Remove one thing & break another

[ontherocks83]

While removing the exhaust manifold off of my Universal M25, I broke the pipe that connects the Oil pressure sensor to the block. I have been able to free up all the coupling pieces and now just need to replace the 2 or 3 inch extension pipe itself. I looked on westerbekes parts manual and it shows the sensor but displays it as going right into the block without the extension. The problem is (and yes I tried to see if it would fit) there is not enough clearance under the manifold to fit the oil pressure sensor without the extension pipe. Does anyone know where to possibly source the extension piece with the matching thread pattern?

 

[Rich Stidger]

It looks like a standard brass nipple with a female to female coupler. Probably 1/8 or 1/4" NPT parts. You should be able to find them at any decent hardware store. Take your parts to be sure the size matches.

 

[Benny17441]

There lies the principle of " If it ain't broken, don't fix it". Also " if the job is a two hour job, better reserve six"

 

[TomY]

Check actual thread carefully with a thread gauge. There are small differences between manufacturers - engines, senders, nipples. 26 vs 27 thread per inch for instance not to mention thread types.

 

[RitSim]

Pretty sure this is British Tapered thread which is equivalent to the Japanese pipe thread. The M25 block is actually a Kubota tractor block. My original Oil Pressure switch did fit under the manifold- so if yours doesn't fit it may have been changed at some point. The British pipe nipples are available on Ebay. I did extend my oil pressure sensing line because I attached an electronic oil pressure sender. But placing the sender out too far does raise the possibility of the nipple threads breaking from vibration over time. I agree with carefully determining exactly what you have. It is possible a PO did some work here and didn't do it right (I believe our American standard pipe thread is 27 threads per inch for 1/8" pipe and the BST thread is 26 threads per inch) So it may be possible to force an American nipple in to a BST thread.

 

[Project_Mayhem]

You might be able to do a comparison of threads against one in the hardware store using this method: Place both pieces nipple to nipple overlapping and try to interlock the threads. If they wobble a bit when the threads touch it's a not a match

 

[RitSim]

It is possible that the coupling is actually a thread adapter from one style to another.

 

[JoeWhite]

I agree with RitSim. It appears that the long pipe has solder in the middle, indicating two different pieces soldered together with different thread. If so it is custom made, normally not available in a hardware store. I would recommend purchasing both thread types and test which one fits the engine. You may have to cut them and solder them as the original setup
If engine vibration my be a problem, then place a larger sleeve over the solder and solder it on.

 

[ontherocks83]

It is possible that the coupling is actually a thread adapter from one style to another.

I will try tonight to see if the threads on the extension pipe are the same as the pressure sensor.

I just found there is a specialty plumbing store near my work that I am hoping will be able to help out also.

 

[DayDreamer41]

This may help

The Difference Between NPT, BSPP and BSPT Seals

Pressure systems in the process industry use different ways of sealing depending on the geographical region, size of the pressure system, and…

www.ralstoninst.com

 

[Benny17441]

Get the right part. Look for a factory sensor replacement; it should not be too hard for a U M25 engine.
Kubota PN 15841-39010. You may also consider relocating the sensor, all it takes is a couple of fittings, an oil line and a mounting base.

 

[Justin_NSA]

I find that I can break stuff and usually still be ahead of having it done by someone else

 

[ontherocks83]

Get the right part. Look for a factory sensor replacement; it should not be too hard for a U M25 engine.
Kubota PN 15841-39010. You may also consider relocating the sensor, all it takes is a couple of fittings, an oil line and a mounting base.

The problem is not the part (sensor) itself, that is fine, it is the extension tube that is not in the parts diagram

 

[Justin_NSA]

Looks like something you could find at HD or Lowes. Or a plumbing store.

 

[Benny17441]

The problem is not the part (sensor) itself, that is fine, it is the extension tube that is not in the parts diagram

What I meant is that I'm not sure the one you have is an OEM sensor; that extension tube does not seem to be an original part. Not sure that extension tube is the best answer to the installation of the sensor; it seems quite prone to getting knocked off. In the automotive world when you have a component that would require extensive work to replace it is quite common practice to relocate it. Relocating that sensor would be quite easy; get a 90 degree brass elbow fixture that you can screw into the block, fit a screw in flexible oil line about 6" long and find a small bracket that you can attach to a more convenient location and drill a hole for the sensor to attach to the bracket and connect it to the other end of the oil line.

 

[jssailem]

You might show your isssue to a Hydraulics store. The one I use is pretty resourceful when it come to engineering a solution. And you may find the costs are very reasonable.

 

[ontherocks83]

So I ended up finding a pipe that matches from a local plumbing supply store for $2.50 (win for me). I also ordered a new switch from a Kubota dealer for about $40 in hopes that the current one is after market and the new one may be smaller and fit under the manifold. If not I'll throw the new one on anyways.

Thanks all for the help along the way, the engine info and part info were very helpful at the kubota dealer

 

[Maine Sail]

So I ended up finding a pipe that matches from a local plumbing supply store for $2.50 (win for me). I also ordered a new switch from a Kubota dealer for about $40 in hopes that the current one is after market and the new one may be smaller and fit under the manifold. If not I'll throw the new one on anyways.

Thanks all for the help along the way, the engine info and part info were very helpful at the kubota dealer

Just make sure it is JIS threaded not NPT....The Kubota block is JIS...

 

[ontherocks83]

I just got the new oil pressure switch in from the kubota dealer. I haven't test fitted it with the manifold in place yet, but I did measure it with digital calipers and it is about 3mm smaller in diameter than the one that was on there. I am pretty confident that it should just fit.