40W oil causing wear problems over 30w?
 

As I have said repetedly, we should not be seeing any low air temps. or
engine
room temps.

"low" temps for engine startup is anything you might normally find for a temp
at engine startup, while operating temps are much higher. pull the dipstick on
your engine before startup and compare the difference to the same dipstick/same
oil after the engine has been run long enough to reach operating temp.

40W oil causing wear problems over 30w?
 

Many seem to disagree on the pelube issue. But I agree it can't hurt.

only "hammer mechanics" disagree on prelube. race engines are always prelubed.

wanna hear the difference? start your unrun overnight engine with the engine
compartment open and listen to the sounds you hear. let the engine warm up,
shut it down and restart, listening again. One hell of a difference in sounds.

40W oil causing wear problems over 30w?
 

Doubt that's much of an issue in this case.

Capt. Bill

oh ye of little faith. I drove NYC to Oriental to NYC Friday evening to this
morning. Have had nothing stronger than Coca-Cola since Thursday.

40W oil causing wear problems over 30w?
 

Thought of synthetics. But there are warrenty issue with them.

not if they might the standards (most all do, except some special racing
synthetics).

40W oil causing wear problems over 30w?
 

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.

40W oil causing wear problems over 30w?
 

On Sun, 13 Jun 2004 17:00:28 GMT, wrote:

On 13 Jun 2004 16:07:19 GMT, (JAXAshby) wrote:

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)

He might be, but he might be referring to what was called 'summer oil'
and 'winter oil' by some. It's not that we changed engines; loose
tolerances for the thicker oil of summer, and close tolerances for the
bone-numbing cold of a North Dakotan winter to keep the lubrication in
the crankcase. For those of us who didn't have block heaters, in the
winter, we used 10 weight so we could at least *try* and start the
car.

In winter, if you left 30 weight in the car before you changed the
oil, it wouldn't come out of the can.

This is why you bring the oil into the house the night before.

....then along came multi viscosity oil....10-30, and even 10-40....and
then we thought we were living the easy life.

Yeah, so Jax may, or may not be daft...but there is a an important
difference during cold engine startup.

40W oil causing wear problems over 30w?
 

here is a an important
difference during cold engine startup.

"cold" is 80* outside, in terms of seconds, and seconds, and seconds and still
more seconds waiting pressure oil flow to all the bearings that need pressure
oil, as far as engine startup is concerned. you can hear the difference in an
engine, if you listen.

40W oil causing wear problems over 30w?
 

btw, transmission oil temps usually are not as high as engine oil temps. In
this case, 40W oil is more viscous than 10W-40. In addition, there is a belief
(not as much as in the past, but still a belief) that 10W-40 does not _stay_
40W at operating temps as the engine hours on the oil increases and gets closer
and closer to oil change time. Transmission do not suffer from dry bearings at
engine startup (as the engine does) because the gears are bathed in oil.

40W oil causing wear problems over 30w?
 

For the transmission application I'd opt to use the EXACT grade, as the
viscosity in this case relates to the "film strength" needed to keep
metal-to-metal contact to an absolutel minimum. If you used other than
whats specified you are vulnerable to scoring, galling and .....
ability to reduce wear of the gear tooth surfaces. A transmission or
gear set is considered an "extreme pressure" (lubrication-wise)
application and the oil viscosity (as specified) is VERY important to
keep metal to metal contact from ocurring... in this case the oil
supports the load between the gears and prevents metal to metal contact
..... only if its the specified viscosity. . In a transmission the
reduction in wear is a function of the exact lubricity specified. If
the trans. mfg. specifies 40W (Not 10-40W), then USE 40W .... only.

For the engine applications, the viscosity enables the bearings
(journal - crankshaft) to be lifted to the proper height within their
journals, so that the oil supports the shaft precisely at dead center
in the journal so that the shafting is in the exact cente r.... and has
equal and equidistant clearance (at the higher range of engine load) by
the pressure generated in the gallery/pump and somewhat by the
viscosity. Why viscosity is important is that viscosity (resistance to
flow) will help to support the piston load during the combustion
stroke. ........ However, If you are not 'lugging' the engine (low
rpm at HIGH load) then using a viscosity index of 1 grade lower than
specified ..... should NOT be a problem. If however youre running WOT
(wide-open-throttle) and high load ... then it becomes important to
match the specified viscosity grade (and operate at the specified
engine temp. ... as set by the thermostat.).
The short answer: OK to run lower viscosity, just watch the oil
pressure to be sure its 'similar' as when running the 'specified'
viscosity index oil.

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

40W oil causing wear problems over 30w?
 

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 @