Return-Path: <cwright@pdghightower.com>
Received: from [10.0.0.41] (HELO pdghightower.com) by pdghightower.com
(CommuniGate Pro SMTP 3.4.7) with ESMTP id 313483; Wed, 29 Aug 2001
10:34:43 -0700
Message-ID: <3B8D27B2.E75EBA3D@pdghightower.com>
Date: Wed, 29 Aug 2001 10:34:42 -0700
From: Craig Wright <cwright@pdghightower.com>
Organization: Product Design Group
X-Mailer: Mozilla 4.72 [en] (WinNT; U)
X-Accept-Language: en
MIME-Version: 1.0
To: Tigers Den <tigers@autox.team.net>
Subject: Re: FW: Synthetic Oil
References: <LOBBIIGMLINIBEAPLFOLGEHKCFAA.rpalmer@ucsd.edu>
I agree with the synthetic oil discussion, but one feature hasn't been mentioned
and that is the feature that makes it extremely attractive to me, that is it's
high temperature characteristics. Higher than about 240 degrees regular oil
starts to fail rapidly. How hot is your oil? Most people look at the oil temp
gauge and say that they don't have a problem. The issue is that the gauge
measures the bulk oil temp or the oil temperature going to the bearings,
depending on where the sensor is located. These are good temperature to know,
but what is the temperature of the lifter/cam interface. I assure you that it is
a lot hotter than the bulk temperature. With stock cam, this isn't an issue,
but increase the lift and ramp speed, and you will have higher force springs to
control the motion. All this adds up to high valve train pressures. This became
actually visible to me recently when I had to replace my roller rockers in a 289
with "Stock" type ball and socket rockers in order to be legitimate in a race.
The cam I'm using requires about 340# springs, when opened. This results in 700#
on the rocker fulcrum, which in stock form is sliding friction. They got so hot
in two sessions on the track (20 min each) that they turned blue. That's hot.
Regular oil would have coked. Since most of our engines aren't stock, and the
combination of parts are random and probably not completely tested and
engineered, using synthetic oil increases the real margin to failure.
Craig Wright
Bob Palmer wrote:
> -----Original Message-----
> From: Bob Palmer [mailto:rpalmer@ucsd.edu]
> Sent: Wednesday, August 29, 2001 8:02 AM
> To: Michael Lane Hobson; Tiger List (E-mail)
> Subject: RE: Synthetic Oil
>
> Michael,
>
> Larry has posted a good summary on the question of synthetic oil. As for
> additives like Prolong, Duralub, etc., you can fool some of the people some
> of the time, but . . .
>
> Check out these links:
>
> http://www.ftc.gov/opa/1999/9909/prolong.htm
>
> http://www.ftc.gov/os/1999/9911/prolongcmp.htm
>
> The best you can hope from adding these products to your engine is they
> don't do any harm.
>
> So, the answer to your question about Prolong is pretty clear cut; don't use
> it. On the other hand, the question of synthetic oils in general is a very
> complex one. I might add that, just like non-synthetics, not all synthetics
> are created equal. Mobil 1 is highly rated and I would also use Red Line or
> Castrol Syntex (which I have been using in my Tiger for five years now). I
> am sure there are others that are also good, but just because the oil is
> "synthetic" doesn't necessarily make it better. The structure of the oil
> itself and the additives are all factors. In general though, an engineered
> molecule is going to work better than the mix of molecules found in "dino
> oil" as Larry calls it, the refining process notwithstanding. You can search
> the Web and come up with a lot of information (some true, some false) on
> synthetics. Here's an example:
>
> http://www.mr2.com/TEXT/synth_oil.txt
>
> Note at the end of the article the section on oil filters. A few days ago I
> questioned whether an oil filter was really needed in normal engine
> operation. Subsequent discussion and consideration has convinced me that it
> is. I am not ready to leave my oil in for 25k miles, as is recommended for
> synthetics, but perhaps for 12k or 12 months, whichever comes first and a
> change of filter (filters in my case) with that too.
>
> Happy motoring,
>
> Bob
|