In article ,
(LaBomba182) wrote:

OK, so I'm sitting around with the captain and his engineer friend on the new
boat I'm project managing/co-captaining and we are trying to work out how to
run the same weight oil in the engines, gensets and trannys so we only have
to
fill the clean oil tank with one weight oil and not carry any extra buckets
of
different weight oils with us.
The CAT engines and ZF trannys can use 40W oil as per their specs but the
Northern Lights gensets only recommend up to 30W oil. The CATs could run 30W
but only at 86 deg. ambient air temps. We will certainly be seeing higher
temps
than that.
I tell the capt. and eng. that based on the ambient air temps we will be
seeing
even with the Delta-T fans that if it weren't for a warranty issue I wouldn't
hesitate to use 40W oil in the gensets.
The capt. and eng. disagree. They start saying that running a heavier weight
oil could cause wear problems and make the engine work harder over time. And
as
an example they compare it to what can happen if you use a heavy weight oil
in
a high revving street/race car. I point out that this is a diesel not a high
revving street/race engine. They back off that point a bit but we still go
round and round in a civil fashion.
In the end we will end up putting 15-40W oil in the tank for the engines and
gensets (as per specs) and keeping some 40W in bottles for the trannys.

But other than the warranty concerns, I'm I missing something here?
Would using 40W over 30W in the gensets with of course changing it at the
proper number of hours and making sure that the ambient temps never get low
really cause any long term problems?



Capt. Bill


If you call Alaska Diesel, and check with the Service Manager on spec's
for the Northern Lights Gensets, they will tell you that Delo 400 15W40
is also spec'd for those engines. CAT will also spec Delo 400 15W40
for most of their engines produced in the last 15 years. We use it
"Exclusivly" in out CAT Powerhouse that routinely runs 2.2 Megawatts
during the summers, and I switched to Delo 400 15W40, for my twin 20Kw
Northern Lights Gensets, on advice from the Factory Rep that came thru
here a few years back.

Bruce in alaska
--
add a 2 before @

Subject: 40W oil causing wear problems over 30w?
From: Bruce in Alaska

(LaBomba182) wrote:

OK, so I'm sitting around with the captain and his engineer friend on the
new
boat I'm project managing/co-captaining and we are trying to work out how
to
run the same weight oil in the engines, gensets and trannys so we only have

to
fill the clean oil tank with one weight oil and not carry any extra buckets

of
different weight oils with us.
The CAT engines and ZF trannys can use 40W oil as per their specs but the
Northern Lights gensets only recommend up to 30W oil. The CATs could run
30W
but only at 86 deg. ambient air temps. We will certainly be seeing higher
temps
than that.
I tell the capt. and eng. that based on the ambient air temps we will be
seeing
even with the Delta-T fans that if it weren't for a warranty issue I
wouldn't
hesitate to use 40W oil in the gensets.
The capt. and eng. disagree. They start saying that running a heavier
weight
oil could cause wear problems and make the engine work harder over time.
And
as
an example they compare it to what can happen if you use a heavy weight oil

in
a high revving street/race car. I point out that this is a diesel not a
high
revving street/race engine. They back off that point a bit but we still go
round and round in a civil fashion.
In the end we will end up putting 15-40W oil in the tank for the engines
and
gensets (as per specs) and keeping some 40W in bottles for the trannys.

But other than the warranty concerns, I'm I missing something here?
Would using 40W over 30W in the gensets with of course changing it at the
proper number of hours and making sure that the ambient temps never get low
really cause any long term problems?



Capt. Bill


If you call Alaska Diesel, and check with the Service Manager on spec's
for the Northern Lights Gensets, they will tell you that Delo 400 15W40
is also spec'd for those engines. CAT will also spec Delo 400 15W40
for most of their engines produced in the last 15 years. We use it
"Exclusivly" in out CAT Powerhouse that routinely runs 2.2 Megawatts
during the summers, and I switched to Delo 400 15W40, for my twin 20Kw
Northern Lights Gensets, on advice from the Factory Rep that came thru
here a few years back.

Thanks, I saw that in the eng. and genset manuals and that's what we will end
up doing. Filling the clean oil tank with 15-40W and keeping 40W in bottles
and/or pails for the trannys.

Based on this I still can't see how straight 40W would hurt the gensets in any
way.
As long as the ambient temps stay high.

Hell, multi weight oils start out at their low number and get more viscous as
their temp rises.



Capt. Bill

Hell, multi weight oils start out at their low number and get more viscous as
their temp rises.

no they don't. 15W-40 is the same viscosity ("thickness" if you will) at "room
temp" as straight 15W oil is, and the same viscousity as 40W at engine
operating temperature. 15W-40 is much more viscous at room temp than it is at
engine operating temp. If you doubt that pull the dipstick on a warm engine
and see.

Subject: 40W oil causing wear problems over 30w?
From:

Hell, multi weight oils start out at their low number and get more viscous
as
their temp rises.

no they don't. 15W-40 is the same viscosity ("thickness" if you will) at
"room
temp" as straight 15W oil is, and the same viscousity as 40W at engine
operating temperature. 15W-40 is much more viscous at room temp than it is
at
engine operating temp. If you doubt that pull the dipstick on a warm engine
and see.

Perhaps I misstated. Multi weights oils, as I understand, when they get hot
only thin out to the point that their high weight number would at the same
temp.
Something about polymers uncoiling into long chains.

In other words think of a 15-40W oil as a 15W oil that will not thin more than
a 40W would when hot.

Like I said, that's my understanding. But, I could be wrong. That's why I asked
the question. :-)

Capt. Bill

Perhaps I misstated. Multi weights oils, as I understand, when they get hot
only thin out to the point that their high weight number would at the same
temp.
Something about polymers uncoiling into long chains.

In other words think of a 15-40W oil as a 15W oil that will not thin more
than
a 40W would when hot.

Like I said, that's my understanding. But, I could be wrong. That's why I
asked
the question. :-)

Capt. Bill

That is correct.

multi weight oils start out at their low number and get more viscous as
their temp rises.

Larry Berlin has been making that statement, but Larry seems not to have pulled
a dipstick on a warm engine in so long he can't remember. Or perhaps he is on
weight/blood pressure control medications and can't remember.

It is not true.

and just what fricken surfaces in a diesel engine are "closer together" enough
so that 30W oil will flow and lube but 40W won't??????

If that were the case, those "closer together" surfaces would not get lubed at
all until the engine warmed up enough so that the cold 30W would flow.

Even the hydralic valve lifters on a gasoline engine (with some very tight
tolerances, down to a few thousands of an inch) would not operate (what a hell
of a racket you would hear) on 40W or not-yet-warmed-up-to-operating-temp 30W.

Oil too thick = may not lubricate completely between surfaces that are
closer
together, where the lighter oil is designed to flow.

this is not true in an engine. the difference is important during cold
engine
startup.

Are you daft? (retorical question)

BB

Subject: 40W oil causing wear problems over 30w?
From:

(LaBomba182) wrote:

Subject: 40W oil causing wear problems over 30w?
From:

But other than the warranty concerns, I'm I missing something here?
Would using 40W over 30W in the gensets with of course changing it at the
proper number of hours and making sure that the ambient temps never get
low
really cause any long term problems?


Yes it can.

OK, how ? In what ways?


The short version:

Oil too thick = may not lubricate completely between surfaces that are closer
together, where the lighter oil is designed to flow.

Oil too thin = surfaces may make contact by forcing out lubricant.

In this case I'm still not buying it. (at least not without much better
documentation)
40W is not that much "thicker" than 30W. And this is not a high revving engine
where oil film shearing would be a problem.

And to thin an oil is not an issue here.
Capt. Bill

In article ,
(JAXAshby) wrote:

snipped because I have another point to make


One other thing to remember in diesel engine operation, is
that the Base oil in a diesel engine is also designed as
part of the engines cooling system. Most larger (bigger
than 100Hp) engines have oil heat exchangers that run at the
temps of the cooling system. Oil Temps usually are 35 to
50 Degrees F higher than the cooling system temps found in
an engine. Today's Multiviscosity Oils are formulated to
allow for heat transfer from the friction parts out thru
the cooling system. Higher than normal oil Temps can
surely be a cause of concern, for premature engine failure
and something to be watchful for.


Bruce in alaska
--
add a 2 before @

Good choice on the 15W-40, but no, no , no on the last paragraph.

Oils most assuredly do NOT get thicker with increasing temp, even if
they *are* non-Newtonian fluids.
Multi-grades MEET the viscosity requirement( for their grade) at low
temps AND at high temps( usually 100degC).
But the viscosity, measured in either SuS or cSt, decreases with
increasing temps..

You may enjoy hopping over to www.bobistheoilguy.com and spending some
time there. I think you'll find it worth your while. You may want to
also consider Shell Rotella synth 5W-40, and asking your mfrs about
extended drain schedules.

--

"LaBomba182" wrote in message
...
| Subject: 40W oil causing wear problems over 30w?
| From: Bruce in Alaska
|
| (LaBomba182) wrote:
|
|| Thanks, I saw that in the eng. and genset manuals and that's what we
will end
| up doing. Filling the clean oil tank with 15-40W and keeping 40W in
bottles
| and/or pails for the trannys.
|
| Based on this I still can't see how straight 40W would hurt the
gensets in any
| way.
| As long as the ambient temps stay high.
|
| Hell, multi weight oils start out at their low number and get more
viscous as
| their temp rises.
|
|
|
| Capt. Bill