Scary moment - runaway engine.

[zenataomm]

The comments we've been seeing suggesting chucking things in the blades or lifting the boards and fetching stuff to squirt or even rigging up remotely piped ways of doing it, as sensible as they may appear don't allow for two things.

 

1 - The speed with which a true diesel runaway revs from Bonkety Bonkety to High Pitched Scream.

 

2 - The "Sticky Trouser Effect" which empowers your legs to declare UDI (Unilateral declaration of independence) to the point that running away across the the top of the cut is perfectly achievable regardless of which way your upper torso is facing at the time.

 

Just check your oil levels daily, boat happily in the knowledge it hardly ever happens and be confident that should it happen you'll dine out on it for years.

[Giant]

The governor is at the far end of the engine from the fuel pump and pushes a bar that passes the length of the block. This bar pushes the pump closed against the spring pressure applied by the speed control

 

Got it. Thank you!

[mark99]

This is worth watching - a video re governors.

 

https://www.youtube.com/watch?v=yiLNZP6l0lI

[John V]

2 - The "Sticky Trouser Effect" which empowers your legs to declare UDI (Unilateral declaration of independence) to the point that running away across the the top of the cut is perfectly achievable regardless of which way your upper torso is facing at the time.

 

 

[Tony Brooks]

Couldn't you just put it in top gear and stamp hard on the brakes?

 

That's what I did but it took a few seconds to realise what had happened.

[bizzard]

I wrote nonsense, again. imagination ran away with me, it was frightening.

Edited November 27, 2014 by bizzard

[magnetman]

I had a similar experience several years ago in a Morris Marina van I was driving towards the Avonmouth Bridge on the M5. The throttle cable broke and instead of, as I would have expected, the butterfly closing if fell into the fully open position and the van suddenly accelerated like a mad thing. In a town it could easily have killed someone but since I was on the motorway I had time and space to deal with it. It was just a case of switch the engine off and coast to a halt, not a true runaway in the diesel sense but scary none the less

 

was this a special edition ?

I wrote nonsense, again. imagination ran away with me, it was frightening.

 

I thought the original version was better

[Keeping Up]

I once had a Ford Sierra whose engine management computer had a scary habit of crashing (must have used Microsoft software) and setting the tickover speed to 4500 rpm. It could only be cured by switching on and off again (couldn't find ctrl-alt-del on the dashboard) but of course that would lock the steering, On the open road it wasn't too difficult to control with the brakes, but in a close traffic jam in first gear I got uncomfortably close to the car in front several times.

[Arthur Brown]

If you suspect that your diesel will run away then simply having a CO2 extinguisher ready to (or already plumbed to) fire up the air inlet, is the safest way of stopping the engine. If you can have it remotely operated then that's so much better.

 

Just think why it's running away, and try to cure that.

[Up-Side-Down]

 

 

It it was a diesel engine then that had the

pneumatic Simms governor on the pump

Pedant alert Tony: The Fordson Super Major has a Simms pump fitted with a centrifugal governor!

 

 

so it did run away, its just that you were quick to catch it on the stop control. As no external fuel (like an oil/diesel mixture in the sump) was involved it would stop on the control. If external fuel had been involved there is every chance it would not.

 

Ditto but on an E Type when on a test drive. A far from pleasant experience.

[Tony Brooks]

 

 

 

It it was a diesel engine then that had the

pneumatic Simms governor on the pump

Pedant alert Tony: The Fordson Super Major has a Simms pump fitted with a centrifugal governor!

 

 

so it did run away, its just that you were quick to catch it on the stop control. As no external fuel (like an oil/diesel mixture in the sump) was involved it would stop on the control. If external fuel had been involved there is every chance it would not.

 

Ditto but on an E Type when on a test drive. A far from pleasant experience.

 

 

Note that Innisfree mentioned a "throttle butterfly" and "!strange setup". The throttle butterfly means it was either a petrol/paraffin engine so not applicable to this thread or it was indeed a pneumatic governor. This is not to say later/other models of the same tractor did not have mechanical governors.

 

Mechanical governors do not use throttle butterflys (as far as I know).

[mango]

This is worth watching - a video re governors.

 

https://www.youtube.com/watch?v=yiLNZP6l0lI

Thanks but now I know where the term 'bored of governors' comes from.

[nb Innisfree]

 

Note that Innisfree mentioned a "throttle butterfly" and "!strange setup". The throttle butterfly means it was either a petrol/paraffin engine so not applicable to this thread or it was indeed a pneumatic governor. This is not to say later/other models of the same tractor did not have mechanical governors.

 

Mechanical governors do not use throttle butterflys (as far as I know).

Definitely diesel, IIRCC the inlet manifold only housed a butterfly valve. As far as I can recall the engine speed was controlled by throttling back the air. Only way to reduce or stop it was via the cable that operated a shut off valve of some sort in the injector pump. Edited November 28, 2014 by nb Innisfree

[ukdiggerboy]

i always thought you had to have pressure in the crankcase to force the oil or fuel/oil mix back passed the piston rings in order for it to run on its own oil so the breather would have to be blocked ?

 

Gary

[John V]

i always thought you had to have pressure in the crankcase to force the oil or fuel/oil mix back passed the piston rings in order for it to run on its own oil so the breather would have to be blocked ?

 

Gary

 

Some engines (BMC 1.8) and I suspect the 1.5 have a crank case breather that feeds directly into the intake manifold

[nb Innisfree]

i always thought you had to have pressure in the crankcase to force the oil or fuel/oil mix back passed the piston rings in order for it to run on its own oil so the breather would have to be blocked ?

 

Gary

In the case of my Peugeot cornering hard with an overfilled sump allowed the oil to slop up the cylinders where the lower pressure on the induction stroke of the piston sucked it up past the rings.

 

That's my theory anyway!

 

Some engines (BMC 1.8) and I suspect the 1.5 have a crank case breather that feeds directly into the intake manifold

Maybe that's what happened to my Peugeot.

[ukdiggerboy]

that would do it

[Tony Brooks]

Definitely diesel, IIRCC the inlet manifold only housed a butterfly valve. As far as I can recall the engine speed was controlled by throttling back the air. Only way to reduce or stop it was via the cable that operated a shut off valve of some sort in the injector pump.

 

Sorry Mango

 

 

That would be a reasonable conclusion for someone better versed in cars of the time.

 

There were two versions of the diesel control with a throttle butterfly but both work in a similar way. There may have been one or two pipes connecting the throttle butterfly housing to the diaphragm chamber on the end of the injector pump. The way a drilling was located relative to the throttle butterfly or a butterfly bypass picot tube allowed a depression that was proportional to both engine speed and butterfly position to be passed to the diaphragm.

 

At full throttle and low engine speed a spring forced the governor rack to close to maximum fuel. As the depression behind the diaphragm built op it drew the rack back and thereby reduced the fuel delivery. I could go into various actions at varying speeds and throttle openings but I do not think that is necessary here.

 

If its a diesel and it has a throttle butterfly just be aware if oner of the pipes becomes loose, broken or disconnected the engine could

run away.

Edited November 28, 2014 by Tony Brooks

[mango]

 

Sorry Mango

 

No problem governor.

 

I'm actually interested, but the video took a long time to get up to speed from a simplistic start.

[jollymoggy]

Sorry if I sound like a newbie but can't you just block the exhaust?

[Graham Davis]

Sorry if I sound like a newbie but can't you just block the exhaust?

 

Very difficult to do, and it would take a great deal of pressure on the exhaust side to stop an engine. You are more likely to blow the exhaust apart before it would stop.

 

If you have a CO2 extinguisher handy that will stop the engine if you squirt it into the air intake.

[David Mack]

Sorry, scan read most of the topic I'll be honest! ..whats RAP short for?

Don't know. Norwegian apparently, but there's not a lot of info on the web about them that I have found.

But there is a museum in Norway that has 4 RAP engines:

 

http://translate.googleusercontent.com/translate_c?depth=1&hl=en&prev=search&rurl=translate.google.co.uk&sl=no&u=http://www.kystkultursamlingen.no/motorer&usg=ALkJrhji1D81T1I84g5qia-8QHQt1mUfVw

 

 

[Neil Smith]

Just got back from hols and been reading this thread, this happened to me years ago in an old pug 305 van that was very worn, the breather was fed into the air filter box and this then filled with oil and sucked into inlet so running on its own oil, very scary until I stalled it, so I just took it off and let it hang down the side problem cured.

 

Neil