BMC 1500 smoking on idle

[BMC problems]

My BMC 1.5, raw water cooled, is fine in normal use, starts fine, runs well. But when idling it runs very lumpy and smokes a lot. Light grey smoke. Can anyone help me please?

Edited November 25, 2013 by BMC problems

[Bee]

Slightly retarded timing?

[BMC problems]

How is that adjusted? And is it possible that it slipped?

[Tony Brooks]

Maybe but not my first thought.

 

By loosening the three securing screws and twisting the pump but its likely to be very stiff because of the pipes.

 

How long is it since the valve clearances were checked and the injectors overhauled?

 

It sounds like a slight misfire to me so make sure all the valves have the correct clearance and if so things get more complicated.

 

If its an old engine one cylinder may be down on compression so if you have access to the kit do a compression test, otherwise it would be worth while having the injectors out and overhauled. A BMC will start fairly well on three cylinders so good starting does not prove all the compressions are OK.

 

Not likely to slip but if the oil jet and strainer are clogged you could well have excess wear in the skew gears. Wear anywhere in the camshaft drive or the pump drive skew gears would result in retarded timing.

Edited November 25, 2013 by Tony Brooks

[BMC problems]

Thanks Tony. The fuel pump oil gubbins was checked a year ago. I did wonder about tappets, they sounded a bit noisy so valve clearances next ( the easy bit ).

 

About how often would you expect injectors to need overhauling?

[Tony Brooks]

Thanks Tony. The fuel pump oil gubbins was checked a year ago. I did wonder about tappets, they sounded a bit noisy so valve clearances next ( the easy bit ).

 

About how often would you expect injectors to need overhauling?

 

I would suggest at infrequent intervals and when you have reason to suspect them. Unless you get something nasty in the fuel it should be measured in years. My own, that are slightly different to yours and are a little less likely to clog, have now done maybe 13 years since their overhaul but it is a holiday boat.

 

I would not suspect excess valve clearances unless a spring has broken because the valves would still close. If it is valve clearances they would more likely be tight so a valve is staying open and reducing the compression on one cylinder. When the engine n is running fast it can "overcome" slight compression leaks.

 

If you do take the injectors out please get a look at the manual because there is a copper washer, and inverted top hat heat shield and a small crimped atomisation washer down the hole. It is important that you know what is in there and deal with them appropriately. It will only be hooking the atomisation washer out if the top hat stays in place but they can come out on the injectors.

[BMC problems]

I can find the atomiser washer and copper washer at ASAP supplies but no mention of the heat sheild. Does that mean it shouldn't need replacement?

 

The engine was reconditioned 13 years ago and unknown service history so are injector overhaul and compression test the first things to try?

Edited November 25, 2013 by BMC problems

[Tony Brooks]

The heat shield is a fairly large bit of steel and should not need replacing but it can come out stuck to the injector nozzle and some injector people do not return it. If you do not ensure it is where it should be when you refit the injectors you will defiantly have smoke and bad running, even it it starts. The compression will be very poor. Please look in the manual to see where it is ans how it fits with the head and injectors. then you will know if one comes out.

 

The first thing to try is the valve clearances because you can do that. After that it is up to you. If you have access to a DIESEL compression tester then do that first but most people do not but they can get the injectors out. So although an overhauled set may cost £100 or so it could easily be cheaper than paying an engineer to do the compression test.

[p6rob]

Hi,

 

Calcutts sell the top hat washers, www.calcuttboatsshop.com It's listed as "injector heat sheild". No connection with Calcutts except as a customer. They will also hire out the timing tool for a small fee.

 

If you do find you need to replace your injectors, I have a spare set that have done about 40 hours running which I would sell for 80.00 plus postage, (replaced while I was trying to diagnose problems with my engine).

 

Rob

[EmmaB]

 

 

..

Edited November 26, 2013 by EmmaB

[Speedwell]

Amongst all this good info, I see that nobody has suggested checking your idle speed. Too slow an idle can cause lumpy running. Do things improve if you open the throttle very slightly ?

Arthur

[BMC problems]

Yes it does. Although 'very slightly' is a bit tricky with play in the speed control. Would that cause the clouds of smoke?

[Speedwell]

Yes it does. Although 'very slightly' is a bit tricky with play in the speed control. Would that cause the clouds of smoke?

It's probably unlikely but it's a free trial before you start spending money. If the throttle helps, the next step would be to increase the idle speed using the idle adjusting screw. If that helps, advancing the ignition (injection point) is also free and has worked wonders for me in the past for reducing smoke.

Arthur

[BMC problems]

Indeed. It is an easy and quick thing to try and number one on the list.

 

As for the advancing ignition, which way is advance on the pump body? And what kind of adjustment are we talking in degrees?

[Speedwell]

Indeed. It is an easy and quick thing to try and number one on the list.

 

As for the advancing ignition, which way is advance on the pump body? And what kind of adjustment are we talking in degrees?

I'm afraid I can't remember which way to turn it - opposite to the direction of rotation if you can find out what that is. It's a matter of trial and error. Try a little bit and see if it helps or makes it worse. There should be a scribed mark on the pump and flange to show the "official" correct setting. A modified spanner will probably be needed to get at the rear nut - I had to grind some metal off the outside of the jaws of an open ended spanner to get enough turn.

Have you got a workshop manual ? If not, they are available on line.

Arthur

[cereal tiller]

I'm afraid I can't remember which way to turn it - opposite to the direction of rotation if you can find out what that is. It's a matter of trial and error. Try a little bit and see if it helps or makes it worse. There should be a scribed mark on the pump and flange to show the "official" correct setting. A modified spanner will probably be needed to get at the rear nut - I had to grind some metal off the outside of the jaws of an open ended spanner to get enough turn.

Have you got a workshop manual ? If not, they are available on line.

Arthur

 

 

Easy

 

If you are in front of the engine looking at the pulleys,belts and alternator,the BMC will rotate Clockwise when running

 

The DPA injector pump rotates clockwise as well

 

The DPA pump needs to be swung ANTI clockwise to advance the timing,BUT only a degree or two.

 

The scribe lines on the pump and cylinder block mounting for it should usually line up

 

if you rotate the pump just the thickness of a scribe line,it should be enough.

[p6rob]

 

 

Easy

 

If you are in front of the engine looking at the pulleys,belts and alternator,the BMC will rotate Clockwise when running

 

The DPA injector pump rotates clockwise as well

 

The DPA pump needs to be swung ANTI clockwise to advance the timing,BUT only a degree or two.

 

The scribe lines on the pump and cylinder block mounting for it should usually line up

 

if you rotate the pump just the thickness of a scribe line,it should be enough.

 

I'm pretty certain the DPA pump turns counter clockwise on the 1.5 and consequently you turn the pump body clockwise to advance timing.

The rest is right though.

 

You can confirm this by looking at the order of the pipes on the injector pump. Firing order is 1342, injector pipes are in firing order from right to left; ergo, rotor must turn counter clockwise.

[cereal tiller]

 

I'm pretty certain the DPA pump turns counter clockwise on the 1.5 and consequently you turn the pump body clockwise to advance timing.

The rest is right though.

 

You can confirm this by looking at the order of the pipes on the injector pump. Firing order is 1342, injector pipes are in firing order from right to left; ergo, rotor must turn counter clockwise.

 

Yes,i was thinking of the 2.5 BMC which has a timing chain so everything runs clockwise

 

the 1.5 has a gear in there somewhere which makes the pump contra rotate

 

there is usually a directional arrow on the pump which shows the direction of rotation.

[BMC problems]

Phew. I was about to get confused there. So a couple of things to try.

 

1. Check rocker clearances

Start engine and allow to run up to temperature

2. Leave idle speed alone and try tweaking injector pump clockwise 1° look for improvement

3. Up the idle speed a little, if cures leave alone, if not try rotating pump.

 

4. remove injectors and service (or replace with the ones offered by p6rob)

5. check the static compression

 

It will be the weekend now before I can get to the boat, so I'll report back when I've tried these things. Thanks everyone.

I have got rather a good workshop manual. Includes, maintenance, overhaul and pictures of the service tools.

 

If anyone needs a copy give me a shout.

[p6rob]

I'm no expert, but in an ideal world, I'd go:

 

1,3,5,4,2

 

See if you can hire a diesel compression tester. Mind you, I couldn't find out what the correct compression should be. Does anyone know the official figure???

[Tony Brooks]

As this will be one or possibly two cylinders in trouble if it is a compression thing then the actual figures do not matter. They all need to be no more than 10% maximum difference between cylinders. I always get typical diesel compressions wrong but I think its about 300psi @ cranking.

[Chas78]

I have just had my engine serviced oil/fuel air filters new antifreeze new glows reconditioned injectors valves adjusted (cold) my engine is just as bad to start but now i find it misfires slightly with white plumes of smoke on idle it does not do this when under throttle i don't know what else to do  any help or advice very much appreciated   

[mrsmelly]

1 minute ago, Chas78 said:

I have just had my engine serviced oil/fuel air filters new antifreeze new glows reconditioned injectors valves adjusted (cold) my engine is just as bad to start but now i find it misfires slightly with white plumes of smoke on idle it does not do this when under throttle i don't know what else to do  any help or advice very much appreciated   

Fit an Isuzu?

[p6rob]

1 minute ago, Chas78 said:

I have just had my engine serviced oil/fuel air filters new antifreeze new glows reconditioned injectors valves adjusted (cold) my engine is just as bad to start but now i find it misfires slightly with white plumes of smoke on idle it does not do this when under throttle i don't know what else to do  any help or advice very much appreciated   

Compression test and advance the timing?

Also my current engine starts easily after 20 seconds of glow plug,  check you're getting voltage at each of the glow plugs.

I'm in the process of rebuilding a BMC 1500 for my boat (used to belong to Bunny) Re-sleeved bores, new pistons, crank ground. You're welcome to pop to Brum and see it in pieces if it'll help.

 

[Tony Brooks]

I would want to know a lot more about those "reconditioned" injectors and exactly what was removed/replaced down the injector hole. Did the re conditioner ave the equipment to test Pintaux injectors or did they treat them as pintle ones?