Oil for 8.1 Vortec in 12 ton Motorhome
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Originally Posted By: jongies3
I'd like to try that Castrol 0W-30, but trying to find that anywhere around here's about as easy as finding Pennzoil Ultra, it just don't exist! Everyone and their sister-in-law uses Mobil 1 in these parts so other synthetics are kinda pushed aside.
That is what I currently run in the 8.1, but finding it on the road is hard. It is near the upper end of the 30W range though.
I'd like to try that Castrol 0W-30, but trying to find that anywhere around here's about as easy as finding Pennzoil Ultra, it just don't exist! Everyone and their sister-in-law uses Mobil 1 in these parts so other synthetics are kinda pushed aside.
That is what I currently run in the 8.1, but finding it on the road is hard. It is near the upper end of the 30W range though.
Thoughts on using Mobil-1 0W-40 in the 8.1 since it is near the bottom of the 40W range?
Originally Posted By: vettenuts
Thoughts on using Mobil-1 0W-40 in the 8.1 since it is near the bottom of the 40W range?
And yet you wrote this just a few posts back?
Originally Posted By: vettenuts
Owner's manual specifically states not to use a -40 oil.
If you really are concerned about that warning in the owner's manual then a 0W-40 is a wider viscosity spread than a 5W-40. The problem at the time that gave rise to that warning is directly related to viscosity spread.
Having said that however, you could use Mobil 1 0W-40 with no issues whatsoever in that engine. That oil is nothing like the 10W-40 of the past.
Thoughts on using Mobil-1 0W-40 in the 8.1 since it is near the bottom of the 40W range?
And yet you wrote this just a few posts back?
Originally Posted By: vettenuts
Owner's manual specifically states not to use a -40 oil.
If you really are concerned about that warning in the owner's manual then a 0W-40 is a wider viscosity spread than a 5W-40. The problem at the time that gave rise to that warning is directly related to viscosity spread.
Having said that however, you could use Mobil 1 0W-40 with no issues whatsoever in that engine. That oil is nothing like the 10W-40 of the past.
Not unless you explain how that application makes those engines invulnerable to the supposed "problems" a 40 weight oil would cause in a land engine.
Then again, I specifically addressed land engines by pointing out that most of them lived their life with fleet HDEO oil.
Then again, I specifically addressed land engines by pointing out that most of them lived their life with fleet HDEO oil.
I don't have a dog in this arena. I do build BBC engines for hi-po applications. I do not build tight engines, but rather what I call droolers with extra oiling. Big ends are looser than OEM specs. And they are broken in on most often on VR-1. Once broken in, they are changed to Delo 400 15W-40.
Since VR-1 is no longer saleable in Kalif (
), I have now acquired a stash of Delo 15W-30 SD (severe duty) for new motor break-in and they will still be changed to XW-40 for street. Why, because the street around here can mean long periods of idling or low RPM while creeping through traffic and I trust a good 40 better in those situations. Coupled with a loose converter, it means lots of idle, blast, idle ... driving.
None of the current crop of mixed fleet HDEO's are bad. Some are better than others at some things. The OP does not have one of my engines. He can live on a 30 probably. But all the folks suggesting Rotella T6 are prolly the most right on. Why, because even though it's labeled a 40 (at op temp) it's on the light side for a true 40. I say it's really a 35 and that ought to be just what this 8.1wants when pulling hard.
In addition, even though it's it's a wide spread oil, it is a synthetic (USA style) and very robust oil without any chatter about ring sticking or any other faults. It gets used in all sorts of vehicles that it might not be thought applicable and it always comes back looking like a good choice. Ask the turbo Subie owners, or the Buick GN guys, or the Saab guys...
And I've seen my share of innards of BBC's, some run on Rotella and they look OK. Nothing out of the ordinary. No stuck rings, no abnormal wear patterns, nada ...
It's cheap enough and it's readily available. Run one cycle and do a UOA and see what you get. It's good for a one year change interval easily. Maybe two
Since VR-1 is no longer saleable in Kalif (
None of the current crop of mixed fleet HDEO's are bad. Some are better than others at some things. The OP does not have one of my engines. He can live on a 30 probably. But all the folks suggesting Rotella T6 are prolly the most right on. Why, because even though it's labeled a 40 (at op temp) it's on the light side for a true 40. I say it's really a 35 and that ought to be just what this 8.1wants when pulling hard.
In addition, even though it's it's a wide spread oil, it is a synthetic (USA style) and very robust oil without any chatter about ring sticking or any other faults. It gets used in all sorts of vehicles that it might not be thought applicable and it always comes back looking like a good choice. Ask the turbo Subie owners, or the Buick GN guys, or the Saab guys...
And I've seen my share of innards of BBC's, some run on Rotella and they look OK. Nothing out of the ordinary. No stuck rings, no abnormal wear patterns, nada ...
It's cheap enough and it's readily available. Run one cycle and do a UOA and see what you get. It's good for a one year change interval easily. Maybe two
Certainly cheap enough. T6 5w40 is currently going for 2 for $40 at Love's Truck stops nationwide.
4WD
$50 site donor 2024
Lots of plugging of a particular brand/oil - but I'd select one of the name brand HDEO's. Half dozen of them are up to this task.
Big part of "workouts" like that rig is dealing with (these days) are done by PSD, Cummins, or Duramax ...
Big part of "workouts" like that rig is dealing with (these days) are done by PSD, Cummins, or Duramax ...
I'd use any PCMO fully synthetic 10W30. These should have the least VII and shear back the least. My second choice would be a semi-syn HDEO 10W30.
If you don't want to run T6, the Delo 400 SD would be my second choice. 15W-30 is as stout a multi as you can get and it has the full classic additive package including 1200 ppm zinc. If the motor is tight and using little oil, the downstream effects will be near zero and the wear should be exemplary
Originally Posted By: vettenuts
Originally Posted By: CONMCK
Before deciding on whether a -30 or a -40 is better your owners manual is a good place to start, and I'm assuming your workhorse has an engine oil cooler. So the question is what would the viscosity of the oil be at running temperature? I'm thinking good quality 5w-30 would be fine.
Owner's manual specifically states not to use a -40 oil.
No, it states not to use 10w-40...due to the 30 point spread which GM used to not recommend. As stated by others, that recommendation is not valid anymore with todays oils. 15w-40 or 5w-40 would be great choices in that engine/weight combo.
Originally Posted By: CONMCK
Before deciding on whether a -30 or a -40 is better your owners manual is a good place to start, and I'm assuming your workhorse has an engine oil cooler. So the question is what would the viscosity of the oil be at running temperature? I'm thinking good quality 5w-30 would be fine.
Owner's manual specifically states not to use a -40 oil.
No, it states not to use 10w-40...due to the 30 point spread which GM used to not recommend. As stated by others, that recommendation is not valid anymore with todays oils. 15w-40 or 5w-40 would be great choices in that engine/weight combo.
Originally Posted By: FlyNavyP3
Originally Posted By: Ramblejam
Originally Posted By: FlyNavyP3
However my question is still why?
If you had a 454, and put a stroker kit on it, would you stick with the 5/10w-30?
Actually yes, I would and I have. As well as several stroked SBC Small and Big Mopars as well. Why? Because I built the engines with clearances that would support that choice in oil. I'm currently building a 454 for my 1976 K10 that will also run a 30wt oil. Every one of the engines listed that I built had a specific output higher than the OP's 496 as well.
The race shop I used to work in as a dyno tech and cylinder head guy (pre Navy) almost never put anything heavier than a 30wt in any engine we ever had on the dyno. To include some exotic engines, a twin turbo LS that made over 2,000 hp and was on the cover of Hot Rod magazine, a FE ford that spun 8,800 rpm, a naturally aspirated 4.3 Chevy V-6 for a race truck that made 460 hp without touching the cylinder heads, no roller cam, flat top pistons, and less than 0.500 lift, that engine was spun to 7,600 just to name a few. All of those engines were run on the dyno and in service on nothing more than 10w30 Mobil one.
How long can you wot a 2000 hp car?
Originally Posted By: Ramblejam
Originally Posted By: FlyNavyP3
However my question is still why?
If you had a 454, and put a stroker kit on it, would you stick with the 5/10w-30?
Actually yes, I would and I have. As well as several stroked SBC Small and Big Mopars as well. Why? Because I built the engines with clearances that would support that choice in oil. I'm currently building a 454 for my 1976 K10 that will also run a 30wt oil. Every one of the engines listed that I built had a specific output higher than the OP's 496 as well.
The race shop I used to work in as a dyno tech and cylinder head guy (pre Navy) almost never put anything heavier than a 30wt in any engine we ever had on the dyno. To include some exotic engines, a twin turbo LS that made over 2,000 hp and was on the cover of Hot Rod magazine, a FE ford that spun 8,800 rpm, a naturally aspirated 4.3 Chevy V-6 for a race truck that made 460 hp without touching the cylinder heads, no roller cam, flat top pistons, and less than 0.500 lift, that engine was spun to 7,600 just to name a few. All of those engines were run on the dyno and in service on nothing more than 10w30 Mobil one.
How long can you wot a 2000 hp car?
A 2000hp car uses several gallons of fuel per minute. Not long.
I'm not sure why the duration at WOT is relevant. The point was that the engines survived without incident on 10w30. The 2000 HP was a major dyno mule and made hundreds of 2000+ HP pulls with significantly higher cylinder pressure than the engine in question and significantly higher bearing speed and load. Perhaps the blown marine 540 BBC that we built would be a more appropriate comparison they made 1500-1650 HP depending on the blower and pulley they were run WOT in service more often than not. All apples to oranges compared to the OP usage. However he's also had acceptable service from a 30wt oil as the General suggested. Why fix what's not broken AND use an oil that's specifically not recommended? I really don't understand the desire to willfully ignore a warning when there hasn't been an issue on 30wt.
Just adding another data point--
Our family ran a 2003 Sea Ray mid-cabin cruiser with a pair of regular, non HP 8.1s (370 horsepower variant, if memory serves) for several years and some hundreds of hours. That boat was 18,500# dry, plus 250 gallons of gas, 50 gallons of water, and lots and lots of gear. At a 22 mph cruise, it burned roughly 28 gallons per hour.
The boat spent 20% of its running time at a fast idle speed and 80% at a 3200-3400 rpm cruise for long periods of time. It ran a 25w-40 semi synthetic or dino since new, with a somewhat shady maintenance history by the previous owner. I don't ever recall needing to add oil to either engine while we owned it. Yes, our boat had a closed cooling system with a coolant tank. Boat made a glorious noise at wide open throttle with those engines in almost perfect sync...just don't look down at the fuel flow meter!!
Our family ran a 2003 Sea Ray mid-cabin cruiser with a pair of regular, non HP 8.1s (370 horsepower variant, if memory serves) for several years and some hundreds of hours. That boat was 18,500# dry, plus 250 gallons of gas, 50 gallons of water, and lots and lots of gear. At a 22 mph cruise, it burned roughly 28 gallons per hour.
The boat spent 20% of its running time at a fast idle speed and 80% at a 3200-3400 rpm cruise for long periods of time. It ran a 25w-40 semi synthetic or dino since new, with a somewhat shady maintenance history by the previous owner. I don't ever recall needing to add oil to either engine while we owned it. Yes, our boat had a closed cooling system with a coolant tank. Boat made a glorious noise at wide open throttle with those engines in almost perfect sync...just don't look down at the fuel flow meter!!
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