Oil pressure gauge query?

[jamie N]

On start up, the gauge reads 6-7 bars or so. As it heats up, the pressure decreases, until it shows 1 to 0 bars.
The engine temp remains the same with the cooling system not having to work any harder (it's easy to monitor on this engine), and there's no smoke, nor does the engine use any oil, or have any symptoms of anything being awry such as 'smelly oil' or loss of performance.
The gauge wasn't fitted as a unit with the sender, it was from the back of my garage as a leftover from a different project, which on 'googling' doesn't guarantee great accuracy. The engine's run many hours since a major rebuild, and clean of the cooling passages in the block and head, and hasn't ever been any different since reassembly.
It's probable that with winter being here, I'll replace them as a pair, but has anyone else experienced this?

 

[vyv_cox]

I have experienced something very similar. On my BMC 2.5 engine, no oil pressure gauge was fitted. I installed one, with very similar results to yours. The pressure switch never activated but the gauge showed 0 psi when hot. I assumed the transducer was faulty. Boat sold now.

 

[LadyInBed]

Boat sold now.

Did you sell it to a guy called Jamie up in Fortrose? ?

 

[Sea-Fever]

Is the reading you are referring to at tickover? It’s normal to have lower pressure when hot at tickover.

 

[QBhoy]

Hi. I’d firstly suspect the gauge is questionable. 7bar I think is over 100 psi. That would be ridiculous oil pressure, even stone cold. What engine is this and at what rpm are you at when like this ?

 

[jamie N]

The symptoms are throughout the rev range, and very consistent. If I notice that the pressure is low at start-up, then I'll be very concerned.
Given the time of the season, I'll be able to change the sender and the gauge for a 'matched pair'.
The engine's a Ruggerini RM90, which is in no way remarkable except for a couple of bits of being Italian, if you see what I mean!

 

[vyv_cox]

Did you sell it to a guy called Jamie up in Fortrose? ?

No, it went to a man on south coast of England. It was sold by a dealer, I never met the new owner and don't know his name.

 

[ChromeDome]

I'd replace the set.

First find your engine's oil pressure as specified by the manufacturer. Might look something like this (BMC 1500), probably even stating temperatures:


Check the conversion to other values e.g. psi, bar etc.
Then buy a sensor & gauge to display the relevant range - plus some on top to prevent the pointer from max out when cold.

 

[oldgit]

Budget chinese matched pair of sender and gauge on Ebay from around £10.00- £15.00 .
Works pefectly well on a marine diesel.
You can spent loads more for something of better quality ? with a known name printed on the dial.
Need to ensure the male thread on the new sender unit matches the female on your engine block .
Loads of different threads both imperial and metric, need to get it right , or you will spend more on adaptors than on the new gauge and sender.

2" 52mm Digital LED Oil Press Pressure Electric Gauge 1/8 NPT Sensor Sender 12V | eBay

 

[jamie N]

Thanks for that, that was the way that I've been looking.
Just as an aside for your post and the eBay ad:
Postage:
Doesn't post to Scottish Highlands | See detailsfor postage
Located in: Welwyn Hatfield District (B), United Kingdom
Back in the CA days, that'd be a worthy conversation also.....?

 

[oldgit]

Scottish Highlands ?
Which Junction is that on the M25, cannot recall seeing a sign

 

[VicS]

Scottish Highlands ?
Which Junction is that on the M25, cannot recall seeing a sign

21

M25
Google Maps

 

[jamie N]

Yup: "Scotland! A place past Luton!"
Says it all really............... ?

 

[oldgit]

21

M25
Google Maps

is it me, but all the the traffic seems to be coming south ?

 

[VicS]

is it me, but all the the traffic seems to be coming south ?

M25 so clockwise butyou can spin the picture round and view the opposite direction. Then it looks busier anticlockwise

M25
Google Maps

 

[oldgit]

M25 so clockwise butyou can spin the picture round and view the opposite direction. Then it looks busier anticlockwise

M25
Google Maps

ever thought of doing a job such as " the government's chief finance minister "