Cooper S running on
Discussion
(Or is it Dieseling)
I've been running around in my friends 1275, 1972 Mini Cooper S for a day or two, shaking it down ready for an outing on the Rally of the Tests at the end of this month.
One irritating problem which has been present on this Car for the time I've known it, is it's tendency to run on after the ignition has been cut.
I notice in the manual that the Coopers should have a valve to prevent this, (bracketed in to the right hand side of the engine bay). Question is, are these engines prone to this (hence the valve) what causes it and is it something I should try and resolve?.
The Engine seems to run fine, though it does seem a bit lumpy at idle and doesn't clean up until gets above 2000rpm, not sure if this is linked or just a bit of a balance issue on the carbs.
Carbs are the twin SU set up inch and quarters I believe.
I've been running around in my friends 1275, 1972 Mini Cooper S for a day or two, shaking it down ready for an outing on the Rally of the Tests at the end of this month.
One irritating problem which has been present on this Car for the time I've known it, is it's tendency to run on after the ignition has been cut.
I notice in the manual that the Coopers should have a valve to prevent this, (bracketed in to the right hand side of the engine bay). Question is, are these engines prone to this (hence the valve) what causes it and is it something I should try and resolve?.
The Engine seems to run fine, though it does seem a bit lumpy at idle and doesn't clean up until gets above 2000rpm, not sure if this is linked or just a bit of a balance issue on the carbs.
Carbs are the twin SU set up inch and quarters I believe.
Ian
Be very wary if its running on.
My 1330 Metro motor did that on the standard dizzy when I upped the Comp Ratio by decking the block and other mods.
It ran on, and pinked under load.
Then it destroyed the piston rings on the Johnson when I was out with Andrew.
I tried the Metro anti diesel device but that didn't help.
I changed to a yellow Aldon on the recommendation of Richy (guru1071) and it was fine after that.
Tony H
Be very wary if its running on.
My 1330 Metro motor did that on the standard dizzy when I upped the Comp Ratio by decking the block and other mods.
It ran on, and pinked under load.
Then it destroyed the piston rings on the Johnson when I was out with Andrew.
I tried the Metro anti diesel device but that didn't help.
I changed to a yellow Aldon on the recommendation of Richy (guru1071) and it was fine after that.
Tony H
the 'gasper' valve was only fitted to the carb rover coopers in the early 1990s.
sounds like your car just needs a good tune up, some fresh petrol and a swing on the dizzy.
if it had been set up on the rollers and didn't run-on then, and it does now, its going to be something easy to fix.
if its never had a rolling road session, then it could be that the dizzy doesn't have enough advance, or is wrong for the tune of the engine.
1275's motors always run hot, but with modern rads and dizzys its easy to keep them running right.
on a tuned car its a (dirty) habit to always put them in 4th and let the clutch out as you turn the key off to 'stall' them, this prevents them running on and doing any damage to the valves/pistons - but you are just covering the problem up!
sounds like your car just needs a good tune up, some fresh petrol and a swing on the dizzy.
if it had been set up on the rollers and didn't run-on then, and it does now, its going to be something easy to fix.
if its never had a rolling road session, then it could be that the dizzy doesn't have enough advance, or is wrong for the tune of the engine.
1275's motors always run hot, but with modern rads and dizzys its easy to keep them running right.
on a tuned car its a (dirty) habit to always put them in 4th and let the clutch out as you turn the key off to 'stall' them, this prevents them running on and doing any damage to the valves/pistons - but you are just covering the problem up!
Back in the '60's just about every Cooper 'S' rally car did this. We used to joke about switching off, going in for breakfast and coming out to find it still 'Dieselling'.
Just engage 4th gear before you switch off and as soon as you have switched off, let the clutch up to firmly stop the engine. That always works and prevents damage.
I've always believed it is a function of hot carbon deposits acting as 'glow plugs' rather than ignition timing issues. After all, when it is switched off there is no ignition, so distributor timing is not applicable, unless an incorrect timing has caused local the 'hot spots' in the chambers.
Just engage 4th gear before you switch off and as soon as you have switched off, let the clutch up to firmly stop the engine. That always works and prevents damage.
I've always believed it is a function of hot carbon deposits acting as 'glow plugs' rather than ignition timing issues. After all, when it is switched off there is no ignition, so distributor timing is not applicable, unless an incorrect timing has caused local the 'hot spots' in the chambers.
Actually I'm saying it ran fine, what actually happened is it started loosing Oil Pressure mid way through he second day, even though the levels were fine. By the end of the third day we had zero pressure and a louder and louder transmission whine. Eventually (As I understand it) an idler gear failed and the layshaft snapped.
I expect the Oil pump failed, but what surprises me is that the top end didn't go first, I can only assume that the Oil stayed in the lower part of the system and was in effect causing too much drag by pooling around the Gears.
I expect the Oil pump failed, but what surprises me is that the top end didn't go first, I can only assume that the Oil stayed in the lower part of the system and was in effect causing too much drag by pooling around the Gears.
I will make sure the Garage has looked at the pick up.
Wasn't my Car or my decision, but I guess considering the cost of entry and the commitment we had made to do it, one might be prepared to take the risk that it was a sender error.
It's the second time the Driver has entered (my first) and he was determined to get to the finish as last year the Diff blew on the first day, he agree with the organisors that he would go back home get another of his Cars (he has a few) then knocked the sump plug off it!. It's rare that you break two Cars on one Rally!
At least this time we got a finish, though I had to use a bit of 'rallymanship' to achieve it.
Wasn't my Car or my decision, but I guess considering the cost of entry and the commitment we had made to do it, one might be prepared to take the risk that it was a sender error.
It's the second time the Driver has entered (my first) and he was determined to get to the finish as last year the Diff blew on the first day, he agree with the organisors that he would go back home get another of his Cars (he has a few) then knocked the sump plug off it!. It's rare that you break two Cars on one Rally!
At least this time we got a finish, though I had to use a bit of 'rallymanship' to achieve it.
FWDRacer said:
Could be the most expensive rally you ever do 
Carried on going and thought you might have a sender error
I bet the majority of the engine on strip down is rubber ducked. When that Orange oil pressure light comes on, ignition off and park it.
ouch...Carried on going and thought you might have a sender error
I bet the majority of the engine on strip down is rubber ducked. When that Orange oil pressure light comes on, ignition off and park it.
an expensive mistake!
I only ever let my temper get the better of me once when I knew that my race engine was sick and I just kept on going as I was determined to finish as the race entry had been quite high..............the invoices from the engine rebuild sure made me make sure that I would never do that stupid trick again......
once the pressure goes, or the gearbox / bigends can be heard over anything else - turn it off!
To be honest I think he was working on the theory the engine was going to need a rebuild anyway so why chuck the cost of the entry away with a certain DNF when we could well have got it to the finish and to all intents and purposes did do. Only on the last test did the sound become blindingly obvious that some major was afoot mechanically.
Bear in mind Engine maladies aside this event cost the thick end of £4000.00.
Bear in mind Engine maladies aside this event cost the thick end of £4000.00.
Running on can occure because of lean mixture, advanced ignition timing, carbon buildup, too hot plugs. In every instance a part of the cumbustion chamber gets glowing hot, and diesel ignites the fuel.
The runon can be harmless, but in most cases the same things that cause the dieseling will harm the pistons/rings also.
The runon can be harmless, but in most cases the same things that cause the dieseling will harm the pistons/rings also.
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