Bmc 1.5 smoking, ticking (with air bursts) and dirty/milky oil

[Sharon1928]

So about 3 months ago the nightmare began. The engine’s cooling system has always been a bit leaky but that’s never been an issue, I would top up the bowman heat exchanger before cruising and everything was fine. until one day it wasn’t. (as an aside the calorifier never worked either)

 

The inevitable happened and the coolant must have gotten too low, steam, hissing and dead. Head gasket was my first thought. But i thought, I’ll give some other things a try before I start dismantling the engine.  I bled the fuel lines and it went! All good! How Weird! 500m down the canal and a slow dying of the engine began, it spluttered dead and we had to catch a boat to pull ourselves to the towpath. Milky oil, not starting at all. 
 

We took off the engine head, which I had never done before and it was pretty nasty looking. Seemed obvious, head gasket had gone due to cooling. 
so we put it all back together, what a tough one. Nothing quite wanted to go back the same way, we had leaky fuel lines, broken bolts, dodgy threads and eventually had to make a change to the fuel return system as a spill rail bolt on the cav filter was near impossible to source.

This was the fuel return line that before went from the injectors to the top of the cav filter and then also back to the tank through a double banjo bolt setup. The change we had to make was to put the return back to the cav through a single banjo bolt as that’s all we could find that would fit the large diameter of the filters’ hole and just not bother with the tank return. 
 

I replaced the leaky rubber ends of the bowman head exchanger and tightened up any seals that dripped water before and that was all sorted too. 
 

After this final problem we got it to fire! There was tears and everyone, me, my partner and the mechanic we hired was overjoyed at this. It was quick to start especially due to the cold weather. And we thought the headache was over. All good, we said goodbye to the mechanic and had a drink to celebrate.

 

The next day we fired her up, what a lovely sound it was. But after about 10 minutes of running I heard a tick sound come from cylinder 4. Which I assumed was just a misfire maybe. But it seemed to then cause a consistent loud ticking and puffs of compressed air from just below the glowplug on cylinder 4.

I thought maybe it was a bad glowplug and we had made it have a dodgy seal when we had the engine head off. So I replaced all 4 glowplugs and tried it again. Still ticking and now I notice all the white smoke coming from the exhaust. My heart sank. 

We are trying to stay positive as it’s been a tough winter without power, being able to move and finances taking a huge hit. 

I check the oil and it’s dirty and milky, but not as milky as the first time. 

but the engine seems to run okay. 

i have checked the tappets and push rods, nothing is visibly broken. I doubt it’s the head gasket again as we barely ran it before it did this, it couldn’t have overheated. Surely not. It seems like maybe a seal somewhere is bad. Or something to do with timing maybe? 
 

I’m totally lost as to what has happened. 
Any ideas? 

I’ll add some pictures and video links to this thread ASAP. 

-Matthew 

 

 

 

[Tony Brooks]

If you have no return to the tank from the filter head you are very likely to suffer constant problems with air in the fuel needing the engine bleeding before it will start again.

 

Did you check the block and head faces for truth before reassembling. did you use a crows-foot socket/spanner to torque up the center line of head bolts? did you torque up in the correct  order? Did you run up to  hot and then re-torque?

 

Sounds horribly like the head gasket to me unless the actual head has cracked but I have never known one to crack there.

[john.k]

Its quite obvious the head will have to come off.....and the rest can be revealed .......and as mentioned,check the head and block flatness with a straightedge......a proper engineering one..

[Bee]

It does indeed sound like the head gasket, it can be quite hard to tell if the surfaces are flat even with a sraightedge, I have used engineering blue and a piece of flat glass before now, it is quite a good method but certainly not infallible, glass bends and it takes a bit of practice. When you have redone it change the oil as you will still get emulsified oil under the filler cap if you don't change it. In fact clearing moisture out of the oil ways can take a while anyway. Just my experiences, others might not agree.

[Tracy D'arth]

Establish exactly where the puff of air/smoke is coming from first.

White exhaust smoke is unburnt diesel, one or more cylinders are not firing due to either poor injection or lack of compression.

Get a compression check.

Then you will know what to do.

Just tearing an engine apart because you think you know what is wrong is not a good idea.

 

You need to fit that tank return again, it will not work without it.

[Peugeot 106]

My return line was plumbed through the filter which caused all sorts of problems only solved by continuously having to bleed the injectors. I rerouted it direct back to the tank and it has run perfectly ever since.

If you are having difficulty with fittings for your CAV filter you can get them from RD Diesels 01539 730972. If the filter itself is damaged they also sell replacement CAV 296 filter heads. Be aware there are 2 different threads available. 1/2” UNF and 14mm metric so check which you need and make sure you get new copper washers.  If you have to do any major plumbing and have rigid fuel pipe it may be simpler to change to  approved fuel hose

[Tony Brooks]

1 hour ago, Peugeot 106 said:

My return line was plumbed through the filter which caused all sorts of problems only solved by continuously having to bleed the injectors.

 

What you are saying is no very clear to me because the small BMCs pass any injector leak off through a banjo on top of the filter head where it mixes with a 0.5mm bleed from the filter and then back to the tank. If you are saying that the filter head did not have a bleed back to the tank then all you say is true. Also if the injector leak off was plumbed into one of the filter pipe connections without a bleed back to the tank from the top of the filter then it is very likely to keep air locking. Those fuel systems need both the injector leak off and a small bleed from the top of the filter lead back to the tank.

Edited January 31, 2022 by Tony Brooks

[Peugeot 106]

Sorry for the delay. My CAV filter on my LPWS2 was plumbed with the fuel in from the pump and out to the injectors on one side of the filter head. The return from the injectors went to the top of the filter and then returned to the tank via the other side of the filter head. I changed the return so that the injector return now is piped direct to the tank and the spare inlet and outlet on the filter are both blanked. I hope this makes it clearer  for you as as it was causing a lot of problems as any ingested air couldn't self bleed.

I presume that if you do as Tony suggests and use a tee at the top of the filter any air will find its way out as its like having a permanent bleed screw open. This maybe better perhaps someone else  who has much more experience with other engines than me can advise. 

I'm only chipping in as I had exactly the same problem and couldn't understand what was wrong for quite a while. I kept looking for leaks. It never occurred to me that it could have been plumbed in incorrectly! It's run for over 500 faultless hours since I made the change

.

[Tony Brooks]

1 minute ago, Peugeot 106 said:

Sorry for the delay. My CAV filter on my LPWS2 was plumbed with the fuel in from the pump and out to the injectors on one side of the filter head. The return from the injectors went to the top of the filter and then returned to the tank via the other side of the filter head. I changed the return so that the injector return now is piped direct to the tank and the spare inlet and outlet on the filter are both blanked. I hope this makes it clearer  for you as as it was causing a lot of problems as any ingested air couldn't self bleed.

I presume that if you do as Tony suggests and use a tee at the top of the filter any air will find its way out as its like having a permanent bleed screw open. This maybe better perhaps someone else  who has much more experience with other engines than me can advise. 

I'm only chipping in as I had exactly the same problem and couldn't understand what was wrong for quite a while. I kept looking for leaks. It never occurred to me that it could have been plumbed in incorrectly! It's run for over 500 faultless hours since I made the change

.

 

So the OP was talking about a BMC 1.5 you are talking about a Lister by the look of it. You can not use what happens on one make of engine to advise on another make. Yours does not use a CAV DPA pump and system so your experience is not relevant to the OP.

 

CAV Delphi are perfectly clear that on the DPA pumps using a 296 filter that the banjo bolt right in the top of the filter head should have a 0.5mm hole in its side to bleed a small amount of fuel and any air bubbles back to the tank. I know from experience not doing this in most cases causes constant air locking. Fitting the injector leak off pipe into the side of the filter head may well allow gas to build up in the head unless the injector nozzle seats are in excellent order. Even with a return to the tank on the other side of the head would allow any air coming in with the fuel plus any gas from the injectors to build up to a level that is the same as the feed to the pump before any would flow back to the tank. No wonder you suffered problems. By fitting that bleed in the banjo bolt right on the TOP of the filter you bled any air/gas back to the tank before it makes a level with the feed to the pump. Note - I have little practical experience of those Listers but they do seem to self bleed so i am not sure what cased you problem on a practical level.

 

 

[Peugeot 106]

My return line was plumbed through the filter which caused all sorts of problems only solved by continuously having to bleed the injectors. I rerouted it direct back to the tank and it has run perfectly ever since.

If you are having difficulty with fittings for your CAV filter you can get them from RD Diesels 01539 730972. If the filter itself is damaged they also sell replacement CAV 296 filter heads. Be aware there are 2 different threads available. 1/2” UNF and 14mm metric so check which you need and make sure you get new copper washers.  If you have to do any major plumbing and have rigid fuel pipe it may be simpler to change to  approved fuel hose

[Peugeot 106]

My return line was plumbed through the filter which caused all sorts of problems only solved by continuously having to bleed the injectors. I rerouted it direct back to the tank and it has run perfectly ever since.

If you are having difficulty with fittings for your CAV filter you can get them from RD Diesels 01539 730972. If the filter itself is damaged they also sell replacement CAV 296 filter heads. Be aware there are 2 different threads available. 1/2” UNF and 14mm metric so check which you need and make sure you get new copper washers.  If you have to do any major plumbing and have rigid fuel pipe it may be simpler to change to  approved fuel hose

[Peugeot 106]

Apologies for repeat posts I don’t know what happened.

Apologies if i’ve got it wrong about the CAV filter arrangement for a BMC engine but it definitely worked for a Lister Alpha engine and is in accordance with the Workshop Manual and the Installation Manual including “correct Tank and Pipework design”. The previous plumbing was not in accordance with either.

Funnily  enough the original return to the filter top was a tee with one small probably 5mm tee branch welded up. Maybe if the tee had been connected to the tank rather than blocked it would have let the air out and would have behaved the same as your BMC as it would be on the high point of the filter.

it would be helpful to me and maybe others if you could explain why the BMC is different to other engines. On mine the fuel comes out of the tank into a diaphragm lift pump then onto separate injection pumps and injectors which have return lines. I realise that some injector pumps are all together in a block but thought that the principle was the same?

yes the Alpha is supposed to be self bleeding so that’s maybe why you can get away without the tee on top of filter which might not be the case on the BMC?

 

[springy]

Different pump design. Alphas and most older listers (and many others) use what is basically a single plunger pump for each injector, operated by a lobe on the same camshaft which operates the valves. The CAV DPA as used on 1.5/1.8 BMCs is a "distributor" pump combining a high pressure pump and a "distributor" head delivering fuel to each injector in turn. Driven either from a skew gear on the camshaft on the 1.5, or the timing chain on the 1.8.

 

springy 

[Tony Brooks]

23 minutes ago, Peugeot 106 said:

Apologies for repeat posts I don’t know what happened.

Apologies if i’ve got it wrong about the CAV filter arrangement for a BMC engine but it definitely worked for a Lister Alpha engine and is in accordance with the Workshop Manual and the Installation Manual including “correct Tank and Pipework design”. The previous plumbing was not in accordance with either.

Funnily  enough the original return to the filter top was a tee with one small probably 5mm tee branch welded up. Maybe if the tee had been connected to the tank rather than blocked it would have let the air out and would have behaved the same as your BMC as it would be on the high point of the filter.

it would be helpful to me and maybe others if you could explain why the BMC is different to other engines. On mine the fuel comes out of the tank into a diaphragm lift pump then onto separate injection pumps and injectors which have return lines. I realise that some injector pumps are all together in a block but thought that the principle was the same?

yes the Alpha is supposed to be self bleeding so that’s maybe why you can get away without the tee on top of filter which might not be the case on the BMC?

 

 

This is all about the fuel systems on different engines. I think yours has four separate reciprocating injector pump, some other makes have pumps with similar working parts but all build into one housing, some have rotary injection pumps in a variety of designs. Just to complicate things there are a host of injection equipment makers worldwide. some build under license and some build their own designs. General principles can only take you so far and then you need specific product knowledge. I have that knowledge for the Lucas/CAV/Delphi DPA rotary pump systems and less  specific knowledge of the reciprocating ones apart form the Lister SR/SL types, I know those better.

 

Modern practice on the Japanese base engines tend to fit a bleed from the injection pump and T that into the pipe running from the injectors to the tank. In that way any air that passes into the injector pump is bled back to the tank before it airlocks the high pressure pumping elements. Each engine design achieves that small return bleed in its own way. Yors seems to have originally used the welded up T. The small BMCs use a banjo with two connections. This in effect does the same job as your T.

 

If you want to know more about the injector pump general principles have a look at the FIE subject on my website, tb-training.co.uk

[Peugeot 106]

Thanks Tony. I think I understand your instructive webpage. I note that the only pump without a bleed on the filter is the rotary type which has its own bleed making it self bleeding. I know that the Alpha is supposed to be self bleeding which is why presumably a bleed from the filter is not necessary. The mystery to me is how does the Alpha self bleed work as it has a diaphragm lift pump but no sign of a bleed on it unless the injection pumps cleverly let air out while keeping fuel in. An Alpha engineer who worked on the development told me it is very important that is no back pressure on the return line which would happen if it was returned via the filter. He said that routing the return line via any restrictions could cause smoke due to pressure on the injection pumps and the injector needles and that the return should run back to the tank unrestricted and at ambient pressure. The filter is at a higher pressure than the return assuming that the filter pressure is higher than fuel pressure from the depth of diesel in the tank which the return has to overcome, so even routing into the filter must raise the back pressure  on the system Obviously routing into the filter with the only outlet on the side of the filter as I had is not a good idea as I think I proved but how is it now self bleeding. I’d have thought it should have your tee arrangement but it’s not recommended by Lister Petter and it seems to work. But how? Where is the inevitable air leaving the system or is it somehow bypassing the pumps and/or injectors on its way to the tank?

Tony when I renovated my Narrowboat your webpages were very useful. I still have some printed pages on the boat just in case. There really are some rubbish books printed for Narrowboat enthusiasts

[Tony Brooks]

For completeness some engines like the old Volvo MD series had in effect an inline pump and no bleed back from the filter and fed the injector leak off into the filter, but they never seem to air lock, why and how I don't know. I tried the same plumbing on a BMC 2.2 with inline pump and it would only run for 20 minutes and then need bleeding. On those the filter top has a long banjo bolts and two banjos to get the filter bleed and injector leak off back to the tank.

 

The return to the tank should be to the top so the only back pressure will be caused by the head in the pipe. A set of good injectors should have virtually no leak off. Any return form the filter head should be restricted (CAV sat 0.5mm orifice) so any flow in the return line should be very low. I don't see how it could cause any significant back pressure on the injectors because it is an open ended pipe. How can a (say) an 6 mm bore open ended pipe be pressurized by a dribble of fuel from the injectors and the flow a 0.5mm hole subject to between 4 and 6 psi cause any meaningfull back pressure.  In any case an injection pressure of around 32 bar (480 psi) inside the injector would easily overcome any pressure caused by the head in the return pipe.  I am not even sure excess pressure in a reciprocating injection pump would cause smoking. Yes, it would deliver more fuel but that would speed the engine up so the governor would reduce the fuel to slow it back to its set speed so the fuel delivered would be what it should be. I would have pressed him for an explanation as to how and why.  My years of experience tells me your comments about books also, unfortunately, applies to some engineers.

 

[Sharon1928]

So an update. Firstly, thank you for all your comments! I’ve read all of them and have found the suggestions incredibly useful in working my problem out. 
 

As I’m learning all this for the first time, I only started to interact with my engine about 3 months ago haha. It’s been a steep learning curve. So please do excuse me if I’m speaking like a novice haha.

 

So I’ve ran the engine a bit, then tightened down a bolt on the engine head that seemed like bubbles were coming from it. The mechanic must have just not got that one right. 

 I ran it and it seems like the puffs of air and sound are lesser! The smoke is still pretty heavy. And it still runs a bit inconsistent - like it has a hiccup and revs 5-10% more for a split second every few seconds. The smoke and hiccup must be due to the fuel return from the injectors only going to the cav filter and not going back to the tank via that double banjo bolt. Is that right? 
 

So I just need to source one of those converters to return it to its old state. As that was the bolt that broke and meant the setup had to be changed.  Unfortunately these are hard to find.

 

the only place I can find them is here, but they are sold out  

 

https://calcuttboatsshop.com/epages/c3a6cb0f-3e0f-4132-9636-974f7502e04d.mobile/en_GB/?ObjectPath=/Shops/c3a6cb0f-3e0f-4132-9636-974f7502e04d/Products/A3M4E5005 

 

The whole setup link is here for context. It’s the bottom bit that converts the small banjo bolt diameter to a larger one that will fit the cav filter I have. 
 

https://calcuttboatsshop.com/epages/c3a6cb0f-3e0f-4132-9636-974f7502e04d.mobile/en_GB/?ObjectPath=/Shops/c3a6cb0f-3e0f-4132-9636-974f7502e04d/Products/CKSPILLKIT1.5

 

So aside from that. I’ve replaced the oil filter and done a full oil change. Ran it and it was still quite Smokey and had these same inconsistent revs. But After I checked the oil and it seems pretty clean, some bits of old milky oil in it but 99% clear mineral oil! I suspect that’s due to the old oil being in the pipes and engine still.

I have also acquired a socket wrench kit and tightened torqued down the head bolts again (just a touch) and in the correct order as per the manual. But it’s a bit late to be running my engine, don’t want to wake anyone up or disturb the ducks. I’ll see how that goes in the morning, hopefully no puffs of air and tapping sound. 
 

So I think if I get this fuel return converter bolt the smoke will go away and the revs will be smoother. I just have no idea where to get them from, they seem like a very niche part and are sold out at the only place I found. 

cheers!  

 

 

[Peugeot 106]

Hi Tony thanks for that. My perusal of literature seems to indicate that Beta and Vetus engines return lines don’t through the filter either so as you said one case doesn’t seem to fit all. Beta actually say that it is very important that the fuel is led straight back to the fuel tank. My RYA book of diesels shows a direct return to tank with no reference to any necessity to bleed the filter into the return line.  Horton book says that there is often a non return valve in the return line to prevent siphoning and “back feeding” of the injection pumps which misses out the filter and damages the pumps. In some installations the return discharges into the top of the tank which would prevent siphoning presumably but on others including mine the pipe dips into the bottom of the tank. 

If you have the patience I will post some comments tomorrow. Who knows you may clarify things for me and others too including the OP who by now will realise the importance of a correctly run return line

[Tony Brooks]

I will as again did you use a crows foot (special) socket to tighten the head nuts that are under the rocker shaft?

 

Do you have a torque wrench that allows you to tighten each nut to the correct torque?

 

Did you mechanic use a torque wrench and crows foot?

 

If the answer to any of the above is "no" then even if you have not yet distorted head you may well do so in the near future.

 

I very much doubt the missing fuel return has anything to do with the misfire and smoke. That is more likely to cause revving and air locking. At present I would suspect a head/gasket fault or maladjusted valves, like clearances too tight on one valve. This is very tentative because we don't have enough info and some questions remain unanswered.

 

 

 

 

 

 

 

 

 

 

5 minutes ago, Peugeot 106 said:

Hi Tony thanks for that. My perusal of literature seems to indicate that Beta and Vetus engines return lines don’t through the filter either so as you said one case doesn’t seem to fit all. Beta actually say that it is very important that the fuel is led straight back to the fuel tank. My RYA book of diesels shows a direct return to tank with no reference to any necessity to bleed the filter into the return line.  Horton book says that there is often a non return valve in the return line to prevent siphoning and “back feeding” of the injection pumps which misses out the filter and damages the pumps. In some installations the return discharges into the top of the tank which would prevent siphoning presumably but on others including mine the pipe dips into the bottom of the tank. 

If you have the patience I will post some comments tomorrow. Who knows you may clarify things for me and others too including the OP who by now will realise the importance of a correctly run return line

 

Then your tank is incorrectly installed. It is the supply that should leave the top of the tank with a dip tube inside the tank. , Remember, by and large, hull builders are welders not engineers who have a fair grasp of all the boat systems.

[Peugeot 106]

Exactly my comment. Lister Petter installation Guide shows a dip tube for the return as does Beta Installation Guide. Horton and Vetus diagrams  (ex Weston) show the pipe terminating in the top of the tank. My ex Lister Petter engineer says terminate at the top to limit back pressure but surely it would be less with a dip tube.  I will post tomorrow and I think you will realise why I am confused but slightly concerned at the possibility of siphoning. 

[Sharon1928]

1 hour ago, Tony Brooks said:

I will as again did you use a crows foot (special) socket to tighten the head nuts that are under the rocker shaft?

 

Do you have a torque wrench that allows you to tighten each nut to the correct torque?

 

Did you mechanic use a torque wrench and crows foot?

 

If the answer to any of the above is "no" then even if you have not yet distorted head you may well do so in the near future.

 

I very much doubt the missing fuel return has anything to do with the misfire and smoke. That is more likely to cause revving and air locking. At present I would suspect a head/gasket fault or maladjusted valves, like clearances too tight on one valve. This is very tentative because we don't have enough info and some questions remain unanswered.

 

no to all of those. Just a standard socket wrench. I guess that’s something i assumed was totally needed, oh well it’s done now. 

 

Okay great, how can I check the clearances/valve are adjusted correctly? 
would that be the screw on the rocker? 
 

cheers for your help!

[Tony Brooks]

8 hours ago, Matt_1996 said:

 

no to all of those. Just a standard socket wrench. I guess that’s something i assumed was totally needed, oh well it’s done now. 

 

Okay great, how can I check the clearances/valve are adjusted correctly? 
would that be the screw on the rocker? 
 

cheers for your help!

 

Yes, the screw on the rocker.

 

So the head nuts that demand tightening in the correct sequence and all to the same degree of tightness to prevent a warped head and ongoing head gasket problems have been tightened to "guess" tight. It seems one has been tightened even more then the rest and as for the center row of nuts that are under the rocker shaft I have no idea how you tightened those in the correct order and to the correct torque without a crows foot.

 

Number 2 and 3 cylinders are very close together with no cooling gallery between them. This produces an engine that tends to be very touchy about the way the head gasket and head nuts are dealt with.

 

It seems that you did not check the block and head surfaces for truth as well. The whole job seems to be an example of how to do the job to encourage early failure and from what you say I fear it might be failing now.

[Tony Brooks]

10 hours ago, Peugeot 106 said:

My perusal of literature seems to indicate that Beta and Vetus engines return lines don’t through the filter either so as you said one case doesn’t seem to fit all.

 

I think that you will find Beta and Vetus fit the bleed back to the tank on the injector pump. I know all the Betas I have seen do it on the injector pump inlet connection. This means that if they get a bubble of air passing down the fuel line it is vented back to the tank before it gets into the the pumping elements and air locks them. The odd one out that I don't understand are those Penta MDs

[Peugeot 106]

Certainly true for the Beta Tony I have the Installation Manual. So I think the lesson learnt is that we must check the Install Manual for our particular engine especially if changing engines as the return line requirements may  be different and could cause all sorts of problems ii you just carry on as before without checking. Thank You!

[Tony Brooks]

10 minutes ago, Peugeot 106 said:

Certainly true for the Beta Tony I have the Installation Manual. So I think the lesson learnt is that we must check the Install Manual for our particular engine especially if changing engines as the return line requirements may  be different and could cause all sorts of problems ii you just carry on as before without checking. Thank You!

That is so true, there are also differences between the same engines in different boats and so on. That is why it is important to try to not mix different engines and boats in the same topic. It is also why I often ask for more information.