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