In article ,
(LaBomba182) wrote:

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.

Like what? Frequently race cars *do* use heavy weight engine oils
because of the high temperatures involved. You use the lightest you can
get away with because you want to reduce parasitic power loss, but
that's not for engine durability - keeping the engine in one piece is
why you have to use heavier oil in the first place. As for "work harder
over time", I don't know what the "over time" part is about, but yes,
there is higher parasitic power loss with greater viscosity. But again,
this isn't a race engine where you're concerned with peak power output
anyway. Where you'd see it show up, if noticeable at all, is gal/hr.

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.

Something you *do* want to stay away from are the wide-range
multi-viscosity ratings. They are obtained with the use of modifiers
that a) break down the most quickly of any of the oil components, and b)
displace the oil itself in the lubrication mix.

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?

I'm reluctant to guess without knowing the manufacturer's reasons for
specing a particular viscosity. *Generally*, unless you're doing
something silly like running 135wt gear oil in something that calls for
30wt, or oil used in hydraulic systems, the tradeoff is simply parasitic
loss vs adequate viscosity at high temp. Most damage is caused by oil
that is a) chemically incorrect for the application (GL-4 vs GL-5,
antagonistic modifier packages, etc.), b) underfilled, overfilled, or
never changed, c) inadequate viscosity at high temps.

KeS

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?

Race cars do not even remotely apply to this question. Race car
engines and transmissions only need to last for the duration of one race.

Correct. That's one reason I wasn't to taken with their using that as an
example to boost their argument.

You
are more interested in longevity.

Again can you be specific as to how 40W could shorten the longevity of a diesel
compaired to using 30W?

You started out looking for a way to do
something more conveniently. Just accept that this is one convenience that
you
will have to do without.

Looks that way.

Put the correct oil specified by the manufacturer in
each machine, and look for something else where you can cut a corner without
causing future problems.

Interestingly enough, 15-40W is spec correct for both the mains and genset.


Capt. Bill

Interestingly enough, 15-40W is spec correct for both the mains and genset.

15-40W lubes a cold engine sooner upon cold engine start up than 30W or 40W oil
does.

You can hear the difference.

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.

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

Interestingly enough, 15-40W is spec correct for both the mains and genset.

15-40W lubes a cold engine sooner upon cold engine start up than 30W or 40W
oil
does.

You can hear the difference.

While that maybe true, in this case we will not be seeing low ambient temps.
And if we were to, we would change the weight of the oil.

Capt. Bill

15-40W lubes a cold engine sooner upon cold engine start up than 30W or 40W
oil
does.

You can hear the difference.

While that maybe true, in this case we will not be seeing low ambient temps.
And if we were to, we would change the weight of the oil.

"cold" is maybe 80* for engine startup while oil operating temps can be well
over 200*. 15W-40 lubes much quicker at 80* than does 40W.

Sure you do. Your 90 deg F startup temp is a world of difference from
the 100 -110 deg C operating oil temps, in terms of pumpability.


"LaBomba182" wrote in message
...
| Subject: 40W oil causing wear problems over 30w?
| From:
|
| Interestingly enough, 15-40W is spec correct for both the mains and
genset.
|
| 15-40W lubes a cold engine sooner upon cold engine start up than 30W
or 40W
| oil
| does.
|
| You can hear the difference.
|
| While that maybe true, in this case we will not be seeing low ambient
temps.
| And if we were to, we would change the weight of the oil.
|
| Capt. Bill

Subject: 40W oil causing wear problems over 30w?
From: "spare-me-spam"

Sure you do. Your 90 deg F startup temp is a world of difference from
the 100 -110 deg C operating oil temps, in terms of pumpability.


Perhaps true. But not enough to warrant a change in weights.

Capt. Bill

Perhaps true. But not enough to warrant a change in weights.


the SAE thinks otherwise.

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

(LaBomba182) wrote:

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.

Like what? Frequently race cars *do* use heavy weight engine oils
because of the high temperatures involved. You use the lightest you can
get away with because you want to reduce parasitic power loss, but
that's not for engine durability - keeping the engine in one piece is
why you have to use heavier oil in the first place. As for "work harder
over time", I don't know what the "over time" part is about, but yes,
there is higher parasitic power loss with greater viscosity. But again,
this isn't a race engine where you're concerned with peak power output
anyway. Where you'd see it show up, if noticeable at all, is gal/hr.

The Northern Lights Tech I spoke with about this on the phone said he could see
no real down side except for perhaps an increase in oil consuption. But due to
the fact that 40W is not mentioned in the specs manual it could be a warrenty
issue.



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.

Something you *do* want to stay away from are the wide-range
multi-viscosity ratings. They are obtained with the use of modifiers
that a) break down the most quickly of any of the oil components, and b)
displace the oil itself in the lubrication
mix.

I'm not a big fan of multi wieghts either. But they are speced for the mains
and gensets.


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?

I'm reluctant to guess without knowing the manufacturer's reasons for
specing a particular viscosity.

In the manuals the oil recommendations are based on ambient air temps.

*Generally*, unless you're doing
something silly like running 135wt gear oil in something that calls for
30wt, or oil used in hydraulic systems, the tradeoff is simply parasitic
loss vs adequate viscosity at high temp. Most damage is caused by oil
that is a) chemically incorrect for the application (GL-4 vs GL-5,
antagonistic modifier packages, etc.), b) underfilled, overfilled, or
never changed, c) inadequate viscosity at high temps.

That's the way I have always understood it.

Capt. Bill