Oil Pressure Gauge

[Alimacdee2]

Recently fitted a mechanical Oil pressure Gauge whilst retaining the oil light. The original oil sensor switch was failing wasn't coming on till hot, and what with the oil pump needing priming after the engine rebuild, I thought I'd try replicate the setup I had with my first CB750. An 1/8 bspt adapter with thread sealant and a bsp T piece worked good.  I'm getting about 70 lb/in cruising speed drops to about 20 lb/in psi at idle in traffic which was an eye opener.. but I would think that's normal, the oil pump would reduce with engine revs   I'm running 20/50 mineral oil.  and the unions are all oil tight. Handy thing I have a photo of the original Gauge from 1978 showing similar pressure.

[McCabe-Thiele (Ted)]

These days oil pressure gauges have pretty much gone, as have manual dip sticks on many vehicles.
I was advised decades ago that fitting an oil pressure gauge just gives you one more thing to worry about plus the added risk of an oil leak from the pipework.

Back in the day you could buy oil pressure switches for BL cars that had a higher psi operating point (20psi?) if the pressure dropped you would notice the oil light illuminate on your dashboard immediately. (They sometimes flickered when the engine oil was very hot, giving cause for worry!)

Neat looking layout in the photo btw.

[Alimacdee2]

thanks, if the fittings aren’t quite matching could introduce a leak, never been a fan of domed fittings because of this, Ive been careful to use correct hose with bsp flat seat fittings which match the gauge and the t-piece, with fibre washers, though not required I have fitted 5mm spring clips to the hose now.
Not to everyone’s taste!

MSELMA004/4 APS Oil Pressure Gauge Capillary Hose 1.2m Long with 2 x 1/8 BSP flat seat female fittings

If I could figure out the plumbing I would fit one of these.

[Oddjob]

Another way they used to tap into the oil way was to fit an adapter to the blanking plug under the points or alternator covers. You drilled it and fitted an adapter piece and you left the oil pressure switch totally alone. Some even had the oil pressure gauge fitted instead of the blanking plug. Not ideal if you don’t have crash bars fitted.

[Alimacdee2]

yes I’ve seen those you still get nice kits for that type of fitment, I wanted a lit gauge cluster without any changes to wiring etc a reversible non-destructive upgrade!