8N Runs Hot

DieselPro

New User
New guy here.. Helping a friend.. Got a fresh 8N rebuild with a lot of new parts. New radiator, new water pump, timing set to specs, no thermostat. & just enough water to cover the radiator core. Problem >in 2-5 minutes steam will start coming out the radiator. Water does not appear to be flowing through the radiator. Put old water pump back on and still the same. You can apply just a little water pressure to the pump inlet with a water hose and the thing runs quite cool with water coming out the core just fine..All the gaskets align with the ports.. Got any ideas?
 
or without the thermostat the water is traveling to fast through the radiator its not have enough time in the radiator to cool down
try putting the thermostat back in
 

Problem is there seems to be no water flowing... I don't understand why it's not pushing the water through. All new hoses everything open. Odd thing is the water hose pushes the water through with no problems.

As a side note we have never seen this tractor before and no history on it as the previous owner has passed away. Really need to figure this out as the whole tractor has been restored but it won't run over 5 minutes idling.
 
Collapsed hose on the inside? Plugged new radiator? Air locked,try anti freeze
instead of water?
 

Same thing I thought. I went behind my friends work and checked that stuff out. I pulled the pump, water hoses, ran water through the radiator, checked timing,checked for bubbles in the water. I even pulled the water pumps apart. I am going to try some other stuff but I thought maybe someone on this site may have had a similar problem. This one seems special.
 
" without the thermostat the water is traveling to fast through the radiator its not have enough time in the radiator to cool down "

No it's not.

It might travel faster, but the effect is the same.

If it removes 10* of heat every minute w/ a t-stat and 5* every 30 seconds w/o one, the end result is the same. Faster moving coolant transfers less heat per trip but makes more trips per unit time so "cooling" is the same.
75 Tips
 
You need to determine the temperature of the coolant in the radiator from top to bottom with a non contact thermometer. The difference in coolant temperature from top to bottom should be approximately 25 degrees. Sweep the entire radiator. I wouldn't mind 225 at the top and 200 at the bottom. The thermostat needs to be in the system.
 
Good. You have the math to back up my statement! ;)

I was a history major; give me a simple, verbal explanation and I'll get it. You won't get far w/ me proving your answer w/ math!

Ohm's Law is the extent of my higher math.
75 Tips
 
The theory is always simplified and averaged so we can discuss it with reasonable intent. In actuality, entropy and other environmental factors can create changes in the system that are generally considered unmeasurable, so your statement is being considered in the simplified form assuming all external factors are equal in the system. Air temp is consistent, it doesn't start raining half way through the flow period, a leak in the system doesn't occur, etc. , etc.

BTW, i didn't really do that well in my electrical classes, even though they tried to equate it to mechanical systems....oh well. They've kept the N series electronics pretty simple.
 
Yea, I'm pretty current on the Kettering ignition system......first developed in 1911! ;)

At a cruise-in last year, I parked my 29 Ford next to a new Camaro, both cars with hoods up. We took turns pointing to stuff on the engines saying " WTF is that?" !

He showed me the coil-on-plug set up on his engine and I swear he didn't believe me when I said a Model T had the thing.
 
That's an old wives tale that simply isn't true. There are hundreds of old tractors that have had the T-stat removed and cooling system works just fine.
 

it also seems to me that the longer the water spends cooling in the radiator, the longer it spends heating up in the head.
 
(quoted from post at 15:57:30 08/25/20) Now that's funny. What goes around comes around!

Only problem is the coolant is not flowing like it should...

I am about to remachine the water pump to closer tolerances and perhaps increase the flow. Lot of clearance in the pump vanes and the housing.
 
The only time I ever had one of my 8n's ejecting steam from the radiator, the problem was the fan belt was a bit loose!.
 
(quoted from post at 17:57:17 08/25/20)
(quoted from post at 15:57:30 08/25/20) Now that's funny. What goes around comes around!

Only problem is the coolant is not flowing like it should...

I am about to remachine the water pump to closer tolerances and perhaps increase the flow. Lot of clearance in the pump vanes and the housing.

Have you checked to see if the impeller or pulley is slipping on the shaft?
trouttman
 

New pump and new belt and hoses... pump turns like it should I even checked rotation and if fan was on right. Took pump off and inspected. Clearances look sloppy but so does the original pump.
 
When you pull it back apart, check to make sure a mouse, chipmunk or red rag didn't make its way down the hose prior to assembly.
It really sounds like some sort of oddball blockage to me.
 

I actually did look for a rag stuffed in something... Odd thing is it runs quite cool with the water hose stuffed in the water pump. Quite sure it will be something unexpected. Keep the guesses going as I can't figure this one out.... It has all the symptoms of a water pump with the vanes gone... That's not it, but that's how I view it.
 
(quoted from post at 07:45:21 08/27/20)
Some years back it was reported some aftermarket pumps had the impeller of a reverse type...

https://forums.yesterdaystractors.com/viewtopic.php?t=1226586&highlight=impeller

https://forums.yesterdaystractors.com/viewtopic.php?t=377951&highlight=impeller
Both the old and new had the same curvature, even though it looks backwards it is the right one.... The clearances are very loose so I will be checking into that as soon as possible. I read on yesterdays tractor that the flow should increase noticeably when you rev it up..I'll check into that as well. Thanks for the link!
 
You have a serious blockage someplace or something else serious going on. Make sure all the rust and junk is out of the bottom of the cylinder block. Water has to exchange through the bottom passages up to the head and back to the radiator. These old things are very very tolerant of things like plugged up radiator cores and such. Even running straight water in it shouldn't cause an issue like this. So to have something like this happening this fast you have something WAY WRONG... Either have water sitting in the head (which is why it's steaming so fast) from the block being all gunked up or a cracked head/blown head gasket.
 

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