Hello everyone. (I also posted this in the 3rd gen forum by mistake- sorry). I got my new 2002 3500 24V ISB 6-spd 2 months ago and have 18000 KM on it already. I take this thing to work everyday on oilfield projects - great truck. My dealer can't find a positive airflow shutoff device, this is a required safety device for diesels operating near an oil and gas facility. Do any of you have any suggestions as to manufacturer and how to install this thing? Thanks.

My buddy just had one installed on his Dmax a month ago. About $1800 Canadian for the kit installed, has a speed switch (electronic RPM setting) and the shutoff valve is electric. It fits into the intercooler lines feeding the engine. When activated the valve is closed with the electric solenoid and when open is full flow.

I will have to contact him about who actually manufactures it, then maybe a dealer your way can hook you up.

We went to a truck outfitting shop for large trucks, pickers, winch tractors etc. They knew exactly what we needed. If I want to use this truck I will also have to get one installed.

J-eh

Sounds kinda like an exhaust brake in the intake tract.

What purpose does having this device serve? I'm sure it's for safety reasons, but how exactly does it provide that safety? What does it prevent?

It would prevent a run away engine if you encountered a fuel rich air environment.(I imagine that could be found rather easily in an oil/gas field)

Wow. Cool. I didn't realize that something like that could even happen.

Diesels have no throttle valve in the intake tract.<br>No way to shut it down if it finds an &quot;alternate&quot; fuel souce.<br>It will &quot;run-away&quot; until it over-revs and grenades.

The &quot;run away&quot; was also talked about in the shutting off while refueling thread.<br>The truck gets a whiff of the gasser next to you refueling and runs away.<br><br>Kinda figured out what it was, this helps more.<br><br><br>phox

I've only heard of it happening once or twice to trucks while refueling but it's always a good idea if your refueling next to gas pumps to shut down the truck. <br><br>Shovelhead is right it will rev till it blows. :o provided there is enough vapor in the air to keep it reving that long.<br><br>The guys running in the new ATPA pulling class have to have on of these as well. And it's basiclly the same thing as an exhaust brake but on the intake side.<br><br>Be Careful out there.<br><br>Darrell

I should have specified that its called a Positive Air Shutoff system.<br><br>As you all illuded to, its to keep someone for catching Cummins parts in the eye... [laugh]<br><br>Most if not all Oil and Gas companies won't let you on site without at least a manual setup. But now the standard system is the electronic system. They set the overspeed setting to just over red-line and its live all the time. There is also a manual E-switch just incase you need it.<br><br>The valve is not like an exhaust brake, but more like a gate valve on a swing, there is no impedence of flow.<br><br>FYI...J-eh

Here at the dealer we have been using Positive Air Shutoff Valves from Roda Deaco Valve. Very easy to install and they have 3 model to choose from(manual, electric, and manual electric combo). Call them at 1-780-465-4429 or on the web at www.rodadeaco.com 8)

<br>I should have specified that its called a Positive Air Shutoff system.<br><br>As you all illuded to, its to keep someone for catching Cummins parts in the eye... [laugh]<br><br>Most if not all Oil and Gas companies won't let you on site without at least a manual setup. But now the standard system is the electronic system. They set the overspeed setting to just over red-line and its live all the time. There is also a manual E-switch just incase you need it.<br><br>The valve is not like an exhaust brake, but more like a gate valve on a swing, there is no impedence of flow.<br><br>FYI...J-eh<br><br><br>J, I think Spanky had to put one of those on all his trucks just recently.

Thank's Nigel for the contact and web link. Just sent them a msg, let you know what happens.

Hi J,<br><br>These things have been around for years on both stationary and marine diesels. Also, Detroit Diesel use something similar to what you are talking about in their 6V71 and 8V71 engines. These are connected (installed in) to the intake air system. They can be electrically (from a speed switch) operated, mechanically operated (from remote pull station) or locally operated for manual shut down. Once operated these usually need to be manually reset.<br><br>There are various types - some spring operated, some using a compressed air actuator and then there are the the ones that are spring loaded but electrical solenoid vales actuate the operation by moving a stop pin to allow valve to work.<br><br>I have seen two types - a guillotine valve and a swing valve. Both operate to completely shut of the air supply - no breathing no working. Work well, very positive and quick.<br><br>The operating system can vary but they all essentially do the same job. Try your local Detroit Diesel dealer - they might just be able to help. I think that all the Greyhound buses (all diesel buses) have these so that the engine cannot run away speedwise, in the event of a governor failure. The manual emergency stop in the drivers cab is used to activate this mechanism. To start the engine, the driver had to reset a spring loaded flap valve before the engine would fire up (no air as it was shut). <br> <br>As I understand it, our engines only regulate (through the governor) fuel delivery. They do not actually shut down on an overspeed surge by actually shutting down the engine. Instead the is reduced to lower power output (computer programming). Engine would still run but at a reduced output until the code is cleared by the dealer (reflashing memory?).<br><br><br>Hope this helps.<br><br>Mariner

I work for a major truck manifacturing plant and have seen
a few of these, mainly on fire trucks. It is installed on the
intake side of the charge air cooler,it almost looks like a pac
brake ,and is used to shutdown the engine instead of the
switch to prevent an electrical spark possibly at the battery
,or the cutoff switch. I hope this helps.

I do realize what you guys are talking about but I have to say I dont really see why or how this product would ever be needed. I mean thinking about the fact that there is no venturi butterfly in the intake that stops air from coming in. So the theory is that any fumes from other fuels like gas could enter the air intake and cause the engine to over speed. Factoring that there is NO restriction means that the engine is operating at max CFM all the time. Diesels running on a totally different A/F ratio than gas. This would mean that a lot of alternate fuel would have to enter in the system to permit a correct air to fuel ratio for anything to happen. What is the chances of this happening anywhere you could take a breath of air, let alone at a public gas station. Has anyone ever actually seen this happen? I've never even heard of this before but I've heard of diesels that ran for miles on gas before popping. I think it is a one of those things thought up by someone paid to think up think up stuff that has no knowledge of whats being regulated. You know what I mean.

I saw and witnessed 2 destroyed VW diesels due to engine oil overfill- the oil foamed and was thrown out of the crankcase vent into the intake. Engines overreved and threw rods. (Even though inj. pump was shut off).
I also saw a Steyr truck (local brand over here) run away with the guy frenetically trying to stop it from the pump due to spillage of fuel from a barrel onto the air filter inlet. Truck engine was wrecked, driver had sheer luck that none of hte parts hit him (trying to use the manual stop on the inj. pump).
I can't imagine that a combustible mixture existing on a fueling station and nobody noticing it, but I can imagine spillage of fluids or high pressure LNG causing a runaway on a site.

Jst my 2c

AlpineRAM

Enterprise Engine is using one in their truck you could try calling then Like DarrellB said onthe hp Twin pullers some rules require them. Doug @ EEP 740-246-6329

...So the theory is that any fumes from other fuels like gas could enter the air intake and cause the engine to over speed. ...... This would mean that a lot of alternate fuel would have to enter in the system to permit a correct air to fuel ratio for anything to happen. What is the chances of this happening anywhere you could take a breath of air, let alone at a public gas station. Has anyone ever actually seen this happen? ......


In the industry we use it for you are around &quot;gas&quot; all the time. Not gasoline but natural gas and a whole bunch of other ugly chemical compounds that a diesel would love to run on. This is not ment for gas-oline stations rather having your truck on site with tools, and a pipeline is flared or gas is vented and the truck runs away on the gas. I have heard of it happening and there is just cause to have these units installed. These are not for the average vehicle.

J-eh

I guess I could see that happening around a natural gas line or propane. How much does one cost and why wouldnt it work in decelerating like and exhaust brake (but not with such force)? Or maybe working in conjuction with a exhaust brake?

The fully electronic RodaDeaco system runs about $1200 CAD installed. My buddy has one on his Dmax... You can get a manual version for about $800.

The problem with the valve as a brake is that it is not a butterfly system. Its a spring or solenoid actuated slide valve that is open or shut, no in between. The electronic versions have a solenoid that is activated at 105% of redline and then holds shut till 0 Rpm is reached.

Another interesting tidbit about the need for the shut-off is that they are not there just to protect the engine...they are there to protect the plant in which the engine decides to scatter. When engine goes boom.... the surrounding plant makes BIGGER BOOM,which, exponentially expands at the rate of how many other fuel sources are readily available to keep the BOOM cycle recurring.

It has happened down here many times in the petrochemical industry over the years....Hard lessons learned the hard way.

Cummins Alberta has them and installs regularly on gensets and truck engines for oilfield application. For the uneducated an excess of airborn fuel can be released from several sources including un-purged fuel/crude oil tankers, pipelines and any remote metering or compression station. There are products transported in trucks, railcars or pipelines more volatile than gas or diesel such as condensate or bitumen solvent. Under the right circumstances an engine runaway could happen in less than 15 seconds as the people at Trimac Calgary witnessed one night in the shop when a un-purged and steamed tanker was placed in a warm shop. The truck sat inside for 20-30 minutes releasing residue vapors, the ceiling fans pushed the vapors down onto a truck that had been inframed and at the same time was in start up mode. The mechanics turned over the 8V92 attempting to prime/bleed air from the fuel system, the gaseous air was drawn into the intake with the diesel compressing it and igniting. The flywheel blew up at 4200 RPM blowing the cab from the frame and imbedding the 3-4 flywheel fragments in several items including the roof. The positive air shutdown if installed could have been tripped and all inflowing air/fuel movement effectively stopped. The potential of a secondary explosion of the fuel tanker and residual fumes in the shop could have been deadly as the flying pieces were striking other metal and concrete objects causing sparks. Just one example of why they are a required piece of equipment in fuel rich oilfield environments. Just think about this next time &quot;Johnny in a Hurry&quot; fuels his running truck on warmer days when fuel vapors come from fuel tanks being filled with liquid expelling combustable vapors which travel at air intake levels. PK