Alarmstat Good or Bad?

[bcaddel]

I had a couple of instances last summer when our MCI 7 got up over the 210 engine temperature mark. We pulled over and turned the misters on the radiators and once we would top the hill we turned them off and all was well. I checked the heads with an IR gun and it indicated we were around the 210 temp so I assume the temp gauge is fairly accurate.

We have an Alarmstat on both heads and when I take the lead off of either sensor and touch it to a ground it kills the engine and the hot engine light comes on. Does this mean the actual Alarmstat is bad since it didn't shut down while we were driving and hitting that temp?, Is there a way to test at what temp the Alarmstat activates. I was thinking about pulling them out and putting them in the oven at 210 degrees and checking continuity to see if they worked. Is there a better way to test them?

I also see they come in 210 and 220 degrees when buying new ones, which one do you recommend. Last but not least is there a way to eliminate the "shutting down of the engine" and just having the warning light?

Thanks
Bob

[Chopper Scott]

One thing to consider also is that you can push the start button which bypasses the engine kill feature and at least move the bus to a safer spot. There is a fuel pressure switch that shuts down the starter when the engine is running when you push the button. It serves 2 purposes in not allowing you to engage the starter once it is running and also to allow you to bypass the shutdown.

[bcaddel]

I was not aware of that feature, do you have to hold down the start button or when you push it or does it activate the non shut down feature for a set amount of time?

Thanks for info
Bob

[buswarrior]

push and hold the starter button in.

Most have a strong spring and will turn your finger blue in a hurry.

You MUST ensure that the fuel pressure switch is present and working, in order to keep the starter from engaging. It is popular to just bypass them if suspected failed, in the hands of the unknowing.

If being driven by the bill payer and chief financing officer, I am supportive of disabling the auto shut down. When the hot engine light and alarm goes off, I want to choose where to pull over, with power available to do so.

happy coaching!
buswarrior

[JackConrad]

When we re-wired our coach, we kept the visual & audible hot engine warnings (as well as low oil), but eliminated the auto shutdown.  We installed 210* alarmstats.  Just our way, YMMV  Jack

[JohnEd]

REPLACE that alarm stat.  No brain-er!

Now here is the rub:  before you install a device that is so critical to your escaping a $20K "out of frame", FULL, overhaul....verify the function and calibration.  The "oven method" will not work.  You need to submerge the device in a pot of water and raise the temp slowly to 210F with a VOM connected to the device.  With the VOM set for "buzzer" you can even take your eyes off the meter.  This should be an "annual PM" and at least the grounding to verify the alarm and light circuits are operating is an absolute min.

I would have an alarm stat and temp sender and meter on each head.  We do have two thermostats and that is the high failure item and each can be a single point of catastrophic failure.  Cheap insurance, no?

This is an event: first time I have even come close to not agreeing with BW completely.  I would stop in the middle of a busy city street and back up traffic from Portland, Or. to Chula Vista, Ca.  rather that take a $20K hit and spare all of them the inconvenience.  And if I am one that is in that jam I will understand your decision.   Maybe for a moment but the top of the hill is out of the question.  I burned up a Cressida's engine doing exactly that same thing, so don't think I was always smart.  Not a single motorest that I spared the inconvenience stopped to give me $10 or$20 bucks out of appreciation....nary a one.

John the jaded

[bcaddel]

AlarmStats (210) are on order, and will be here Tuesday in time to get them installed prior to Fishing Trip to California Delta.
Thanks for the input!
Bob

[kyle4501]

I would stop in the middle of a busy city street and back up traffic from Portland, Or. to Chula Vista, Ca.  rather that take a $20K hit . . . .

If you get rear ended by a loaded semi, it's gonna be a lot more than a $20K hit - especially if someone gets hurt. . . .

I vote with BW, I'd rather have the choice. False shutdowns aren't much fun either . . . .

[luvrbus]

I am not a fan of a shutdown a light and a buzzer works for me when the shutdown does shut a DD down most of the time it will not save your engine as the temperature will rise way above 210 when the engine shuts downs


good luck

[bcaddel]

What do I need to do to disable the shut down feature and keep the warning light/buzzer?

[JohnEd]

Kyle,

There are more than a single certainty if you are rear ended by a SEMI......at any speed you might select for the rear endee from dead stop to 80+mph.  Be it you are riding a motorcycle or in a Pre.  Damage WILL exceed $20K and someone WILL get hurt.  Plan on those dismal eventualities and you can't go wrong.  Regardless of whether the weather(   )  is clear and visibility is a couple miles or whether it is zero feet total white out pea soup fog  AND the road surface is anything from dry to sheet ice under snow pack......you are required to be able to  stop your motorcycle/semi safely at all times.  "I didn't have time to see the school bus/ambulance/Prevost" is not an adequate excuse....ever.   If you are moving you are admitting that you are in control. On the other hand and possibly moire at the point is "$#!% happens".  I would never stop on a roadway or even on the shoulder if I had an alternative that didn't put me and mine at risk.  I am not going to spend $20K so any can spurn common safety considerations and the law.

Since reaching 65 I have noticed that I have lost all my "cat like" reflexes and have lived more within the laws of road and physics.   Not setting myself up as better or anything.

I know this sounds harsh and I do not intend that tone. Truly, I don't.  It is only due to my lack of writing skills.  I don't think you intended all the possible interpretations of your post, either.  

John in defense

[James77MCI8]

Since my 8 is a stick, the over ride is wired through the step light switch.

[kyle4501]

John,
Possible interpretations? WTH?
It is simply the fact that I want to decide when the engine shuts down - NOT some sensor.

Giving up that control to save $20k brings a risk of getting rearended if you are stopped in a travel lane. Personally, I'd prefer to risk the engine before inviting a collision or personal injury - regardless of who is at fault.
(Edited to add) The thought that you are spending $20k so others "can spurn common safety considerations and the law" is missing the point that we should all do what we can to avoid creating hazardous conditions. Maybe you should reconsider the whole engine protection system & change it so that it gives the driver more time to do something. It is my opinion that if the engine NEEDS to be stopped immediately as a result of an alarmstat, damage has already been done & letting it run a little longer won't have much impact on the engine repair bill & can save lots more $$$ by minimizing other costs.
(I ain't suggesting driving to the next reputable garage for repairs - but rather to get to the closest place that minimizes the hazard to ALL.)
BTW, there are laws concerning creating a hazardous condition, so you may be more liable for the semi rear ending your brokendown bus than you would like.

The traveled portion of the roadway is for travel - not emergency parking. If more people were considerate of others using the road, driving would be less stressfull. Just because one has a right to use the road, doesn't mean he should expect a safe parking spot in the middle of it.  

[JohnEd]

Guys,

GAG,,,,get a grip!

REPLACE that alarm stat.  No brain-er!

Now here is the rub:  before you install a device that is so critical to your escaping a $20K "out of frame", FULL, overhaul....verify the function and calibration.  The "oven method" will not work.  You need to submerge the device in a pot of water and raise the temp slowly to 210F with a VOM connected to the device.  With the VOM set for "buzzer" you can even take your eyes off the meter.  This should be an "annual PM" and at least the grounding to verify the alarm and light circuits are operating.

I would have an alarm stat and temp sender and meter on each head.  We do have two thermostats and that is the high failure item and each can be a single point of catastrophic failure.  Cheap insurance, no?

This is an event: first time I have even come close to not agreeing with BW completely.  I would stop in the middle of a busy city street and back up traffic from Portland, Or. to Chula Vista, Ca.  rather that take a $20K hit and spare all of them the inconvenience.  And if I am one that is in that jam I will understand your decision.   Maybe run for a moment but the top of the hill is out of the question.  I burned up a Cressida's engine doing exactly that same thing, so don't think I was always smart.  Not a single motorest that I spared the inconvenience stopped to give me $10 or$20 bucks out of appreciation....nary a one.


Does this make me sound like selfish uncaring oaf that would murder women and children for the sake of a few bucks?  I do stand by my point that I would back up traffic from Canada to Mex to avoid a $25K wallet hit.  But I think I said something about a "city street".   If what you say is true then there would never be a breakdown on a paved surface....anywhere.  Have you ever driven the Long Island Expressway? 80 MPH in rush hour traffic, two lanes, no shoulders, concrete divide and a 4 foot concrete wall on the outside.   It is like driving in a mill sluice.  Once a week, or more, people stop on that roadway to change a flat tire on a car.  The traffic is backed up 30 miles(?)  I drove on a flat down that Expressway and was on the rim long before I got to an off ramp.  Budget Rental guy was miffed when he saw it and suggested that next time I park or call a wrecker.  Seeing as I was parked on the extended off ramp he had to know where I had the flat and besides, I made that clear.  He was so upset that I felt obligated to add to his burden and I refused to drive the car until it had been inspected by a mechanic.  I suggested we trade cars and he categorically refused because of paperwork and liability.  He turned so purple I thought he was going to go blind when he got in his car and couldn't find the ignition keys and then noticed me standing in front of his hood holding out his keys and shaking my head "NO!".  When he got his breath back he called for another car to be delivered with the new paperwork.  We didn't chat while we waited for it to arrive.

Now, back to the auto shut down and bus talk instead of bus road safety.  I have only heard of the safety system on a Prevost.  It was described as giving a warning and then NOT shutting down the engine for 20 or 30 seconds due to a time delay circuit.  Whatever, there was a delay.  On top of that there was an override so you could ride it to destruction if need be.  That was for the over temp and the low oil pressure shutdown worked the same way and probably fed the same fuel disable circuit.  I couldn't agree more with those of you that say you want to be able to decide if it is safe and when before you allow your engine to shut down.  I also heard it said that the auto disable should be left active in the remote chance that Wifey or some "helper" is driving you bus and, well, "just didn't understand what that buzzer and light really meant".  ARGHHH!!!!  And you know they would only be driving in the first place because you had had a heart attack.

Now BOTN and Cliffford have Pre books.  Be nice if "some one" posted a copy of the delayed auto shutdown circuit with the emergency over ride.  And if that was a lie I was told, maybe Sean could gin one up for us.  I like stock with parts support and documentation if at all possible.  My preference.  But "any way is OK if need be".

Think higher of me Kyle...I have earned it.

John

[Rick 74 MC-8]

Why not have the best of both a 210 that sets off the lites and buzzers and a 220 that shuts it down

                                                                                   Rick 74 MC-8