Water pump

My water pump is leaking a lot of water past the cylinder plunger when not on bypass. It is pumping into the boiler ok as the sight glass level gradually increases over time. I've tried tightening the gland packing but it still leaks on each stroke of the pump. Could the solution to the leaking be to dismantle the boiler clack valve and increase the height that the ballbearing can move?

Thanks
Martin

Hi

Check that the piston of the water pump is smooth and you actually have enough thickness of gland packing.

Also when you put the piston on to the rod with the countersink bolt. Did you seal around the head and threads before tightening.

lynnr wrote:Hi

Check that the piston of the water pump is smooth and you actually have enough thickness of gland packing.

Also when you put the piston on to the rod with the countersink bolt. Did you seal around the head and threads before tightening.

I will have put 2 thicknesses of gland packing as per the instructions. Is it worth putting another ring of packing?

Not sure what you mean about sealing around the head and threads.  I applied thread sealer and centre punched the M6 csk screw.  Not clear how this would be the cause of my problem.  Please explain.
Looking on the bright side at least it does pump water!

If I need to put in more packing is it easier to remove the pump body from the side plates or remove the ram from the pump body by taking off the pump eccentric?

What about the clack valve at the boiler end. Could the issue be that the pump is having to pump too hard against the clack valve?

Regards
Martin

Any more ideas/responses please?
Regards
Martin

parador wrote:

I will have put 2 thicknesses of gland packing as per the instructions. Is it worth putting another ring of packing?

Not sure what you mean about sealing around the head and threads.  I applied thread sealer and centre punched the M6 csk screw.  Not clear how this would be the cause of my problem.  Please explain.
Looking on the bright side at least it does pump water!

If I need to put in more packing is it easier to remove the pump body from the side plates or remove the ram from the pump body by taking off the pump eccentric?

What about the clack valve at the boiler end. Could the issue be that the pump is having to pump too hard against the clack valve?

Regards
Martin

Hi Martin

I suggest to eliminate the check valve possibility disconnect the pipe between the pump and check valve, and then try again, if it is still leaking, then you can be sure that the check valve isn't the problem. Is the water just leaking out of the gland or is it leaking all over?

Many thanks

Will@STW

Hi Martin

Ignoring the leak at the moment. When the mechanical pump valve is in the fill position and the engine running. Can you hear the clack valve ball lifting and dropping. I hear Crystal's and also can feel the pipe pulse with the pressure. Does the pipe going to the clack get cold at the clacks end when pumping as it should. The ball does not want very much lift to work correctly and any lift at all will pump due to the small volumes involved. This can also be tested by loosening the brass plug above the valve a turn without problem (Has the effect of winding back the ball stop in the valve). If it suddenly starts working your ball lift is almost nil.

If you hear the ball and or the pipe gets colder, then the valve is working. Taking the pipe off the clacks will not really prove anything as you loose any "back pressure" in the system.

When running quick Crystal will leak a little out the back of the pump, but I do not worry as its is the nature of the assembly between over tight and loose.
I actually sometimes get a jet of water out the elbow of the pump casting as it is slightly porous in a spot and has some filler (applied at the factory) in it.

Hi Martin,
I had a similar issue on my Agri, as Lynn suggested, I sealed around the countersunk head of the screw with a dollop of silicon.
No leaks for the last two seasons.

Barry

Thanks for the further replies.

Will - The water is only leaking out of the gland and then only when pumping into the boiler.

Lynn - I didn't hear the ball at the clack end but to be honest I wasn't listening for it at the time. The pipe definitely goes cold at the clack end when the by-pass valve is closed so water is being put into the boiler - this can also be seen in the boiler sight glass after a while. There are no water leaks from the pump body at all except from the gland when pumping into the boiler. I tightened the gland as much as possible when the engine was running and the amount of water did reduce a little but it is still passing at least an 'eggcup full' of water on each outward movement of the plunger.

Bazzer - I didn't seal around the countersunk head so I think this will be worth trying next.

So in summary I think I will take the pump off and increase the gland packing and also polish the piston and seal around the countersunk head.

Regards
Martin

I got mine to seal on my showmans by fitting a O ring followed by a washer made from ptfe that was a very good fit in both the pump body and the ram followed by another O ring

parador wrote:

Will - The water is only leaking out of the gland and then only when pumping into the boiler.

Mine does that, I thought its a "feature"

I must get round to re-packing the pump as I'm sure that will cure it.

Took the pump body off the engine today and confirmed that there are in fact 2 rings of gland packing. Interesting to note that the piston had been polished by the packing even though the engine has only been run for about 3 hours in total. I might use some 1200 emery paper on the piston as there are some very faint machine lines running along the piston.

I will definitely smear some silicon sealer on the face of the piston but I am undecided whether to put another wind of gland packing or a rubber O ring or both.

Martin

parador wrote:

Will - The water is only leaking out of the gland and then only when pumping into the boiler.

Hi Martin

In that case that proves that it is nothing to do with the clack valve end of the pipe. If it were then water would also be squirting from the nut over the bypass valve as well (it would basically come out of anywhere it possibly can).

Thanks

Will@STW

parador wrote:Took the pump body off the engine today and confirmed that there are in fact 2 rings of gland packing.  Interesting to note that the piston had been polished by the packing even though the engine has only been run for about 3 hours in total.  I might use some 1200 emery paper on the piston as there are some very faint machine lines running along the piston.

I will definitely smear some silicon sealer on the face of the piston but I am undecided whether to put another wind of gland packing or a rubber O ring or both.

Martin

What sort of packing are you using, is it PTFE and the correct size?
Also the ends must meet when the ring is pushed into the stuffing box, and the joints of additional rings should be opposite, I'd fit as many rings of packing as you can - but don't mix O-rings and gland packing, besides O-rings are not designed to be squashed in that manner.
With a good seal you will be able to hear the suction valve lifting while turning the engine over by hand.
I fitted an inline non-return valve from LSM on my engine just below the flywheel partially out of sight as I struggled to get the pump boiler check valve to behave.

Quick update.  I sealed the screw as suggested with silicon sealant and replaced all the packing and added an additional ring of packing(and also an o ring).  Pump now works fine with no water leaks.

Regards
Martin