Ford 6600 Gauges

[crankit]

I've got a late model Ford 6600(Australian) that my grandparents bought new in 1979.

The original gauge cluster was stuffed, water damaged and all the wires eaten by rats. Looking online all the 6600 gauges I found had the older style bimetallic gauges. The exact match to what was originally in the tractor appeared to be the early 6610 gauge set which I tracked down and bought. The original and the new guages both appear to have magnetic gauges. I wasn't keen on the completely different looking aftermarket gauges.

The problem I'm having is this gauge set reads the temperature just on the red zone when at operating temp and 1/4 cold when cold. I've checked with an infrared thermometer and most locations on the engine are near 182 farenheit when working. I also remember the original gauge worked correctly when I was a teenager years ago.

I then tried to buy a new sender but for a 6610 as i'm assuming earlier 6600 are bimetalic and different resistance. New sender has the gauge just touching red when engine is cold.
Measuring resistance I get
Original sender = 205 ohms at 180 fahrenheit and 870ohms at room temp.
New sender = 110 ohms at 180 fahrenheit and 202 ohms room temp


The old and new temp sensor.

Which wire goes to which terminal on the gauge? Perhaps i've screwed up the wiring???

What is this? - This was connected to the old gauge set inline what I'm guessing is the power terminal.

 

[Sean in PA]

I'm not familiar with the wiring on that model,, but i can at least help with that last picture and question. It is a diode, which only allows current to flow in one direction. I assume that it was installed to protect the instrument cluster in case someone hooked something up backwards, but I'm not sure if it came from the factory with that on there or if it was added by someone later.

 

[Bern]

Ford switched from bi-metal to magnetic gauges in June 1979, so your tractor originally may have had either from the factory
depending on the exact build date. The sending units are different between the two styles of gauges.

Ford was not much for specs back in the day for this kind of stuff, however I did track down a bulletin that says 100 ohms
should make the magnetic gauges read half-way for both temp and fuel, grounding them should make it read full right, and
open circuit full left. So, if we assume that 180 degrees operating temp should give you a mid-scale reading, then it sounds
like your temp sensor is correct.

Look carefully on the back of the cluster, there should be a S terminal molded into the back of the case for each gauge.
This is where your sender wire should be attached. Also, remove the rectangular resistor block from the back of the fuel
gauge. This is only used on 10 series tractors with dual tanks.

 

[sotxbill]

I believe the diode... was used to make the restricted air filter light come on,,, anytime the oil pressure light came on... So that when you first turn on the ignition, all three check lights came on, till you started the motor. This feature was added when they went to the paper air filter over the oil bath.

 

[M-MAN]

You could make up a little pigtail
with a variable resistor and put it
inline between the sending unit
wire and the gauge. Once you get
the reading correct glue the knob
in place. Variable resistors are
fairly cheap and reliable.

I would use the old sender as it's
not that far off.

 

[crankit]

(quoted from post at 07:30:34 08/12/23) I believe the diode... was used to make the restricted air filter light come on,,, anytime the oil pressure light came on... So that when you first turn on the ignition, all three check lights came on, till you started the motor. This feature was added when they went to the paper air filter over the oil bath.

Ok that might explain why there is an extra wire on one of the lights with a female spade terminal. This must go across with the diode to the air filter light perhaps.

Still not sure about the resistance of the new sender. If the replacement sender showing 100ohms for mid range on the temp gauge is the correct value, My gauge is off the dial at operating temperature with this new sender. It's like the gauge wants about 300ohms to show mid range. 200 Ohms is just touching the red zone. 200 ohms is about where the old sender had the gauge touching the red zone when operating.

I"m getting full battery voltage to the top left terminal. Can't understand whats going on here. Almost makes me wanto put a resister onto the new sender to get the value right on the gauge.

I'm not sure if this helps but serial number for my tractor is.

Prefix = 6BCO
Serial number = B361406
Engine Number = E428986
Clutch housing stamp RH side = 9J03b
Date stamp on transmission housing = 10-9-79

Made in England, assembled in Australia.

 

[Sean in PA]

9J03b is an assembly date of September 3, 1979, during the day shift.

B361406 is a serial number from the assembly plant in Basildon, in the UK. That "Assembled in Australia" bit was probably a final reassembly. I think that after it was built in England it was partially disassembled for shipping to AU, and the reassembled down under. It might have been partially disassembled to avoid tariffs, or to simply make it easier to pack them more tightly on the ship to lower the shipping cost, or both.

I know that Japanese motorcycles back in the late '70's and early '80's were shipped to the US partially disassembled, and the final assembly was done at the dealerships. That was to avoid an import tariff on foreign made motorcycles that had been put in place to give Harley Davidson a fighting chance against the low priced imports.

 

[1955]

That's a very nice tractor!

I have to do some diagnosing on my 3000 which has the same style cluster. The tach and proof meter work but my fuel gauge is at full and temp is at full cold.

 

[crankit]

(quoted from post at 08:11:35 08/12/23) 9J03b is an assembly date of September 3, 1979, during the day shift.

B361406 is a serial number from the assembly plant in Basildon, in the UK. That "Assembled in Australia" bit was probably a final reassembly. I think that after it was built in England it was partially disassembled for shipping to AU, and the reassembled down under. It might have been partially disassembled to avoid tariffs, or to simply make it easier to pack them more tightly on the ship to lower the shipping cost, or both.

I know that Japanese motorcycles back in the late '70's and early '80's were shipped to the US partially disassembled, and the final assembly was done at the dealerships. That was to avoid an import tariff on foreign made motorcycles that had been put in place to give Harley Davidson a fighting chance against the low priced imports.

Sounds right Sean, The cast wheels, Rops frame, guards and fiberglass top all seem to be unique to Australia and would have been manufactured here. What came from England must have just been the assembled frame/transmission/engine.

I was guessing 1979. Earliest picture I have of the tractor in the family is from 1980 so grandparents may have purchased it in 1980.

I notice the same thing with the Aussie Massey Ferguson 100 series with their unique to Australia cast wheels.

This post was edited by crankit on 08/12/2023 at 08:30 am.