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Servicing a BMC 1.8 - What to do when


Grassman

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In the 5 years I've had my boat I've always used a local 'boat mechanic' to do all the work on my boat. But he has retired suddenly and moved away from the area and the existing mechanics are inundated with work anyway, so I have begun to have a go at engine maintenance myself.

 

I can do a basic engine oil and filter change but have yet to attempt changing the fuel filter, but after searching the mine of information on here I intend to try it. I'm sure there are other things that I will be able to attempt as well, especially using this wonderful forum as a reference. 

 

What I'd really like to know from all you much more knowledgeable folk is what maintenance/checking is required when, a kind of idiots guide to what I should be checking and when, such as every service, every other service, bi-annually, annually etc.   I religiously change the engine oil and filter every 200 to 250 hours and intend to change the fuel filter and check the separator every 400 to 500 hours. and probably check the gearbox oil at a similar interval, but it's the other things I should be checking and/or doing that worries me a little.

 

Your advice would be gratefully received, and a list would be wonderful!

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5 minutes ago, Grassman said:

In the 5 years I've had my boat I've always used a local 'boat mechanic' to do all the work on my boat. But he has retired suddenly and moved away from the area and the existing mechanics are inundated with work anyway, so I have begun to have a go at engine maintenance myself.

 

I can do a basic engine oil and filter change but have yet to attempt changing the fuel filter, but after searching the mine of information on here I intend to try it. I'm sure there are other things that I will be able to attempt as well, especially using this wonderful forum as a reference. 

 

What I'd really like to know from all you much more knowledgeable folk is what maintenance/checking is required when, a kind of idiots guide to what I should be checking and when, such as every service, every other service, bi-annually, annually etc.   I religiously change the engine oil and filter every 200 to 250 hours and intend to change the fuel filter and check the separator every 400 to 500 hours. and probably check the gearbox oil at a similar interval, but it's the other things I should be checking and/or doing that worries me a little.

 

Your advice would be gratefully received, and a list would be wonderful!

Take care changing the fuel filters on that engine with a rotary injector pump, make sure you have bled all the air out of the filter unit before  trying to start the engine. once air gets into the injector pump it can be a devil to get rid of. There is a set method but still a nuisance. To save me explaining it all better to read Tony Brooks notes on it.

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My annual service consists of the following:

Oil change

Change of filters

Change of air cleaner element

Adjustment of tappets

Check of tension of alternator and water pump belts (I do this every time I use the engine)

 

I also carry spares for most of the things that may go wrong e.g.- water pump impellor, rubber moulding for heat exchanger, hoses, belts, spare alternator etc., etc.  

Edited by koukouvagia
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If you buy clean fuel,and there is no water in the tank,then there is no need to regularly change fuel filters...........they will happily run for years with clean fuel,even on a truck that uses thousands of gallons........edit...........bleeding a 296 filter and a DPA pump is a job for someone with a middling amount of mechanical knowlege.........and before you do,I suggest you get a couple of the little bleed screws for the pump in case you drop one................be aware ,if you stsrt the engine with air in the system,it will then be vry problematic to get it bled ,and will need some experience..........and just nip up the bleeder screws,dont break them off.

Edited by john.k
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Check tappets every fourth service .  Preferably after retorquing the head studs, crows foot 5/8” AF wrench needed. Not essential but a good idea to prevent head gasket failure.

gearbox oil should be changed with engine oil change but I too do tend to go to the third or fourth service.

Inspect all hoses and cables, check wires for good connections, alternator belt, fuel connections. Check fuel lift pump mounting, they tend to loosen.

Look for leaks of fuel, oil and water, top up header tank ( but don’t fill to top, leave room for the expansion.)

Stern gland?

 

 

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Check the strainer in the top of the lift pump if your lift pump has a domed top - do not remove the O ring from the cap. Do when you change the filter.

 

I do not agree with John.K re the fuel filters. You may well not NEED to change them but for the cost of a couple of 296 filters why would you not, especially as it gives you the bets chance of draining and inspecting them so you get early warning of potential water or bug problems.

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8 hours ago, Grassman said:

I religiously change the engine oil and filter every 200 to 250 hours.....

That's actually a longer interval than the original manufacturers handbook specifies.

 

BMC said oil and filter changes at 150 hours.

 

Probably not that serious, particularly if you are using good quality oil, but I'd suggest trying to limit the interval to no more than say 200 hours.

 

There's certainly a knack to bleeding the fuel system, and sometimes I used to think I had it, and sometimes I didn't(!)

 

A local engineer that I had some respect for reckoned for reasons that he never fully understood that some were dead easy to bleed, and others right pigs, even though there was no visible difference in the arrangements between the engines involved!  Sounds daft, but he did a lot of them!

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........if you have a gravity tank,then you will have no trouble,if the lift pump has a long lift ,that where trouble lies.............for those who dont know,the AC lift pump was originally designed to be a cheap alternative to the "Autovac"on the 1934 Hillman Wizard..."cheapest  car on the market.".........AC also made more expensive pumps with removable valve chambers ,and proper brass fittings.,but British engines never used them.....preferring .instead to use Amal pumps where better quality was indicated.....Gardner and various other diesel makers used them.More used the CAV plunger pump on the injector pump.

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10 minutes ago, Keith M said:

it's a long time since I was involved with propulsion engine servicing such as a 1.8 

One of the jobs you have to be careful with is cleaning the heater plug holes, I made a tool for this job.

 

The 1.8 is not so critical in this respect as the 1.5 because it uses nice fat, high powered low plugs in the vast majority of cases (there are a few 1.8s with the pin type 1.5 glowplugs I understand.

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Thanks everyone for this great advice.

 

Regarding changing the diesel filter and subsequent bleeding, just as some of you have experienced, sometimes it's gone alright but sometimes they've had to remove the injectors in a certain sequence to bleed it. It's a job that worries the hell out of me, hence my reluctance to try it myself. But I do have my diesel polished every two years and I also have a fuel separator (aglometer I think it's called??) so hopefully that minimises the chances of problems.

 

I've noted the oil change intervals too and will do them more frequently in future as well as they other things you've all suggested. The engine has done nearly 12,000 hours so it's important I look after it!

 

The previous owners had it re-conditioned at about 8,000 hours but due to lack of details on the paperwork I don't know to what extent that re-conditioning was. Without tempting fate it runs very well with very little smoking except for a bit of white smoke briefly when starting from cold.

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Grassman,you do not need to remove injectors,all you need to do if the pump becomes completely airbound is to crack all the injector  lines on the head......Not disconnect,not free many turns.......crack so fuel froth comes out..............after bleeding  the pump and filter a good as you can........if you froth the fuel in the pump,,let things settle for 10 minutes ,and air will come out without venting gallons of fuel.............my method is to start with the lines just cracked ,and as froth stops nip up the union nut.on each cylinder ,and the motor should fire evenly.................EDIT........all this can be avoided by making sure the system is bled properly before cranking over.If the engine starts ,runs for 10 secs,then stops,you are in trouble as the pump is completely airbound with frothed fuel.

Edited by john.k
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If you bleed the screws on the pump in the correct order and crack 2 injector pipes, it will bleed easily. Its simply a case of doing it the right way, by the book.

For a simple filter change, shut off the fuel, replace the filter, turn on the fuel and vent the return banjo union on the filter top connection properly by manually pumping the lift pump before trying to start. This will fill the filter and drive out the air.

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I have seen too many idle stabilisation dampers ripped out out the pump turret and top bleed screws snapped by ordinary boaters so I would never advise bleeding as per the book. Some, of not all, idle stabiliser s are glued into the turret.

 

This is what I do on all DPA type pumps and it works 98% of the time. just twice in about 48 years have I had to  remove the return to the filter head and spin it on the starter.

 

1. loosen the large bolt on the engine filter held that secures the bleed off pipe banjo to the head. (5/8" AF?).  Slowly and purposely use the priming level on the lift pump to pump fuel through the system. If the lever seems to have more slack that pumping cation you are either going too fast or you need to turn the engine over one turn - a flick on the starter usually sorts it. Keep  priming until you are sure only pure fuel and no air is coming from the loose union. Tighten the union.

 

2. Now the injector pump. Only use the bleed screw on the cylindrical body of the pump (8mm AF I think). Do NOT get mixed up with the one in the throttle lever turret or the one in an injector banjo bolt head that some have. Prime until pure fuel and no air is flowing from the bleed screw. NOW - IMPORTANT - keep priming for at least another 30 seconds  because air bubbles do seem to get trapped in pipes. Tighten bleed screw.

 

If you have only done a service then thing should now start but if it wont have a look at the exhaust. If you only have a few wisps of white smoke you need to bleed again (step 1 and 2) but if you have loads of smoke the  bleeding is almost certainly OK.

 

3. - No smoke - having done steps 1 & 2 again now loosen all four injector pipes although less will do. One full turn is more than enough. set to full throttle (just in case the governor needs a nudge to open - it should not but not worth not doing). Spin on starter until fuel starts to drip out of the loosened injector pipe unions. Tighten the unions and it should then start.

  • Greenie 1
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On 09/02/2019 at 16:03, Tony Brooks said:

I have seen too many idle stabilisation dampers ripped out out the pump turret and top bleed screws snapped by ordinary boaters so I would never advise bleeding as per the book. Some, of not all, idle stabiliser s are glued into the turret.

 

This is what I do on all DPA type pumps and it works 98% of the time. just twice in about 48 years have I had to  remove the return to the filter head and spin it on the starter.

 

1. loosen the large bolt on the engine filter held that secures the bleed off pipe banjo to the head. (5/8" AF?).  Slowly and purposely use the priming level on the lift pump to pump fuel through the system. If the lever seems to have more slack that pumping cation you are either going too fast or you need to turn the engine over one turn - a flick on the starter usually sorts it. Keep  priming until you are sure only pure fuel and no air is coming from the loose union. Tighten the union.

 

2. Now the injector pump. Only use the bleed screw on the cylindrical body of the pump (8mm AF I think). Do NOT get mixed up with the one in the throttle lever turret or the one in an injector banjo bolt head that some have. Prime until pure fuel and no air is flowing from the bleed screw. NOW - IMPORTANT - keep priming for at least another 30 seconds  because air bubbles do seem to get trapped in pipes. Tighten bleed screw.

 

If you have only done a service then thing should now start but if it wont have a look at the exhaust. If you only have a few wisps of white smoke you need to bleed again (step 1 and 2) but if you have loads of smoke the  bleeding is almost certainly OK.

 

3. - No smoke - having done steps 1 & 2 again now loosen all four injector pipes although less will do. One full turn is more than enough. set to full throttle (just in case the governor needs a nudge to open - it should not but not worth not doing). Spin on starter until fuel starts to drip out of the loosened injector pipe unions. Tighten the unions and it should then start.

 

I think something like this instruction on how to bleed the BMC should be made a sticky, or perhaps an archive or similar?

 

The subject often comes up and its a procedure anyone who changes a fuel component or filter should be aware of.

 

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