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Never-Sieze, Oil Pressure, Tires

To: british-cars@autox.team.net
Subject: Never-Sieze, Oil Pressure, Tires
From: Kirby Palm <palmk@freenet.scri.fsu.edu>
Date: Sat, 29 Jan 94 16:05:05 18000
>From: Philip Searle <searle@indigo.ucdavis.edu>
>
>The
>Stromberg 150CD GT6 carbs didn't seem up to supplying the 2.5 
>so it's now back
>on the original rebuilt 2.0 (much smoother anyway).

I found that the 2.5 fitted with the 150s was anemic, as well.  My
solution was to install the GT6 intake manifold and, doing a little
"Dremel Engineering" on it, mounting the TR6 175 carbs on it.  They
are a tad taller than the 150s, but I managed to get them to fit under
the GT6 hood anyway.


>From: Bob Tufts <rbt@itc.Kodak.COM>
>
>The thought has occured to me that it sure would be 
>nice if the car manufacturers would use never-seize 
>on all the threads of bolts.

I agree.  I learned about never-sieze when working at Pratt & Whitney
Aircraft on multimillion-dollar jet engines.  They use the stuff on
everything.

For manufacturers, there is a better alternative.  They can use bolts
that are coated with an anti-sieze substance, so the assembly line can
continue to simply pull bolts out of the bin and install them.  Of
course, this would probably add $.50 to the cost of a car, and the
accountants would have fits.

Meanwhile, I would like to point out that manufacturers of outboard
motors don't use never-sieze.  There is simply no hope for those of us
who believe in fixing things rather than throwing them away and buying
new.


>From: Dennis <IEDXW@asuvm.inre.asu.edu>
>
>I'm gonna change the oil filter (Amsol) to a "normal" one and see what
>happends.  And I'm gonna fit an oil gauge.

There has been several comments regarding oil pressure lately, and I
am forced to point out the true meaning of oil pressure.

What is important in an engine is oil FLOW.  However, it is difficult
to measure flow, so pressure is measured as an indication of flow.  If
pressure gradually decreases over the years, it is an indication that
wear is opening the bearings a little, and hurts nothing; no action is
required, and using thicker oil or additives are likely to cause more
harm than good.  A sudden change in oil pressure, in EITHER direction,
is likely to be an indication of trouble, and should be investigated.

If I installed a filter that caused the pressure to drop by 15 psi, I
would be impressed; most filter assemblies include a bypass for when
the filter becomes plugged that opens at less pressure than that.  But
knowing the cause, I would not be concerned, and in fact may be
inclined to feel the filter is doing a really good job.

There is nothing magic about any particular oil pressure reading.
Make sure it's not zero, and make sure it doesn't suddenly change, and
otherwise don't get paranoid about 60 vs. 75 or such nonsense.


>From: tooze@vinny.cecer.army.mil (Marcus Tooze)
>
>3) Dumb question alert....
>Continuing the tire size q and a, will P155/80/R13 fit my 74 Midget
>with regular rostyle wheels?? In fact could somebody explain the tire
>sizing code...i.e. whats the above relate to in physical terms??

I can handle that one.  First, to use an example that would be more
typical:  P155/80SR-13.  The P means nothing important.  The 155 is
the overall width of the tire in mm, measured from sidewall to
sidewall (NOT the width of the contact patch, although obviously
related).  The 80 includes an implied decimal point, as in .80, and is
the aspect ratio of the tire: the height of the tire above the rim
divided by the width.  The S is a speed rating, meaning this tire is
good for continuous driving at 180 km/hr.  The R means it is a radial
tire.  And of course, it fits a 13" wheel.

Someone decided long ago that the standard aspect ratio was .80, and
it is sometimes implied and omitted; so, a P155SR-13 would be the
exact same size tire.  In the USA, it is illegal to sell a tire that
does not have at least an S speed rating, so it is often omitted as
well, so a P155R-13 is also the same.  And the P and R can also be
omitted.

Speed ratings include the S; H, which is good to 220 km/hr; V, good to
250 km/hr; and Z, which is good for going obscenely fast.  If the tire
is good for a rating above S, it WILL be included in the size
designation; don't believe BS from tire salesmen to the contrary.
Such capability requires considerable effort and usually increases the
cost of the tire considerably, the tire companies will not forego
writing it clearly on the side of the tire.

To make life simpler, the width designations are all rounded to the
nearest number ending in 5.  Also, since most tire salesmen cannot
handle mathematics, it has become fairly standardized that increasing
the width by 20 while decreasing the aspect ratio by .10 will result
in the same overall height.  Therefore, a 175/70SR-13 tire would be
wider, but would have the same height and give the same ground
clearance and speedometer readings, and 195/60SR-13 would be even
wider.  A 165/75SR-13 tire size would provide the slightest width
increase.

IMHO, an 80-series tire is unacceptably unstable.  The tire is too
tall and skinny, and the corners roll under on even the gentlest of
corners, resulting in rapid tire wear, heavy steering effort and
handling characteristics bordering on unsafe.  The 75-series is
marginally acceptable, and will improve characteristics markedly.  I
personally won't buy any tire with an aspect ratio higher than 70,
regardless of the size wheel, weight of car, etc.  Everyone I have
convinced to follow this rule when replacing 80-series tires has
thanked me later.

-- 
                                ---  Kirbert
---------------------------
| Kirby Palm, P.E.        |
| palmk@freenet.tlh.fl.us |
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