Anti Run on (ARO) Valve

[Z320]

Currently I have some thoughts about a  more simple system to avoid run on problems,

but on another forum it is stated from some guys its all only because of the wrong tuning…..

[BlueTR3A-5EKT]

4 minutes ago, Z320 said:

Currently I have some thoughts about a  more simple system to avoid run on problems,

but on another forum it is stated from some guys its all only because of the wrong tuning…..

As I said the cars are out.  

That does not mean they fixed last years issues.

 

Peter W

[Z320]

Peter,

you are a bad guy, you put a nasty idea in my mind…

[BlueTR3A-5EKT]

10 minutes ago, Z320 said:

Peter,

you are a bad guy, you put a nasty idea in my mind…

Go for it.   Where there is a solution a person will seek it.   

[Z320]

Peter,

I found your valve, #51 it from a ZS 1755CDTU, also used by Mercedes Benz

Indeed it is the idle air stop valve, #50 is the air regulation screw.

From the sketch and photos I assume it is normally closed, with 12 V opened (on the sketch), that makes it very simple to use.

This ZS carb doesn't works with the Pierburg valves I used.

#51 (perhabs slightly different) is also used on the VW beetle with Solex 31, 33 and 34-PICT-3 and -4 carbs.

They are pretty easy to get and "cheap", if anybody has an idea - he is invited to share.

Ciao, Marco

Edited August 8, 2022 by Z320

[BlueTR3A-5EKT]

The valve assembly used on Mini Metro is here   Pt no ADU9535

https://www.trgb.co.uk/products/tr2-4a-anti-run-on-valve

 

Tge Moss instructions on how to fit.  https://www.moss-europe.co.uk/media/pdf/STN127Z_instructions.pdf
Different part number as it is a kit not a single valve.

 

Peter W

[Z320]

Please everybody, in my opinion don’t use this at all.

Please!

Edited August 9, 2022 by Z320

[BlueTR3A-5EKT]

2 hours ago, Z320 said:

Please everybody, in my opinion don’t use this at all.

Please!

Why not?

Austin Rover specified and fitted it to thousands of new cars to solve the running on issue caused by raising the compression ratio of the A series engine.

Peter W

[Z320]

Anybody an idea why not?

 

[stillp]

9 hours ago, BlueTR3A-5EKT said:

Why not?

Austin Rover specified and fitted it to thousands of new cars to solve the running on issue caused by raising the compression ratio of the A series engine.

Peter W

I used to work for a company that supplied many thousands to Ford in the late 1970s for the early Fiestas with the  over-square engine.

Pete

Edited August 9, 2022 by stillp

[Z320]

Hi TR drivers, this is what I see with a closer look on this valve:

to stop the run on issue (failture) of an engine this valve makes the mixture worse (failture)

to let the engine hopefully die (neg. x neg. = pos. result). Like a fire fighter fights with fire with fire.

This can work luckily, or burns down the hole forest …

From the description this is a “normally OPEN” valve, means it is switched CLOSESD by ignition ON by 12 V.

A “normally CLOSE” valve like the “12H4295” valve from the “TR6 emission control system” is more safe,

but the electric description must be more detailed and this needs some more effort and knowledge.

OK: valve installed, ignition on, valve closes, fire, engine runs.

Test  #1:

engine runs and is hot, runs on idle, ignition off, the valve opens, mixture gets lean, engine always dies?

N-yes, only more or less. Because with a lean mixture an engine can also run on.

A friend mine installed the valve on his TR250 and confirmed me this about 2015.

Today I asked him again about, it is currently unpluged and it always wistles, oh my dear!

2016 I asked him to do test #2:

engine runs and is hot, runs on idle, keep ignition on, unplug the valve, it opens, mixture gets lean, engine dies?

N-yes. With the ignition still ON the engine runs badly with the lean mixture.

Not my experiences, I’ve been told.

Now to the point:

when I introduced my Pierburg valves 04/2016 at the TR IG club magazine

I got a feedback from a club mate who installed the Moss valve from above.

The valve failed at his holiday at the Alps because of a fuse contact problem (possible on a TR?),

remained open, but the car was possible to start with the choke.  It run badly on idle and some hot on the raod – but it was summer!

He wondered about, the reason was not found and he had to travel home.

“I nearly burned down the engine on our way back home until I noticed the valve was always open and the mixture always lean”.

Not my experience, I’ve been told.

In my opinion the inventor of this valve gave no thought on what happens if it fails for any reason, or he did and gave the risk to the customers.

If my Pierburg valves fail nothing happens, and if the 34 PICT-3/4 valve fails you have no idle, that's correct.

Ciao, Marco

Edited August 9, 2022 by Z320

[BlueTR3A-5EKT]

3 hours ago, Z320 said:

Hi TR drivers, this is what I see with a closer look on this valve:

to stop the run on issue (failture) of an engine this valve makes the mixture worse (failture)

to let the engine hopefully die (neg. x neg. = pos. result). Like a fire fighter fights with fire with fire.

This can work luckily, or burns down the hole forest …

From the description this is a “normally OPEN” valve, means it is switched CLOSESD by ignition ON by 12 V.

A “normally CLOSE” valve like the “12H4295” valve from the “TR6 emission control system” is more safe,

but the electric description must be more detailed and this needs some more effort and knowledge.

OK: valve installed, ignition on, valve closes, fire, engine runs.

Test  #1:

engine runs and is hot, runs on idle, ignition off, the valve opens, mixture gets lean, engine always dies?

N-yes, only more or less. Because with a lean mixture an engine can also run on.

A friend mine installed the valve on his TR250 and confirmed me this about 2015.

Today I asked him again about, it is currently unpluged and it always wistles, oh my dear!

2016 I asked him to do test #2:

engine runs and is hot, runs on idle, keep ignition on, unplug the valve, it opens, mixture gets lean, engine dies?

N-yes. With the ignition still ON the engine runs badly with the lean mixture.

Not my experiences, I’ve been told.

Now to the point:

when I introduced my Pierburg valves 04/2016 at the TR IG club magazine

I got a feedback from a club mate who installed the Moss valve from above.

The valve failed at his holiday at the Alps because of a fuse contact problem (possible on a TR?),

remained open, but the car was possible to start with the choke.  It run badly on idle and some hot on the raod – but it was summer!

He wondered about, the reason was not found and he had to travel home.

“I nearly burned down the engine on our way back home until I noticed the valve was always open and the mixture always lean”.

Not my experience, I’ve been told.

In my opinion the inventor of this valve gave no thought on what happens if it fails for any reason, or he did and gave the risk to the customers.

If my Pierburg valves fail nothing happens, and if the 34 PICT-3/4 valve fails you have no idle, that's correct.

Ciao, Marco

Yes accepted reasoning.    Cutting fuel supply or blocking the air path is better to stall the engine.

Perhaps the use of such a small air valve on an engine nearly 3 times the capacity of the engine it was intended for is the mistake.  

Maybe 2 or even 3 air solenoids should be fitted on a 6 cyl TR  to stop the possibility of an owner starting the engine with full choke when the air (ARO) valve solenoid has failed ‘open’

That is error proofing in the design.      Rather than idiot proofing, as Ford would say as idiots do not drive our cars.

 

Peter W

Edited August 9, 2022 by BlueTR3A-5EKT

[Z320]

Hi Peter,

If you want I can do this test this evening:

I fit a cork on the vacuum nipple of the inlet manifold and pull it while the engine runs on idle?

More air leak and more lean mixture is not possible!

I don’t know what happens, bets are welcome.

Ciao, Marco 

[Charlie D]

Marco,

Would this sort of thing work?

https://www.ebay.co.uk/itm/253817383938?

Normally closed, 12 volt, quite large pipe sizes available, and fairly cheap. (Even cheaper I guess direct from China.)

Maybe not from these suppliers, but they are a common item.

I've used similar on a DIY vac-forming machine and they were reliable.

 

Charlie.

[Z320]

Hi Charlie,

yes, this could work but I'm not shure about the result.

Today I did what may maths teacher always told us: make a test with the extremes!

I drove the car for some miles, outside 30°C, car was warm,

for a control test I switched it off first without using my Pirburg valves: without any run on issues.

Started it again and then pulled off the hose from the inlet manifold nipple, diameter of the nipple inside about 10 mm.

The mixture went extreme lean and the ignition was still ON (I was without my lovely wife).

The engine died a painfull death, please see the video.

The result may be different with the ignition OFF?

But probably making the mixture suddenly max lean is not the right way.

If you want to go that way you have to know the valve seat of this solenoid valves is much smaller than the dimension of the valve.

And a 1/2" valve is already relatively big. You need a terminal on you ignition switch with 12 V when the ignition is OFF.

Or a changeover relay with 87/87a contacts, and something to switch the valve off again (still on 12V),

like a timer elay or a pressure switch (TR6 emission control system).

Currently "Steve" posted this sketch about at issue the Triumphexp forum.

Ciao, Marco

 

 

Edited August 11, 2022 by Z320

[Z320]

Hi all,

yesterday I spend some time browsing ebay for valves, checking dimensions, pick out some nipples, brass, taps and dies,

making own thought about the issue apart what is told.....

Now just some questions to all of you:

A lean mixture causes run on problems too?

At summer the density of warm air is lower and the mixture automaticly leaner?

This is why there are more run on problems at summer?

Does it make sense to fit a air valve on the inlet mainfold to make the mixture more lean at the moment the ignition is switched off?

Thanks in advance for your thoughts.

Marco

[stuart]

Ive had a number of 4a through the workshops with run on issues and they have all been cured by careful tuning. Forget factory manual settings, each car needs to be tuned individually

Stuart.

[BlueTR3A-5EKT]

1 hour ago, Z320 said:

Hi all,

yesterday I spend some time browsing ebay for valves, checking dimensions, pick out some nipples, brass, taps and dies,

making own thought about the issue apart what is told.....

Now just some questions to all of you:

A lean mixture causes run on problems too?

At summer the density of warm air is lower and the mixture automaticly leaner?

This is why there are more run on problems at summer?

Does it make sense to fit a air valve on the inlet mainfold to make the mixture more lean at the moment the ignition is switched off?

Thanks in advance for your thoughts.

Marco

Running on cure when all tuning has been done.

Best solution is to cut the fuel supply and ignition spark to stop the engine.  
This will of course hide the bad tuning or carbon build up in the combustion chamber, valves, ports. etc.

Peter W

 

[Charlie D]

Just a note about the type of valve I mentioned on eBay.

Working Temperature: -5~85℃

They would probably need to be mounted remote from the manifold.

[Z320]

Hi Charlie,

sorry me, I don’t spend more effort on this, for me the issue with this air valves is clear. 
My TR4A is lovely tuned and performed very well yesterday at a really hot summer day.

And my Pierburg valves clear the situation in the few cases when needed.

Ciao, Marco 

[Nobbysr]

If any one is looking for an alternative

i fitted an anti-run on valve to my GT6. it was an MG part no. the numbers below are Moss UK number

valve, anti run on
ADU9535

Anti-Run On Valve
STN127Z

Both of these can be used, I originally  used an overdrive solenoid which closed the seal when the ignition came on and opened when the ignition switched off  on a timer for five seconds, so you would need a relay and a timer it worked extremely well and the only mod was a hose connector drilled and tapped into the inlet manifold

The attached pic is very similar to my set up
hope it helps
Steve

[monty]

On 8/12/2022 at 9:46 AM, stuart said:

Ive had a number of 4a through the workshops with run on issues and they have all been cured by careful tuning. Forget factory manual settings, each car needs to be tuned individually

Stuart.

Agreed Stuart, any rare run on problems with my car have been cured by a retune & higher octane fuel.

[Z320]

Currently there are 2 of the Pierburg valves I used on eBay Germany

each 149 Euro, or price offered

[tim hunt]

My 4A can occasionally run on, particularly if I have had a fill of E10. I cannot set tickover any lower, it is around 700rpm. I find the best way to avoid running on is to floor the accelerator at the same instant I cut the ignition - works for me.

Tim