Perkins 4108 Oil Pressure Sender

[avazquez]

I am installing an oil pressure dial in my Perkins 4108. It has both the alarm and the analog reading. I can’t find a dual type sender and TAD recomends a T and two sensors: a switch for the alarm and another one fir the actual reading. Has anyone done this before? Any pictures or advice? Thanks!

[jpendoley]

You need a oil manifold that has three ports. One for the oil into the manifold from a port in the block (on mine its in front of the IP), one port for the pressure sender and one port for the low pressure alarm. Attached pictures: the manifold in a vice, a picture of the mounting location and a picture of the manifold with pressure sender and alarm installed on the manifold and bolted onto the block. My engine is a Westerbeke 40 which is on a 4-107 block. Hope that helps.
Jim

[avazquez]

Interesting. So the oil manifold is connected to the engine block through a hose? I wonder if the 4108 has the same holes and if there is a part number. Wonder if it’s better than just a pipe with a T and the two sensors. Looks much sturdier. I just don’t feel confortable with a T pipe and the sensors. I feel like it could crack eventually with so much vibration.

[jpendoley]

The hoses on my engine have hydraulic end fittings-NAPA made them up for me. I figure if they are good enough for hydraulics they should hold up on out little diesels. Compare the picture of my block to yours-I believe they will be identical. Westerbeke only changed the bits that attach to the block-the block is stock-at least that is my understanding.

[Madehn]

The plan that TAD gave you is perfectly fine- two senders T eed to one port- for the sender that is for the light/buzzer be sure that you get the right type - there are three types of senders- one is for gauges, one is for lights and is normally closed switch and one is for lights that is a normally open switch. Mine works by taking a positive wire from the ignition switch that is live when the key is "on" only. That wire goes through the light and buzzer then to the oil pressure sensor. The sensor switch is normally closed. turn the key on that the light and buzzer ground through the closed switch and go off. Start the engine and oil pressure opens the switch and then the light/buzzer go off. you can test the sensors from any auto parts store with an ohm meter. you want 0 ohms resistance between the sensor wire terminal and the body of the sensor when there is no pressure.

[Scubaseas]

Originally Posted by avazquez

Interesting. So the oil manifold is connected to the engine block through a hose? I wonder if the 4108 has the same holes and if there is a part number. Wonder if it’s better than just a pipe with a T and the two sensors. Looks much sturdier. I just don’t feel confortable with a T pipe and the sensors. I feel like it could crack eventually with so much vibration.

Even better if the manifold is mounted off the engine and connected with a hose. Putting a brass tee on the engine is a bad idea. The weight of the sensors and the vibration of the engine will crack the tee. The senders will last longer if they are not mounted on the engine or at least that's been my experience.

[svfinlandia]

Originally Posted by avazquez

Interesting. So the oil manifold is connected to the engine block through a hose? I wonder if the 4108 has the same holes and if there is a part number. Wonder if it’s better than just a pipe with a T and the two sensors. Looks much sturdier. I just don’t feel confortable with a T pipe and the sensors. I feel like it could crack eventually with so much vibration.

I have a Perkins 4–236. It is an older model (1983) but I think it has two separate senders. One for the alarm and one for the analog pressure gauge. I am not at the boat or I would take pictures. I know it is a different model then your engine, but it might be very similar. Anyone else with knowledge of both model Perkins engines to confirm?

Al, S/V Finlandia

[DougR]

When I owned a 4-108, the engine was fitted with a separate oil pressure sender screwed into the oil gallery directly on the port side of the block, and the low oil pressure alarm switch was screwed into the remote filter housing right below the injection pump. Worked fine....

That said, there is no reason that you couldn’t use a proper “T” fitting with both sender and switch fitted into it, or a multi port manifold connected to the oil gallery with a small hose. Both have been done successfully.

The photo shows both options.....a heavy duty “T” fitting made of steel that isn’t going to crack, and also an aluminum manifold to accept all sort of senders and switches. The small threaded holes in the manifold go all the way thru and are for mounting on vibration isolators.