OIl leak

[Guenter]

Ron - thanks that helps. My leak is not that strong, at least not yet - which makes me hopeful it is not the rear oil seal. Just curious - did your leak develop gradually over time, or did the seal fail all at once and needed attention.
Also thanks for the mainsheet tech notes - I will use that as the blueprint when and if I have to attempt replacing it.

Eric - thanks for the pictures and explanation. That is exactly how I had envisioned pulling the engine if I had to. I lifted the engine in the past when I replaced the engine mounts also using a lift with 4x4 across the companionway. Also single-handed. Your pictures show me there is plenty of room in the galley area.

All in all - appreciate all the help from this forum. It's time for me to stop guessing and speculating, fire up the engine and determine where the leak is actually coming from. But I can move forward with possible scenarios and outcomes in mind.     

[Guenter]

Closure on this topic: While attempting to remove my oil pressure gage I discovered that the 1/8"NPT pick up tube threaded into the engine block above the starter motor was cracked and snapped right off when using a wrench on the oil pressure gage. It is very apparent that this is the cause of my excessive oil leak - obviously. The leak path is out of the cracked pipe down the side of the engine and underneath to the oil pan, from there dripping into the engine bed.

I never liked the set up how the previous owner used a piece of threaded pipe (almost 3.5"long with a heavy T-piece on the end, one end for the pressure gage and one for the pressure switch (initially there was a hose connected to a mechanical oil pressure instrument in the cockpit). The vibration of the engine did its part over the years. I ordered some Hex 1/8 NPT adapters, male and female that should be a lot more robust installation.

Most importantly - there is no apparent need to replace the aft oil seal nor the valve cover seal - at least not for now, but if I do some day - thanks to all your help I will now know how.

Thanks again
Guenter - Seaclypse Hull # 153     

[KWKloeber]

Guenter

Note that the Kubota engine port is NOT 1/8" NPT.  It is 1/8" JIS (Japanese Industrial Standard) which is for all practical aspects interchangeable with British BSPT thread.

You can buy a BSPT-male x NPT-female adapter or a BSPT x NPT pipe nipple from McMaster and other sources.

[KWKloeber]

Guenter

I'll add that it's better off to:

Make a bracket to affix the tee/pressure sw/pressure sender to the exhaust manifold and use a flex hose.
Or
Mount the tee off the engine with a flex hose.
Or
Install the Westerbeke parts/bracket/hose that mounts a bracket and tee on the unused engine mount holes. I've done that on two M-25s/XPs.

(note that the original early M25s (like mine) had the pressure sw/tap for pressure sender mounted atop the bell housing with a flex hose between them.)

[Guenter]

Wow - thanks for bringing that up. I would have not caught that - the remaining piece of thread on the pipe that broke off threads nicely into the 1/8" NPT female adapters I bought - could well be the pipe is already the wrong thread to begin with, as it does not look factory installed. Since the spec'd OD of the male NPT is bigger than the JIS/BSPT, the presumably 1/8" NPT pipe may have already "cut" a bigger thread into my engine block. Entirely possible I am afraid, the ODs of 10.3 and 9.7mm are very close so that the pipe probably formed 1/8 NPT into the block - by forming I mean displaced/cold formed versus cut. Not ideal and new leak potential.   

I now also ordered a 1/8 NPT female to 1/8 BSPT Male adapter - that should do it. Should be in the clear from here on out with my 1/8 NPT T-block adapter.
 
Also appreciate the rail/bracket advice. The adapters have a solid shoulder(hex) and the assembly will be significantly shorter than the original set up - I will go with that for now - if vibration remain an issue, I may divert to the flex hose and bracket solution.

I will be at the boat Sunday and investigate.

Thanks again

Guenter - Seaclypse #153
 

[KWKloeber]

Guenter

I doubt that the larger diameter made any difference.  They threads are tapered and are so close you can't tell the difference (1.7833^o bspt / 1.7899^o npt.) And presumably, the NPT nipple was tightened no more than a BSPT thread would have been.  So effectively, the OD of what was threaded in was the same as BSPT, but maybe there was a turn less thread in the oil port.  Again effectively then, the connection was was just a titch weaker than if it had been a BSPT nipple. 

The thread angles also differ (55^o BSPT / 60^o NPT) and the thread pitch differs (28 tpi BSPT / 27 tpi NPT.)

I'd think that if anything, there was a slight cross-theading due to the 28 tpi vs 27 tpi thread pitches.

An oil pipe nipple like that failed on a C-30 Universal (did the fewer mated threads contribute to that?)  Certainly hanging a heavy pressure sender off the end in the wrong direction was key (caused a large moment at the pipe thread.)  See the pic of the one that failed.  Rather than orienting it properly. See mine.

Note that the Kubota oil switch is BSPT/JIS not NPT.  If you need to use PTFE to prevent a leak at the block I would consider bonding the nipple rather than relying on the engine for ground.  See pic for my type of bond.

[Guenter]

Thanks for the additional info.

Meantime, I went to the boat and assembled everything. I am glad I purchased the male 1/8 BSPT to female 1/8 NPT adapter - as the 1/8 NPT male alone did not thread into the engine block (telling me the old broke off pipe was 1/8 BSPT to begin with). The 1/8 BSPT fits flawlessly (no surprise here). Because I have used teflon (in the old installation) and a liquid sealant this time around, I bonded my pressure gage (not the switch) with a grounding wire to the engine block as well.

My T-set up looks like yours, pressure sender points up, but my pressure switch points down, so heavy bending momentum during engine vibration should not be a concern. I will watch it closely, may consider a support bracket down the road attached to the exhaust manifold.

Yet have to fire the engine, but I don't anticipate any leaks.

Guenter 

[KWKloeber]

Thanks for the additional info.

Meantime, I went to the boat and assembled everything. I am glad I purchased the male 1/8 BSPT to female 1/8 NPT adapter - as the 1/8 NPT male alone did not thread into the engine block (telling me the old broke off pipe was 1/8 BSPT to begin with). The 1/8 BSPT fits flawlessly (no surprise here). Because I have used teflon (in the old installation) and a liquid sealant this time around, I bonded my pressure gage (not the switch) with a grounding wire to the engine block as well.

My T-set up looks like yours, pressure sender points up, but my pressure switch points down, so heavy bending momentum during engine vibration should not be a concern. I will watch it closely, may consider a support bracket down the road attached to the exhaust manifold.

Yet have to fire the engine, but I don't anticipate any leaks.

Guenter 

Good deal

If the pressure sender is heavier (like mine) it's better to point it "down", which I am going to do, and put the lighter switch on top.

I'm interested how you bonded the assembly.  A pic?

Remember that any of the threads could have a poor ground if ptfe is used. I have a friend that continually complains that his temp gauge is inaccurate due to corrosion on the TStat cap but **refused** to install a bond when I offered to mail one to him. 

Something about a horse and water and drinking.

[Guenter]

Sorry, no meaningful pics on the bonding at the moment.
- on the pressure gage I wrapped a wire around the threads on the pressure side (not the sender wire stud) and soldered it, encased it with some epoxy and added a shrink tube to seal it in. Did that 5+ years ago and never had any grounding issues, the oil pressure instrument reads consistently.
- pressure switch - mine has one wire, so the switch is grounded through the pipe fitting and engine block. It always worked in the past since 2004, despite teflon. The newer switches sold at CatalinaDirect have + and - terminals. If my new set up has a weak bond, I intend to clamp a grounding wire to it with a hose clamp, but I don't anticipate that this will be needed. 

But, my TStat temp reading is off at times as well (stuck at cold temp then jump to op temp) - never thought of the bonding issue until your last reply. While at it, I will add a bonding wire to that as well.

You led the horse to water and it will drink!   

[KWKloeber]

Did that 5+ years ago and never had any grounding issues, the oil pressure instrument reads consistently.

OHHHH, I thought that was a recent addition with the pipe nipple replacement!

The newer switches sold at CatalinaDirect have + and - terminals. If my new set up has a weak bond, I intend to clamp a grounding wire to it with a hose clamp, but I don't anticipate that this will be needed. 

By "new" oil switch -- do you mean this one?
XPA; B series engines oil switch
It's the only 2-terminal switch I see. 
That's for "A" and "B" engines (with the convoluted Westerbeke engine wiring) that require a N/O switch (open; closes with oil pressure.) 

You need a N/C switch (closed; opens with oil pressure.)  There are two-terminal N/C switches, but that one on CD is not.

The switch for your engine is
M-25; XP; etc oil switch
$64 or $28 from Kubota.

I don't have data but I'd guess that the oil pressure or hi-temp switches are less susceptible to high resistance on the threads than a gauge sender (which relies on impedance to read correctly.)

Many senders and switches are actually NPTF npt-fuel thread, which have a full (not truncated) peak and rely on that interference fit to seal (not by ptfe or pipe dope in the thread "valley".)  You may see these listed as "Dry Seal" senders.

If I install a sender or switch with no PTFE or dope, I use the copper-infused never seize so the thread doesn't gall/corrode into the block.
https://www.amazon.com/Permatex-09128-Copper-Anti-Seize-Lubricant/dp/B000HBM8HU/ref=asc_df_B000HBM8HU

I use ABA mini clamps from Steve to make bonding wires for senders:
https://www.ultimategarage.com/shop/index.php?cPath=309_30&sort=2a&filter_id=16&page=2

[Guenter]

Yes, M25 XP #Z4290 is the correct switch, I see now CD offers both.

Good old ABA clamps - I used to work for Norma, German hose clamp manufacturer, who bought ABA in 2004 or so, then they bought Breeze. The ABA mini is perfect for your bonding application because of the screw (versus worm drive), perfect for a ring terminal. Oetiker one-ear clamps are suitable as well, but permanent (non-serviceable/removable other than cutting it off), putting the wire end under the band, crimp down and done for good. Doesn't look as neat, but works well.

Happy Sailing - May 15 is splash day for me.