Ferrari Mailing List: Re: All about oil????

[LarryT (l02turner]

Thanks for the article - I think I'll try some of the Cam stuff -

Larry T (66 MGB, 74 911, 91 300D)
www.youroil.net for Oil Analysis and Weber Parts
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----- Original Message ----- 
From: "Hans E. Hansen" <FList [at] hanshansen.org>
To: "Larry Turner" <l02turner [at] comcast.net>
Cc: "The FerrariList" <ferrari [at] ferrarilist.com>
Sent: Wednesday, March 26, 2008 4:40 PM
Subject: Re: [Ferrari] All about oil????


> OK, here is the article that I mentioned in the previous post.
>
> BTW, AEHass' arguments *may* be right, but given a choice,
> I think I'd rather trust  the Ferrari engine designer over an amateur
> arm chair automotive engineer.  The gist of his arguments, if I
> recall correctly, is that all you need is 10psi/1000 rpm and that
> anything over that is overkill, causes excess friction/heat in the
> oiling system, etc.
>
> However, consider:  Suppose you attach a massive oil pump to
> your engine.  Think irrigation pump.  You could run just about
> any fluid - water, gasoline, acetone - and maintain 10psi/1000 rpm
> or better.  Would you really want an ultrathin fluid lubricating your
> engine's innards, even if it were in gusher quantities?
>
> I've always thought that the viscosity of the lubricant should match
> the clearances of the parts.  Most gears use thicker oil/grease
> because they don't necessarily mesh tightly.  Some precision
> gearsets do, however, and they are lubed with a much thinner
> oil.  Back a few decades ago, Smokey Yunick specified some
> quite loose clearances for his NASCAR engines, and he ran
> 50w to help "fill the gap".  I think that now days the latest thinking
> on this subject is to build racing engines with much tighter
> clearances and use a thinner oil.  It's my understanding that
> modern F1 engines use oil about the consistency of gasoline,
> but their bearings have near zero clearance.
>
> A few decades ago I worked on an injection pump for a diesel PU.
> The entire apparatus was lubed by the fuel itself.  But the
> clearances for most of the parts were just a few 1/10,000 's.
> To get the piston into it's cylinder, you had to cool it with
> freon to shrink it slightly, otherwise it was a real bear to line
> it up so it would go in.  Again, tight clearances, thin lube.
>
> According to my 308 service manual, the rod bearings are
> clearanced in the range 0.046 to 0.089mm with a 0.120mm
> wear limit.  As all my past engine work was in inches, let me
> convert:  approx 0.002 to 0.0035 inches, 0.005 limit.
> These, to me anyway, are not real tight bearings, especially the
> upper assembly limit.  This is about the outside of the range of what
> we would build a small block Chevy to.  In particular, the outside
> wear limit seems almost huge.  I don't think I'd like oil that had a
> real thin film thickness in there, regardless of how much of it the
> pump was supplying.
>
> Hans.
>
> On 3/26/08, Hans E. Hansen <FList [at] hanshansen.org> wrote:
> > Peter:
> >
> > I see what you're saying.  But it certainly is difficult to second guess
> > the Ferrari engineers.  However, charts that I've seen on actual oil
> > viscosity measurements seem to converge a bit at elevated temps.
> > ie: at room temp there is a big difference between the flow rates
> > of a single weight 20w oil and a single weight 50w.  But at high temps
> > the difference isn't as great.  Other than efficiency issues, tho, I 
> > can't
> > see what the harm is in using the thicker oil, as long as the 1st number
> > is low enough to allow decent flow at cold temps.  Ferrari's 10w50
> > recommendation would seem to have that covered.
> >
> > Jeff, Matt:  Wasn't the zinc/phosphorus issue tossed around here
> > just a while back?  Or maybe it was on another car forum.  Anyway,
> > I have kicking about an excellent article about that, and some 
> > suggestions
> > for additives.  There is a company distributing the pure ZDDP additive.
> > Seems the real issue is cam wear with flat tappets (ie, not roller 
> > lifters),
> > however, I suspect that the additive is a good thing to have for cold
> > starts for those of us with carb'd engines, as there is considerable
> > raw gas washing the cylinder walls.  I'll dig around and attach the
> > article and product sources.
> >
> > Paul:  Sounds like your car runs  (temp-wise) like mine.  In winter,
> > the water only gets to about 150ish, and the oil doesn't (or just
> > barely) moves off of the peg.  I've thought about replacing the oil
> > temp sensor, but I'm not sure it is faulty.  In hot weather or on the
> > occasional track day I do see temps like what you would expect.
> >
> >
> > Hans.
> >
> >
> > On 3/25/08, Peter Pless <ferrarilist [at] pless.com.au> wrote:
> > > That all makes sense Hans...BUT...what if ferrari wasn't really 
> > > concerned
> > > with what happened at 212 deg, but more what happened at 260 deg on a 
> > > very
> > > hot day or on the track? Which if the reality is that the 50 mineral 
> > > oil
> > > drops to the same thickness at that temp as a 40 synthetic? That's 
> > > really my
> > > question. Is it possible that 50 is thicker than ferrari would like in 
> > > a
> > > perfect world because they had to protect the engine at 250+?
> > >
> > > Does that make sense?
> > >


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