I'd try and get the idling down first - I seem to remember trying to tune a Spectre for someone and finding it virtually impossible to get it nice as the speed kept creeping up when it got hot during the job.
Seem to remember having a load of trouble with my Vogue engined Hunter shaped Minx which turned out to be a grooved carb jet (the swing needle had ground a groove in it! - new jet cured that problem. - if only the others had been so easy!)
I think the correct starting point for ignition timing is 8 degrees - static I think - for 96 - 98 Octane. By current standards 8 degrees advance is quite considerable. A few degrees retardation may help but may reduce performance and strangely could make things worse by causing overheating. Probably worth moving the distributor a touch and seeing if it runs better or worse.
The standard spark plug was N9y (Champion) which from what I remember was a standard long reach plug in its day and probably is still available with a few Cs added to its description.
Thinking of that car brings back all sorts of memories - one of which is the strange behaviour of other lesser Arrow range drivers - seemed to afflict the elderly who would pull up besides me at traffic lights in their well polished cars (Gazelle and Hunters) and then roar away from my scruffy Minx at the lights. Trick was to let them get a littlke ahead then put mine in 2nd and floor it - and go straight past - really upset them - but I never really understood what they were trying to prove in the first place!
rootes engine help!!
Moderator: RichardW
Anti knock ratings - 'Octane'
Not so - you are not comparing like with like. 'Old' 100+ (i.e. Premium) octane rating was calculated on the 'Motor Method'; now Octane ratings are quoted in Research Method. A lead free 96 Octane is around 88 Motor Method... try leadfree in a hot 1275S with 12:1 CR and watch the pistons melt.
Measurement methods
The most common type of octane rating worldwide is the Research Octane Number (RON). RON is determined by running the fuel through a specific test engine with a variable compression ratio under controlled conditions, and comparing these results with those for mixtures of isooctane and n-heptane.
There is another type of octane rating, called Motor Octane Number (MON) or the aviation lean octane rating, which is a better measure of how the fuel behaves when under load. MON testing uses a similar test engine to that used in RON testing, but with a preheated fuel mixture, a higher engine speed, and variable ignition timing to further stress the fuel's knock resistance. Depending on the composition of the fuel, the MON of a modern gasoline will be about 8 to 10 points lower than the RON. Normally fuel specifications require both a minimum RON and a minimum MON.
In most countries (including all of Europe and Australia) the "headline" octane that would be shown on the pump is the RON.
Measurement methods
The most common type of octane rating worldwide is the Research Octane Number (RON). RON is determined by running the fuel through a specific test engine with a variable compression ratio under controlled conditions, and comparing these results with those for mixtures of isooctane and n-heptane.
There is another type of octane rating, called Motor Octane Number (MON) or the aviation lean octane rating, which is a better measure of how the fuel behaves when under load. MON testing uses a similar test engine to that used in RON testing, but with a preheated fuel mixture, a higher engine speed, and variable ignition timing to further stress the fuel's knock resistance. Depending on the composition of the fuel, the MON of a modern gasoline will be about 8 to 10 points lower than the RON. Normally fuel specifications require both a minimum RON and a minimum MON.
In most countries (including all of Europe and Australia) the "headline" octane that would be shown on the pump is the RON.
R.I.P. January 2010.
XM 2.1 auto VSX 1996 - Bosch Inj, Xantia HDi 90 estate 1999, Xantia 1.9TD 1997
Previously...
GS 1970, Dyane 1974, Xantia 94 VSX TD, XM 94, 2.1 auto - Lucas Inj, XM 92 2.1 estate - Lucas Inj
XM 2.1 auto VSX 1996 - Bosch Inj, Xantia HDi 90 estate 1999, Xantia 1.9TD 1997
Previously...
GS 1970, Dyane 1974, Xantia 94 VSX TD, XM 94, 2.1 auto - Lucas Inj, XM 92 2.1 estate - Lucas Inj
Not so - you are not comparing like with like.
'Old' 100+ (i.e. Premium) octane rating was calculated using the 'Motor Method'; now Octane ratings are quoted in Research Method. A lead free 96 Octane is around 88 Motor Method... try leadfree in a hot 1275S with 12:1 CR and watch the pistons melt.
This is the raison d'etre for octane improvers for use in motor sport high performance engines. Lead free was introduced initially to prevent catalytic converters being ruined by the lead contenet, rather than the environment per se.
'Old' 100+ (i.e. Premium) octane rating was calculated using the 'Motor Method'; now Octane ratings are quoted in Research Method. A lead free 96 Octane is around 88 Motor Method... try leadfree in a hot 1275S with 12:1 CR and watch the pistons melt.
This is the raison d'etre for octane improvers for use in motor sport high performance engines. Lead free was introduced initially to prevent catalytic converters being ruined by the lead contenet, rather than the environment per se.
R.I.P. January 2010.
XM 2.1 auto VSX 1996 - Bosch Inj, Xantia HDi 90 estate 1999, Xantia 1.9TD 1997
Previously...
GS 1970, Dyane 1974, Xantia 94 VSX TD, XM 94, 2.1 auto - Lucas Inj, XM 92 2.1 estate - Lucas Inj
XM 2.1 auto VSX 1996 - Bosch Inj, Xantia HDi 90 estate 1999, Xantia 1.9TD 1997
Previously...
GS 1970, Dyane 1974, Xantia 94 VSX TD, XM 94, 2.1 auto - Lucas Inj, XM 92 2.1 estate - Lucas Inj
Not so - you are not comparing like with like. 'Old' 100+ (i.e. Premium) octane rating was calculated on the 'Motor Method'; now Octane ratings are quoted in Research Method. A lead free 96 Octane is around 88 Motor Method... try leadfree in a hot 1275S with 12:1 CR and watch the pistons melt.
R.I.P. January 2010.
XM 2.1 auto VSX 1996 - Bosch Inj, Xantia HDi 90 estate 1999, Xantia 1.9TD 1997
Previously...
GS 1970, Dyane 1974, Xantia 94 VSX TD, XM 94, 2.1 auto - Lucas Inj, XM 92 2.1 estate - Lucas Inj
XM 2.1 auto VSX 1996 - Bosch Inj, Xantia HDi 90 estate 1999, Xantia 1.9TD 1997
Previously...
GS 1970, Dyane 1974, Xantia 94 VSX TD, XM 94, 2.1 auto - Lucas Inj, XM 92 2.1 estate - Lucas Inj
Had a Solex carburettor do that in the Renault 4.What causes 'running-on' ? Retarded ignition?
Idling has become high after engine is warm.. uncomfortably high...
The pivot of the butterfly had slop and was letting air in, causing fast idle that could not be reduced, and the engine was running-on too.
The only way to stop it was to clutch into 3rd gear.
The finding with retarding the ignition is that it causes difficult starting and reduced acceleration.
Always advanced the ignition to where it just pinged ‘occasionally’.
2002 C5 2.0i AL4 230,000 km 76372389