Engine safety SHUTDOWN

[JohnEd]

Guys,

Recently there has been some episodes where "OVER TEMP" has claimed perfectly good engines.  In one such incident (no names here) the owner "got lucky" and saved his heads and only dropped $13,000 to get back on the road.  There is an over temp engine safety device that shuts off fuel and prevents " destroying the engine.  This is an important topic in terms of safety, destroying our engines and destroying our finances.  No joke!

I think that this of such gravity that an annual inspection would be in order prior to setting out on one of our "quests" for adventure/socialization/warmth.


My objective here is to identify the safety devices we might expect to find on our two cycles and delineate the tests for system operation and the operation of the particular sensor itself.  I will list the ones I know of and I hope to get the following info: Any additional sensors, How to verify that the safety system is working and how to check the calibration of the individual sensor, optional designs for additional systems.

Systems known to me that disable the engine:

   1.  OVER TEMP

            I have seen pics that showed "two" sensors on the 8V92.  One on each head 
            and both were ganged and either would shut off fuel.  I think that you could
            Test the system by applying a short to the connector on the sensor.  At what   
            temp should this activate?  Can it be verified by simply putting it in a pot of   
            water and slowly raising the temp and monitoring for operation at the   
            specified temp?  That would make sense...I think.  How about the 6V and the         IL6 and 8V71?
 
   2.  LOW OIL PRESSURE

                       Should be a "switch"...right?  Logically it could be tested by grounding but I           don't know that the sensor circuit  is the same on all DD.  I guess that the        system could be tested but how would you test the operation of the sender       itself?

Systems known to create a particularly obnoxious alarm and bright RED light. Or should create.

   3.  LOW OIL LEVEL

           I guess the operation of this device could be verified at the oil draining during 
          oil change or during the "fill" phase even more easily.  Is it NO or NC and how
          to test the system?  I don't think that this sensor/system should disable the 
          engine but I sure would like a "heads up" before I tackled the multi mile   
          Grapevine 6+% Grade or start into a multi hour sustained 70 MPH cruise.

   4.  LOW COOLANT

          I guess you could check this by just monitoring the alarm while draining the
                    appropriate amt. of coolant during the draw for the annual coolant chemical analysis.

   5.  OIL OVER FILL

          I have seen two things that kill an engine that registers as overfull crankcase.  One
                    is coolant leaking into the oil and the other is fuel leaks due to malfunctioning fuel hoses
                    in the head. While both of these conditions will lead to sudden death I think that an
                    alarm to get the driver pulled over for some serious checking is enough.

   6.  LOW VOLTAGE

          Batteries will be drawn down and there is a chance of electrical fire.  Alarm.

   7.  OVER VOLTAGE

         Batteries will be destroyed and everything else "electronical" may be trashed and 
         there is a chance of electrical fire. Alarm.

Anything else?  I don't know which engines have what safety systems but I think that we should all strive to "upgrade" all out engines to this minimum plus your suggestions.  What do you Pro's think?

Then there are the same issues with the generator......

Thanks,

John



           

      

[BG6]

            I have seen pics that showed "two" sensors on the 8V92.  One on each head 
            and both were ganged and either would shut off fuel. 

I don't want ANYTHING that will automatically shut off the engine.  I can think of times that I would happily sacrifice the engine to get an extra couple of miles before the thing melts down.

[John316]

I don't want ANYTHING that will automatically shut off the engine.  I can think of times that I would happily sacrifice the engine to get an extra couple of miles before the thing melts down.
[/quote]

On the contrary, I want the engine to shut down if there is a fatal problem. We have an override switch on ours. If we are in traffic and it shuts down, punch the button and drive off the road, and then melt down . I do want it to shut down if I am in the country driving with no other traffic around. Then I can correct the problem, and not cost me lots of $$$.

JMHO...

God bless,

John

[buswarrior]

I want good alarms, and then I will decide when to shut off the engine.

Along with good alarms comes good gauges. Alarms draw one's attention to the gauges to ascertain the problem.

Until you've had auto shutdown, at speed, on a busy stretch of road, with no shoulders, be careful what you wish for.

Never mind a false shut-down due to system failure...

Auto shut down is for fleet owners who have hired hands driving that cannot be trusted to do the right thing when an alarm goes off.

A busnut certainly will do the right thing and pull over and shut it down promptly.

It's my money, my coach, and my engine. I will decide at what point it is turned off.

It won't change the outcome for the engine, some seconds one way or the other. Running it another 20 seconds hot won't change anything.

However, it sure will make a difference in the stress level of choosing a parking spot!

happy coaching!
buswarrior

[JohnEd]

John and Warrior,

Now we are talking.  I did not have "emergency bypass" in my list of system components to be tested.  That's an input I needed.  I agree with Warrior except I want to have to initiate the bypass or alarm override manually.  Otherwise I want it to shut itself off....period.  I mean you cannot leave the thing in bypass but need to toggle a momentary contact switch to initiate.  I am with you Warrior, if it burns up I want to be there, in charge and fully informed when the heads crack or the rod comes out to play.  Otherwise, I want it to care for itself and do the prudent thing.

Do all versions of the 8V92 have the same over temp switches in each head?

I know there is a temp sender in one head and from DD's use of "two" overtemp switches I assume that we can get an overtemp condition in one head and have the other within spec.  Is there a port for the second sender in both heads?

I don't have any access to books or engines that I can use for this research.  I hope some of you have the data at arms length and can contribute.  I will consolidate the result and post it for all.

Thanks,

John

[Busted Knuckle]

JohnEd,
All Detroit heads should have a "port" to put shut down stat's in them! I have never seen one yet that didn't!
By the way they come in different temp settings!  FWIW   BK 

Oh marine heads might not have them, but when ya gotta a lake, river, or ocean for a radiator who needs to worry! LOL!

[TomC]

I have a very piercing alarm that covers high water temp, low oil pressure, low water level, low air pressure-but only makes the alarm and allows me to decide when to shut off the engine or pull over, etc.  Having the engine shut off automatically can be down right dangerous in certain circumstances-like on a mountain road, etc.  I had my oil filter mount break off, which gave me zero oil pressure suddenly, the alarm went off, and luckily I was able to immediately pull off the road and shut off the engine.  I want to make that decision, and not some automatic shut down device-you just know that sometime it will shut you down prematurely stranding you somewhere possibly causing a multi-hundred dollar tow bill.  Give me that none electronic engine every time.  Good Luck, TomC

[Chopper Scott]

My 8v 71 has overtemp shutdowns in each head plus manual temp gauges for each side in the rear. However.... the gauge to the dash is only coming off the left head. As each side has it's own thermostat I am thinking that a failure on one side could lead to a meltdown on one side with the dash gauge showing no problems on the other. I had the bus shutting down and showing an overtemp warning at some inopportune times and I pushed on the start button to over ride the shutdown. If the fuel pressure sender is working correctly the starter will not engage. I checked the rear manual heat gauges and they were under 200 degrees and the dash gauge showed maybe 180. After dealing with this on almost every hill I came to I found the offending shutdown sender and disconnected it. Problem solved for awhile until it did it again. This time I disconnected the second sending unit and had no more problems. I am going to replace both senders (they are not the originals that could be adjusted) and also check out the dash temp as it is 20 degrees cooler than the 2 rear manual gauges. Maybe somone more knowledgeable could tell us the max temp we want these engines to run before damage could result. I'm thinking the 71's and 92's are different as far as max temps. Thanks

[BG6]

I don't want ANYTHING that will automatically shut off the engine.  I can think of times that I would happily sacrifice the engine to get an extra couple of miles before the thing melts down.

On the contrary, I want the engine to shut down if there is a fatal problem. We have an override switch on ours. If we are in traffic and it shuts down, punch the button and drive off the road, and then melt down .
[/quote]

Think about this.  If you have an overheat issue, and the engine shuts down, you probably aren't going to get it to start again.  If the engine is still running, you can make the decision for yourself.

Imagine being in an evacuation -- lots of traffic creeping along, engine temps going up -- and your engine hits the Magic Degree and dies.  Not only have you sunk yourself, but you're blocking everyone behind you.  If you can get that extra few minutes running, you can get to a turnout.   If you think this is farfetched, let me note that a lot of evacuations take place in places popular with RVs, such as forests (fire), deserts (flash flooding), etc. 

When an engine shuts down while overheated, cooling water stops, so all of the hot stuff just expands, which can make history of the engine.  If the engine is going, you may be able to idle the temps down and save it.

So, the way I see it, one way or the other, your engine is history.  I would rather have the choice to go until meltdown.

[JohnEd]

Tom,

I think the best solution is to have it shut down automatically IF you don't intervene within maybe 20 seconds.  I envision starting the bus to have air pressure build and oil warm and going back into the house to get "another load".  You come out and there is an alarm and a red light and an undamaged engine....just an odd shot.  It provides options and flexibility and costs next to nothing.  Does violate the KISS rule, however.

Great story about the filter taking ALL the oil pressure with it.

I agree that a shutdown might create a dangerous situation on the road but roads ARE dangerous by their nature.  If I were to push on in spite of a warning that I would be destroying my engine, I would look forward to all those that I had spared an inconvenience to chip in for my new engine, right?  After all!  The cause of the dangerous situation is roads without mediums and shoulders with enuf room to safely pull "any" vehicle of the roadway.  Imagine the snarling traffic jam that would result from a bus being broken down on a busy city street at rush hour?  Oh, well!  Make that "call the wrecker" or "call the wrecker and DD for a rebuilt".  Pick one scenario. I am not going to kill people to avoid an expense I have exposed myself to, I would eat the expense first.  I am with you on that.

Isn't it true that the stock DD over temp shutdown has no bypass?

Thanks for your input and I hope for many more posts,

John

[compedgemarine]

on my Eagle the shutdown system will turn on a light on the dash and activate the timer. my timer is 2 minutes. if you can not get off the road in the 2 min it takes before it shuts down then you can turn the key off a second and back on and it will reset the timer. I figure at that point the light on the dash has been on for 2 min and if I cant or dont do something in that time it needs to protect itself some how.
steve

[gyrocrasher]

on my Eagle the shutdown system will turn on a light on the dash and activate the timer. my timer is 2 minutes. if you can not get off the road in the 2 min it takes before it shuts down then you can turn the key off a second and back on and it will reset the timer. I figure at that point the light on the dash has been on for 2 min and if I cant or dont do something in that time it needs to protect itself some how.
steve

Wow. IMHO 2 minutes is a looonng long time for an engine in crisis. Mitch

[pvcces]

JohnEd, I believe that I saw the optional engine shutdown time delay relay in our service manual had a 45 second delay.

My choice would be just the alarm with no automatic shutdown.

Tom Caffrey