Help...wires on my 425 ripped by a stick

[Homebrew]

I was brush cutting in the woods, backed up and a large stick wedged up into the engine compartment and pulled apart some wires. The PT immediately stopped and I got nothing when I turned the key. After I got the stick removed, I saw that a connector had been pulled apart as well as a wire to the fan and perhaps another wire. Got the connector back together and it started and got it back to the garage. I know where the fan wire goes....I turned the key on and touched this wire to the connector and the fan started. THe problem is that it looks like there's an additional wire with a connector on it that I can't figure out where it goes. Maybe it goes to the taped wire in the picture. Anyone know if this wire is supposed to be connected to anything or is for diagnostic purposes? The picture shows arrows to the two wires in question (the one with a connector and one taped up). It sure doesn't look like the one with the connector pulled out of the one with the tape.

 

[MossRoad]

I have a few extra wires on my Kohler. Perhaps you have some on your Robin?

 

[Marks481]

On my PT 422, in the back right corner there is a wire bundle (with the fan connector, ignition switch ground wire?) , which also had an extra connector which is wired to the pressure switch on the engine. I suspect that it is the same on your engine. Check for continuity with ground with the engine stopped (should be zero resistance) and running (should be infinite).

Apparently the robin engine comes with a wiring harness, but the wire from the pressure sensor is not used by Power Trac. That spare connector is now wired to a Sonalert alarm buzzer, which should be a stock arrangement, IMHO.

 

[BobRip]

On my PT 422, in the back right corner there is a wire bundle (with the fan connector, ignition switch ground wire?) , which also had an extra connector which is wired to the pressure switch on the engine. I suspect that it is the same on your engine. Check for continuity with ground with the engine stopped (should be zero resistance) and running (should be infinite).

Apparently the robin engine comes with a wiring harness, but the wire from the pressure sensor is not used by Power Trac. That spare connector is now wired to a Sonalert alarm buzzer, which should be a stock arrangement, IMHO.

Tim, I did the same thing but also added a light. So at low oil pressure or engine stopped I get a Sona alert and a light on the dashboard. This wire was originally not connect on mine either. A 422 of course. You can trace this back to the engine mounted oil pressure sensor.

 

[Marks481]

Assuming you have the 25HP Robin engine, it probably has the same wiring arrangement. You can look in the service manual (pg 44) at Robin Suburu, which has the color coded wiring diagram. On my PT422, the oil pressure switch is a gray wire (Robin22 wiring diagram below).

Subaru Robin - Service and Support

I did the same thing as Bob... sonalert buzzer with a cut-out toggle switch and a warning light.

 

[TheBigHeadKid]

Tim

I'll have to agree... that should be standard equipment. Where did you get those gauges? What model ? ...etc

Is there a thread about your modification that I have missed?

The schematic you attached... I do not see where you tied in the Sonalert.
Dave

 

[Marks481]

On the upper right side of the schematic is the oil pressure switch. Power Trac doesn't connect anything to this gray wire... their is an unused bullet socket connector in the aft right side of the engine compartment.

I ran a wire from this to the sonalert, and another wire from the ignition switch to through a cut-off switch to the sonalert. I put a warning lamp wired around the buzzer/switch, so the light will always glow even if the buzzer is cut-out.

The oil pressure switch is grounded when it sees no pressure, and is open-circuited when the engine is running.

Some mention of it here:
http://www.tractorbynet.com/forums/power-trac/99371-pt422-aux-cooling.html

I bought the gauges here (there were on sale atthe time for about $50 each):
R6859R - ISSPRO EV Marine - Red Pointers: Transmission Oil Temp. Gauges - Towing - egauges.com

I bought the sonalert buzzer from ebay for about $10. I don't remember the model number, but it isn't hard to figure out which one you want from mallory's website.

 

[cqaigy2]

On my PT422, the oil pressure switch is a gray wire (Robin22 wiring diagram below).

I did the same thing as Bob... sonalert buzzer with a cut-out toggle switch and a warning light.

Wow, nice job on the panel and schematic!!
Hm is seem to say wow a lot in this forum.

 

[J_J]

Tim,

Are the oil temp senders pretty standard? The reason I am asking, is how does one calibrate the oil temp sender to the receiver? Years ago, while working as a Navy electronics technician I made up a thermistor assembly hooked up to a meter and put the sensor in the dipstick tube, but you had to calibrate the meter for it to read accurately. One way to check for accuracy would be to use a calibrated temperature meter, put it in the oil or hydraulic fluid and compare, if it is not accurate enough, maybe a variable resister could be added to the circuit.

 

[ponytug]

Mostly they fall into a couple of standard types. In general, it isn't an issue because you are putting a ford diesel sender in a- gasp- ford diesel-, but around here it is a reasonable question.

Thermistors have also gotten better since then. If you buy a 10k, it is really 10k. I haven't calibrated a thermistor in decades.

All the best,

Peter

Tim,

Are the oil temp senders pretty standard? The reason I am asking, is how does one calibrate the oil temp sender to the receiver? Years ago, while working as a Navy electronics technician I made up a thermistor assembly hooked up to a meter and put the sensor in the dipstick tube, but you had to calibrate the meter for it to read accurately. One way to check for accuracy would be to use a calibrated temperature meter, put it in the oil or hydraulic fluid and compare, if it is not accurate enough, maybe a variable resister could be added to the circuit.

 

[Marks481]

Are the oil temp senders pretty standard?

Usually you buy the temperature sensor with the gauge, so there is no calibration requirement.

Most transducers are fairly standard (0-10V or 4-20 mA), but the sensors have varying temperature or pressure ranges corresponding to the 0-10 V (or 4-20 mA) scale.

I did not draw the schematic above, it came out of the Robin EH65 22 Hp engine service manual. Bobrip pointed me in that direction when I was trying to figure out how to hook up the low pressure alarm.

The real trick with the temperature gauges is figuring out where to install the engine oil sensor. I threaded one into one of the drain holes on the block, but couldn't get it to seal (the hole has straight threads, and I could not find an adaptor which would fit my pressure transducer). I ended up using an oil filter relocation kit, but don't really like that solution either.

I used a hose clamp to clamp one onto the inlet hose to the hydraulic cooler. I have never seen this get more then 130F, so I don't believe this is the best indication of hydraulic temperature, since I believe much of the hydraulics bypasses the cooler. I think the best solution is to drill and tap a hole to insert it into the hydraulic tank or attach a thermowell to the hydraulic tank cover (which Clarke did):

http://www.tractorbynet.com/forums/power-trac/88385-mini-modification-4.html#post1006075

 

[Homebrew]

Well...I re-wired the PT. From my engine manual, the two wires left unwired are a gray wire from the oil pressure switch and a black wire that the manual shows going to tacho/hour meter. Everything seems to be running fine...the fan kicked on after 15 or 20 minutes of use.

I just noticed this, but I'm assuming the body of the PT has always gotten very hot and I just didn't notice before. It stands to reason that if the hydro oil gets hot, that heat will transfer to the metal frame of the PT...I was just surprised how hot the frame gets. Is this normal? Should I be concerned about something?

 

[MossRoad]

Well...I re-wired the PT. From my engine manual, the two wires left unwired are a gray wire from the oil pressure switch and a black wire that the manual shows going to tacho/hour meter. Everything seems to be running fine...the fan kicked on after 15 or 20 minutes of use.

I just noticed this, but I'm assuming the body of the PT has always gotten very hot and I just didn't notice before. It stands to reason that if the hydro oil gets hot, that heat will transfer to the metal frame of the PT...I was just surprised how hot the frame gets. Is this normal? Should I be concerned about something?

The hydraulic tank is part of the frame of the tractor. After an hour or two of heavy use, like mowing, the tank will get too hot to touch. This is normal. The best thing you can do is keep the oil cooler clean and make sure the fan is working.

 

[cqaigy2]

My 422 gets pretty warm too, especially when mowing. I usually use my pt for mowing or the bucket for digging type work. The digging, even in hard clay, doesn't put near the amount of heat into the oil as mowing does.

 

[Marks481]

I think the radiated heat from the exhaust manifold and muffler add significantly to this temperature.

I believe that PT's use of 1" square tubing with 90 degree corners significantly chokes the exhaust, raising engine temperature. The uninsulated exhaust header across the middle of the engine compartment doesn't help either.

One of the things on my project list is to weld up a new exhaust manifold with round tubing and smooth corners, possibly even dual mufflers like Beechwood and Rivco did with their PT180s (Unfortunately the pictures disappeared, they both did a great job with the conversion... sure wished I had saved the pictures):

http://www.tractorbynet.com/forums/power-trac/87286-180-mods-2.html#post991267

http://www.tractorbynet.com/forums/...ler-4.html?highlight=dual+muffler#post1172262

 

[ponytug]

Tim,

Good luck in the conversion! Why not go the whole 9 yards and have the headers and muffler coated with a ceramic insulating coating to keep the temperature down in the engine compartment?

All the best,

Peter

 

[Marks481]

I hadn't heard of that before. Is it commonly offerred by local companies?

I tried wrapping my exhaust header with fiberglass insulating tape, which I think is only a stop-gap solution (smoothy exhaust flow would be better), since I suspect that this just means that it conducts more heat right up to the cylinder head.

 

[woodlandfarms]

Powedercoating is a wierd process where the metal object is charged electrically, then some sort of electromastic paint is sprayed on. You then bake the part in a hot oven for a while and you have this tough as nails covering over your metal object in really cool colors.

On muscle cars, we powdercoat the exhaust headers so heat is reduced in the engine compartment.

Yes, it works well and it is available in your area I am sure. Heck, you can buy a kit do do it if you want.

 

[Marks481]

I am familiar with powdercoating. We do alot of that for protection of pieces and parts onboard USN submarines (just finished 4 year stint building the USS HAWAII at Electric Boat Shipyard).

I just didn't realize that people applied this process to their exhaust manifolds. If I ever get past the planning stage on this exhaust header thing, I will look into it.

The process is temporarily on hold because my PT422 is in a storage unit and I am living in an apartment... really expected this to be only a 1-2 month deal while I sold my old house, relocated, and bought a new house.

The housing market is a pretty chancy thing right now, so I am sitting tight while I watch the explosion of number of houses for sale. The funny thing is that despite the incredible number of houses for sale, I haven't really seen much change in the asking price for the past 7 months. I suspect that alot of people are upside down on their mortgage, and can't afford to lower the price, whether because they purchased recently or that they saw the rapidly increasing housing prices a copuple years ago and cashed in on a significant equity loan to "upgrade" their house.

It is quite amazing to see some pretty nasty looking houses that people have obviously spent $50k on adding hot tubs, upgrading the kitchen, etc. Sort of like gilding the pig. I am a bit leary of buying a house that the owner purchased new for $155k five years ago, and now thinks is worth $400k. I really don't want the hot tub or the stainless steel appliances and granite countertops.

 

[woodlandfarms]

Just FYI on Powdercoating. There is a belief in the auto world that the you should use silver or white on your powdercoating to help reflect the heat. Someone out there has to know if this is bunk or not. I think a nice bright yellow or red would be a good color on your 425.

As for the housing market. Our house in LA has gone down in value for sure. My parents are shopping in Eugene, Oregon, and they are having the same experience you are.

I am hearing good things about finding short sales, but it takes some looking to weed through the chaff.

I think you are right to wait this one out. At least until we have a new president. But it sucks to be you. An apartment when you could afford a house is no emotional fun.

Carl