Hot Coil

[Guest Ian & Carole]

OK my RHOCaR buddies.

 

Completly not hood related but that never stops you all, sadly I feel I ought to know but am at a complete loss.

 

The Daimler has decided that it wont run when warm / hot.

 

Have changed plugs, points, rotor arm, leads and coil.

 

Runs fine until it warms through and then at the best hunting and at worst nothing.

 

The only thing I am aware of is the coil is running that hot you are unable to touch it, it is that hot.

 

1987 4.2 litre 6 cylinder.

No balast resistor in system

Compresions are all at spec

Dwell angle spot on ignition timing spot on.

 

Any ideas greatly considered exept fuel can and insurance claim !!

[richyb66]

Are you sure the replacement coil isn't designed for a ballasted system, If it is, you'll be running 12v througha coil designed to take 6 to 9 volts and it's going to get hot and start to break down..

[sj-bradley]

If the coil is that hot, the insulation around the coils could have melted resulting in a short circuit through the coil.

 

It will burn out and fail so I'd replace it.

 

you say you replaced the coil? Sounds like there is a short causing a high current through it constantly somewhere. This must be in the low voltage side.

 

You say no ballast resistor? That would be only for starting when the drain on the battery is high from the starter. You do have a 12 volt coil and not a 6 volt one that needs a ballast resistor?

 

Guessing here,

Simon.

[speedtripledan]

my v8 coil got red hot when i connected it wrong and shorted the - down to earth thinking it was meant to be earth and not switching from the dizzy, prob not your problem but a short sounds likely to me..

[Guest Ian & Carole]

Brand new 12v coil fitted.

[richyb66]

Condenser?

[Guest Ian & Carole]

Is it an Auto choke? Could it be sticking on?

Nope...........good old cable

Condenser?

every thing I have read says no but am collecting one in the morning to try.

 

Thanks so far guys.

[Guest MarkB]

Sounds like a vac pipe or breather pipe has perished, spray some brake cleaner on the inlet side if things

[stevedohc2b]

Ian on Chris Brown it is a + earth system are you sure you have the right coil . What happens if you re fit the old coil?

If something is hot could be a short.or bad contact / arching.

Are you sureyou have fitted the right plugs , some have a restance built in and the right gap

Stephen

[Guest chris brown]

Not an easy one Ian, I thought you were going to fit an electronic unit when I fitted one it did make it run much smother that was after they supplied the correct unit (third attempt) you need to know which dissy you have but it does meen that all looks origonal under the bonnet except for one extra wire from the dissy.

If you dont find the problem it might be just worth a try

BTW have you checked all the plastic/fibre washers/insulaters are all good on mine I found the one where the lead enters the dissy via a nut and bolt was cracked in fact it fell to bits on removel.but there again it is 35 years older than yours

 

 

http://www.ebay.co.uk/itm/Electronic-Ignition-Conversion-Kit-to-fit-6cyl-Lucas-22D6-25D6-/121037385990?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item1c2e63f106

[IanS]

Mechanical fuel pump sticking?

 

I have also had hot tickover running problems with closing up vlave gaps when hot leaving the valves just open.

[Guest Ian & Carole]

Not an easy one Ian, I thought you were going to fit an electronic unit when I fitted one it did make it run much smother that was after they supplied the correct unit (third attempt) you need to know which dissy you have but it does meen that all looks origonal under the bonnet except for one extra wire from the dissy.

If you dont find the problem it might be just worth a try

BTW have you checked all the plastic/fibre washers/insulaters are all good on mine I found the one where the lead enters the dissy via a nut and bolt was cracked in fact it fell to bits on removel.but there again it is 35 years older than yours

 

 

http://www.ebay.co.u...=item1c2e63f106

Bought two Chris one for the Beauford and one for the Daimler, the daimler one doesn't fit and they seem unable / willing to try and help.

 

Mechanical fuel pump sticking?

 

I have also had hot tickover running problems with closing up vlave gaps when hot leaving the valves just open.

Twin electronic fuel pumps both working to correct output pressure and compression test is good at 130/35 lbs.cold on open throttle.

[Longboarder]

Ian, what ignition do you have ? Is it simple points dizzy and coil or is there any amplifier/electronics in there? What make of dizzy is it? If you test resistance in the coil LT and HT circuits what figures do you get?

I haven't come across a coil too hot to touch that was still healthy.

 

Nigel

[Guest Ian & Carole]

Ian, what ignition do you have ? Is it simple points dizzy and coil or is there any amplifier/electronics in there? What make of dizzy is it? If you test resistance in the coil LT and HT circuits what figures do you get?

I haven't come across a coil too hot to touch that was still healthy.

 

Nigel

Hi Nigel

Points and 12v coil, no electrificery in there.. Lucas Dizzy (45D6)............ I believe ??

Every thing is now new and yes the coil does get hoter and hotter until the car cuts out!!

[Longboarder]

Worth testing. Depending on the specs of the coil, primary resistance between the two LT terminals should be roughly 1.0 to 3 ohms. Secondary resistance between either LT terminal and HT terminal should be 4500 to 8000 ohms. These are just ball park figures and the coil might be a little different. Replace with a standard old fashioned non electronic points coil. If you use an electronic coil you will burn the points in minutes even though it promises to give a fatter spark. (When did you last check the dwell? When fitting the new coil or after the new coil started to falter.)

 

Nigel

 

Just wondering if the new coil was intended for electronic ignition. They tend to have much lower primary circuit resistance, less than 1 ohm.