BMC 1.5 cold start probs

[paulg]

This engine is driving me nuts.Bought the boat to do up it's been abused and neglected for years. Both of us! So of course it wouldn't start Injectors overhauled,filters replaced,fuel tank removed, fuel drained and gravity fed with fresh.System bled (at least 100 times!) What a daft place to locate the injector pump bleed screw! still no joy so in desperation replaced the CAV? rotory pump and Success. Got the boat home sail+motor no probs. Now commeth the winter and the next problem,COLD STARTING.This little baby will not have it unless it gets a blast of blowlamp up the air intake.It does try and will eventually fire but the starter motor getting hot and bothered by these tantrums. I have removed and tested the heater plugs, but not reamed out the orifaces(11/64 drills thin on the ground).So, what do you good Samaritans out there have for me? Is the BMC a lemon? Are they particularly difficult in cold weather?Will Compression test show up problem? Once fired it sounds sweet no smoke under load.Oh, I forgot to mention I found 3 used tins of Easy Start in a locker! ....No, I haven't!

paul

 

[Johnjo]

Have you checked that the heater plugs are working??
these engines will not start without .
mike

 

[tr7v8]

This is old technology, so will need working heater plugs in good nick, replace if unsure and plenty of usage of them. Check the power feed(s) to them are good as well.
From memory in commercials they need absolute full throttle whilst turning in order to fire up then bring it back once it does.
Generally providing the compressions are OK & the battery is healthy they fire up OK.

Jim
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<P ID="edit"><FONT SIZE=-1>Edited by tr7v8 on 16/01/2003 22:49 (server time).</FONT></P>

 

[Johnjo]

Agree with that, as long as you have a battery with a
bit of grunt,
mike

 

[steel_slug]

Reaming out the heater plug orificessss should make a big difference. All 4 plugs must be A1, check tips of plugs glow within 10 secs of power being applied. DO NOT use ether it will ultimately become dependant on it. DO NOT use ether as well as glow plugs. Check the valve clearances as a tight one (or two) will cause a loss of compression.

HTH

Paul M

PM

 

[lauradee]

lets put the record straight.
easy start puts ether in the cylinder where it explodes as soon as the compression reaches the point where it ignites. so no timing involved. it is just like a petrol engine where the engine is pinking.
the piston rings either break or the uncontrolled explosion actually compresses the piston ring lands and traps the piston rings, usually in the not seal position. they then dont seal because they are trapped and you have low compression and the engine wont start because of this. THE ENGINE ISNT ADDICTED !! it is a simple mechanical problem.
how ever the problem is not cheaply solved. new pistons and perhaps liners or rebore.
the bmc 1.5 is usually a good starter as long as the glow plugs work, check for continuity with a bulb.
the easy start cans are not a good omen, talk nicely to a friendly diesel fitter with a compression tester and see if you have to get your wallet out!!

if the engine is shagged (common engineering term quite often utilised in situations such as this) a cheap way out is to waft wd40 down the intake when you try to start it (dont use the glow plugs !!)
it works in the same way as easy start but the propellant is not as agressive as ether and doesnt cause so much damage and it will get you away until you can rebuild the engine.
stu

 

[mtb]

AS you know by now the bleeding of a 1.5 is well a B*******.
One battery is not enough jump leads required or even better a booster charger.

When you bled it did you check to make sure the lift pump had enough travel ?
There are two bleed screws on the dpa pump but before that go back through the system and check your connections just one iffy copper washer and although you can normally start the engine after a while it will air lock as once off it will suck air in .

Bleed from the filter head first and once clean fuel free from air bubbles comes out move to the dpa , bleed it then crack an injector pipe .
One thing to note if there's a leak or some air in the injection system you'll hear the revs surge just slightly this may not be a regular surge .
TWENTY SECONDS glow plug or you will burn em out , and once one has gone the next will soon follow . It will take a while to start but once the fuel is up then just glow plugs twenty seconds and away it should go ,and not at full throttle either !!.
Testing has already been suggested so do that but at £41.50 why worry , from ASAP down in Beckles they will post em for £2.50 .
You could use a welding rod to clean out the holes as the build up of carbon wont help when fitting the new ones .

Interesting re ether, Cummins have a starting system using it , there's a meter valve on the intake , mind you I would only ever use it if it was a last last resort .

The compression test will tell all get this done but from what you say I don't think you have low compression as once running fine and no smoke under load .The compression test figure should be around 22:1 .
These are a great engine and so economical to run , the new modern engines cant compare and will not last like the BMC .

cheers
Mick

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[PeteMcK]

The posts below pretty well say it all. All I'd add is that I find you don't often need to bleed the injection pump itself. Bleeding the filter outlet followed by cracking one of the injector unions and spinning the engine until it fires - 5 seconds or so - always seems to be enough. I'd add to what the others say and emphasise that the heaters MUST work for cold starting. I carry a can of Easy Start for emergencies but I've never had to use it; there's a risk of damaging the piston lands. To clean out the heater orifices, I squirt in some Holts(?) Aerosol De-coke and leave overnight. RedEx would probably soften the carbon just as well. And you need a good battery and a good starter. It's a good engine which will repay a bit of effort.

 

[colvic]

Just had to replace our 1500 and had hoped to buy one from Mick (below) but gearbox problems etc. ruled that out, but really wanted to keep it.

Always a little "awkward" to start, but once going sounds just like yours, no smoke, lots of power and runs forever.

Being based in the Med helped with cold starting but the following REALLY did help;

Checked glow plugs and use for about 30 secs.

Connected a 2nd. battery so that the old and slowish starter motor had more than enough juice.

This worked without fail and as we had an old style injection pump that leaked from a "glued" joint, it cured the bleeding problem as the engine span quick enough to bleed itself.

Mike Bamford at AMC/Thornycroft Engines is very helpful and will offer genuine help and not charge when not required to. Once told me not to have the injector pump exchanged as mine was probably better than the one I'd get!!

Tel: 01772 611144 or FAX 01772 616364.

Hope you sort things cos you'll be happy when you do,


Phil

PS Thornycroft modern replacement (Mitsubishi block) costs just over £4100.

 

[johnneale]

My 1.5 is a good 30 years old - Starting sequence is thus :-
Heater on for 15 secs and full throttle crank for 10 secs - wait 15 secs then repeat.
If it doesnt start after 30 secs, reduce throttle to 1/2. Even in sub zero conditions it has always started after 1 min. Theory is that if the cylinders get really flooded with diesel it seals up the rings a bit. It smokes like a chimney and does 2 hours per gal but has all the power I need. I dont have a heater relay fitted but a big push switch connected directly to the heater plugs on the panel so starting is a 2 handed operation. I also see the odd air bubble creeping down the return line from the injectors after it has started, but despite checking everything I cannot find where the air is getting in. Still it works - and if it aint bust dont fix it.