Fuel pump rebuild

[flatplane8]

I was thinking of getting the fuel pump on our JP3M rebuilt over winter. No real issues, more precautionary. Do these CAV fuel pumps wear out over time? I just want to make sure the engine is running as best it can.

 

Thanks,

 

Simon

[frangar]

Does it make a clicking noise?......I had the pump elements replaced on mine because it did.....made it quieter for a bit!...also how much diesel do you get in the pumps sump?

 

Cheers

 

Gareth

[sebrof]

If you have the space, you could always fit a day tank, and dispense with the fuel pump. Gravity has proven to be very reliable over the years.

[by'eck]

If you have the space, you could always fit a day tank, and dispense with the fuel pump. Gravity has proven to be very reliable over the years.

 

I think he means the injection pump

[BEngo]

I was thinking of getting the fuel pump on our JP3M rebuilt over winter. No real issues, more precautionary. Do these CAV fuel pumps wear out over time? I just want to make sure the engine is running as best it can.

 

Thanks,

 

Simon

 

 

If you keeep the fuel clean these pumps last for ages (thousands of running hours). I assume the engine is running OK,and the sump is not filling up with diesel, which says the pump is pretty fair. If so, you can do some checks yourself. Put a spare, clean (new or just rebuilt) injector on each output in turn and turn the engine over by hand or on the starter, at full throttle, so you can look at the injection spray pattern, keeping it well away from your ( and other's) skin. The pattern should be even and should finish sharply, with no dribbles. There are several good piccies out on t'web- Google is, as ever, your mate.

 

If the injection pressure is OK (which is why you need a new/rebuilt injector), the spray pattern is good with no dribbles and the pump sump is not filling up with diesel I would save your money. You could for peace of mind take it to an injection equipment specialist and ask him to test it (which should be cheaper than having it taken apart), but that does not involve much more than putting it on a test bench and looking at the output pressures and abruptness of injection cut-off, which is what you can do by looking at the spray patterns and checking for absence of dribble. (A test bench do can lots of other things too, but they would only be necessary if the poump had been giving obvious trouble or had been in pieces).

 

N

[sebrof]

I think he means the injection pump

 

Ah!

[flatplane8]

Ah!

 

Yes, sorry, perhaps the wrong term used. Thanks Bengo for the tips! I will check but the oil level in it doesn't seem to be increasing (due to diesel leaks...) so maybe I should just leave well enough alone

[sebrof]

Yes, sorry, perhaps the wrong term used. Thanks Bengo for the tips! I will check but the oil level in it doesn't seem to be increasing (due to diesel leaks...) so maybe I should just leave well enough alone

 

I found a spare injector pump in my boat, complete with a nice brass hour counter. CJ Diesel in Isleworth/Hounslow overhauled it for me, and now the original one (sans hour-counter) has become the spare. Not a cheap job, but a comfort to know it is in A1 condition, especially as a faulty engine on the tidal Thames is a thing very much to be avoided. If you never venture below Teddington, it won't be such a concern for you.

 

CJ's advice is to change the oil in the pump annually as it tends to become diluted with diesel.

[Dorman]

I found a spare injector pump in my boat, complete with a nice brass hour counter. CJ Diesel in Isleworth/Hounslow overhauled it for me, and now the original one (sans hour-counter) has become the spare. Not a cheap job, but a comfort to know it is in A1 condition, especially as a faulty engine on the tidal Thames is a thing very much to be avoided. If you never venture below Teddington, it won't be such a concern for you.

 

CJ's advice is to change the oil in the pump annually as it tends to become diluted with diesel.

 

Showing my ignorance--where is there oil and how do you change it?

 

Simon

[Proper Job]

Showing my ignorance--where is there oil and how do you change it?

 

Simon

The oil is in the pump body.

 

There is a filler/level plug at one end. I use a syringe and a bit of thin tube to get the old stuff out/put new stuff in. Use what ever oil you use in the engine

[Dorman]

The oil is in the pump body.

 

There is a filler/level plug at one end. I use a syringe and a bit of thin tube to get the old stuff out/put new stuff in. Use what ever oil you use in the engine

Will do thanks--you learn something everyday

[steamraiser2]

The BPE type injector pump that the JPs have is a straight forward item and will give great service for many years. What is an issue is the pump camshaft.They do wear the cam lobes, especially if the pump has been low on oil or has leaking elements, which allows fuel to leak in to the oil reservoir. If your pump needs a camshaft you will struggle to find one these days. To have one rebuilt properly will be around £300.00. Beware of the injection "specialists" who only do half a job. They are around!

[flatplane8]

I changed the oil on mine at the weekend, and took off the inspection cover for a look. One thing I noted was that there was a bit of play in the toothed quadrant on two of the elements in relation to the rack, the third one has no discernible play.

 

Would this potentially lead to slightly erratic fueling? It seemed like play in the mesh between the two, as the element rotated slightly on the ones with free play.

[steamraiser2]

If your fuel pump originates from a wartime JP it may have a rack made of softer material which wear a little faster.In extreme circumstances it might cause you a problem but its pretty unlikely

[flatplane8]

If your fuel pump originates from a wartime JP it may have a rack made of softer material which wear a little faster.In extreme circumstances it might cause you a problem but its pretty unlikely

 

I'm not sure how old our engine is, or even if its a 'bitsa' made up from multiple sources. A fuel injection specialist said it probably wasn't worth worrying about.

[steamraiser2]

It will be if it's worn out, you can't readily get one !

[BWM]

On Monday, November 21, 2011 at 06:57, steamraiser2 said:

The BPE type injector pump that the JPs have is a straight forward item and will give great service for many years. What is an issue is the pump camshaft.They do wear the cam lobes, especially if the pump has been low on oil or has leaking elements, which allows fuel to leak in to the oil reservoir. If your pump needs a camshaft you will struggle to find one these days. To have one rebuilt properly will be around £300.00. Beware of the injection "specialists" who only do half a job. They are around!

I have recently checked the spill timing on my jp3 and the pump appears to have developed a noise which sounds a lot like the rattle that you would hear from an aerosol spray paint being shaken, only louder. Could I have dislodged something to cause this, I can't remember the noise being there before..

[BEngo]

Are you sure that you put the pump delivery valve back together properly after spill timing it?

Check too that the injector pipes are properly secured and not tapping against something.

Otherwise the screwdriver listening technique is in order I think. 

N

[BWM]

4 hours ago, BEngo said:

Are you sure that you put the pump delivery valve back together properly after spill timing it?

Check too that the injector pipes are properly secured and not tapping against something.

Otherwise the screwdriver listening technique is in order I think. 

N

Yes, I've rechecked the delivery valves but was worried that I may have dislodged something lower down. The noise seems to be coming from the body of the pump. 

[BEngo]

Hmmm. Sucks teeth:)

 

Working up from the bottom, in the pump housing are:

The camshaft and bearings

A roller tappet for each cylinder

A stiffish spring per cylinder

A pump element for each cylinder, all tied together by the rack

A set of delivery valves and output connections.

There are  various fuel inlets,  oil fillers and drains and an access plate or three but none of these should move in operation.

Checking the spill timing should not disturb any of the moving bits except the delivery valve, spring and holder so your rattle may just be coincidence.

However, if any of the main parts are seriously deranged or even badly worn the engine will run badly, the timing may vary from cylinder to cylinder and serious damage could be caused.

BPE pumps all  'click' quite loudly in use but given the scarcity of camshafts etc. I would be thinking of giving the pump a trip  to my favoured injection specialist for a looking at.

N

 

[BWM]

7 hours ago, BEngo said:

Hmmm. Sucks teeth:)

 

Working up from the bottom, in the pump housing are:

The camshaft and bearings

A roller tappet for each cylinder

A stiffish spring per cylinder

A pump element for each cylinder, all tied together by the rack

A set of delivery valves and output connections.

There are  various fuel inlets,  oil fillers and drains and an access plate or three but none of these should move in operation.

Checking the spill timing should not disturb any of the moving bits except the delivery valve, spring and holder so your rattle may just be coincidence.

However, if any of the main parts are seriously deranged or even badly worn the engine will run badly, the timing may vary from cylinder to cylinder and serious damage could be caused.

BPE pumps all  'click' quite loudly in use but given the scarcity of camshafts etc. I would be thinking of giving the pump a trip  to my favoured injection specialist for a looking at.

N

 

Thanks, that's reassuring. I may have been more aware of the noise after carrying out the timing, will probably take the pump into the same place that reconditioned the injectors just in case.