BMC 1.5 problem update

[paulg]

A BIG thank you to all who responded with really helpful ideas re cold start. I was so fired with enthusiasm I went for it's jugular this afternoon.Removing heater plugs to clear out carbon I found the spanner didn't fit one of the plugs.Different plug type. On removal of offending plug (Champion) it was obviously spattered with ..well..spatter. 1st thought was "wrong plug, wrong fit ,shorted out.On closer inspection it's blown a tiny hole thro the "element" Thats it, Got you you b.....d .Removed all and short circuited across battery and suprise suprise 3 of them (Bosch) are glowing red within 15 secs. No prizes for figuring out the odd one is goosed.So we made progress. The annoying thing is I checked all the plugs for "glowiness" 12 months ago.I only wish I had removed/replaced them .I would have twigged the odd plug size and looked there earlier .Oh ,and I wish I hadn't sheared the thread on one of the good plugs when I put them back in. Two steps forward one back.But thats an improvement for me with this engine! So feelers went out and 4 new(ish) plugs should be behind the bar on Sunday.watch this space....

paul

 

[Johnjo]

After you have fitted the new ones would me a good idea to check
that they are actually working,
No faults in the electrics that supply the power.

regards mike

 

[stubate]

and i hate to be a killjoy

but one bad glo plug wont make that much difference to starting unless the good glo plug cylinders are lo on compression and the bad glo plug cylinder is hi in compression.
need to check the compression on all cylinders with a compression tester.
sorry
stu

 

[colvic]

Re: and i hate to be a killjoy

I found that having just one faulty glow plug made starting very difficult.

Phil

 

[boatmad2]

Re: glow plugs

depends on how wired series or parallel

 

[colvic]

Re: glow plugs

I'm not with you on this one; If wired in parallel there is a 12v feed to each plug though this feed may just be plug linked to plug etc.. I'm OK on that but how inseries for that would mean they'd be wired like Xmas tree lights and 4 into 12v would mean plugs rated at 3v or on a 6cylinder motor 6 into 12v giving a plug working at 2v.

Trust I'm not being stupid here but I don't see how they can be connected in series.


Phil

 

[aztec]

Re: glow plugs

all heater plugs are wired in parralel. one common supply, linked across the plugs.

<A target="_blank" HREF=http://homepage.ntlworld.com/s.amos/index.html>http://homepage.ntlworld.com/s.amos/index.html</A>

 

[Col]

Re: and i hate to be a killjoy

You do need all 4 working. 1 down will make a huge difference, even on a newish engine.

<A target="_blank" HREF=http://www.arweb.co.uk/argallery/colspics> Cols Picture Album</A>

 

[clyst]

Re: glow plugs

Aztec ol' chap surely thats wired in series ! Forgive me if I'm wrong.

Regards

Terry

 

[Anchorite]

Re: You\'re wrong (but forgiven) NM

§

 

[colvic]

Re: glow plugs

Connected in series is joining one after another, i.e. set of batteries in a torch.

Paralle is when all positive ends are joined together and all neutral ends together, such as having more than one battery in the domestic bank on your boat.


Phil

 

[clyst]

Re: glow plugs

AH but thats not what Aztec said is it? he says one common supply linked across each plug . Is that not one wire "in" to first plug then on to second etc or am I reading it wrong . Its me age you know!!

 

[chippie]

Re: glow plugs

The ground of one plug is not wired to the positive of the next one is it ? That would be series. A common ground and a common feed is parallel.

 

[clyst]

Re: glow plugs

Gotcha!! yep your right !! brain not engaged it just didn't sound right but as you say its the ground thing .

Cheers

Terry

 

[colvic]

Re: glow plugs

The live feed goes to each plug whether fed from one to another or individualy, and each plug goes to the return...the engine block..so each plug is effectively a seperate circuit so ensuring that if one or more fail the rest still function.

I must say I was surprised how hot they got when tested out of the engine but when you think of all that cold metal to heat up they have quite a bit of work to do. Our new engine has auto preheat, just like a car, so looking forward to giving it a test.


Phil

 

[Strathglass]

Re: glow plugs

Within the next few days I intend to measure the current each of the glow plugs draw on a Ford XLD. I will post the results here. I have a fairly precise meter but I think the meter leads will reduce the actual readings slightly.

Iain

 

[colvic]

Re: glow plugs

Iain,

Make sure your meter will read at leat twenty amps to be on the safe side. Our system has a heavy duty relay to connect to the plugs and the cable to the plugs is quite substantial.

Phil

 

[Strathglass]

Re: glow plugs

Not a problem Phil.

Don't mind your posting at all, better being safe than sorry.

20A on either AC or DC and 2% of reading accurate on 20 Amp DC range.There is a 200mV drop at 20A.

On 20 Volts DC range 0.05% of reading.

I don't let anyone borrow it.

Iain

 

[lauradee]

mines a pint of lager

we are in the snug of the local arent we?
stu

 

[lauradee]

take no notice of the kids in the snug!

get a compression tester and a light bulb and settle it once and for all,
stu