Mobil 5W30 TS 1996 Impala SS LT1

[jason07-1zzfe]

quote:

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Originally posted by Patman:
It's really nice to know this engine is easy on the oil, as it should be the same case with my LT1.

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Not really. You don't have the oil cooler, which was why I was able to identify that he does, because his oxidation was so much lower than yours even with twice as many miles and still being driven hard.
Not only that but are pushing more HP...=more heat, so you should require the cooler more than him. And from what you say, it runs 230 normally. That sounds extremely hot to me. Imagine what it gets when you beat on it.
Personally I would be unconfortable running 30wt anything. I wish some one would try 20w50 or a 10w-40 at least, and get in analyzed. (seeing as GM recommeds them outside of US)

Have you seen this graph? Obvioulsy it will be different for different oils, but it's interesting.
http://www.redlineoil.com/redlineoil/rovis.pdf
Temp has a large effect on the viscosity, even synth. Just as a comparison, the 30wt running in your engine would still be thinner than a 20wt in mine. Yet my mfr recommends 40 and 50wt oils.

 

[VaderSS]

I still don't think 230F is all that hot, but yes, the oil cooler would make a difference. I would not assume that it would be that big of difference.

Patman, did you ever get an analysis of the Mobil 1 10W30 you were running before?

The only analysis I've seen of his is with Maxlife SJ 10W30 and a standard filter. You can't really compare that.

I'm probably pushing 250-255RWHP (last I checked was before the catback was installed and that was 242RWHP), or around 300 at the crank, and I have a heavier car with an automatic so the amount of heat generated would probably be greater in my car.

 

[VaderSS]

Another slant I got from the an Impala owner;

quote:

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Although I wouldn't necessarily exclude ingested Si (Silicon) due to poor
intake filtration, a very probable source of Si. in the engine oil is going
to be residual Silica sand (in the form of Silicon oxide) in the engine
block and the other sand castings that the oil is in constant contact with.
As a 19 year veteran of the automotive aluminum sand casting and permanent
mold industry, I can tell you from experience that there is no way to
completely remove all of the silica sand from the casting surface and
subsurface. Although the engine assemblies are cleaned very well before
installation, it is not uncommon to see 50-100 ppm of Si from new equipment.
This level should drop as the component breaks-in and regular oil changes
take place. If it does not continue to drop, then I would suspect other
sources such as "dirt" ingression. Others to consider are:

Anti-foaming oil additives based on polymeric methyl silicone. Since
silicone contains the element Si, this additive will show a positive Si
content when using a spectrometer, with typical levels between 1 to 10 ppm.

Silicone based sealant: Although minimal, there could be some leaching of
the sealant into the lubrication system and again, the Silicone is Si based.

Coolant contamination - some coolants contain Si based inhibitors. In an
engine application, high Si readings in conjunction with other elements such
as Na (Sodium), K (Potassium) and B (Boron) may indicate a coolant leak.
These did not show up in the analysis, however, plus the spectrometer used
may not have the ability to analyze those elements.

Now back to the ingested sand issue. In this case you would want to look for
unusually high Si and Al (Aluminum) readings from the spectrometer, as for
the most part, sand is primarily free Silica and Alumina. The ratio of most
common sand is approximately 3.5 parts Silicon to 1 part Aluminum. Although
the chemical analysis shown supports this ratio, there are also many
possible sources of elemental Aluminum in our engines that could provide
these numbers.

I hope that this is useful.

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[ssmokn]

If you had your intake manifold gasket replaced they definitely used silicone. There are two gaskets used (one for each set of intake ports) and the front and rear of the manifold have no gasket. They are sealed with RTV. Actually, it is not the gasket that leaks but rather the rear left (passenger side) of the manifold develops a leak. The EGR tube runs very close to the intake manifold on its way to the exhaust manifold and the extreme heat bakes the RTV over time and causes the leak.

I doubt this would cause very high silicon readings. It is only one bead front and one bead on the rear of the manifold and the silicon is not sitting in oil (just oil that is splashing around). It may eleveat the levels some but I doubt it elevates them very much.

 

[Bigbody350ss]

Hello everyone, i'm new to the site. Was interested in this oil discussion and had a few questions.

I have a '96 impala, newly reguilt engine. All stock except for my K&N and air resonator delete plug.

I believe the factory recommends a SAE 5w30 for this LT1, but after having my engine rebuilt and moving onto a full synthetic.

1 - Would it be ok to use a heavier weight? (I took it as I live in CA so i'm never in a super "cold" climate / snow. I currently use 10w30)

2 - I use either Mobil 1 or castrol, is that bad that I switch them up? Or is it ok as long as i'm sticking to the same weight on a full synthetic?

I would appreciate the input and would love to answer any other questions about the impala, i've had mine going on 10years now. For my decade anniversary i'm getting her some headers. Thnx.

 

[Bigbody350ss]

HOLY $h!+... I didn't realize the last post before mine was back in 2002, LMAO! I hope someone still reads this