Carbon build up

ocarros

ocarros

Member
Is there any fuel additive or treatment anyone would recommend that might reduce / eliminate carbon build up in engine?
 
ocarros said:
Is there any fuel additive or treatment anyone would recommend that might reduce / eliminate carbon build up in engine?
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You don’t get a lot of carbon build up with modern fuels. I wouldn’t worry about it.
 
My engine runs on after switch off and thru a process of elimination, I think that too much carbon is present. Timing and idle is sorted, car has been serviced. Without taking engine out and apart I want to see if any fuel additive might help
 
Try a cooler-running grade of spark plug. My 2000 TC – rebuilt engine, no carbon build-up, all settings set correctly, super unleaded fuel – ran on when fitted with the NGK BP7ES plugs (Champion N7Y equivalent) that it's supposed to have. I have fitted BP8ES (N6Y equivalent) and the problem has gone. I reckon it might be something to do with the greater volatility of modern fuels. What version of P6 do you have?
 
As mentioned, a decoke is best. The head isn’t that bad to remove.

You can try this as a way of removing the worst of the carbon. Warm up the engine to full operating temperature with the air cleaner off. When hot rev to about 2000rpm, using a trigger style spray bottle set so it shoots a single stream unload into each carb mouth.

the theory is that the cold water immediately boils and steam cleans the combustion chamber of carbon. I’ve used it myself and it does seem to help.
 
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I've a 2000 SC using N9YC plugs. Plugs only went in last May so I'm going to remove them to see what state they're in. Have only had the car a year and mileage isn't high but idles have been wrong for years along with timing. Don't know anything about service history nor lead additive being used prior to purchase. It was running on when I got it. Nowhere near as bad now but it's now coming to the top of the jobs I need to do

I'll try that with the cold water and see how it goes. Is it just one single jet stream of water and leave it for a few weeks? Or should I see an improvement straight away?
 
If it's mid-1966 or later it shouldn't need a lead additive, as all 2000s had hardened exhaust valve seats once the 2000 TC went into production.
 
ocarros said:
I'll try that with the cold water and see how it goes. Is it just one single jet stream of water and leave it for a few weeks? Or should I see an improvement straight away?
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you should see a change after the treatment. Reckon on using close to a litre of water over the period of the spraying. Not all at once! Keep pumping the trigger until you hear the car stumble a bit, let it clear, then start pumping again.
 
jp928 said:
Surely ALL alloy heads have hardened valve seat inserts?
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Yes, but some are harder than others. A friend who worked in the Solihull factory back in the day and later became a key Rover PR man (and who owns a very early UK-spec 2000 TC) was the source of the knowledge re all 2000s getting TC-spec valve-seat hardness. TC production started mid-1966 but UK cars weren't built until October. I'm seeing him next week so I'll try to remember to ask him when he thinks non-TCs got the harder valve seats. A car registered on 1 August might be on the cusp.
 
An update for all. I found a place here in Ireland and they recommended a product they sell (am I allowed to mention names / products?). Anyway. Short story is that after adding this additive to the fuel tank and going thru a tank and a half of fuel, my run on has disappeared. Amazing stuff have to say! Run on gradually got less and less each time I drove Rua and then last weekend and today - no run on at all. Am delighted
 
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