Speeding Along Now
Posted 30 April 2013 - 06:05 PM
I have a metro engime in my mini, so I need a anti run on valve? Or is it a good idea to fit one?
In the haynes manual it says if you havent got it, it could prevent the engine from idling or running at low speeds.
Would like to hear peoples views on this, thanks
On Sabbatical
Posted 30 April 2013 - 06:43 PM
I think you are confusing 2 different things. An anti run-on valve is a purge valve fitted to the inlet manifold that opens to atmosphere with the ignition switched off. It is used to ensure that highly tuned engines that would tend to run-on will shut down the instant they are switched off by massively leaning out the mixture. It does nothing for idling or part throttle running. What you would need for that would be an over-run valve. This is a small poppet valve built into the throttle disc which would actually increase the chances of running on!
Speeding Along Now
Posted 30 April 2013 - 06:48 PM
I think you are confusing 2 different things. An anti run-on valve is a purge valve fitted to the inlet manifold that opens to atmosphere with the ignition switched off. It is used to ensure that highly tuned engines that would tend to run-on will shut down the instant they are switched off by massively leaning out the mixture. It does nothing for idling or part throttle running. What you would need for that would be an over-run valve. This is a small poppet valve built into the throttle disc which would actually increase the chances of running on!
Ahh right sorry, so do you think it would be benefitial on a 1275 or just highly tuned engines? Thanks
Uncle Cooperman, Voted Mr TMF 2011
Posted 30 April 2013 - 06:52 PM
On Sabbatical
Posted 30 April 2013 - 06:54 PM
Some Minis need an anti run-on valves and others don't. Fitting one if it isn't needed is just something else to go wrong which could easily leave you stranded somewhere. You can't really tell if your particular build will need one until you tune it and see if it runs on. Unless it happens to be exactly the same as one of the cars that has been built with one as standard, then it would probably be wise.
On Sabbatical
Posted 01 May 2013 - 11:23 AM
And the Metro Turbo, RSP Cooper and ERA Turbo. Really only engines that can be expected to have very hot combustion chambers at shutdown and run on carbs need them.
Original Spamster
Posted 01 May 2013 - 11:54 AM
plus the later mainstream cooper
I am a shed dragger.
Posted 01 May 2013 - 11:58 AM
I have an MG metro engine (without the valve) in my sprite and the damn thing is forever running on. I've considered fitting one, but at £50 for a used one I think I'll just put up with it!
Edited by AVV IT, 01 May 2013 - 11:59 AM.
..is NOT a girl!
Posted 01 May 2013 - 12:30 PM
On Sabbatical
Posted 01 May 2013 - 12:48 PM
I have an MG metro engine (without the valve) in my sprite and the damn thing is forever running on. I've considered fitting one, but at £50 for a used one I think I'll just put up with it!
Want one? I've got one I've had for years and won't ever need.
The Turbo Metro didn't have a run on valve as such, if it opened under boost it'd be a major fire hazard. Some did have a fuel vent valve.
Really? I thought they did. You must be right, and the Mini Turbo can't have had one either. It just had the carb vent valve and I think it also had a carb drain valve.
Edited by Dan, 01 May 2013 - 12:59 PM.
Stage One Kit Fitted
Posted 01 May 2013 - 02:42 PM
I have a MG metro engine. I find 20-30 of idle before switching off prevents run-on.
I use that time to triple check I've switched the damn headlights lights off so the battery isn't flat when I next use the car!
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