Oil pressure gauge install

I want to install an oil pressure gauge and voltmeter in my 1988 Volvo
240DL wagon. There are 2 blanks to the right of the cluster with 52mm
holes under them (I wish every car dashboard was as well-designed for
upgradability as this!). I'm probably going to go with VDO gauges from
eGauges.com. The voltmeter install seems straightforward - wire into a
wire that's hot when the ignition is on, wire into the lighting circuit,
earth to a convenient place, done.

Now, as far as the oil pressure gauge, should I get an electric or a
mechanical gauge? If I use a mechanical gauge, should I use copper or
plastic tubing to connect it? I've heard of oil pressure gauge lines
fracturing and spraying oil all over the interior, which sounds like a
pain to clean up even if it doesn't destroy the motor or burn your leg.
I know that some copper alloys work harden, but nylon gets brittle when
it's cold.

However, mechanical gauges are both cheaper and more accurate than the
electric ones + sender, so they do have their advantages.

And let this not turn into a "with idiot lights and modern computers, why
install extra gauges at all? discussion - IMHO, every car should have
tach, oil (not water) temp, pressure, and volt gauges - fuel gauge is
optional as long as there's a reserve light since I'm used to riding
motorcycles.

Cheers,
Andrew

 

I prefer mechanical gauges simply because they tend to have 270 degree
faces as opposed to electrical gauges which often only have 90 degree
faces, making the mechanical ones easier to read at a glance. The
mechanical gauges also appeal to my "keep it simple, stupid" philosophy
of things automotive. I would probably use the nylon tubing, just tie
it up securely and wherever it goes through the firewall make sure
there is a grommet to keep it from chafing. If you use copper there's
a small chance it may fatigue from movement of the engine... I know
that on my older cars that were factory equipped with oil pressure
gauges, they were equipped with copper tubing, but there was a shor (6"
or so) section of rubber hose between the copper and the point of
connection at the cylinder head (and that rubber hose is a common
failure item, but that's another issue entirely.)

You will probably want to use a tee-fitting so that you can retain your
stock idiot light sender, ask whoever you're buying the gauge and
tubing from about this... alternately if you use an electrical gauge,
at least the VDO ones offer a dual sender to drive both the gauge and
the idiot light.

good luck,

nate

 

I have a Jeep CJ7 that gets twisted up and off roaded hard on a regular
basis and has been rubber side up on two occasions in the Canadian
winter cold off roading. It has the nylon or plastic tube for the oil
pressure gauge which has never given any troubles in spite of all the
vibrations and flexing in -25F temps and colder even.

I have flexed it a couple times so much the body interfered with putting
the shifter in reverse, so that line has seen lots of movement and
vibration in the real cold.

I would have worries about copper because of the engine movement if
nothing else. My old Volvo 240's could torque that engine pretty
good... The mounts get soft with age and the engines tended to get
floppy. Pretty sure one GLT at least had the nylon tube.

With the number of old 240's around, I would be real tempted just to go
to the auto wrecker and get a set of stock Volvo gauges with the senders
and tube. The wiring harness very likely has the connections for the
lights tucked in there somewhere too.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
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(More Off Road album links at bottom of the view page)

 

I haven't seen any 240s with full gauges in the local yard. 'round here,
people are *smart* and tend to keep them and fix any issues rather than
junking them. Despite new engine/tranny mounts, the engine still moves
quite a bit. I think Volvo designed them to be soft so they'll shear in a
crash and allow the front end to "crumple."

So I think that I'll go with either a good nylon kit or a VDO electric
gauge with sender. The gauge is like $25, and the sender is $25 for the
one without a warning light contact, $33 for the one with. Voltmeter is
another $25. I think I also need a sender bushing since my engine is
threaded for 14mm x 1.5 rather than 1/8NPT and the 14mm sender is like
$65.

-Andrew

 

People keep them here too, but they do get wrecked occasionally. I've
seen lots of oil/volt guages at the local yards around here, never
bothered to pick any up since my 240 already has them.

 

I found a 240 series Volvo in a junkyard with an original oil pressure gauge.
It is electric. I took it and the sending unit. Now I have to check to see if
my wife's 240 GL has the factory wiring sitting in back of the dash. If not,
then I have some wiring additions to do. The unit seems to be a VDO.

Ken
Canada

 

If you don't like the nylon hose idea, you can pick up a -3 braided hose kit
from the speed shop that sells you the gauge. It's teflon lines racing
brake line, inside of a stainless steel braided outer, basically impervium.
That's what I use on race cars. Copper is bad, use steel brake line tubing
if you want hard lines. Probably the nylon line is perfectly fine, though.

Brian