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DESPERATE FOR SOME BMC ADVICE


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Evening all..

 

Firstly hello from north devon im new to the forum but have been a secret lurker and noticed some people who really know there stuff on the old bmc engines..

 

My engine in question is a 2.2 bmc with a distributor type pump 

 

Ive bought a boat which had the engine installed but not fully fitted in so ive been battling away getting things installed and correct etc... Engine hadn't been ran in about 4 years i changed the oil and oil filter, changed the fuel filter, Ive got the feed to the lift pump coming from a temporary can of clean diesel as ive removed the twin tanks for cleaning and painting...

I bled the system up as per manual says and got the engine started very smokey and once you rev the engine and let off the throttle its just dies down and then stalls. It wont restart unless i crack off the injectors crank it till fuel comes out then tighten them up and then she will fire back to life. Again it will idle lovely all be it a little smokey diesel smoke eye watery not oil burning rev it up let of and try re rev and it just slowly dies down and stops, repeat the bleed procedure and again she fires up..

I had a small leak from the injector pump banjo bolts where it feeds the injector pipes (distributor type pump not inline) i removed the pump marking its posistion before removal replaced all washers to all 4 injector pipe banjos refitted pump, bled the system and again the exact same problem...

Im thinking air leak in the system but ive checked and checked every thing..... Was going to by pass the filter housing and go directly in the injector pump via a hand primer but i still have the pump return line and the injector return line going to the housing and with the feed pipe removed this will surely draw more air into the system...

 

Its getting very frustrating as i want to progress with the rest of the build but cant....

 

Look forward to any ideas...

 

regards rob 

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If there is a leak letting air in to the system it could be anywhere between the fuel tank take off and the hp pump. A friends 1.8l BMC had one at the olive going in to the water trap, for example. Eventually found it as you could hear a very faint hiss of the air being drawn in when hand operating the lift pump while bleeding.

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16 minutes ago, Jen-in-Wellies said:

If there is a leak letting air in to the system it could be anywhere between the fuel tank take off and the hp pump. A friends 1.8l BMC had one at the olive going in to the water trap, for example. Eventually found it as you could hear a very faint hiss of the air being drawn in when hand operating the lift pump while bleeding.

I've ruled out fuel tanks as im in to a temporary can of diesel.. I have primed up the system using the primer and it goes hard i cant hear any air leaks and no visable sign of diesel leaks..

6 minutes ago, Mike the Boilerman said:

 

This certainly implies air in the fuel.

 

Do you get air out when you 'repeat the bleed'?

 

 

Ive only cracked off number 2 and 3 injectors at the pipes and i have to crank it for say 10 seconds then diesel flows again.. Its deffo a air issue i think i need to try and over ride the filter housing and try go directly into the pump.. But what to do with the return and leak off pipe...

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1 minute ago, Mike the Boilerman said:

 

No...

Excellent thanks mike.. So i have a outboard style primer bulb and hose. if i go from the can into the pump feed in and hand prime it and stick a bucket under the filter housing  to catch any drips when running, if she revs and runs after i guess problem is either the filter housing or lift pump or the plumbing inbeteen.....

Im curious now.... Roll on daylight.. I'll report back to discuss my findings 

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40 minutes ago, BMC ON L PLATES said:

Evening all..

 

Firstly hello from north devon im new to the forum but have been a secret lurker and noticed some people who really know there stuff on the old bmc engines..

 

My engine in question is a 2.2 bmc with a distributor type pump 

 

Ive bought a boat which had the engine installed but not fully fitted in so ive been battling away getting things installed and correct etc... Engine hadn't been ran in about 4 years i changed the oil and oil filter, changed the fuel filter, Ive got the feed to the lift pump coming from a temporary can of clean diesel as ive removed the twin tanks for cleaning and painting...

I bled the system up as per manual says and got the engine started very smokey and once you rev the engine and let off the throttle its just dies down and then stalls. It wont restart unless i crack off the injectors crank it till fuel comes out then tighten them up and then she will fire back to life. Again it will idle lovely all be it a little smokey diesel smoke eye watery not oil burning rev it up let of and try re rev and it just slowly dies down and stops, repeat the bleed procedure and again she fires up..

I had a small leak from the injector pump banjo bolts where it feeds the injector pipes (distributor type pump not inline) i removed the pump marking its posistion before removal replaced all washers to all 4 injector pipe banjos refitted pump, bled the system and again the exact same problem...

Im thinking air leak in the system but ive checked and checked every thing..... Was going to by pass the filter housing and go directly in the injector pump via a hand primer but i still have the pump return line and the injector return line going to the housing and with the feed pipe removed this will surely draw more air into the system...

 

Its getting very frustrating as i want to progress with the rest of the build but cant....

 

Look forward to any ideas...

 

regards rob 

I had an old Landrover with this type of injector pump. Not as bad as you but if I didnt start it for about 4 days I would have the same problem unless I pumped up the lift pump before starting. I dont think it was an air leak but fuel draining back somehow

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1 hour ago, ditchcrawler said:

I had an old Landrover with this type of injector pump. Not as bad as you but if I didnt start it for about 4 days I would have the same problem unless I pumped up the lift pump before starting. I dont think it was an air leak but fuel draining back somehow

Problem is mate when it's running and you rev it up it just does and stops.. dont even have to leave it. It just wont restart with out bleeding. 

Off to the boat tomoz so I'll report back with my findings. 

 

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I'd test it on gravity feed. Suspend the temporary fuel tin from the ceiling on a string higher than the engine, this will elliminate suction air getting in. If it works ok like that you know its a sucking in air probably from the fuel filter backwards via lift pump and whatnot

Connect the fuel tubing from the tin direct to the inlet side of the engines fuel filter unit.

Edited by bizzard
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11 minutes ago, bizzard said:

I'd test it on gravity feed. Suspend the temporary fuel tin from the ceiling on a string higher than the engine, this will elliminate suction air getting in. If it works ok like that you know its a sucking in air probably from the fuel filter backwards via lift pump and whatnot

Connect the fuel tubing from the tin direct to the inlet side of the engines fuel filter unit.

I was going to say that, also make bleeding the low pressure side easy

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Just now, ditchcrawler said:

I was going to say that, also make bleeding the low pressure side easy

Yes. Only needs to punch a hole in the bottom of the tin and stuff a length of tubing into it, won't matter if its leaky, air won't get in. And make up a temporary fitting to fit the tube onto at the inlet port of the fuel filter.

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7 hours ago, bizzard said:

Yes. Only needs to punch a hole in the bottom of the tin and stuff a length of tubing into it, won't matter if its leaky, air won't get in. And make up a temporary fitting to fit the tube onto at the inlet port of the fuel filter.

Or syphon out the top of the can. Tastes 'orrible though.

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42 minutes ago, Jen-in-Wellies said:

Or syphon out the top of the can. Tastes 'orrible though.

Yes i've been there before with a mouth of diesel haha not nice..... I bought this 

https://www.amazon.co.uk/gp/product/B01DJ89SSY/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

 

My plan is to put one end in my gerry can and the other end on the pump fuel in.. This way i can prime the pump by squeezing the bulb till all the air is out then suspend the can up high so gravity takes over. Im thinking this way will also eliminate the fuel lines, filter and the mechanical pump..

Every thing is pointing to air in the system but ive tried every thing and i cant see or hear any obvious leaks...

 

Very strange how it revs up but soon as you let off the throttle and try go back on throttle it just bogs down and dies.. Im guessing air creates all sorts of issues.........

 

Off to the boat after work today about 4pm should have just enough day light to do this test... Ill report back my findings maybe ill try load up a video if it stalls again so you guys can see and hear exactly what shes does...

 

If this doesent work in thinking its going to be the diesel pump. i see theres a special tool to set the injection pump timing and re aligns the pointer on the crank case.. Ive searched high and low and not found this tool. 

 

Thanks for all your help every one 

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4 minutes ago, BMC ON L PLATES said:

Yes i've been there before with a mouth of diesel haha not nice..... I bought this 

https://www.amazon.co.uk/gp/product/B01DJ89SSY/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

 

My plan is to put one end in my gerry can and the other end on the pump fuel in.. This way i can prime the pump by squeezing the bulb till all the air is out then suspend the can up high so gravity takes over. Im thinking this way will also eliminate the fuel lines, filter and the mechanical pump..

Every thing is pointing to air in the system but ive tried every thing and i cant see or hear any obvious leaks...

 

Very strange how it revs up but soon as you let off the throttle and try go back on throttle it just bogs down and dies.. Im guessing air creates all sorts of issues.........

 

Off to the boat after work today about 4pm should have just enough day light to do this test... Ill report back my findings maybe ill try load up a video if it stalls again so you guys can see and hear exactly what shes does...

 

If this doesent work in thinking its going to be the diesel pump. i see theres a special tool to set the injection pump timing and re aligns the pointer on the crank case.. Ive searched high and low and not found this tool. 

 

Thanks for all your help every one 

1. The timing tool, doubt you will find one now and probably very hard to find an engineer who has one but it it stats and revs up then despite the smoke I doubt the timing is too far out.

 

2. The DPA 2.2 should use the three part   engine fuel filter as used on the smaller engines and those are notorious for getting assembled with twisted seals or, possibly more likely in this case, an undersized, damaged or missing small O ring that fits under the head of the centre bolt on most of this type of filter.

 

3. I am not clear as to where you have connected the rubber hose.  If it is to the pipe that used to connect to the tank then check the unions on the lift pump. There are all too easy to fit with crossed threads if you connect them after fully tightening the pump. The lift pump can has a soft washer around the centre bolt. these fail or get left out and overtightening that bold can squash the domed cap so it won't seal properly.

 

4. If you are passing fuel through the lift pump then the body screws might eb a bit loose or the diaphragm past its best but this is a long shot.

 

5. How dirty were the filter and any water trap? There is a plastic strainer under the big hexagon on the injector pump inlet union (plus springs and gizmos). If that were blocked the transfer pump inside the DPA may well suck air.

 

Both the 4 to 6 PSI created by the lift pump plus whatever pressure is added by the transfer pump should ensure that and open ended return to the tank can not suck air.

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3 hours ago, BMC ON L PLATES said:

Yes i've been there before with a mouth of diesel haha not nice..... I bought this 

https://www.amazon.co.uk/gp/product/B01DJ89SSY/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

 

My plan is to put one end in my gerry can and the other end on the pump fuel in.. This way i can prime the pump by squeezing the bulb till all the air is out then suspend the can up high so gravity takes over. Im thinking this way will also eliminate the fuel lines, filter and the mechanical pump..

Every thing is pointing to air in the system but ive tried every thing and i cant see or hear any obvious leaks...

 

Very strange how it revs up but soon as you let off the throttle and try go back on throttle it just bogs down and dies.. Im guessing air creates all sorts of issues.........

 

Off to the boat after work today about 4pm should have just enough day light to do this test... Ill report back my findings maybe ill try load up a video if it stalls again so you guys can see and hear exactly what shes does...

 

If this doesent work in thinking its going to be the diesel pump. i see theres a special tool to set the injection pump timing and re aligns the pointer on the crank case.. Ive searched high and low and not found this tool. 

 

Thanks for all your help every one 

Where is your spill rail pipe going? I am just thinking that you may be getting air into the top of the fuel filter that way

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4 hours ago, Tony Brooks said:

1. The timing tool, doubt you will find one now and probably very hard to find an engineer who has one but it it stats and revs up then despite the smoke I doubt the timing is too far out.

 

2. The DPA 2.2 should use the three part   engine fuel filter as used on the smaller engines and those are notorious for getting assembled with twisted seals or, possibly more likely in this case, an undersized, damaged or missing small O ring that fits under the head of the centre bolt on most of this type of filter.

 

3. I am not clear as to where you have connected the rubber hose.  If it is to the pipe that used to connect to the tank then check the unions on the lift pump. There are all too easy to fit with crossed threads if you connect them after fully tightening the pump. The lift pump can has a soft washer around the centre bolt. these fail or get left out and overtightening that bold can squash the domed cap so it won't seal properly.

 

4. If you are passing fuel through the lift pump then the body screws might eb a bit loose or the diaphragm past its best but this is a long shot.

 

5. How dirty were the filter and any water trap? There is a plastic strainer under the big hexagon on the injector pump inlet union (plus springs and gizmos). If that were blocked the transfer pump inside the DPA may well suck air.

 

Both the 4 to 6 PSI created by the lift pump plus whatever pressure is added by the transfer pump should ensure that and open ended return to the tank can not suck air.

Hi tony...

 

1. I thought so on the tool just be nice to have it set up correctly per manual.

 

2. Yes it as that horrible filter with the bottom bowl and gaskets etc.. 

I replaced the filter and all the seals even fitted a new o ring onto the bolt its self which was half way down it. Under the belt head itself was a copper washer which has just turned up today as I didn't have the size..

 

3. I connected my rubber hose to the copper pipe that feeds the lift pump. I haven't had the lift pump apart but I've checked all the connections and even tried thread tape on the threads still no different.. Pump holds pressure as in I can prime the system and it stays hard till it runs then dies then I have to give it a few pumps more..

 

4. Next plan today is to over ride the lift pump and the filter housing running the pump straight off of a can no filter no mechanical pump etc..

 

5. The filter wasnt in a good state but engine was sat in a shed for 4 years. I replaced the fuel filter and as tanks wernt great I haven't plumbed into them.. I saw that filter last night in the parts manual but I haven't looked at ot yet. I just checked the fitting was snug against the copper washer and sealing ok. 

 

And finally today I plan to remove the injection pump FEED pipe from the housing and plumb that into my can. I was worried about the return and leak off pipe sucking in air but like you say with that pressure that side it shouldn't so now I can proceed with my test and report back..

 

Thank you for your kind help.. Also fantastic web site I'm on there most nights looking... 

1 hour ago, ditchcrawler said:

Where is your spill rail pipe going? I am just thinking that you may be getting air into the top of the fuel filter that way

Yes spill pipe runs back to the filter housing via a banjo bolt on top.. 

I hadn't thought of that but how could that be sorted if it was pushing air back. Would it suggest it's getting air from the pump or injectors...

 

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9 minutes ago, BMC ON L PLATES said:

 

Yes spill pipe runs back to the filter housing via a banjo bolt on top.. 

I hadn't thought of that but how could that be sorted if it was pushing air back. Would it suggest it's getting air from the pump or injectors...

 

So it doesn't vent back to the tank. I think that could be A problem not necessary THE problem as it also lets any air out of the top of the filter

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8 minutes ago, BMC ON L PLATES said:

Hi tony...

 

1. I thought so on the tool just be nice to have it set up correctly per manual.

 

2. Yes it as that horrible filter with the bottom bowl and gaskets etc.. 

I replaced the filter and all the seals even fitted a new o ring onto the bolt its self which was half way down it. Under the belt head itself was a copper washer which has just turned up today as I didn't have the size..

 

3. I connected my rubber hose to the copper pipe that feeds the lift pump. I haven't had the lift pump apart but I've checked all the connections and even tried thread tape on the threads still no different.. Pump holds pressure as in I can prime the system and it stays hard till it runs then dies then I have to give it a few pumps more..

 

I connected my rubber hose to the copper pipe that feeds the lift pump. I haven't had the lift pump apart but I've checked all the connections and even tried thread tape on the threads still no different.. Pump holds pressure as in I can prime the system and it stays hard till it runs then dies then I have to give it a few pumps more..

 

4. Next plan today is to over ride the lift pump and the filter housing running the pump straight off of a can no filter no mechanical pump etc..

 

5. The filter wasnt in a good state but engine was sat in a shed for 4 years. I replaced the fuel filter and as tanks wernt great I haven't plumbed into them.. I saw that filter last night in the parts manual but I haven't looked at ot yet. I just checked the fitting was snug against the copper washer and sealing ok. 

 

And finally today I plan to remove the injection pump FEED pipe from the housing and plumb that into my can. I was worried about the return and leak off pipe sucking in air but like you say with that pressure that side it shouldn't so now I can proceed with my test and report back..

 

Thank you for your kind help.. Also fantastic web site I'm on there most nights looking... 

Yes spill pipe runs back to the filter housing via a banjo bolt on top.. 

I hadn't thought of that but how could that be sorted if it was pushing air back. Would it suggest it's getting air from the pump or injectors...

 

 

 

Re 2 above. There is something wrong here and it could be the cause. Some filter heads have an O ring around the bolt and some a soft washer but whichever it is the washer or O ring needs to be under the actual bolt head.  Carefully inspect the bolt hole in the filter head. If the top of the hole has a small taper then it needs the O ring to seal it. If the hole is totally parallel with a machined face around it then it is sealed with a soft washer. You don't use both but on O rind tops I have, in the past, had to add a nylon washer because of damage to the bolt head etc but it is far from ideal. Some time ago there were reports of undersized O rings being supplied with some pattern filters. If your filter head is of the O ring type then I would suggests that you get a genuine CAV branded 296 filter so you know you have the correct O ring.

 

Re 3. Thread tape (PTFE tape) should not be required and if used could get shards into the system. They seal on olives and if the olive has not been crushed or the fitting cross threaded I have never had a sealing problem.

 

It sounds as if the lift pump is not working as it should and anyway you really should bleed with the priming lever on the lift pump so you know the diaphragm part is OK. Have you checked the fuel strainer under the lift pump cap? If not do so now but on no account take the rubber O ring out of the cap because they swell and are all but impossible to get back in. I would try to connect the BASE of a can direct to the lift pump so its gravity fed and the try bleeding again. Once bled take the inlet pipe from the injector pump an check the fuel deliver while cranking - the lift pump may be damaged or broken.

 

I must  advise you strongly not to feed the injector pump directly, do it via the filter. If you do you increase the chances of getting dirty fuel inside the injector pump.

 

Make sure the banjo bolt on top of the filter is the correct one with a hollow centre and a 0.5mm hole drilled in the side so if any air gets into the filter head it  is returned to the tank/leak off container via the   return pipe that is in some way fixed by the banjo bolt. If you have two banjos on that bolt you need three soft copper washers, nit two..  I had exactly your symptoms when one of my engineers piped a BMC 2.2 without fitting a return to the tank from the filter head. I know there should be no air in the fuel but there always seems to be some and it will build up in the filter head until it is passed to the injector pump and stops the engine. If it was not needed CAV would not have specified it. This also applied if you have blanked the return off.

 

 

 

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1 hour ago, Tony Brooks said:

 

 

Make sure the banjo bolt on top of the filter is the correct one with a hollow centre and a 0.5mm hole drilled in the side so if any air gets into the filter head it  is returned to the tank/leak off container via the   return pipe that is in some way fixed by the banjo bolt. If you have two banjos on that bolt you need three soft copper washers, nit two..  I had exactly your symptoms when one of my engineers piped a BMC 2.2 without fitting a return to the tank from the filter head. I know there should be no air in the fuel but there always seems to be some and it will build up in the filter head until it is passed to the injector pump and stops the engine. If it was not needed CAV would not have specified it. This also applied if you have blanked the return off.

 

 

 

That was the point I picked up on, I don't think there is a tank return

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47 minutes ago, ditchcrawler said:

That was the point I picked up on, I don't think there is a tank return

If there is not and the return system is sealed then that is likely to be the problem. If so an easy fix - take the sealing off and as others said direct the return into a bucket.

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