters are also at the top of the heap and are readily available and fairly inexpensive. Part number is Napa 1069

rspiecha
08-16-2006, 03:49 PM
Is the Mobil 1 or K&N filter ok??? I can always find them at Autozone.

Thanks

Rob

trickskier
08-16-2006, 04:03 PM
Is the Mobil 1 or K&N filter ok??? I can always find them at Autozone.

Thanks

Rob

That's all I use. But may think about switching to WIX.

trickskier
08-16-2006, 04:13 PM
I'l chime in here with save your money and just buy dino oil and change at regular 50 hour intervals.

From my reading the Napa Gold filters are also at the top of the heap and are readily available and fairly inexpensive. Part number is Napa 1069

Brian I don't know if I quite agree with you on your choice of oil. I am a maintenance freak. I have been around shops and race cars all my life. I have always been told that it is very important to run a good quality oil & oil filter. From what I've been told it's the additive packages that make the difference. I believe in preventative maintenance, I hate the thought of breaking down. So I don't mind spending a few extra $$$ if the product will prevent a breakdown in the future.

As for the Fram products I would not use that JUNK on my lawn mower!

bigmac
08-16-2006, 06:54 PM
Brian I don't know if I quite agree with you on your choice of oil. I am a maintenance freak. I have been around shops and race cars all my life. I have always been told that it is very important to run a good quality oil & oil filter. From what I've been told it's the additive packages that make the difference. I believe in preventative maintenance, I hate the thought of breaking down. So I don't mind spending a few extra $$$ if the product will prevent a breakdown in the future.

As for the Fram products I would not use that JUNK on my lawn mower!

The point being that any CH-4/SJ or higher oil, dino or otherwise IS good quality oil. Synthetic oil is absolutely NO less likely to prevent a breakdown than dino oil of the same API service classification.

No offense meant, but the auto racing fraternity is not any more immune to hype and hucksterism in the oil biz than anyone else. Andy Granatelli was a HUGE part of auto racing, and he is universally known as the PT Barnum of the oil business.

As to additive packages, that used to be true before the days of catalytic refining/hydrogen cracking/iso-dewaxing. Now, the quality of the oil is determined almost entirely by the base stock it comes from. Our family oil biz has had very close ties to Lubrizol (http://www.lubrizol.com/index.asp) for 40 years. No bigger additive manufacturer in the world.

Farmer Ted
08-16-2006, 07:09 PM
what would happen if I were to switch from synthetic to regular oil on an engine that has 350 hours and has been using nothing but synthetic (I assume) since the post break in period?

bigmac
08-16-2006, 07:13 PM
what would happen if I were to switch from synthetic to regular oil on an engine that has 350 hours and has been using nothing but synthetic (I assume) since the post break in period?

Nothing.


:dance:

Farmer Ted
08-16-2006, 07:53 PM
Since we're on Mobil 1, what's the deal with the 15,000 mile oil? I can't remember what they call it, extended performance or something but how can that be good running oil for 15,000 miles between oil changes?

I think the Air Force did something like that awhile back but did a filter change every 5,000?

bigmac
08-16-2006, 08:15 PM
Since we're on Mobil 1, what's the deal with the 15,000 mile oil? I can't remember what they call it, extended performance or something but how can that be good running oil for 15,000 miles between oil changes?

I think the Air Force did something like that awhile back but did a filter change every 5,000?Oil "wears out" based on breakdown of the viscosity index improver, and accumulation of soot and other combustion products. The latter issue is handled by detergent additives to keep those particles in suspension, and the detergent content of virtually all modern multi-viscosity oils is generally the same, synthetic or dino. The other part of the additive packages is the VI improver, and group II oils like Pennzoil or Rotella T 15W40 have more of that than group III oils (synthetics). And that long-chain polymer VI improver does break down (shear), but not much, because group II base oils use far less VI improver than in the old days. So, to go 50 hours in your MasterCraft, or to go 6000 miles between oil changes (as recommended in the last 3 GM trucks I've owned) is something current "dino" oil can do easily.

No, soot accumulation makes "extended oil changes" unwise no matter what the oil. Think of it like doing dishes in soapy water in your sink - wash the first dish, no problem, but aren't you just a little uncomfortable with washing that last dish in that grungy, food-scrap-laden water? Even though it has the same amount of detergent you started out with?

Jesus_Freak
08-17-2006, 01:51 PM
Hey bigmac, your PM box is full.

bigmac
08-17-2006, 02:52 PM
Hey bigmac, your PM box is full.

:o



.

.

BrianM
08-17-2006, 03:08 PM
Brian I don't know if I quite agree with you on your choice of oil. I am a maintenance freak. I have been around shops and race cars all my life. I have always been told that it is very important to run a good quality oil & oil filter. From what I've been told it's the additive packages that make the difference. I believe in preventative maintenance, I hate the thought of breaking down. So I don't mind spending a few extra $$$ if the product will prevent a breakdown in the future.

As for the Fram products I would not use that JUNK on my lawn mower!

I use high quality dino oil and filters. I run the Rotella T 15w 40 with Napa Gold 1069 filter. The Rotella meets and exceeds all current ratings for Indmar and as I stated before the Napa Gold filters get great ratings and I belive are actually the same as the Wix as well. I change oil and filter every 50hours and at the end of the season.

If you think that you are doing you and your engine better by running synthetic by all means run it. But the research isn't there to show any increased benefits over running high quality dino with regular change intervals.

TRBenj
08-18-2006, 10:28 PM
Bigmac, out of curiosity, what oil do you use? I have been using Castrol GTX in my car for several years and recently put Shell Rotella 15w40 in the boat. From what Ive read, Castrol, Shell and Valvoline seem to be better oils than Pennzoil and Quaker State.

Whats your take on it?

bigmac
08-18-2006, 11:18 PM
Bigmac, out of curiosity, what oil do you use? I have been using Castrol GTX in my car for several years and recently put Shell Rotella 15w40 in the boat. From what Ive read, Castrol, Shell and Valvoline seem to be better oils than Pennzoil and Quaker State.

Whats your take on it?I use Rotella T, but only because it's easier to find than any of the others. All those oils are the same quality level IMHO. In my cars I run whatever it is that they sell at Rapid Oil Change - Valvoline, I think. In my dirt bikes and quads (all thumpers, no ring-dings), I use Valvoline, again only because they sell it at the local hardware store right next to the Rotella T. In my Harley, I use the HD synthetic, mainly because it can be used also in the chain case and transmission, and also because that sucker runs darn hot.

IMHO, people should pay MUCH more attention to the brand of oil filter they use than they do to the oil.

Footin
08-18-2006, 11:21 PM
Mobil1 15W-50 oil, Wix filter.