Mack "B" Model Question

[bulldogboy]

A question was asked on another FB page, "Did the grill louvers on "B" models open and close due to the temperature?" We had five gas "B" models in our fire department and none had movable louvers. Were they available on the larger "B" models or diesels?

[mechohaulic]

the shutters operated based on engine temp. never noticed but the fire trucks MAY HAVE  eliminated the shutters to maintain cooler eng temps. for the most a fire truck spends engine time stationary ;goes up down the  road but at a fire it's sits. there are a number of VERY knowledgeable fire truck personal on this site. many of which will prove my thoughts incorrect.

[theakerstwo]

the last year b models was built some did not have shutters.I have seen one .

[yarnall]

I believe that none of the gas jobs had functional shutters, but I am not certain. 

[mowerman]

Operating temperature that’s all I got Mechohaulic very much explains it … The older ones used to run too cold most of the time… bob

[terry]

I've had several gas and diesel B models, only seen one gasser working shutters.    terry

[Freightrain]

A gaspot will make heat no matter what.  Only a diesel needs to work to get "hot".  I suppose if it was going to a cold climate they might want shutters?

[Big R]

Our ‘57 b-42 gas job has shutters

[mowerman]

That’s interesting because the next thing I was going to add was I am almost certain They only use them for the diesels thanks for your input now they just use an air operated fan… bob

[HarryS]

My B-61 (diesel) was sold new in Atlanta. It has shutters and no thermostat. It runs mostly with shutters closed except really hot weather.

[mowerman]

 maybe that’s probably the way most of them ran . You would think especially back then they will be doing everything to cool them off I’ve had two Max with the shutters seems like what I remember they really don’t open a whole lot like you said.., .Bob

[Freightrain]

I'm not sure if my 237 has a thermostat?  Don't think my 673 did either.   I ran them hard enough that the shutters were open most times.  Only time they did close was on long downgrades.  You could tell they closed due to the increased fan noise.  It's not hard to keep the engine over 160* most days.

[theakerstwo]

Larry if that was a 237 then it should have a thermostatI Alot of the END 673 engins in the later 50s did not but did use a 170 degree shutterstat.The also did not have a oil cooler on some of them.

[mowerman]

I am not sure my 62 Model I believe it has shutters and the thermostat but I can’t remember it was too long ago.. bob

[mowerman]

OK now I remember it was a 180 Thermadyne for sure had a thermostat and shutters I remember now because the thermostat looked like a flying saucer… bob

[Freightrain]

19 hours ago, theakerstwo said:

Larry if that was a 237 then it should have a thermostatI Alot of the END 673 engins in the later 50s did not but did use a 170 degree shutterstat.The also did not have a oil cooler on some of them.

My 673 did not have an oil cooler.  My chassis is newer but not sure if the engine was original to it?

The 237 came from a fire engine, not sure if that matters.  I never looked in the housing to see if there is a thermostat.

[theakerstwo]

The thermostat housing comes apart and has three bolts in it.

[MorrisMe]

Just picked up a B-21 Gas fire truck and it has the shutters, they are plumed into the cooling system, but I have not started the truck yet or check the function.   It does look like the would work based on temp.

[Freightrain]

8 hours ago, MorrisMe said:

Just picked up a B-21 Gas fire truck and it has the shutters, they are plumed into the cooling system, but I have not started the truck yet or check the function.   It does look like the would work based on temp.

You can just put air in the system and they should close when the engine is cold.

[mechohaulic]

front shutters almost always worked off engine temp' that was the purpose of the shutterstat mounted in coolant system. eng temp opened and closed the air to the front  shutters. took air to close the shutters. in the event a problem arose  there was a brass shut off valve mounted on fire wall  #4 aeroquipt line going to shutterstat which could be closed taking air away from front shutters keeping them open.

[Freightrain]

Whatever you do, make sure the airlines are hooked on the correct side of shutterstat.  Ask me why!

If backwards, once the shutters close the valve will be stuck shut and won't open the shutters until you drop the air off from the feed line.  The truck will tend to overheat.....duh!   When I put my old shutterstat in the 237 it turned another 1/2 turn and I just screwed the lines on and didn't notice the "inlet" marking.  Doh.

[mechohaulic]

your not alone.  think that's why the shutterstats are stamped ;; inlet: who pays  (paid) attention . 

[Freightrain]

I forgot my wallet that day and couldn't afford to pay attention......LOL.

[mattb73lt]

My B42 had fixed (non-operating) shutters when I got it, having a EN402 installed from the factory. From what I've seen, I believe they were an option on smaller gas jobs. I put them in, from a donor, when I converted it to diesel. The diesel engined B's all seem to have them, except the very late production ones the had that fixed grill. Fire trucks are a whole different animal. I would think they would've had shutters as they were built to operate statically for long periods while pumping. The shutters would help keep the engine at operating temps while in extreme cold conditions.