Actually, Rick, it was me (not Andrew). And don't apologize -- I put the
word "useless" into your mouth, as it were. It turns out I pretty much agree
with your analysis, now that you explain it at length. What is "useless" is
when you can't even rely on the gauge for this "binary" info, as was the
case when trying to restart my friend's car and the electric gauge
erroneously read "0".
I suspect it really isn't that critical for the oil pressure gauge to have
instantaneous response in these cars, anyway. I have to admit I once drove
my car a 1/2 mile with no oil in the sump before I noticed the gauge
bottomed out, with no apparent ill effects (I know it wasn't an erroneous
reading because the oil was all on the driveway!).
on 5/2/01 6:42 AM, R. O. Lindsay at rolindsay@dgrc.com wrote:
> "Andrew B. Lundgren" wrote:
>
>>> I don't know why Rick considers ALL the oil pressure gauges useless. Mine
>>> provides what appear to be perfectly reasonable and consistent readings,
>>> with numbers that correspond very well to what one would expect, again given
>>> the known history of the engine.
>
> Sorry for the confusion Andrew. Perhaps my note was penned at
> the end of a stressful day and the words were poorly chosen expressing
> my frustration rather than my true opinion. I apologize for that.
> I don't consider the Smiths gauges 'useless'. I simply wanted to
> emphasize that they are not precision instruments. Rather, they are
> "indicators." Some are probably spot-on while others are off by a
> mile! If +/- 10psi is acceptable <midscale> precision, then they are
> fine. And I would argue that +/- 10psi is perfectly acceptable precision
> because 98% of the time, all the gauge tells us is "all is okay" or
> "Houston, we have a problem."
> I suspect that the mechanical gauge is more precise than the electric
> gauge but that's just my bias. The electric gauge is also a thermal
> mechanism that is, by design, s_l_o_w to respond to changes. That, I
> don't like because oil starvation causes damage quickly and possibly
> quicker than a thermal gauge can warn the driver. Perhaps I am spoiled.
> In my other sports car, the oil pressure gauge has very little 'damping'
> and responds almost instantly to changes in pressure. That car also
> performs comfortably at 7700rpm and would 'eat it's own lunch' if it
> lost oil circulation and the driver didn't notice it VERY quickly. It also
> maintains 100psi -- at idle. The precision of that VDO gauge in that car
> is as poor as the MG's but serves the same basically binary purpose:
> 'everything is okay' or 'we have a problem'. It simply is not damped
> and responds quickly.
> So why do they build gauges that are heavily damped? Because most
> of us don't like to see the instrument hands swinging around on the
> face of the gauges! It is unnerving to see the oil pressure gauge move
> around. Yet, that is exactly the information we NEED to see if we want
> more than a GOOD / BAD indicator.
> Have I communicated my original thoughts, this time without
> overemphasizing the opinion -- and without 'flames'?
>
> Best regards,
>
> --
> Rick Lindsay
> Diamond Geoscience Research
> 5727 S. Lewis Ave., Tulsa, OK
> Voice: +1 918-747-3456
> Fax: +1 918-747-8599
>
>
--
Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the red one with the silver bootlid.
///
/// mgs@autox.team.net mailing list
/// (If they are dupes, this trailer may also catch them.)
|