Engine running on

[gouldsborough7]

I am sure this subject was discussed before, but I've got a new twist and am looking for advice.

When my car was being MOT'd yesterday, my local garage proprietor (who was doing the test and loves kit-cars) spoke about a valve that could be inserted in the servo pipe. This was possibly a mod done to later Fords, and worked off the ignition key switch. In the engine ON position the valve closed, and when OFF the valve opened to atmosphere and stopped the engine 'running on'.

Can anyone point me in the direction of a supplier of above valve?

Cheers
Mike

[austinm]

Re: Engine running on

Hi Mike,
If you Google Anti run-on valve you will get a lot of information on these valves.
MG used them on the MG 1300 Metro, also Rimmer Bros. list a valve for American spec Triumphs.
I also saw a mention of a valve in use on a Ford Sierra Engine which was fitted into a Robin Hood kit.

Regards Austin

[j.fernie]

Re: Engine running on

Mike,
Advice I was given for the B-series engine was to press the accelerator to the floor as you turn off the ignition. It works very well with the SU set up. Don't know if webers respond in the same way.
Cheers
Jim

[gouldsborough7]

Re: Engine running on

Hi Jim
When I first had the car, I did the pedal-pressing routine a couple of times, and stopped doing this when my wife & I stopped at Tescos for a few bits of shopping. The resultant loud BANG caused a few people to look around, wondering if terrorists had arrived possibly.

Regarding a valve, I have searched on the Internet, and have only seen some American suppliers with hiked-up prices. I'll try Rimmers and see what is available. Failing that, I might have to go to the scrappers, which I would admit I haven't done for a considerable number of years.

I'll feed my success or failure onto this message board in case other guys want to follow the same route.
Cheers
Mike

[jon_cox]

Re: Engine running on

https://www.europaspares.com/BRAKE_PARTS/BRAKE_PIPE_and_FLUID/VACUUM_PIPE_NON_RETURN_VALVE___LV15069__3817.html
This is what you are looking for. It stops the air which is under pressure in the servo from being forced back to the inlet manifold which creates the running on problem.

[jon_cox]

Re: Engine running on

That link did not work so....

www.europaspares.com/BRAKE_PARTS/BRAKE_PIPE_and_FLUID/VACUUM_PIPE_NON_RETURN_VALVE___LV15069__3817.html

[jon_cox]

Re: Engine running on

OR........

www.cobraclub.com/forum/general-cobra-discussion/11556-vacuum-pipe-non-return-valve.html#post90037

[gouldsborough7]

Re: Engine running on

Thanks Jon
I was surprised to learn that my problem was as described in your message. I was naively working on the idea of fitting a valve, which electrically allowed air into the induction system via the servo pipe.

I got a quote from a Rover/Triumph specialist for over £80, which put me off the idea I would admit. Eurospares non-return valve at £29 looks a lot better.

Is this valve merely fitted into the servo pipe, with the aid of a Stanley knife, and I guess Jubilee clips? Not sure about the cheapo plastic valve on the Cobra Club site.
Cheers
Mike

[James]

Re: Engine running on

Hi Mike,
I got the valve from a Sierra at the breakers and it works a treat. The ´recycling agent`, as he likes to be called, let me have it for free (miracles do still happen!) but made me promise to test the brakes properly before going into trafic "You might put it into the pipeline the wrong way round" he said - as if I would ;-)

[gouldsborough7]

Re: Engine running on

Hi Guys
Just to round this one off, I took the plunge and bought a valve from Eurospares (thanks for the tip, Jon). There is no decent scrappie nearby, and I thought this valve was important to work properly, being in the servo pipe.

By the time Euro had added carriage & VAT to the bill, it cost almost £40. When I saw this cotton-reel size bit of metal in a Jiffy bag, with no obvious moving parts or other complexity, I felt that Eurospares were fleecing me more than a bit.

Anyway, fitted the valve in 5 minutes, and have since only run the car a couple of times. Bingo - no running-on! So, hopefully problem was solved & simply, but I think at too high a price.

Should I write to Eurospares and politely complain? Is the valve made of titanium or other valuable metal?

Cheers
Mike

[macdonald.dm]

Re: Engine running on

Can someone explain how fitting a non-return valve in the vacuum line actually prevents running on? Thanks.

[gouldsborough7]

Re: Engine running on

Yes, I would like an explanation of this as well. Originally, I accepted this without too much thought, but the more I think about it, the technicalities become a bit mixed up.
Cheers
Mike

[jon_cox]

Re: Engine running on

Simple really. The servo works by using the vacuum in the inlet side of the engine. This presure differential is returned to equilibrium when you switch off the engine. I.e. there is an amount of air sucked in through the carb when the servo diaphram is relaxed. This in turn sucks petrol vapour into the inlet manifold which is then ignited in the cylinders by the residual heat NOT spark from plug. The older your engine and the more coked up it is the more likely you will suffer running on as this glows red hot for longer.
By fitting the valve it stops the relaxing diaphram from sucking in the air to equilise the system and therefore no petrol vapour and no running on.
This is a problem which is solved by different solutions. Many cars had solenoids fitted to the fuel inlet side of the carb which closed when the ignition was turned off stoppping the fuel from getting sucked in.

[macdonald.dm]

Re: Engine running on

Cool - thanks Jon!

[gouldsborough7]

Re: Engine running on

Yes, thanks Jon.

After fitting the valve in my servo pipe the problem mostly disappeared. However, I had a recurrence of the running-on a few times, and especially during my experience on the M25 during a traffic jam - see separate message I raised on this one earlier this week. I am hoping a new carb of the correct design will sort this problem out as well as the other snags.
Cheers
Mike