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| [GMCnet] Synthetic oil Just some thought's [message #282221] |
Thu, 16 July 2015 01:11  |
BobDunahugh
Messages: 2465
Registered: October 2010
Location: Cedar Rapids, IA
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From: yenko108@hotmail.com
To: robmueller@iinet.net.au
Subject: RE: Synthetic oil
Date: Wed, 15 Jul 2015 23:27:39 -0500
I'm not saying here that any oil type is good, or bad. All engine
oils are the best they've ever been now days. And you need to match the oil to the service duty it's expected to handle. There are lots of angles to the
story of oils. What we have now is old tech engines in a new tech world. And
what's below should be considered fruit for thought. New tech products aren't
always the best for our old tech engines. All I ask is to think about what
you're doing. We need to do things that put us in our own comfort zone. Bob
Dunahugh
They say that syn's take heat better. That is correct. Gas engines have
been using mineral base oils for over 100 year. And now, oils are better than
they ever have been. And have performed well over all these years. If you had
gas engines operating at 300 degrees. OK. Synthetic oils would be the oil of choice. But our engines don't. We're in the 200 area. I just don't see syn oils as
fixing a problem that doesn't exist for us. I believe our old oils are good to
290 degrees. That's well above where we'll ever go. If we hit 250 degrees, our
engines are gone no matter the oil. I don't know syn oil limits. Let's say 1000
degrees. If that range was raised to 1500 degrees. Does that mean that it's
even better at 1500. Still doesn't make it any better for us when we operate in
the 220 range max.
SYN's can be used
for more miles. But that doesn't mean that the filter's life is extended. It's
really simple. The longer any oil is in use in any engine. The more the oil filter
gets restricted by contamination. And that means that the more oil is unfiltered due to the oil
filter bypass valve. By 3000 miles. I'll bet that our oil filter bypass valve
has alot more oil going thrue it then the filter. With our old
tech engines. They put alot of contaminants in the oil that the filter can't
take out. The oil, and filter needs to be changed at 3000 miles. I use diesel
oils in everything I have. SM rated oil is to be used in engines with SPARK
ignition systems only. CJ rated oils are for COMPRESSION ignition engines. (
Diesel ). Some oils are rated SM/CJ. These oils can be used in both. Diesel
oils are made to handle more heat, and contaminants then oils rated for spark ignition. ( gas ) SYN oils are great in
modern engines. As those engines are much cleaner do in part because of EPA
regulations. Thus contaminate the oil less. In our 08 Chevy Uplander. At 1000
miles. The oil is very clean at that mileage. At 1000 miles in the GMC. It's
black. And the best way to get that contamination out is to simply drain it.
Draining will get 99% of the contamination out of the crankcase. Not just what ever,
the filter may get. My daughter is a doctor. She can afford to get rid of her
98 Chevy Astro. She bought it new. She just loves that van. It's at 339,000
miles. Uses just under 1 qt for 3000 miles. I have a 96 Astro that's at
294,000. Same story. Can anyone say that syn oils could top that service. I've
seen 3 GMC's that have syn oils in them. And everyone of them have more oil
mist under them then my GMC with 154,000 miles. If you want a gas engine to
last. Change the oil ( whatever it is ) every 3000 miles to really get the junk
out.
I know there are people that build engines that recommend
syn oils. That's fine. I'm not saying they're wrong at all. And I don't know
the bases of what their recommendations are. Other than what I've mentioned
above. Just at lease change the filter every 3000 miles. But if you're going to
do that. Why not drain the rest of the contamination out will your under there
anyway. Oils cheep.Engines aren't. Most of the engines that I build are run
hotter, and harder than our GMC's. And the throttle is wide open most of
the time at extreme RPM's. That's alot more load than any GMC will ever see. As
for recommendations for oil. I don't have any. I just mention what's above. I'm more interested in the oil filter change. As for our old tech stock engines. I recommend
what GM recommends on change intervals. After all. Their the ones that designed the engine. I'm not big
on someone's opinion that aren't based on basic facts. They're not the one that's going to paying for the next
rebuild. You are.
.
In short. Think about it. Does this really make some
sense? Bob Dunahugh
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| Re: [GMCnet] Synthetic oil Just some thought's [message #282238 is a reply to message #282221] |
Thu, 16 July 2015 13:42  |
Dennis S
Messages: 3046
Registered: November 2005
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EDITED quote follows for context
BobDunahugh wrote on Thu, 16 July 2015 01:11
I'm not saying here that any oil type is good, or bad. All engine
oils are the best they've ever been now days. And you need to match the oil to the service duty it's expected to handle. There are lots of angles to the
story of oils. What we have now is old tech engines in a new tech world. And
what's below should be considered fruit for thought. New tech products aren't
always the best for our old tech engines. All I ask is to think about what
you're doing. We need to do things that put us in our own comfort zone. Bob
Dunahugh
Bob,
Thank you for sharing your thoughts. You touch on high temp operation, extreme rpm and extended life of synthetics.
The one big reason I have understood when listening to the engine builders reasoning for synthetics is cold start orotection.
The explanation I have heard/understood is that synthetics hold to the internal surfaces better during storage -- and since our coaches are likely to stand for longer periods of time, synthetic oil provides enhanced lubrication at a critical time. It is often commented that most internal component wear is occurring at start-up.
Beyond that -- there are any number of GMC owners whom I respect that offer their experiences.
1- uses syn 15-50
2 - uses MoS2 additive
3 - uses ZDDP additive
4 - uses only diesel oil
So -- interesting to discuss -- and as you say we should each evaluate our own coach usage and equipment -- then make a thoughtful decision, not rely on a single view point one size fits all decision.
Me -- I have an inventory of diesel oil that I have stocked for the engine and the Onan.
Dennis
Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: [GMCnet] Synthetic oil Just some thought's [message #282265 is a reply to message #282263] |
Thu, 16 July 2015 20:49 |
A Hamilto
Messages: 4508
Registered: April 2011
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USAussie wrote on Thu, 16 July 2015 20:35Mark,
I've been running Shell Rotella T 15W-40 in the Onan.
Please advise why that is not a good idea and straight 30W is better.
I would think that Shell Rotella of 2015 is way superior to straight 30W of the 1970's.
The operative words in the above sentence are; "I would think."
Regards,
Rob M.
The Pedantic Mechanic Is Shell Rotella synthetic?
As the oil wears in use, the viscosity modifiers also wear (or shear to be specific) and the oil gradually loses some of it high temp capability. For example a 10W40 will degrade over time to perform like a 10W30 and then a 10W20 until it is effectively a 10 weight with no high temp protection.
Synthetic oils have an inherently wider viscosity index, and hence require less viscosity modifiers to achieve the same performance as dino oil; conversely they do not break down as much as when they wear.
Air cooled engines run hotter and are subject to greater temperature swings because they don't have the mass of the block and the coolant to function as a heat sink. Also, water cooled engines are thermostatically controlled resulting in a narrower operating range. Small air cooled engines have no thermostatic controls and are especially vulnerable to overheating when operated at less than full rpm with a heavy load.
Besides, my sister is a mechanic for the National Guard, maintains and repairs everything from weedeaters to 2-1/2 ton trucks, road graders, and dozers. She ran a lawnmower (small engine) repair shop for 10 years before joining the guard, and was trained in small engine repairs. And she says use straight 30 weight oil.
If you disagree with the logic, at least listen to the experience.
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| Re: [GMCnet] Synthetic oil Just some thought's [message #282266 is a reply to message #282238] |
Thu, 16 July 2015 20:44 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
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Dennis,
In Double Trouble's 455 built by Ken Frey 80,000 miles ago I use:
1) Shell Rotella T 15W-40
2) SFR Oil additive (ZDDP):
https://sfrcorp.com/product/sfr-100-petroleum-oil-fortifier/
3) Liquid Moly:
http://www.liqui-moly.de/liquimoly/produktdb.nsf/id/en_1011.html?OpenDocument&land=GB&voilalang=e&voiladb=web.nsf
Regards,
Rob M.
The Pedantic Mechanic
-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Dennis Sexton
Sent: Friday, July 17, 2015 4:43 AM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Synthetic oil Just some thought'
Bob,
Thank you for sharing your thoughts. You touch on high temp operation, extreme rpm and extended life of synthetics.
The one big reason I have understood when listening to the engine builders reasoning for synthetics is cold start orotection.
The explanation I have heard/understood is that synthetics hold to the internal surfaces better during storage -- and since our
coaches are likely to
stand for longer periods of time, synthetic oil provides enhanced lubrication at a critical time. It is often commented that most
internal component
wear is occurring at start-up.
Beyond that -- there are any number of GMC owners whom I respect that offer their experiences.
1- uses syn 15-50
2 - uses MoS2 additive
3 - uses ZDDP additive
4 - uses only diesel oil
So -- interesting to discuss -- and as you say we should each evaluate our own coach usage and equipment -- then make a thoughtful
decision, not rely
on a single view point one size fits all decision.
Me -- I have an inventory of diesel oil that I have stocked for the engine and the Onan.
Dennis
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Synthetic oil Just some thought's [message #282269 is a reply to message #282265] |
Thu, 16 July 2015 21:18 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
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Mark,
Comments below in CAPS for clarity, I'm not shouting.
Regards,
Rob M.
The Pedantic Mechanic
-----Original Message-----
From: A.
Is Shell Rotella synthetic?
NO
As the oil wears in use, the viscosity modifiers also wear (or shear to be specific) and the oil gradually loses some of it high
temp capability. For example a 10W40 will degrade over time to perform like a 10W30 and then a 10W20 until it is effectively a 10
weight with no high temp protection.
Synthetic oils have an inherently wider viscosity index, and hence require less viscosity modifiers to achieve the same performance
as dino oil; conversely they do not break down as much as when they wear.
I'M A BIT CONFUSED BY THESE TWO STATEMENTS, ARE YOU SAYING THE SYNTHETIC 1OW-30 IS BETTER THAN DINO 10W-30?
Air cooled engines run hotter and are subject to greater temperature swings because they don't have the mass of the block and the
coolant to function as a heat sink. Also, water cooled engines are thermostatically controlled resulting in a narrower operating
range. Small air cooled engines have no thermostatic controls and are especially vulnerable to overheating when operated at less
than full rpm with a heavy load.
AGREED 100%
Besides, my sister is a mechanic for the National Guard, maintains and repairs everything from weedeaters to 2-1/2 ton trucks, road
graders, and dozers. She ran a lawnmower (small engine) repair shop for 10 years before joining the guard, and was trained in small
engine repairs. And she says use straight 30 weight oil.
NOW THAT'S A COOL SISTER!
If you disagree with the logic, at least listen to the experience.
WILL HAVE TO COGITATE ON THAT A BIT! ;-)
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Synthetic oil Just some thought's [message #282273 is a reply to message #282269] |
Thu, 16 July 2015 22:22 |
A Hamilto
Messages: 4508
Registered: April 2011
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USAussie wrote on Thu, 16 July 2015 21:18Synthetic oils have an inherently wider viscosity index, and hence require less viscosity modifiers to achieve the same performance as dino oil; conversely they do not break down as much as when they wear.
I'M A BIT CONFUSED BY THESE TWO STATEMENTS, ARE YOU SAYING THE SYNTHETIC 1OW-30 IS BETTER THAN DINO 10W-30?... Sort of, but not exactly. In the same service, dino oil will turn into a single, and lower, weight oil sooner than synthetic. That's why Emery uses 15W40 dino oil in his GMC instead of 10W30. I believe if you change it often enough, it won't break down enough to matter. In our 403s and 455s, the dirt suspended in the oil needs to be removed pretty often, and you do that by changing the oil every 3000 miles, which I don't think gives it enough time for the viscosity enhancers to decompose.
I digested the stuff from "bobistheoilguy" "university" and came to the conclusion that anything bigger than a "10" before the "W" is not good at start up. Anything smaller than "10" before the "W" is not going to resist squeezing out of the main and rod bearings to lubricate like it is supposed to in these 1970s clearance engines. Anything bigger than "30" after the "W" is overkill, except in Death Valley in the Summer. But if you find yourself going much more than 3000 miles between changes, the 10W40 might hold its viscosity better.
Current formulations are better than anything available 40 years ago. There are people running their 403s and 455s on everything from 5W20 dino to 15W40 synthetic. They all have their reasoning.
Care for it and drive it. But be aware that what's good for the 403/455 is not necessarily good for the Onan.
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| Re: [GMCnet] Synthetic oil Just some thought's [message #282279 is a reply to message #282273] |
Thu, 16 July 2015 22:52 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Mark,
My modus operandi for lubricating the GMC is simple; at the end of our summer's use (maybe up to 5000 miles) I:
1) Change the 455's oil using Shell Rotella T 15W-40
2) Replace the oil filter with a Wix 51049
3) Add 5 ounces of SFR Oil Treatment to boost the ZDDP levels to 1400 ppm
4) Add 300ml of Liqi Moly
3) Change the Onan's oil using Shell Rotella T 15W-40 (no matter how many hours used)
4) Replace the Onan's oil filter with a Wix 51762
5) Grease all zerks with Valvoline Synpower
Regards,
Rob M.
The Pedantic Mechanic
-----Original Message-----
From: A.
> I'M A BIT CONFUSED BY THESE TWO STATEMENTS, ARE YOU SAYING THE SYNTHETIC 1OW-30 IS BETTER THAN DINO 10W-30?
Sort of, but not exactly. In the same service, dino oil will turn into a single, and lower, weight oil sooner than synthetic. That's
why Emery uses 15W40 dino oil in his GMC instead of 10W30. I believe if you change it often enough, it won't break down enough to
matter. In our 403s and 455s, the dirt suspended in the oil needs to be removed pretty often, and you do that by changing the oil
every 3000 miles, which I don't think gives it enough time for the viscosity enhancers to decompose.
I digested the stuff from "bobistheoilguy" "university" and came to the conclusion that anything bigger than a "10" before the "W"
is not good at start up. Anything smaller than "10" before the "W" is not going to resist squeezing out of the main and rod bearings
to lubricate like it is supposed to in these 1970s clearance engines. Anything bigger than "30" after the "W" is overkill, except in
Death Valley in the Summer. But if you find yourself going much more than 3000 miles between changes, the 10W40 might hold its
viscosity better.
Current formulations are better than anything available 40 years ago. There are people running their 403s and 455s on everything
from 5W20 dino to 15W40 synthetic. They all have their reasoning.
Care for it and drive it. But be aware that what's good for the 403/455 is not necessarily good for the Onan.
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Synthetic oil Just some thought's [message #282299 is a reply to message #282279] |
Fri, 17 July 2015 07:54 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
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USAussie wrote on Thu, 16 July 2015 22:52Mark,
My modus operandi for lubricating the GMC is simple; at the end of our summer's use (maybe up to 5000 miles) I:
1) Change the 455's oil using Shell Rotella T 15W-40
2) Replace the oil filter with a Wix 51049
3) Add 5 ounces of SFR Oil Treatment to boost the ZDDP levels to 1400 ppm
4) Add 300ml of Liqi Moly
3) Change the Onan's oil using Shell Rotella T 15W-40 (no matter how many hours used)
4) Replace the Onan's oil filter with a Wix 51762
5) Grease all zerks with Valvoline Synpower
Regards,
Rob M.
The Pedantic Mechanic
I do exactly the same thing minus the moly.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Synthetic oil Just some thought's [message #282316 is a reply to message #282265] |
Fri, 17 July 2015 10:46 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
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A Hamilto wrote on Thu, 16 July 2015 21:49<snip>
Besides, my sister is a mechanic for the National Guard, maintains and repairs everything from weedeaters to 2-1/2 ton trucks, road graders, and dozers. She ran a lawnmower (small engine) repair shop for 10 years before joining the guard, and was trained in small engine repairs. And she says use straight 30 weight oil.
If you disagree with the logic, at least listen to the experience.
While all the clipped points are valid, the thing that your sister may have missed is that us the live in the north country have to deal with cold. I used to use a straight 30 in the little engines until I had one that set up so bad that we couldn't even crank it so we could plow the driveway.
And yes, little engines do beat the crap out of their lube oil.
Matt - still waiting for the truck.
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Synthetic oil Just some thought's [message #282328 is a reply to message #282320] |
Fri, 17 July 2015 12:39 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
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A Hamilto wrote on Fri, 17 July 2015 11:12Matt Colie wrote on Fri, 17 July 2015 10:46...us the live in the north country have to deal with cold. I used to use a straight 30 in the little engines until I had one that set up so bad that we couldn't even crank it so we could plow the driveway. ... Correct. Straight 30 weight oil is not applicable to a snow blower, whatever that is. 30 weight is good down to about 40F. Not many of us mow our lawns below that. If you are running your small engine in temps below about 30F exclusively, multiviscosity is the way to go. In single digits and below, I'd want 5W30 in mine.
But by the time it gets down into the 40's, very few of us are still camping.
I hope I never need my snow blower wile I'm camping
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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| Re: [GMCnet] Synthetic oil Just some thought's [message #282363 is a reply to message #282279] |
Fri, 17 July 2015 22:11 |
Arthur Mansfield
Messages: 290
Registered: April 2010
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Why do you use ZDDP and Liq Moly. By the way Moly is not a liquid but a solid lub. Moly works into the surface and provides lubrication when starting after sitting for a while. One needs to be sure the moly used is small enough to not plug the oil passages. The 1st time I saw the use of moly was in a 1955 Plymouth It was added for 2 oil changes once the motor was brok in. At 100000 miles the engine was just as quit as it was new. I use 20 50 oil and add moly. Do not use Moly until the motor is broke in.
Art
On Jul 16, 2015, at 10:52 PM, Robert Mueller wrote:
> Mark,
>
> My modus operandi for lubricating the GMC is simple; at the end of our summer's use (maybe up to 5000 miles) I:
>
> 1) Change the 455's oil using Shell Rotella T 15W-40
> 2) Replace the oil filter with a Wix 51049
> 3) Add 5 ounces of SFR Oil Treatment to boost the ZDDP levels to 1400 ppm
> 4) Add 300ml of Liqi Moly
> 3) Change the Onan's oil using Shell Rotella T 15W-40 (no matter how many hours used)
> 4) Replace the Onan's oil filter with a Wix 51762
> 5) Grease all zerks with Valvoline Synpower
>
> Regards,
> Rob M.
> The Pedantic Mechanic
>
> -----Original Message-----
> From: A.
>
>> I'M A BIT CONFUSED BY THESE TWO STATEMENTS, ARE YOU SAYING THE SYNTHETIC 1OW-30 IS BETTER THAN DINO 10W-30?
>
> Sort of, but not exactly. In the same service, dino oil will turn into a single, and lower, weight oil sooner than synthetic. That's
> why Emery uses 15W40 dino oil in his GMC instead of 10W30. I believe if you change it often enough, it won't break down enough to
> matter. In our 403s and 455s, the dirt suspended in the oil needs to be removed pretty often, and you do that by changing the oil
> every 3000 miles, which I don't think gives it enough time for the viscosity enhancers to decompose.
>
> I digested the stuff from "bobistheoilguy" "university" and came to the conclusion that anything bigger than a "10" before the "W"
> is not good at start up. Anything smaller than "10" before the "W" is not going to resist squeezing out of the main and rod bearings
> to lubricate like it is supposed to in these 1970s clearance engines. Anything bigger than "30" after the "W" is overkill, except in
> Death Valley in the Summer. But if you find yourself going much more than 3000 miles between changes, the 10W40 might hold its
> viscosity better.
>
> Current formulations are better than anything available 40 years ago. There are people running their 403s and 455s on everything
> from 5W20 dino to 15W40 synthetic. They all have their reasoning.
>
> Care for it and drive it. But be aware that what's good for the 403/455 is not necessarily good for the Onan.
>
>
> _______________________________________________
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> Unsubscribe or Change List Options:
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| Re: [GMCnet] Synthetic oil Just some thought's [message #282371 is a reply to message #282363] |
Sat, 18 July 2015 00:06 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Art,
Comments below in CAPS, I'm not SHOUTING.
Plus it's a bit of a "tongue in cheek" response so SMILE when you read it! ;-)
Regards,
Rob M.
The Pedantic Mechanic
-----Original Message-----
From: 1104agm
Why do you use ZDDP and Liqui Moly.
HERE'S A LINK TO THE PRODUCTS:
http://www.liqui-moly.com/liquimoly/web.nsf/id/pa_eng_home.html
https://www.sfrcorp.com/
1) I'M DUMB ENOUGH TO BELIEVE THEIR MARKETING BS
2) I HAVE MORE MONEY THAN SENSE
3) THEY WON'T HURT
4) THEY MIGHT HELP
SELECT ANY ONE OR MULTIPLES OF THE ABOVE.
By the way Moly is not a liquid but a solid lub.
YEP, SEE ITEM 1) ABOVE
Moly works into the surface and provides lubrication when starting after sitting for a while.
YEP, THAT'S WHAT ITEM 1) ABOVE SAYS
One needs to be sure the moly used is small enough to not plug the oil passages.
YEP, I TRUST LIQUI-MOLY NOT TO SELL A PRODUCT THAT WOULD DO THAT AFTER ALL IT IS A GERMAN COMPANY NOT CHINESE!
The 1st time I saw the use of moly was in a 1955 Plymouth. It was added for 2 oil changes once the motor was brok in. At 100000
miles the engine was just as quit as it was new. I use 20 50 oil and add moly. Do not use Moly until the motor is broke in.
YEP, THAT'S WHAT ITEM 1) ABOVE SAYS
Art
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Synthetic oil Just some thought's [message #282378 is a reply to message #282273] |
Sat, 18 July 2015 05:28 |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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> On Jul 16, 2015, at 9:22 PM, A. wrote:
>
> USAussie wrote on Thu, 16 July 2015 21:18
>> Synthetic oils have an inherently wider viscosity index, and hence require less viscosity modifiers to achieve the same performance as dino oil;
>> conversely they do not break down as much as when they wear.
>>
>> I'M A BIT CONFUSED BY THESE TWO STATEMENTS, ARE YOU SAYING THE SYNTHETIC 1OW-30 IS BETTER THAN DINO 10W-30?...
> Sort of, but not exactly. In the same service, dino oil will turn into a single, and lower, weight oil sooner than synthetic. That's why Emery uses
> 15W40 dino oil in his GMC instead of 10W30.
Not true. I use totally synthetic Mobil 1 15w50 and have for years now. Emery
> I believe if you change it often enough, it won't break down enough to matter. In our 403s and 455s, the
> dirt suspended in the oil needs to be removed pretty often, and you do that by changing the oil every 3000 miles, which I don't think gives it enough
> time for the viscosity enhancers to decompose.
If you are going to spend the extra money for a goods synthetic it would be a waste of money to change it at 3000. I typically change at 5000. Good modern oils have modern detergents (suspension agents) that keep insolubles in suspension between changes. Emery
>
> I digested the stuff from "bobistheoilguy" "university" and came to the conclusion that anything bigger than a "10" before the "W" is not good at
> start up. Anything smaller than "10" before the "W" is not going to resist squeezing out of the main and rod bearings to lubricate like it is supposed
> to in these 1970s clearance engines.
I don't agree with a lot of what bobthe oil guy says. Much of it I'd outdated and not up to date with currently available oils. Emery
> Anything bigger than "30" after the "W" is overkill, except in Death Valley in the Summer. But if you find
> yourself going much more than 3000 miles between changes, the 10W40 might hold its viscosity better.
>
> Current formulations are better than anything available 40 years ago. There are people running their 403s and 455s on everything from 5W20 dino to
> 15W40 synthetic. They all have their reasoning.
>
> Care for it and drive it. But be aware that what's good for the 403/455 is not necessarily good for the Onan.
>
Very true. Emery
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| Re: [GMCnet] Synthetic oil Just some thought's [message #282380 is a reply to message #282221] |
Sat, 18 July 2015 08:10 |
bobby5832708
Messages: 237
Registered: November 2006
Location: Winter Springs FL
Karma: 3
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Senior Member |
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Rob,
Instead of Rotella I use Chevron Delo 15/40 in my 455 and Onan for the following reasons:
1. Delo has 117 ppm of moly, Rotella has 0.
2. Delo has 1490/1312 ppms of zinc/phosphorus, Rotella has 1098/965.
3. Costco has Delo on sale occasionally, Walmart has Delo for about the same price as Rotella last time I looked (it's been a while).
4. Using Delo I don't have to spend extra for the zinc and moly additives, it appeals to my 'frugal' tendencies.
Go to www.pqiamerica.com and click on Diesel Oils then click the arrow to see the lab tests of that particular oil. The numbers I wrote above are from year 2013 CJ-4 oils.
A while back someone much smarter than me wrote that moly was a good anti-wear additive for engine oils. Apparently Chevron (and several other oil manufacturers) thinks so too. So far the original 455 and original Onan 6000 in my GMC still run and sound fine.
Winter temps around here (cold starts) are about 50F to 70F so I don't think the 15/40 is too thick even during the 'cold' months (correct me if I'm wrong). If I were to run the GMC in a cooler climate I would probably try to find a 10/30 oil but for right now the 15/40 seems to be fine.
The usual disclaimers: JWID, YMMV, YEMEIAMPIYDWID (your engine may explode into a million pieces if you do what I did), etc, etc.
Bob Heller
2017 Winnebago 29VE
Winter Springs FL
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| Re: [GMCnet] Synthetic oil Just some thought's [message #282385 is a reply to message #282380] |
Sat, 18 July 2015 10:15 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Bob,
Looks like you're smarter than I am you are definitely better informed that's for sure as you get to the same point without spending
the extra cash!
Thanks for the link, looks like I have some reading to do!
Regards,
Rob M.
The Pedantic Mechanic
-----Original Message-----
From: Bob Heller
Rob,
Instead of Rotella I use Chevron Delo 15/40 in my 455 and Onan for the following reasons:
1. Delo has 117 ppm of moly, Rotella has 0.
2. Delo has 1490/1312 ppms of zinc/phosphorus, Rotella has 1098/965.
3. Costco has Delo on sale occasionally, Walmart has Delo for about the same price as Rotella last time I looked (it's been a
while).
4. Using Delo I don't have to spend extra for the zinc and moly additives, it appeals to my 'frugal' tendencies.
Go to www.pqiamerica.com and click on Diesel Oils then click the arrow to see the lab tests of that particular oil. The numbers I
wrote above are from year 2013 CJ-4 oils.
A while back someone much smarter than me wrote that moly was a good anti-wear additive for engine oils. Apparently Chevron (and
several other oil manufacturers) thinks so too. So far the original 455 and original Onan 6000 in my GMC still run and sound fine.
Winter temps around here (cold starts) are about 50F to 70F so I don't think the 15/40 is too thick even during the 'cold' months
(correct me if I'm wrong). If I were to run the GMC in a cooler climate I would probably try to find a 10/30 oil but for right now
the 15/40 seems to be fine.
The usual disclaimers: JWID, YMMV, YEMEIAMPIYDWID (your engine may explode into a million pieces if you do what I did), etc, etc.
--
Bob
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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