Perkins 4.108 Oil Switch Location

[YUVAMIZ]

Hello All,

Looking for help locating our oil pressure switch on our 1982 Perkins 4.108. Does anyone have a photo they can share of where their oil switch is located on the engine?

Thank you for any help!

[rls8r]

YUVAMIZ -

Sorry, I don't have a photo of my engine - but here is a page from a Perkings 4-108 Parts Manual (dated 2/81) showing the location of the oil pressure gauge/switch. As far as I can recall, the gauge sends information to the oil pressure gauge and the switch sends information to the low oil pressure alarm. I know the drawing shows a 6-cylinder engine, but the manual shows it's for a 4-108. My gauge and switch are mounted on a small manifold that is attached to the engine block at the location shown in the drawing. Hope this helps a bit.

[skipperpete]

That picture is a 6-354 perkins regardless of what the caption says, the vertical injector pump mounting point is clearly visible, 4-108’s have a horizontal pump.

[YUVAMIZ]

Thank you rls8r and skipperpete for the input. I looked up the 4108 equivalent document (link provided below) and it looks like two "pressure switch boss" plugs were designed in the same area as the 6-354. The pressure switch boss (Qty. 2) is denoted as #9 on the Cylinder Block diagram on page 1.

https://www.sextan.com/wp-content/up...4-108parts.pdf

[Searles]

It’s just in front of the starter motor ,my sons old I o r one tonner has a1982 4108m ,runs well never use the glow plugs ,spin for about 10 seconds leave for 10 secs, start ,when hot, first turn ,away she goes .⚓️⛵️

[YUVAMIZ]

For anyone else looking for this info in the future, I also found the following threads really helpful with photos:
https://www.cruisersforum.com/forums...on-210269.html
and:
https://www.cruisersforum.com/forums...ux-198356.html

[lifeofreilly57]

I have my 4108 in my garage currently, being rebuilt.
I'll send a picture later today if I can figure out how to load a picture here.

[DougR]

In the attached photo you can see the white oil pressure alarm switch as mounted in the adapter plate for the remote oil filter. It has a single red wire connected to it.

The sender for the oil pressure gauge cannot be seen, as its hidden behind the water pipes. It's location is on the side of the block just above the front end of the starter motor.

[YUVAMIZ]

Nice looking engine DougR! My 4.108 does not have a remote oil filter and the adapter plate for the oil filter does not have a port for sensing oil pressure like yours does.

Transatlantic Diesel shared the following two pictures which may be helpful for anyone else searching for this info!


Note: 1/8" NPTF threads


Note: 1/2" NPT Threads

Thanks again for all the help everyone!

[lifeofreilly57]

Originally Posted by YUVAMIZ

Nice looking engine DougR! My 4.108 does not have a remote oil filter and the adapter plate for the oil filter does not have a port for sensing oil pressure like yours does.

Transatlantic Diesel shared the following two pictures which may be helpful for anyone else searching for this info!


Note: 1/8" NPTF threads


Note: 1/2" NPT Threads

Thanks again for all the help everyone!

I tried to upload a picture here but am having a hard time. If anyone has a hint, let me know. I was a bit frustrated trying to upload the picture, I'm sure it's simple but it eluded me.

The location shown in the picture in this post is good. The location next to the oil filter is the one I ue on the motor. I used a hydraulic hose made up by a local hydraulic hose vendor with 1/8 npt to 1/8 npt. Added a T to the end and used the T to mount two pressure sensor switches, one to my alternator controller to delay the alternator energizing til oil pressure was up (it's a 200 amp alternator) one to the oil pressure alarm.
My oil pressure gauge sender is mounted to one of the upper oil gallery holes.
As for the pressure switches, buying a switch with a normally closed and normally open connections lets you use a single pressure switch. Normally closed to the alarm, normally open to the alternator controller.

[lifeofreilly57]

One more thing, the pressure witches are easily sourced on Amazon, mostly used for generator safety switches but will work on any motor with 1/8 npt ports.
Pressure sensors for your oil pressure gauge are usually sold by pressure to resistance scales, it's usually prudent to use one made by the gauge manufacturer, it avoids a lot of stress.

[rls8r]

lifeofreilly57 -

Sounds like my setup is something like yours. I don't have a starter key so I needed some way to initially energize the alternator - so I used the oil pressure switch. My pressure switch sends a small current to the alternator rotor to generate a magnetic field until the oil pressure climbs - then it shuts off the current once the generator is spinning and can generate its own field.

Adding photos is relatively straightforward. If hitting the "Post Reply" button puts you in the "Quick Reply" pane go to the "Advanced" reply window. You should see the text box where you type the text of a reply - and below it you'll have a pane with "Additional Options." One of the options is to "Attach Files." Click the "Manage Attachments" button to open a floating window where you can "Upload File from your Computer." Hit the "Choose File" button and use the tree to go to the graphic that you'd like to upload (you can select up to six files). After you've selected the file(s) you want to upload hit the "Upload" button. You may want to "Preview Post" to make sure that everything is as you want it before hitting "Submit Reply."