BMC 1.5D Starting issues

[colinnorth]

Every morning I have the same problem. It takes an awful lot of cranking to get my engine started.

Once started, it runs like a dream. If I start the engine again (say after lunch) starts immediately. Can repeat this all day. I am confident enough to be able to stop/start at locks etc., during the day.

Next morning, an awful lot of cranking to get her going. Then runs like a dream all day.

Whilst talking to my local garage diesel mechanic, his diagnosis (from a distance) was that the diesel injection pump was internally worn and that fuel was leaking back overnight.

The engine is 40 years old and the injection pump is original.

Is this a likely scenario?

A rebuilt pump is not cheap so I would like to be reassured before buying a replacement.

Is it easy enough to replace and re-time?

Many thanks.

Colin

[RLWP]

No, it isn't easy to replace. The 1.5 is annoyingly sensitive to getting the timing right

 

When you crank the engine, how long does it take before you get white smoke at the exhaust?

 

And - I'd check your heater plugs first

 

Richard

[colinnorth]

It does take time before white smoke appears and (from memory) it is erratic white puffs rather than a streaming cloud then becomes a cloud, then starts.

Glow plugs tested and all OK, 12V arriving at glow plugs, tested by meter.

I am at Fenny Compton Marina and was looking to get a replacement injection pump from Warwick (by car).

[Tony Brooks]

I am with Richard on this. Far more likely things than a worn pump. Anyway unless its leaking into the engine (rising oil level) or externally the valves in the lift pump should stop it leaking back and I think the regulating valve might do as well.

 

1. Answer Richard's question and await comment first.

 

2. Check the glow plugs, in fact as its a1.5 I would worry them out and drill any carbon out of their holes. Carbon around the tip is well known for causing bad cold starting. 7/64 drill in a HAND drill I think.

 

3. Get a compression check done. If the glow plugs are OK I would put lack of compression before fuel leaking back. Especially as on a typical narrowboat the fuel level is far higher than the pump. Richard's question is designed to give an answer to this.

 

4. From a wet and dry compression test post the pressures obtained for further advice.

 

If you cant get a compression test done see if you can find someone with a 1.5 that cold starts well  who will allow you to turn their engine over by hand so you can judge how difficult it is to turn it through compression. Then compare it wth yours. My bet is yours will go over easier.

[Tony Brooks]

6 minutes ago, colinnorth said:

It does take time before white smoke appears and (from memory) it is erratic white puffs rather than a streaming cloud then becomes a cloud, then starts.

Glow plugs tested and all OK, 12V arriving at glow plugs, tested by meter.

I am at Fenny Compton Marina and was looking to get a replacement injection pump from Warwick (by car).

That is not a glow plug test - its a wiring test. They could all have burned out tips and you would still get 12V at the plugs. Use a high current DC ammeter or take them out and put them across the battery to see if the tips glow. Warm engine and 1/4 turn clock wise, then anticlockwise and so on, you will need to snap the carbon around the tips.

 

The smoke sounds more like lack of fuel but it could just as well be the lift pump or blocked filters. Still check the glow plugs first.

 

PS Only a bit over half a day's cruise to Calcutt who know BMCs

Edited March 17, 2020 by Tony Brooks

[RLWP]

7 minutes ago, Tony Brooks said:

Get a compression check done.

I can help with this. I would still check the resistance of the glow plugs first, and take them out. Tony has been kind and left out the fact they are very fragile and break easily, so go careful

 

Richard

Edited March 17, 2020 by RLWP

[Tony Brooks]

Just now, RLWP said:

I can help with this

 

Richard

Yes, Richard is good with BMCs and he travels.

[colinnorth]

Tony & Richard,

 

Thank you for your input on this...

 

I can confirm that I regularly (and have done so within the last few days): Reamed the glow plug holes with the appropriately sized drill,

tested the DC resistance of the plugs (3 @ 3.5ohms and one at 2.1ohms, the latter being a replacement with a quicker warm-up and higher current.

They glow when placed across a 12V battery, the higher resistance ones drawing about 4A and the lower resistance one about 8A.

I am not aware of any fuel leakage into the engine (dip-stick levels have never risen).

The drip tray under the engine has no signs of fuel (only black oil drips) and the pump has no damp patches that I can find.

I think I would like to speak to Richard about the possibility of a compression test.

The only compression test I can perform is to rotate the engine with a large screwdriver across the (starting handle) indents and find it fairly difficult to do. I have nothing to compare this with.

Thanks Gents, Colin

 

[Tony Brooks]

Although not bets practice put a socket on the alternator pulley nut and use a ratchet to turn the engine over clockwise. Push hard on the belt on the side that goes slack so it does not slip in the pulley - that is easier.

 

Comparing it with any modern indirect injected diesel will give you some idea so Beta, Nanni. Mitsubishi etc.

 

You seem to be on top of maintenance so assume you have changed the filter or filter and have emptied then/it into a bowl so you an look for dirt/water/bug.

 

 

Edited to add, although a wet and dry compression test shoudl show it up it may be a good idea to check the valve clearances in case any are tight from valve seat regression.

Edited March 17, 2020 by Tony Brooks

[colinnorth]

Tony,

Thanks for your reply.

Getting to another engine may not be easy, but I will try that one...

I will change the fuel filter. It is a spin-on replacement as I could not get on with the original one. It may well be due for replacement, I will check when I return to the boat tomorrow.

I had the head off about a year ago (one of the exhaust manifold bolts had sheared off and needed drilling out), The valve clearances have not been checked since about 20 hours after that job was completed, so about 220 engine run hours ago.

Colin

[Tony Brooks]

9 minutes ago, colinnorth said:

Tony,

Thanks for your reply.

Getting to another engine may not be easy, but I will try that one...

I will change the fuel filter. It is a spin-on replacement as I could not get on with the original one. It may well be due for replacement, I will check when I return to the boat tomorrow.

I had the head off about a year ago (one of the exhaust manifold bolts had sheared off and needed drilling out), The valve clearances have not been checked since about 20 hours after that job was completed, so about 220 engine run hours ago.

Colin

So valve clearances probably OK then. Did you check the lip at the top of the bores then? Its an indication of how bad bore wear is.

[colinnorth]

When the engine is running, it runs well and there is no noticeable tappet noises or irregular sounds. The engine sounds smooth when running which is why I have not looked at the valve clearances in this context.

I checked the cylinder bores by finger for any scoring or damage and all was (in my opinion) very good with minimal noticeable wear. With each cylinder at TDC there was no detectable slop or movement that I could induce in the pistons to indicate wear. Not very scientific I know but it is about my limit of knowledge. There was no detectable carbon or oil build-up in the cylinder bores or in the head for that matter. Whilst the head was off I did re-seat the valves using grinding paste but was of the opinion that this was not really necessary as everything seemed clean and well fitting.

I have PM'd Richard with the thought of getting a compression test done.

Colin

[Tracy D'arth]

If the valve clearances have closed up it will sound quiet but if the valves are tight the smallest amount of leakage past the valves will reduce cold compression and cause poor starting.

Check the rocker clearances first.

[Tony Brooks]

11 minutes ago, colinnorth said:

When the engine is running, it runs well and there is no noticeable tappet noises or irregular sounds. The engine sounds smooth when running which is why I have not looked at the valve clearances in this context.

I checked the cylinder bores by finger for any scoring or damage and all was (in my opinion) very good with minimal noticeable wear. With each cylinder at TDC there was no detectable slop or movement that I could induce in the pistons to indicate wear. Not very scientific I know but it is about my limit of knowledge. There was no detectable carbon or oil build-up in the cylinder bores or in the head for that matter. Whilst the head was off I did re-seat the valves using grinding paste but was of the opinion that this was not really necessary as everything seemed clean and well fitting.

I have PM'd Richard with the thought of getting a compression test done.

Colin

For future reference the bores tend to wear barrel shaped with less wear right at the top and more part way down. They also wear one sided, the thrust side that is the same as the side with the largest lip.

[Tracy D'arth]

And on old BMCs its the piston rings that wear most not the bores I found. They are quite large pistons = heavy so they wear on thrust sides of the tops and non thrust sides of the skirts.

[colinnorth]

Thanks guys, this is all sounding a bit expensive...

[Tony Brooks]

5 minutes ago, colinnorth said:

Thanks guys, this is all sounding a bit expensive...

Not yet it does not. You need that compression test and discuss the next step.

[OptedOut]

Sounds like you have air leaking into the fuel system overnight hence the progressive nature of the 'white smoke' as cranking continues.

 

If you have a CAV diesel filter with a piped  up banjo bolt fitting on top, (next to the central smaller securing bolt) check the very small restrictor hole in the banjo fitting securing bolt

 

Edit: Should you  have the banjo fitting on the top of the filter I would suggest taking the bolt out prior to a 'first start' and operating the fuel lift pump lever to check for air in filter, you may have to turn the engine a little if the lift pump is on the camshaft lobe. Easier method would be to remove the bolt and just crank the engine as normal, fuel should flow out immediately with no air present.

Edited March 17, 2020 by OptedOut
added info.

[Bee]

Whoa! steady on. You'll end up re boring the thing, reconditioning the pump and the injectors, might as well regrind the crank whilst you're at it, sticking it all back together and the blasted thing still won't start because the glow plugs are knackered!  You need to VERY carefully get those out (half a thou backwards and forwards and so on) and the chances are that is your problem. If it runs nicely once it starts then you are already many times better off than some of us.

[alan_fincher]

59 minutes ago, Bee said:

Whoa! steady on. You'll end up re boring the thing, reconditioning the pump and the injectors, might as well regrind the crank whilst you're at it, sticking it all back together and the blasted thing still won't start because the glow plugs are knackered!  You need to VERY carefully get those out (half a thou backwards and forwards and so on) and the chances are that is your problem. If it runs nicely once it starts then you are already many times better off than some of us.

 

Ahem!
 

6 hours ago, colinnorth said:

I can confirm that I regularly (and have done so within the last few days): Reamed the glow plug holes with the appropriately sized drill,

tested the DC resistance of the plugs (3 @ 3.5ohms and one at 2.1ohms, the latter being a replacement with a quicker warm-up and higher current.

They glow when placed across a 12V battery, the higher resistance ones drawing about 4A and the lower resistance one about 8A.

 

[Bee]

23 minutes ago, alan_fincher said:

 

Ahem!
 

 

Oops!

[Karen Lea Rainey]

I once purchased a BMC 1.5 that had the same symptoms  for over 8 years, I used a long 4mm drill bit and tapped it through the carbon build up , the problem was the glow plugs worked but they couldn't  reach the firing point because of carbon build up.

When a BMC is turned over enough the heat in the cylinder will eventually reach enough to make it start. I bet once the engine is warm it starts perfectly every time. Check the carbon build up around  the tip of the glow plug with a LONG 4mm drill bit and tap it through the carbon, dont be shy about tapping through the build up.you will need to remove/ loosen 2 or 3 fuel injector pipes to do it properly.

If I could do it I'm sure you can, I did do a post on the subject a few years ago. Might be worth reading it!

[Tracy D'arth]

That has just jogged my memory.  There are preheat plugs that are shorter than the original ones, with the same thread.

Check you have the correct ones, it matters.

 

Can I try to go back to sleep now please, blasted dogs woke me up.

Edited March 18, 2020 by Tracy D'arth

[RLWP]

2 hours ago, Tracy D'arth said:

That has just jogged my memory.  There are preheat plugs that are shorter than the original ones, with the same thread.

Check you have the correct ones, it matters.

 

Interesting, i haven't come across those yet. There are definitely two types of plug on these B type engines but they have different threads

 

Richard

[Mikexx]

On 17/03/2020 at 14:23, OptedOut said:

Sounds like you have air leaking into the fuel system overnight hence the progressive nature of the 'white smoke' as cranking continues.

 

If you have a CAV diesel filter with a piped  up banjo bolt fitting on top, (next to the central smaller securing bolt) check the very small restrictor hole in the banjo fitting securing bolt

 

Edit: Should you  have the banjo fitting on the top of the filter I would suggest taking the bolt out prior to a 'first start' and operating the fuel lift pump lever to check for air in filter, you may have to turn the engine a little if the lift pump is on the camshaft lobe. Easier method would be to remove the bolt and just crank the engine as normal, fuel should flow out immediately with no air present.

 

I was thinking about this. It takes a little time for unburnt diesel to exit the exhaust and so wondering how long this takes the OP to see smoke and then how long to start?

 

I would be tempted to operate the lift pump until it feels hard and unresponsive after the engine is stopped. To make sure you have a complete lift pump quantity of fuel at pressure to overcome any leak. And try again when cold to see how pumps are required to get in the same state in the morning and compare. Or indeed any other time after stopping and starting a while later.

 

If the fuel stop tap works this would also ensure fuel doesn't drain back into the tank, as well the return valve in the lift pump. I have known a return valve to fail in a lift pump.

 

To be honest I thought these pumps were very sensitive to air such if any air got in them they would never start and require bleeding .