Install oil pressure gauge

[Gary Sweat]

I had an oil pressure gauge on my YM1900 until the nylon line broke. At the time I did not know there was a copper line kit available for it. When the line broke I decided to put a new oil light sending unit back in and just use the light as I had read some don't think it is worth taking the chance of getting ripped off on limbs.

However the brand new sending unit I just got in is DOA and the light stays on, so now I want to go back to the gauge. The gauge line end did not fit very well in the threaded hole in the block but it held. I was never happy with it but could not find the right adapter.

I think Yanmar uses the BSPTT but not sure. Does anyone know where I can find an adapter for the Yanmar threads to standard NPT?

 

[winston1]

Gary, from my reading it would seem the Yanmar threads may be 1/8" bpt, if that is so here is and adapter. Might do a little measuring and compare with the attached dimensions. McMaster-Carr

 

[Gary Sweat]

Gary, from my reading it would seem the Yanmar threads may be 1/8" bpt, if that is so here is and adapter. Might do a little measuring and compare with the attached dimensions. McMaster-Carr

Thanks, that looks to be the one I need. I'm pretty sure the pressure switch is bad. I took it out and cranked the engine and oil gushed out of the hole. I want to put the gauge back in just to make sure. This time I'm putting in the copper line. The nylon lasted about 2 years but the weather got to it I guess.

 

[reb]

When I put the gauges on my 1500D I found the oil pressure adapter in a set of metric adapters from the local auto parts store.

The copper line is a good idea. I used the same piece I bought about 42 years ago. It has served in 5 or 6 vehicles now.

 

[Gary Sweat]

When I put the gauges on my 1500D I found the oil pressure adapter in a set of metric adapters from the local auto parts store.

The copper line is a good idea. I used the same piece I bought about 42 years ago. It has served in 5 or 6 vehicles now.

Well, I just got back from the auto parts store getting a new gauge and to my surprise it has the adapter plug in it that I needed I went with the electrical set up this time. Hope I don't have any issues with the sending unit. The gauge has a second tab that you can hook the warning light up to so I can have both. The sender is rather bulky but with the adapter it should be out far enough to screw in without hitting the frame.

 

[California]

Gary, when I replaced my oil pressure sender I discovered that US and British pipe thread standards are similar. Apparently the pipe diameter and threads per inch are the same but BSPT has greater taper toward the nose of the sender. So a Japanese/BSPT sender will always thread into the smaller BSPT hole in the Yanmar block, but some USPT fittings are large enough at the nose that you can't catch the first thread.

I went through all this and tried the various combinations a couple of years ago. I posted my results in this (longwinded!) thread about replacing my oil pressure sender. I found that my various brass fittings weren't distorted after threading them in securely in the Yanmar block, and my experiments didn't hurt the block. But about half the fittings in my (US) brass fittings collection were too large at the tip to catch the first thread.

My point here is that you might try a USPT brass 'street elbow' (M to F threads) and aim that sender upward instead of sticking it straight out where it can snag on brush.

 

[jonyyuma]

You might prefer that it is 90 degrees up, so it can drain after you turn off the engine.Ya know, not accumulate any sediment in it from cycling.Jy.

 

[Gary Sweat]

Well, here is how I wound up mounting it. Mostly because it tightened up at that angle and also because I would have to relocate the wiring. The photo doesn't show it but the sender is at the same level as the steering rod. Now that the loader is on there is a lot of steel in the way of limbs and such so hopefully it won't snag the wires. If it does then I'll have to come up with a shield around it.

 

[jonyyuma]

At least the bulb is not turned down.It should slide by the limbs? Why is the loader always in the way?? Bending over the arms can be a chore? At least for me. Jy.

 

[winston1]

One thread per inch difference on npt verses bpt. McMaster-Carr

 

[Gary Sweat]

At least the bulb is not turned down.It should slide by the limbs? Why is the loader always in the way?? Bending over the arms can be a chore? At least for me. Jy.

I know what you mean! Used to be a breeze to work on. Just one of them things ya don't think about while building something.:confused2:

 

[California]

One thread per inch difference on npt verses bpt. McMaster-Carr

Interesting! I just learned something.

At 27 tpi for USS and 28 tpi for the BS in the Yanmar block , and assuming you can thread the brass fitting into the block about 6-7 turns before it takes excessive force to go any more and also won't leak (based on my observation), then it's in about a quarter inch. The Mcmaster-Carr diagram says 0.26" engagement if the threads matched. Since the threads don't match, I expect a little less than a quarter inch engagement.

27 tpi calculates to a thread pitch of roughly .040. (1 inch / 27).

In that quarter inch of engagement, the threads are mis-aligned about .010 overall, which is about 1/7 of .010 (about .0014) per each thread.

Assuming you use brass fittings, and that a tapered threaded fitting is intended to deform to attain a seal, then screwing a 27 tpi brass fitting into a 28tpi hole a quarter inch deep seems pretty harmless. Not ideal, but 'good enough for the girls I go with' as an old Carpenter friend used to say!

And applying theory to practice, putting 1/8 USPT fittings into my Yanmar block temporarily to verify that I had a dead oil pressure sender sealed fine, and didn't distort anything so far as I could see. I had also bought a HF oil pressure test gauge and whatever the threads were on that, it screwed in fine too.

 

[Gary Sweat]

Got the gauge installed. I like the fact it came with the ability to keep the light too. Built into the sending unit. Here are the pics with the engine running at about 1100rpm. It is 68 degrees in my garage so the oil pressure will drop I'm sure when it gets hot. At least it seems the oil pump is working fairly good. I run Rotella T 15-40 and so far it seems to work ok.

And yea, I let the grinder slip when I was enlarging the hole to 2" so I get to repaint the dash again

The switch below the oil gauge is the TS. I wanted something to remind me if it was not off.

 

[Gary Sweat]

Interesting! I just learned something.

At 27 tpi for USS and 28 tpi for the BS in the Yanmar block , and assuming you can thread the brass fitting into the block about 6-7 turns before it takes excessive force to go any more and also won't leak (based on my observation), then it's in about a quarter inch. The Mcmaster-Carr diagram says 0.26" engagement if the threads matched. Since the threads don't match, I expect a little less than a quarter inch engagement.

27 tpi calculates to a thread pitch of roughly .040. (1 inch / 27).

In that quarter inch of engagement, the threads are mis-aligned about .010 overall, which is about 1/7 of .010 (about .0014) per each thread.

Assuming you use brass fittings, and that a tapered threaded fitting is intended to deform to attain a seal, then screwing a 27 tpi brass fitting into a 28tpi hole a quarter inch deep seems pretty harmless. Not ideal, but 'good enough for the girls I go with' as an old Carpenter friend used to say!

And applying theory to practice, putting 1/8 USPT fittings into my Yanmar block temporarily to verify that I had a dead oil pressure sender sealed fine, and didn't distort anything so far as I could see. I had also bought a HF oil pressure test gauge and whatever the threads were on that, it screwed in fine too.

I don't see how leaving a 27 tpi permanently would hurt anything. If it seals and you have a 1/4" into the threads that should be more than secure enough for a gauge. It's not like it is trying to hold anything up. I don't think you could take it out and put it back more than a few of times before the threads on the gauge would be to distorted and wouldn't seal but then, why would you need to? Unless it was some really thick brass, I don't see how it could damage the steel threads in the block. I just got lucky and the bspt adapter came with the gauge.

 

[Neat 1500]

i used all electric gauges to remove the "showered in hot oil" problem. i bought mine from Hong Kong and all the fittings and the like fitted the Yanmar perfectly.

 

[Gary Sweat]

i used all electric gauges to remove the "showered in hot oil" problem. i bought mine from Hong Kong and all the fittings and the like fitted the Yanmar perfectly.

Where did you get your gauges from? I still want to put in a temperature gauge.

 

[Neat 1500]

Where did you get your gauges from? I still want to put in a temperature gauge.

i found them on Ebay, i will go looking again for the seller as i want another set for the YM14.

 

[normde2001]

Most guys use SUNPRO 1 1/2' triplet gauge kits, (separated), available at Autozone or most autoparts stores. Harbor freight also has similar gauges for about 1/2 the price, and probably just as good.

 

[Gary Sweat]

Most guys use SUNPRO 1 1/2' triplet gauge kits, (separated), available at Autozone or most autoparts stores. Harbor freight also has similar gauges for about 1/2 the price, and probably just as good.

Back about 2 years ago I bought the triple set from Autozone but only put in the oil gauge at the time. The face plate ring around the gauge rusted up over time and eventually the oil line at the gauge broke. This time I looked for one that was either stainless steel or aluminum. I want to put the other two in now as long as they have the same material for the face plate.

I wanted 1 1/2" but all they had in stock was 2". Easy to read but takes up a lot of room on the dash.

 

[Gary Sweat]

i found them on Ebay, i will go looking again for the seller as i want another set for the YM14.

Thanks. The oil gauge I purchases is a iEquus performance and cost 49.00. I like it because it came with several different size fittings and had the BSPT fitting, all of the wire connectors and really good instructions on how to install it. I got it at O'reilly auto parts and supposedly the sender can be purchased separately if it ever craps out.