Bmc 1.5 wiring

[andyhall50]

Hi

I recently joined because I have bought a fishing boat with a 1500 engine in it. The engine was swapped by the previous owner. 

Only the starter motor and alternator are wired in. 

I want to wire in the oil pressure light and gauge, Water temp sensor and eventually glow plugs.

I want the oil pressure and temp sensors connected before I move the boat later in the week.

I have added photos of the various wiring sensors but not sure what a couple are for. The oil pressure has a tee so guessing one for the light and one for the gauge.

Any advice on getting it wired up properly will be really needed and appreciated.

[Jen-in-Wellies]

Welcome to the forum. I'll defer to the experts, but it looks like some of the sensors have been painted grey with everything else. The paint will need removing from the terminals to get a good connection. 

For oil pressure warning and water temperature warning, the wiring is simple. Ignition switched +12V goes to one side of the bulb. The other side of the bulb goes to a single terminal on the sender. The oil pressure sender has two terminals and as you suspect, is probably oil pressure guage sender as well as warning light. Measure the resistance with the multimeter vetween each terminal and a bare bit of metal connected to the engine block, with the engine off. The one with 0ohms is the warning light. The one with a non zero resistance goes to the gauge. The sender with two pins, near the alternator looks to be a more modern one, added after the engine was built. Perhaps a water temperature sender for a gauge. The plug type, I think is two pin minitimer. What gauges and lights do you have on the panel?

[Tony Brooks]

Sorry, but the images are too close for me to identify exactly where the senders are on the engine, and it looks as if you may have an extra sender in an unusual position, photo 3.

 

The first photo seems to show an oil pressure warning lamp switch.

 

I think the second photo is, I THINK either a water temperature sender or warning lamp switch, or even both in one.

 

You will find generic instrument wiring diagrams in the electrical course note on my website, see my signature.

 

 

Edited Monday at 07:47 by Tony Brooks

[andyhall50]

Thank you, much appreciated.  I am on the boat tonight, I will take more photographs showing the locations. 

 

The 2nd picture is at the back of the engine I think it's into the water system. The plug looked strange.

 

I have no idea what tt he 3rd picture is. Would it be a temperature sensor on the head?

 

The engine was put in from a canal boat before I bought it.

 

Thanks again

[Tony Brooks]

44 minutes ago, andyhall50 said:

Thank you, much appreciated.  I am on the boat tonight, I will take more photographs showing the locations. 

 

The 2nd picture is at the back of the engine I think it's into the water system. The plug looked strange.

 

I have no idea what tt he 3rd picture is. Would it be a temperature sensor on the head?

 

The engine was put in from a canal boat before I bought it.

 

Thanks again

 

Since when did BMC 1.5s have a pulley at the back of the engine? The sender in that photo looks as if it is in the correct position for the normal temperature sender. The plug is a "standard" modern automotive connection, so it is probably not an original BMC 1.5 sender/switch so a replacement that fitted. I think it is at the front (fan belt and water pump) end of the engine.

 

The third image. That is the most likely explanation, so possibly a switch for warning lamp in the first photo and a sender for a gauge in the third photo. You need to test them as @Jen-in-Wellies suggested to find out if this is likely.

 

Back in the day BMC produced a number of different spec engines for specialist applications and then the Indians also did some alterations, so one never knows what you will find.

 

 

Edited Monday at 09:09 by Tony Brooks

[andyhall50]

Thanks again. I said back because it was the further most point from me. 🤣 does make sense that the pulleys are on the front and the gearbox at the back.

[Tony Brooks]

34 minutes ago, andyhall50 said:

Thanks again. I said back because it was the further most point from me. 🤣 does make sense that the pulleys are on the front and the gearbox at the back.

 

Thanks, you had me going there. This is why photos covering a larger area, yet still showing what is being questions always help. 

[andyhall50]

Hopefully this will show where they are.

[andyhall50]

On the first photo, there is a metal pipe coming I nvvup from under the gearbox. It has just been taped up. What is it for and what should I do with it?

[Tony Brooks]

1 hour ago, andyhall50 said:

On the first photo, there is a metal pipe coming I nvvup from under the gearbox. It has just been taped up. What is it for and what should I do with it?

 

If it is the one with what looks like masking tape between the metal pipe and convoluted hose/trunking, then I think it is carrying gearbox oil from the oil cooler back into the gearbox or from the gearbox into the oil cooler. It looks like a PRM hydraulic box, so well done, but as you say fishing boat, I assume sea use. If so learn how to put the "get you home" device into action, so you can get back home after a gearbox hydraulic failure or loss of gearbox oil. Also try it to ensure it does not lock the box into astern.. 

[andyhall50]

2 minutes ago, Tony Brooks said:

 

If it is the one with what looks like masking tape between the metal pipe and convoluted hose/trunking, then I think it is carrying gearbox oil from the oil cooler back into the gearbox or from the gearbox into the oil cooler. It looks like a PRM hydraulic box, so well done, but as you say fishing boat, I assume sea use. If so learn how to put the "get you home" device into action, so you can get back home after a gearbox hydraulic failure or loss of gearbox oil. Also try it to ensure it does not lock the box into astern.. 

Yes that's the one. Should I be concerned that it isn't connected anywhere? What should I connect it to? 

Is it like an oil clutch? Sorry not git a lot of experience with these engines.

[Tony Brooks]

1 hour ago, andyhall50 said:

Hopefully this will show where they are.

 

 

The oil pressure switch/sender in the T. The small hexagon one with the single blade connector is the warning lamp switch.

 

The big disc one with two terminals is a very old "Smiths" type oil pressure sender. If you need an oil pressure gauge and the exiting gauge and sender do not work, then I think that you would find it easier to buy a new matched sender and gauge.

2 minutes ago, andyhall50 said:

Yes that's the one. Should I be concerned that it isn't connected anywhere? What should I connect it to? 

Is it like an oil clutch? Sorry not git a lot of experience with these engines.

 

It looks to me as if it is connected to the gearbox oil cooler - the cylindrical thing mounted across the front of the gearbox, but I can't see it very clearly, I even blew the photo up to try to get some more detail.

 

If it is just a tube with some kind of plumbing fitting on it then I think it is for attacking a pump to drain the gearbox oil. If so feel under the box and that pipe should connect to the lowest point.

 

The gearbox is a bit like a small part of a car gearbox with one sets of gears for ahead and another for astern. One gear in each set is free to spin on its shaft so they can't drive (like the synchromesh gears in a car). To engage a gear oil is fed into the selected gear's multi-plate clutch which locks the gear onto the shaft. Neutral is obtained by letting the oil in the relevant clutch run back into the bottom of the gearbox, so the gear is no longer locked onto the shaft. There is a full set of manuals on the PRM website. 

[andyhall50]

18 minutes ago, Tony Brooks said:

 

The oil pressure switch/sender in the T. The small hexagon one with the single blade connector is the warning lamp switch.

 

The big disc one with two terminals is a very old "Smiths" type oil pressure sender. If you need an oil pressure gauge and the exiting gauge and sender do not work, then I think that you would find it easier to buy a new matched sender and gauge.

 

It looks to me as if it is connected to the gearbox oil cooler - the cylindrical thing mounted across the front of the gearbox, but I can't see it very clearly, I even blew the photo up to try to get some more detail.

 

If it is just a tube with some kind of plumbing fitting on it then I think it is for attacking a pump to drain the gearbox oil. If so feel under the box and that pipe should connect to the lowest point.

 

The gearbox is a bit like a small part of a car gearbox with one sets of gears for ahead and another for astern. One gear in each set is free to spin on its shaft so they can't drive (like the synchromesh gears in a car). To engage a gear oil is fed into the selected gear's multi-plate clutch which locks the gear onto the shaft. Neutral is obtained by letting the oil in the relevant clutch run back into the bottom of the gearbox, so the gear is no longer locked onto the shaft. There is a full set of manuals on the PRM website. 

Thank you. You are very knowledgeable.  I thought it was a drain as it does go to tt he lowest point. Should I blank it ?

When you said prm gearbox, wee done.  What did you mean?

Is gearbox failure common with this one?

[Tony Brooks]

7 minutes ago, andyhall50 said:

Thank you. You are very knowledgeable.  I thought it was a drain as it does go to tt he lowest point. Should I blank it ?

When you said prm gearbox, wee done.  What did you mean?

Is gearbox failure common with this one?

 

As long as you don't plan to sink the boat and as long as it does not spit oil out, there is no need, but doing so would help keep any muck out. I think that box has a breather mounted on the top.

 

PRM hydraulic gearboxes are arguably the most reliable and long-lasting of any you are likely to come across today. However, that looks like a very old box to me, possibly dating from the 1960s.

 

[andyhall50]

49 minutes ago, Tony Brooks said:

 

The oil pressure switch/sender in the T. The small hexagon one with the single blade connector is the warning lamp switch.

 

The big disc one with two terminals is a very old "Smiths" type oil pressure sender. If you need an oil pressure gauge and the exiting gauge and sender do not work, then I think that you would find it easier to buy a new matched sender and gauge.

 

It looks to me as if it is connected to the gearbox oil cooler - the cylindrical thing mounted across the front of the gearbox, but I can't see it very clearly, I even blew the photo up to try to get some more detail.

 

If it is just a tube with some kind of plumbing fitting on it then I think it is for attacking a pump to drain the gearbox oil. If so feel under the box and that pipe should connect to the lowest point.

 

The gearbox is a bit like a small part of a car gearbox with one sets of gears for ahead and another for astern. One gear in each set is free to spin on its shaft so they can't drive (like the synchromesh gears in a car). To engage a gear oil is fed into the selected gear's multi-plate clutch which locks the gear onto the shaft. Neutral is obtained by letting the oil in the relevant clutch run back into the bottom of the gearbox, so the gear is no longer locked onto the shaft. There is a full set of manuals on the PRM website. 

Just had a look and lots of older ones there. Where should I start, any idea which old model it might be?

[Tony Brooks]

18 minutes ago, andyhall50 said:

Just had a look and lots of older ones there. Where should I start, any idea which old model it might be?

There should be a plate on the gearbox, but it may have fallen off. Others may have a better idea, At a very rough and unreliable guess, possibly a 175 or 280.

 

Any of them should explain how they work though.

Edited Monday at 20:03 by Tony Brooks

[andyhall50]

Thank you. Somewhere to start looking.

[MtB]

17 hours ago, andyhall50 said:

Yes that's the one. Should I be concerned that it isn't connected anywhere? What should I connect it to? 

Is it like an oil clutch? Sorry not git a lot of experience with these engines.

 

A point to highlight about this... you don't need experience with these engine as here we are discussing the gearbox, not the engine.

 

There are a number of different gearboxes that might be fitted to a BMC engine, all made by companies nothing to do with BMC. Tony suggests you have gearbox made by PRM. Similarly, PRM make lots of models of gearbox, any of which might be found fitted to a wide variety of engines! 

[Tony Brooks]

9 minutes ago, MtB said:

 

A point to highlight about this... you don't need experience with these engine as here we are discussing the gearbox, not the engine.

 

There are a number of different gearboxes that might be fitted to a BMC engine, all made by companies nothing to do with BMC. Tony suggests you have gearbox made by PRM. Similarly, PRM make lots of models of gearbox, any of which might be found fitted to a wide variety of engines! 

 

But the topic title and first question about warning lamps and gauges was engine related but the topic drifted a bit. Good to point out that the gearbox make and model and engine make and model tend to be a perm any two from many.

[andyhall50]

4 hours ago, Tony Brooks said:

 

But the topic title and first question about warning lamps and gauges was engine related but the topic drifted a bit. Good to point out that the gearbox make and model and engine make and model tend to be a perm any two from many.

Thank you again. We did drift off. I dont have any experience of the engine or the gearbox. I have a bukh dv24 on my sailboat, we had a narrow boat with a jp2 on it. I have made a log splitter with a hr2 driving it. But this engine and box is new to me. 

 

Went to the boat this evening, the oil pressure guage on the boat is a mechanical one. Found a small diameter pipe running to the engine but the sender on this engine is electrical. The previous engine was a bmc 1800 I believe.

 

I am stripping all the wiring off the boat that has nothing to do with the engine and starting again. It is a mess.

 

[Tony Brooks]

1 hour ago, andyhall50 said:

Went to the boat this evening, the oil pressure guage on the boat is a mechanical one. Found a small diameter pipe running to the engine but the sender on this engine is electrical.

 

Then you can screw an adaptor in place of the electrical oil pressure sender and connect the pipe to that - that will work as long as the gauge is OK.

 

 

[MtB]

2 hours ago, andyhall50 said:

I am stripping all the wiring off the boat that has nothing to do with the engine and starting again. It is a mess.

 

They very often are, in my limited experience!

 

Even those that aren't a mess can be hard to understand just by looking at them....