Re: [OMC-Boats] Instrument Question

On Fri, 6 Mar 2009, Ted Robinson wrote:
> I have a related question on instrumentation on my 1970 Seasport wth the
> 155hp V-6 kaiser engine. I am thinking of adding gauges for the temp &
> oil press, but keeping the warning lights intact. My basic knowledge of
> hydraulics tells me that the oil press would still be accurate after
> teeing off at the existing oil press fitting, but. I am not sure how much
> temp accuracy would be lost by teeing off at the water temp fitting. Any
> ideas or helpful info?

Pressure is pressure, so anything you do is fine. The traditional way of
hooking up pressure gauges is through a long plastic hose to a mechanical
gauge, and that works just fine. As for the temperature sensing, using a T
will inevitably introduce a delay, but it may be small in practice due to
the good thermal conductivity of water. Make sure the T is small and be
sure to orient it downwards, so an air bubble can not be trapped in it
(this will definitely lead to incorrect readings). A better alternative
might be to look for an alternative location for the second sender. There
might be additional plugged ports you can use, though I can't think of any.
I'm guessing the block drains are too small to fit in a temp sender, and I
can't recall any others on the thermostat housing. We often cut a hose and
install a metal coupler with a sender bung welded into it, but this is less
practical for very large diameter hoses. You'd have to put one of the big
hoses from the water pump in order to get the engine temperature - putting
it on a line going from the engine to the exhaust manifold would be correct
most of the time, but wouldn't accurately reflect temperatures during
warm-up or if your thermostat failed. That still might be the easiest
option though.

Ethan

-- 
<a href="http://www.engr.wisc.edu/~brodskye/"> Ethan Brodsky </a>