In article <Pine.SGI.3.91.950624160024.22405E-100000@civ>,
Barry Adams <adams@civ.utoronto.ca> wrote:
> What causes some anxiety, is that at a long stop when the pressure is
> down to the 20-25 psi range, the red oil pressure light comes on. Some
> comments from Egil, and perhaps others, suggest that this should be a cause
> for concern while others suggest 20 psi at idle is no big deal.
> The question then is: do I heed the oil pressure gauge reading (which I
> assume to be true) or do I deficate bricks because of the shining warning
> light?
*IF* it is the oil lamp you are seeing, not the charge lamp:
The trigger point for the oil lamp sender is usually approx. 3-5 psi.
Like you, I would have trusted the oil pressure gauge. I see three
possibilities (in order of priority):
1. The oil pressure sensing unit is bad.
2. The wire to it is frayed and occasionally touches ground.
3. The PO has installed a racing type oil pressure sender.
Such a device would have a setpoint of about 20 psi, and
is designed to give a much better oil pressure warning when
*driving*, not only as a disaster indicator as the original
item. Even though it is the better idea, it would not be
installed originally as it is expected to flash or stay lit at
idle.
> Moreover, how is the warning light triggered?
By a pressure sensor normally located pretty low on one side of the
block (also on the TR4, I assume). It works by grounding the one wire
connected to it. The wire goes to the oil lamp. The other side of the
lamp is connected to 12V via the ignition switch.
> 3. What is the wisdom on nonleaded gas? As far as I know, the 4A's engine
> is original and not prep'ed for nonleaded gas. I have been using an additive
> (although I have consumed only two tanks so far). Are there better
> alternatives other than redoing the valves, seats, etc.? Such an expensive
> alternative at this point would cause some serious family discord!
> Suggestions?
In Norway, lead for petrol is being phased out, and is replaced
by a potassium based additive (added by the oil company). It seems like
it is working pretty well, and have been used for several years in
several European countries.
Egil
--
Email: egilk@oslonett.no Voice: +47 22523641/92022780 Fax: +47 22525899
Smail: Egil Kvaleberg, Husebybakken 14A, 0379 Oslo, Norway
Web: http://www.oslonett.no/home/egilk/
Web: http://www.oslonett.no/home/egilk/t2000.html
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