BMC Thornycroft 1500 starting (& now smoking) issues!!

[silverbuttocks]

Hi All,

 

We have a TC BMC 1500 in our NB. Over the past few months it has taken longer and longer to start, up to around 1 min of turning over and nearly catching before finally catching, with a 40 sec pre-heat. Between November and today we have had a mechanic visit 4 or 5 times (who we trust), and he has gone through all of the obvious issues (glowplugs, compression, valve clearances, diesel injectors (we had them serviced)) and each time the problem has persisted. Now it's got to the point that our mechanic has tinkered enough to try and get it to start that it now smokes like a ba***rd. Basically now I'm not sure if the problem has been made worse or that the engine just isn't happy. A week or so ago (before refurbished injectors were fitted and some tinkering took place) it would take a long time to start but when started it would run very well, pretty quiet, and with very little smoke. Now this isn't the case (although we'll see tomorrow if it starts quicker).

 

Two things: anyone got any ideas?? Also, does anyone know of a BMC specialist in the Oxfordshire area that could come and give us a second opinion? I trust our usual mechanic, but maybe he's missed something obvious on this occasion??

 

I can't remember all of the things that our mechanic has done offhand, but I probably would do if reminded. He basically worked through the starting problem bit by bit, starting with obvious things like glow plugs and moving right through to injectors...

[p6rob]

All other things being equal. If it smokes more than it used to, suspect the timing is now too retarded.

 

Did it previously start well when warm, or did it always have to churn before catching?

 

Do you have a note of the compression readings?

 

Is the smoke: white, grey, black or blue?

 

Calcutt boats isn't a million miles from Oxford, don't know if they do call outs though.

 

 

Rob

[bottle]

To start a BMC they need 30 seconds of pre-heat and that is normal.

[silverbuttocks]

Thanks Rob!

 

So, it takes about 30 secs to 1 min or turning over when cold to get it to start. The starter motor and battery are fine - it turns and keeps ALMOST firing, then not catching, then turning over and eventually starting. Once it has started and is warm then it starts again immediately with no problem. It was only the initial cold start that was a problem. It would smoke during this starting process, but not much afterwards. But when you are a CC you don't want to have to turn your engine over for 1 minute before it starts as it is loud, smokey and presumably unhealthy for the starter motor. Like I say, once it is warm it starts again fine. This was the original issue that our mechanic was dealing with...

 

Now I think the smoking (in idle and under throttle) is due to the some change he made in valve clearances, timing, something like that - I'm no mechanic. I don't know whether this has sorted out the starting problem as I will have to wait until tomorrow morning to find out. But I would rather that it didn't start instead of the amount of smoke being emitted now. Of course I would rather have both problems solved, and presumably the new smoking issue could be easily rectified given that it is due to recent changes. The smoke is white.

 

Yes, Calcutt sorted out our refurbished injectors (which didn't solve the starting problem!). I imagine that getting them over would be particularly expensive!!

 

oh, and there's a slight misfire. there probably was before but it wasn't very noticeable - now it is much more noticeable.

To start a BMC they need 30 seconds of pre-heat and that is normal.

yes, i know. i always give 30 secs preheat. the starting problem is after the pre-heat - it then takes between 30 secs and a minute to actually start

[Woodstock]

To start a BMC they need 30 seconds of pre-heat and that is normal.

Ours takes "seven elephants"- and believe me I sometimes hear the OH whispering:- 1 elephant, 2 elephant ....- Goodness knows where he got that from

[bottle]

yes, i know. i always give 30 secs preheat. the starting problem is after the pre-heat - it then takes between 30 secs and a minute to actually start

 

Ah! maybe it was the way you posted.

 

See my signature.

 

White smoke = unburnt fuel.

 

It maybe timing as Rob says or valves not seating properly

[BEngo]

Ed Boden has a good rep round the southern GU and knows his way round a BMC. That is not far from Southern Oxfordshire. Might be worth giving him a call?

 

 

From BoatshopUK:

 

 

Tel: 07941 048847 Website: Not Available Specialising in diesel engine service and repair. Operating on the Grand Union, Oxford andThames. Ed. Boden

 

Usual disclaimer.

 

 

N

[David Schweizer]

My experience with the BMC 1.5 is that it requires virtually no pre heating in the summer and at least a minute in the winter, or slightly less if it was run until hot the previous day. Without trying teach you to suck eggs, are you opening the throttle lever to almost fully open when cranking? if not that can cause catching but not firing.

 

If all else fails, and you need to get it to an engineer, one of the best in the Midlands is Jonathon Hewitt at Union Canal Carriers Braunston, he does do call outs but Oxford may be a bit far for someone he doesn't know.

Edited February 7, 2014 by David Schweizer

[Tony Brooks]

I find this worrying, and not sure that trust is justified.

 

1. Now a slight misfire after valve clearances were "tinkered with". You could well have one or more tight valve clearances so one or more cylinders are not getting sufficient compression to fire.

 

2. No mention of the glowplugs actually being removed and the holes "decarboned". Its well known the every few years 1.5 glow plugs should be tken out and small d ill put through the hole. If you do not then they are a pig to start.

 

3. No compression data given despite being asked for. The owner should have been given this.

 

If it is taking ages to starts then the exhaust will be full of unburned fuel which will smoke (white fumes) for a fair while after starting. AS would any cylinders with low compression (tight valves) as they pas unburned or partially burned fuel into the exhaust.

 

At least check the valve clearances yourself and remember too loose never did much harm to a boat engine, too tight will eventually get expensive.

 

If you continue to use your engineer I would insist on very detailed invoices from now on, if he objects draw your own conclusion.

[p6rob]

It sounds like the initial problem could be down to glow plugs, fuel drain back or fuel leak.

 

If you've got access to a multimeter, measure the voltage at each glow plug with the ignition in the heat position. Each plug should show similar voltage in.

Assuming they've all got voltage, the wiring is good.

Try removing each glow plug, depending on whether the mechanic removed them or not, they will either come out easily, or they could need careful persuasion because of carbon build up.

Try gently winding them out and in, back and forth, in slow short increments. This will help prevent the pin snapping off if they are held by carbon build up.

Once out, apply 12v to the glow plug and see if it glows, careful they get hot.

If the plugs did need persuading out, get an 11/64 drill bit or metric equivalent (Calcutts sell the correct one, or give it free with a set of plugs) fill the flutes with grease and gently ream away the carbon build up from the head.

There are videos on youtube by Sebastian Hibbert which explain what I'm trying to say far more succinctly.

 

http://youtu.be/K4rTfRx82e8

 

http://youtu.be/UG5eiFR0wpQ

 

Rob

 

 

 

 

 

The current smoke while running will most likely be timing related.

 

Assuming it's still fitted; there is a pointer near the top left mounting stud of the injector pump. There is a line scribed into the injector body that should line up with that.

If you can see it, is the scribed line: in line, clockwise or anti clockwise to the pointer?

 

If the scribed line is no longer in line with the pointer (and that it was up until timing was altered) I'd start by loosening the injector pump and turning it until they are back in alignment. You would need to loosen the injector pipes as well as the injector pump retaining nuts. On mine I only had to loosen the pipes at the injector end. As your injectors have recently been replaced, I'd assume it should be relatively straightforward.

 

If there isn't a pointer, advance the timing by turning the pump about 1/4" clockwise. Get it warm and see if it has stopped smoking under load. If not, turn it a further 1/8". If it starts knocking, turn it back a tad. You're looking to get the least smoke possible without knocking. I was advised NOT to make these adjustments with the engine running as it can damage the pump.

Ours takes "seven elephants"- and believe me I sometimes hear the OH whispering:- 1 elephant, 2 elephant ....- Goodness knows where he got that from

I count in Mississippis.

[station tug]

I find this worrying, and not sure that trust is justified.

 

1. Now a slight misfire after valve clearances were "tinkered with". You could well have one or more tight valve clearances so one or more cylinders are not getting sufficient compression to fire.

 

2. No mention of the glowplugs actually being removed and the holes "decarboned". Its well known the every few years 1.5 glow plugs should be tken out and small d ill put through the hole. If you do not then they are a pig to start.

 

3. No compression data given despite being asked for. The owner should have been given this.

 

If it is taking ages to starts then the exhaust will be full of unburned fuel which will smoke (white fumes) for a fair while after starting. AS would any cylinders with low compression (tight valves) as they pas unburned or partially burned fuel into the exhaust.

 

At least check the valve clearances yourself and remember too loose never did much harm to a boat engine, too tight will eventually get expensive.

 

If you continue to use your engineer I would insist on very detailed invoices from now on, if he objects draw your own conclusion.

the fella knows his stuff..................iv run out of greenies...

[p6rob]

The misfire could equally be caused by timing mal-adjustment. I know from my tinkering with my engine that 1/8" timing adjustment can make all the difference to smoke levels, ease of starting and smoothness of running.

 

It would help to know the compression readings and if they were done before or after valve adjustment.

 

My suspicion is that everything will be fine once the timing is put back where it originally was and the glow plug holes are cleaned out. I'm currently near Leamington and unfortunately busy this weekend, otherwise I'd come and take a peak. However, if you can wait til next weekend, and are willing to exchange time assisting through locks (the same weekend) up at Radford Semele and Bascote, I could help next Saturday or Sunday.

 

Rob

[alan_fincher]

Ed Boden has a good rep round the southern GU and knows his way round a BMC. That is not far from Southern Oxfordshire. Might be worth giving him a call?

 

 

From BoatshopUK:

 

 

Tel: 07941 048847 Website: Not Available Specialising in diesel engine service and repair. Operating on the Grand Union, Oxford andThames. Ed. Boden

Yes Ed Boden would be my recommendation too, and I think he will travel that far.

 

Ed has a habit of getting straight to the heart of BMC problems in cases where people have already spent significant money elsewhere with someone else.

 

He is also good on producing an expected cost for a job, and sticking to it. If his investigations reveal more than was first suspected, he will give you a good breakdown of your options before proceeding.

 

We don't need him often, but he did a good job on our BMC when we did, (and, in our case, happened to have "in store" a much needed replacement head that could be reconditioned and reused at not silly money).

[HappyBunny]

My constantly entertaining BMC 1.5 also started to produce white smoke recently ... unspent fuel was the general consensus, due to timing being out

 

and was proving tricky to start, and then firing on three and misfiring ......

 

she always used a bit of water, but suddenly wanted more, then started producing the odd air bubble in the header tank .... thought she had an air lock after putting antifreeze in, she is a bit prone to air locks on the calorifier system .... only had a couple of miles to do to get through stoppage and avoid being trapped in Hemel Hempstead, a fate worse than being peeled with a rusty potato peeler

 

and then wouldn't start, engine wouldn't turn over.... flat battery I thought ... but no ....

 

bit of furtleing around and noticed a dribble of water coming from the air intake .... so my head is off again grrrr ... seems to be the head gasket blown, and water getting into one cylinder .... but having it pressure tested .... the only plus point is that I have now watched her head come off enough times to do it myself

 

white "smoke" can also be water vapour, steam

 

[Speedwell]

This is probably a bit too simple but it has not been mentioned before. The perceived wisdom seems to be that 1500s require full throttle to start but, when I had one, it would never start from cold on full throttle, about half throttle seemed to work best.

Arthur

[Androo]

This is probably a bit too simple but it has not been mentioned before. The perceived wisdom seems to be that 1500s require full throttle to start but, when I had one, it would never start from cold on full throttle, about half throttle seemed to work best.

Arthur

Mine is the same. 1/2 throttle with 20 sec preheat in the cold weather. If I have full throttle it doesn't catch

[David Schweizer]

This is probably a bit too simple but it has not been mentioned before. The perceived wisdom seems to be that 1500s require full throttle to start but, when I had one, it would never start from cold on full throttle, about half throttle seemed to work best.

Arthur

 

No not percieved wisdom just 16 years of owning one which is 33 years old.. I don't know when your 1. 5 was built but there are clearly differences between different versions. The one in our boat will simpy not start in the winter on anything less than almost full throttle and the workshop manual supports that.

[Tony Brooks]

A few BMC 1.5s have been fitted with the mechanically governed DPA pump and as the governor is connected to centrifugal weights I doubt opening the throttle would make much difference. Most however use a hydraulic governor and the spring that pushes the governor metering valve to fully open is very, very light when compared with most governor springs. Even a glob of water in the metering valve can stop it opening fully so opening the throttle pre-loads the spring and helps force the metering valve to the maximum fuel position. I can not give any explanation as to why one would start on half throttle but not on full throttle but I ave long since learned that not everything can be explained so the message to the OP and anyone else who is having starting problems is to experiment with throttle position and then do what worked for your boat.

 

I do not rule out timing being the problem on the OPs engine but looking at the history and given he has mentioned a misfire to my mind it makes sense to check the valve clearances before doing anything else.

 

I would also point out other owners that 1.5s use pintaux injector nozzles that have an extra "sideways" hole in them to direct fuel into the hottest part of the pre-combustion chamber whilst cranking. This aids cold starting. These can and do block while leaving the rest of the nozzle working well and if this happens about all you know is that cold starting has become harder. I have known a rare occasion where a specialist has fitted a pintle nozzle into a 1.5 injector (or an owner has bought bargain injectors from certain sources) and that has the same effect. I very much doubt Calcutt would supply injectors like this though.

 

I agree there is a possibility its a head gasket but that is not what one jumps to straight away. When fault finding one looks at the easiest/most likely things first and then the less likely/difficult things. In my view the procedure should go like this for the OP.

 

Measure the cranking voltage at the STARTER (it might not be spinning fast enough).

Check valve clearances

Check timing marks on pump - block adaptor are lined up, adjust if not.

Physically check all glowplugs work and holes are decarboned

Have a good look at what's inside the fuel filter in case its got water/bug in the fuel

Check injectors for correct operation, especially that extra hole.

Have compression check done and the readings recorded for us on the forum.

Only then should any thought be given to stripping the head off.

Edited February 16, 2014 by Tony Brooks

[Leo No2]

This has come from my friend Ray Oakhill and may just help.

 

http://nbstronghold.blogspot.co.uk/2014/01/bmc-engine-starting-problem-solved.html

[David Schweizer]

This has come from my friend Ray Oakhill and may just help.

 

http://nbstronghold.blogspot.co.uk/2014/01/bmc-engine-starting-problem-solved.html

 

You can get extra long drill bits, which is what I use. It is actually quite difficult to source them in imperial sizes but 4.2mm is almost as big and can be sourced quite easily as it is the tapping size for the commonly found 5mm x 0.8mm thread.

 

Edited to add:- I have just discovered that you can actually get 4.3mm long drill bits which are even closer to 11/64" form eBay here:- http://www.ebay.co.uk/itm/HSS-LONG-PROFESSIONAL-DRILL-BIT-FULLY-GROUND-DRILLS-SUPER-PRICE-DRILL-BITS-/271294574301?pt=UK_Home_Garden_PowerTools_SM&var=&hash=item3f2a6aaedd

Edited February 16, 2014 by David Schweizer

[Speedwell]

 

No not percieved wisdom just 16 years of owning one which is 33 years old.. I don't know when your 1. 5 was built but there are clearly differences between different versions. The one in our boat will simpy not start in the winter on anything less than almost full throttle and the workshop manual supports that.

Mine was an original British one, marinised by J. G. Meakes. I wasn't suggesting the throttle setting was necessarily the answer but worth a free try, if not already tried.

Arthur