Perkins 4108 oil pressure ‚jumping‘

[dscha]

Hello!

Depending on the revs the oil pressure goes down to 2 bars, but only around 2100. at 1800 or 2300 it is normal at 4 bars. It also goes up to 4bsrs after the start.

So my question: does the engine have a problem, or is the sensor / gauge the issue?

Any thought are welcome

Thanks!
Dietmar

 

[oldharry]

Mechanical or electric gauge? Its 25 + years since I ran a 4108, so I dont remember. Either way sounds more like a gauge problem. Electric senders can do some strange things when they go off key, or develop wiring faults/ bad connections. I would certainly start with a generic replacement gauge off Amazon/Fleabay. That would at least put your mind at rest - or otherwise!

 

[dscha]

Thanks for the reply. It‘s a vetus electrical gauge. Can i buy any old sensor? Do the all have fhe same pressure/resistance curve? Also i can‘r find what thread the sensor needs to have. Any advise is welcome.

 

[Slipstream 34]

Check the spade connectors on the sender. They can vibrate lose causing your symptoms. Remove the connectors and gently squeeze with a pair of pliers. That should clear the symptoms.

 

[Roberto]

Thanks for the reply. It‘s a vetus electrical gauge. Can i buy any old sensor? Do the all have fhe same pressure/resistance curve? Also i can‘r find what thread the sensor needs to have. Any advise is welcome.

Thread is 1/8"NPT, there are a few possible port positions
Here both electric, on filter head and engine block

Here both on engine block, one electric (green) and one mechanical (red circle) a hose to a gauge

 

[Motor_Sailor]

The thread is 1/8th NPTF.

The sender is https://parts4engines.com/products/perkins-4-108-oil-pressure-sender

The hex nut to unscrew these is on the engine side of the sender body. Getting a spanner in there is the tricky bit. I have to remove my starter motor, but there's so many variations of 4108 that you might have easier access.