Hot start problem

[Vagrant No2]

Try a ballasted ignition coil to 9 volt on ignition supply with a full 12 volt supply from starter when cranking . If I remember this has been a problem with Rover v8 before . They dont like a weaker spark when cranking hot .
Bump start normally shows you are getting a bigger spark due to a more constant voltage/amperage due to no drop by use of starter motor .

[surfenstein]

hi steve,are you running flame traps in the rocker covers?????? if so take them off and clean them out and associated pipework or try it without them,check breathers in float chambers of carbs.when engine is hot and running, just gently lift each carb piston in turn and see if revs pick up if it does then your mixture is too rich.thus when cold it runs and when hot it wont coz mixture is too rich.use a c/o meter in exhaust and set mix up.and what RICK said try ballast resistor from landie or range rover.

[MattF]

and what vince said try ballast resistor from landie or range rover.

The name change suits you Rick.

[surfenstein]

The name change suits you Rick.

oh cock.sorry rick that'll teach me for not reading it properly.

[MattF]

oh cock.sorry rick that'll teach me for not reading it properly.

[Vagrant No2]

The name change suits you Rick.

I look better then Vince in a bikini though .

[surfenstein]

I look better then Vince in a bikini though .

AND UNION JACK SHORTS.

[BioHazard]

AND UNION JACK SHORTS.

In a paddling pool

[Phantom]

Try a ballasted ignition coil to 9 volt on ignition supply with a full 12 volt supply from starter when cranking . If I remember this has been a problem with Rover v8 before . They dont like a weaker spark when cranking hot .
Bump start normally shows you are getting a bigger spark due to a more constant voltage/amperage due to no drop by use of starter motor .

hi steve,are you running flame traps in the rocker covers?????? if so take them off and clean them out and associated pipework or try it without them,check breathers in float chambers of carbs.when engine is hot and running, just gently lift each carb piston in turn and see if revs pick up if it does then your mixture is too rich.thus when cold it runs and when hot it wont coz mixture is too rich.use a c/o meter in exhaust and set mix up.and what RICK said try ballast resistor from landie or range rover.

Thanks guys. Luke runs a ballast resistor on his v8 and don't have a problem. When I last bought a coil I was asked if it had a resistor or not, so do I need a different coil?
Mark when I connected up the rocker cover breathers to the carbs it ran like pooh. So I took them off and just put some tiny K&N style filters on the rocker covers and left the pipes off the carbs. This made it run better I could not get a steady tick over with them on. Even now when hot if I rev it the revs will only drop to 2000. If i let the clutch out and catch it they will drop to 1000 and stay there until I rev it again.

[surfenstein]

Thanks guys. Luke runs a ballast resistor on his v8 and don't have a problem. When I last bought a coil I was asked if it had a resistor or not, so do I need a different coil?
Mark when I connected up the rocker cover breathers to the carbs it ran like pooh. So I took them off and just put some tiny K&N style filters on the rocker covers and left the pipes off the carbs. This made it run better I could not get a steady tick over with them on. Even now when hot if I rev it the revs will only drop to 2000. If i let the clutch out and catch it they will drop to 1000 and stay there until I rev it again.

get yourself a ballast resistor and wire it in.sounds like a piston in one of the carbs is sticking.

[Phantom]

get yourself a ballast resistor and wire it in.sounds like a piston in one of the carbs is sticking.

Cheers Mark I'll get one tomorrow and try it and let you know.

[Phantom]

Try a ballasted ignition coil to 9 volt on ignition supply with a full 12 volt supply from starter when cranking . If I remember this has been a problem with Rover v8 before . They dont like a weaker spark when cranking hot .
Bump start normally shows you are getting a bigger spark due to a more constant voltage/amperage due to no drop by use of starter motor .

So am I right in thinking I need a lower voltage coil and feed a lower current to the ballast resistor to run it and a 12 volt feed from the starter trigger wire when cranking so that the lower voltage coil gets 12 volts to start and then drops to a lower voltage when running. If so where do I find a lower voltage or is this what the resistor does?
Steve.

[MudSurfer]

Even though I'm struggling with some of the info with this (and it's not my thread or issue) I am learning a lot from reading through this....

[Phantom]

Even though I'm struggling with some of the info with this

My understanding is, When an engine is hot a spark is more difficult to produce add to the fact that it is in a cylinder under compression only makes it more difficult therefore it is weaker. Now with a 12volt coil take away some of the power because it is going to the starter and the spark weakens even further, also the rovers don't cope well with a weak spark so no start.
So a ballasted ignition coil runs on lower voltage and when cranking supply a feed of 12 volts from the starter trigger wire directly to the coil and not through the resistor and you give the coil a boost to produce a stronger spark. When it fires and you let go the key the coil then runs on the lower voltage coming through the resistor.
But then again I could be talking pooh.
Hope this helps.
Steve.

[BUSHWHACKER]

The idea of the resistor is that you 'modify' the coil to operate at a voltage lower than 12 V and then use the resistor to get to that voltage under normal conditions.
When you're cranking the engine with the starter the battery voltage drops and hence the sparks get weaker. To combat this you bypass the resistor as long as the starter is operating.
This gives you pretty much similar sparks during cranking and normal operation. It doesn't matter if you're running electronic or mechanical points, it works the same way for both.

Also, a very hot engine underneath the carb/s, plus the hot weather, causes fuel vapour (fog) to form and swirl around in the venturi of the carbs when the engine is off. This effectively prevents air mixing with the fresh fuel when restarting the hot engine. Holding the throttle pedal to the floor when cranking opens the butterfly/s in the carb, usually allowing the vapours to escape.

As the engine cools, the vapour condenses allowing air in from the intake when the engine is started.