Tension on fan belt and overheating of vehicle

[mrcvs]

My 1917 Maxwell threw a blade a few years ago, and it took some time to locate a new fan blade.  I did not have the required 1 1/4" wrench, which was purchased for replacement of the fan blade; of course, had I had this, I could have removed the old blade then and note that there are several round holes into which the blade can be adjusted, so that it can ride lower.  I was using a leather fan belt, with considerable tension, to keep the fan blade from hitting the radiator intake, and the blade has a metal band around it, so it did not prove disastrous, but, over time, the fan belt would stretch and the fan blade would ride against the radiator intake.  With the replacement blade, and realizing this was adjustable, I set the blade lower, and am actually using a bungee cord to provide more tension.  However, the belt is still fairly loose, but all three pulleys, including the one that runs the water pump, do rotate, but maybe this is not enough tension to cause the water pump to circulate to the extent it should.  The car did not overheat prior to the replacement of the blade, but now it does.  I have sent the leather belt to be shortened by 3", and, of course, when it comes back, if the car does not overheat, this was obviously the problem.  In the meantime, is my thought process correct and/or does anything else come to mind?

[Rusty_OToole]

You say there is a series of bolt holes to adjust the belt tension, is there any other adjustment? The rule for generator equipped cars was, you should be able to deflect the belt 3/4" with moderate thumb pressure in the middle of its run.

 

Alternator belts can be tighter because alternators use roller bearings.

[cahartley]

Throw the leather belt away and get one of those >>> http://www.vbeltsupply.com/360j12-serpentine-belt.html?gclid=CKGKvvWD0McCFQqSaQodSbEKzQ

The outside length on the 360 is slightly over 36" and the J12 width is 1 1/8".

They are available in nearly any length you want, they will NEVER stretch or shrink and will last longer than you will.

Run the vee'd side down, it does not require a lot of tension to "get a grip" and if the numbering on the back of the belt bothers you black it out with a felt tip.

[hchris]

Interesting, unless its been modified the Maxwell engine would not have had a water pump, it relied on the thermos siphon principle to circulate the water.

[mrcvs]

Interesting, unless its been modified the Maxwell engine would not have had a water pump, it relied on the thermos siphon principle to circulate the water.

The engine has not been modified at all.  How does the thermos siphon principle work?  I have a 1918 Dyke's automotive manual and that's where I came up with why it might be overheating, plus what is different now vs before.

 

Any other ideas as to what to do?

[hchris]

Thermo siphon is a bit like boiling a kettle, hot water rises, passes through the radiator, cools off, and then cooler water falls to the bottom of the radiator to be recirculated; so the actual cooling process simply relies on the laws of physics and thermal water behaviour, this was the main means of cooling for many manufacturers prior to the introduction of belt driven water pumps.

 

If you still have the original engine installed, then your problem lies with the radiator itself, possibly being blocked; similarly the engine block itself could be partially restricting water flow due to an accumulation of rust and scale, or your fan may not be turning fast enough to provide sufficient airflow through the radiator.

 

Generally speaking most engines will cope without the fan if you can maintain a decent road speed and force a draft through the radiator, the problem is that once you slow down in traffic this draft needs to be substituted by the fan.

 

As to what is different to before, perhaps you have simply got the engine hot enough to shift some of the rust/scale and block things up, perhaps a good flush out of block and radiator may help.

 

Having said all this I am still confused about the "pulley that turns the water pump" my Maxwell has only two pulleys, the drive pulley off the crankshaft and generator pulley, if yours is different to this perhaps a picture might help?

[mrcvs]

Sorry for the confusion. Third point of rotation is the fan blade itself. Radiator should be okay as it was flushed when it was repaired after being punctured by the fan blade.

[Rusty_OToole]

As Hchris says, thermosyphon cooling works because hot water rises, out of the engine, into the radiator, where it cools and sinks to the bottom, then goes into the engine again.

 

For this to work you must have large unobstructed coolant passages in engine and radiator, and oversize rad hoses. You also need a significant temp difference between engine and rad. If you park long enough with the engine running it will overheat, at least in a Model T which had a rather small fan.

[mrcvs]

Oh, that might just explain it all, then!  It is overheating in the time from when I park it, turn off the gas, and wait for the remaining gas to burn, which kills the engine.  It has not overheated when driving it.

 

What damage, if any, permanent or otherwise, could this cause?  It hasn't overflowed significant amounts, but you hear it bubbling once it stops running, you see some steam, and some overflow comes out the overflow tube.

[cahartley]

Having read your updated information I don't think it's "over" heating at all.

It's not at all unusual for water to "cook" a bit after shutting down in a thermobarf system.

Don't fiddle around trying to keep the radiator "filled" either.

The coolant will find its happy level when it's done puking out expanded coolant.

In a Model T the happy level is about 1" over the core.......any more than that and they will puke it out.

[mrcvs]

Having read your updated information I don't think it's "over" heating at all.

It's not at all unusual for water to "cook" a bit after shutting down in a thermobarf system.

Don't fiddle around trying to keep the radiator "filled" either.

The coolant will find its happy level when it's done puking out expanded coolant.

In a Model T the happy level is about 1" over the core.......any more than that and they will puke it out.

Interesting...I noticed when I got this car back in 2011, the coolant level was 'low', and filled to the top.  It did indeed 'puke' out excess coolant and found its happy level.  I thought it was just a quirk of my particular car.

[Larry Schramm]

Throw the leather belt away and get one of those >>> http://www.vbeltsupply.com/360j12-serpentine-belt.html?gclid=CKGKvvWD0McCFQqSaQodSbEKzQ

The outside length on the 360 is slightly over 36" and the J12 width is 1 1/8".

They are available in nearly any length you want, they will NEVER stretch or shrink and will last longer than you will.

Run the vee'd side down, it does not require a lot of tension to "get a grip" and if the numbering on the back of the belt bothers you black it out with a felt tip.

 

I agree.  I run a serpentine belt on my truck. 

 

One time adjustment and no worries about a broken or stretched leather belt. 

 

That is because I drive the truck as much as I can and do not want to be stranded.

[ak]

On 8/30/2015 at 1:17 AM, cahartley said:

Throw the leather belt away and get one of those >>> http://www.vbeltsupply.com/360j12-serpentine-belt.html?gclid=CKGKvvWD0McCFQqSaQodSbEKzQ

The outside length on the 360 is slightly over 36" and the J12 width is 1 1/8".

They are available in nearly any length you want, they will NEVER stretch or shrink and will last longer than you will.

Run the vee'd side down, it does not require a lot of tension to "get a grip" and if the numbering on the back of the belt bothers you black it out with a felt tip.

If your car is fitted with flat pulley (not a pulley with v shaped sheaves) and a fiber timing gear, then the serpentine belt will eat the timing gear teeth down to nubs in no time.  A flat leather belt slips when the tension becomes greater than the gear can take. 

 

[Akstraw]

Jut as few thoughts:

 

For a cooling issue, I would start with a cooling system flush.   Then I would inspect the water pump to ensure it is working properly; smooth bearing action and impeller not rotted away.  

 

Curious to know whether this engine was originally a thermo-syphon, or did it actually come with a water pump?  Is the water pump an aftermarket add?  If so, you may be better without it.

 

I would think that if you have to apply "considerable tension" to any fan belt, then something is wrong elsewhere.   Too much tension can cause excessive wear on bearings, and perhaps even, as mentioned, gear wear.