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TR2/3/3A overheating tr-3
- Thread starter captainde
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that is the only thing keeping me from going to negative ground. I had the 79xx in my stock at the time I needed it so I built the regulator. Not thinking at the time (when I had access to these sort of parts with ease) that I should do the ground swap first then get a 78xx. Other then having to remember it is positive ground I have not had any other ill effect. I imagine as I get older remembering will be a bigger issueTR3driver said:
Hello A,
I got a 7912 VR and installed it, I ordered a 7910 last week, the 7912 works but after about 25-30 minutes the temp gauge starts to climb but the IR thermometer reads 74 at the therm housing, I am running water through the block as of now I am wondering wether the sender may be bad, or the water is causing it to run a little hotter than normal.
Any thoughts would be appreciated.
captainde
I got a 7912 VR and installed it, I ordered a 7910 last week, the 7912 works but after about 25-30 minutes the temp gauge starts to climb but the IR thermometer reads 74 at the therm housing, I am running water through the block as of now I am wondering wether the sender may be bad, or the water is causing it to run a little hotter than normal.
Any thoughts would be appreciated.
captainde
TR3driver
Great Pumpkin - R.I.P
Offline
Water actually cools better than water/glycol, so I doubt that is the problem.
Have you checked the output voltage of the stabilizer when you first start the engine? I'm thinking the input might not be high enough for it to regulate, or it might be oscillating.
I assume you've also checked with the IR thermometer before the gauge starts to climb, so it can't be a calibration problem with it.
Have you checked the output voltage of the stabilizer when you first start the engine? I'm thinking the input might not be high enough for it to regulate, or it might be oscillating.
I assume you've also checked with the IR thermometer before the gauge starts to climb, so it can't be a calibration problem with it.
On other thing you can do since you have the IR thermometer, is to take an ohm meter across the sender and make a graph of resistance vs. temperature as measured with the IR (you will have to disconnect the gauge to get a true reading or you could go back and forth between the gauge and the ohm meter). Keep doing this as the gauge would have gone up, this will tell you if the sender is bad or not. You can also (if you have two meters) hook up a volt meter to the output of your 7912 to see if it is holding, but I suspect Randall is right and your input voltage is not high enough for the regulator to hold 12volts. However for the gauge to read higher the output of the VR would have to be climbing (or the resistance of the sender changing, so that does not point to the VR voltage drop being the problem.
Do you want my temp vs. resistance table from my kitchen stove lab set up? I think I even have a picture of the setup (my wife took it so she could hold it over my head if I ever say she used one of my tools wrong).
Keep us posted.
Do you want my temp vs. resistance table from my kitchen stove lab set up? I think I even have a picture of the setup (my wife took it so she could hold it over my head if I ever say she used one of my tools wrong).
Keep us posted.
TR3driver
Great Pumpkin - R.I.P
Offline
True, but that might be what is happening. The original generator only puts a few amps at idle (at best); and the battery will be somewhat discharged from having just started the engine. So the battery voltage right after starting may be down around 12.2 or even lower. Add a few tenths drop through the ignition switch, fuse and wiring (very common), and the actual input at the VR may only be 12.0.Adrio said:
Then after the engine runs for a bit, the battery's state of charge goes up, the input to the VR may top out at 14.0 or even higher. The original control box didn't regulate very well, and will actually overcharge the battery slightly when the load is small.
Hi Randall,
I checked the voltage in to the VR at idle, it was 12v and the line out was 12v, as rpms increase the line in was 15v and the line out was a steady 12v, but the gauge was at 100C I checked the the t- housing with the IR thermometer, and it was 78-79, and I did get an 80 reading, after fifteen minutes the engine idle was very rough, to the point where I had to keep goosing the throttle to keep it running, my hunch is that it is running hot and maybe my problem is elsewhere, i will switch out the sender unit but I'm not sure it is bad. When I got the car two months ago, the thermastat housing had a lot of caked up antifreeze in it. I removed it and cleaned it out, backflushed the motor through the heater valve, the flow coming out of the rad cap housing was very strong But I guess the water was just going through the top hose and out the gooseneck. and extemely clean. Maybe I should consider an electric fan? The radiator has almost no miles on it and minus crank hole. the fan belt has about an inch of play in it which might be too much.
captiande
I checked the voltage in to the VR at idle, it was 12v and the line out was 12v, as rpms increase the line in was 15v and the line out was a steady 12v, but the gauge was at 100C I checked the the t- housing with the IR thermometer, and it was 78-79, and I did get an 80 reading, after fifteen minutes the engine idle was very rough, to the point where I had to keep goosing the throttle to keep it running, my hunch is that it is running hot and maybe my problem is elsewhere, i will switch out the sender unit but I'm not sure it is bad. When I got the car two months ago, the thermastat housing had a lot of caked up antifreeze in it. I removed it and cleaned it out, backflushed the motor through the heater valve, the flow coming out of the rad cap housing was very strong But I guess the water was just going through the top hose and out the gooseneck. and extemely clean. Maybe I should consider an electric fan? The radiator has almost no miles on it and minus crank hole. the fan belt has about an inch of play in it which might be too much.
captiande
TR3driver
Great Pumpkin - R.I.P
Offline
Shouldn't run rough even as it overheats, so there does seem to be something else going on.
My project TR3 also had a bunch of gunk in the Tstat housing;
and I now seem to be having trouble with rust inside the block loosening up while driving. I've flushed several times, never got much of anything out of the block, but found a bunch in the top of the radiator. Since the radiator was professionally cleaned, I think it had to have come from inside the water jacket.
Need to do it again, as it started running hot on the drive two weekends ago.
IMO an electric fan in front of the radiator will actually decrease cooling at freeway speeds, the fan blades interfere with the smooth flow of air. Behind the radiator is good, had that arrangement on my 3A for many years, but it's not a trivial conversion (have to remove the fan & extension, which means apron off, etc.). I also had an alternator conversion ... the stock generator isn't going to run the fan + headlights (and it does get hot at night around here sometimes).
My project TR3 also had a bunch of gunk in the Tstat housing;
and I now seem to be having trouble with rust inside the block loosening up while driving. I've flushed several times, never got much of anything out of the block, but found a bunch in the top of the radiator. Since the radiator was professionally cleaned, I think it had to have come from inside the water jacket.
Need to do it again, as it started running hot on the drive two weekends ago.
IMO an electric fan in front of the radiator will actually decrease cooling at freeway speeds, the fan blades interfere with the smooth flow of air. Behind the radiator is good, had that arrangement on my 3A for many years, but it's not a trivial conversion (have to remove the fan & extension, which means apron off, etc.). I also had an alternator conversion ... the stock generator isn't going to run the fan + headlights (and it does get hot at night around here sometimes).
xactly what my t-stat housing looked like. Maybe I have a carbureter problem for the uneven idle. I will try another flush and maybe high pressure through the block drain and out through the water pump housing.
I'm all out of ideas, next step if this doesn't work is taking out the radiator and have it rodded out.
captainde
I'm all out of ideas, next step if this doesn't work is taking out the radiator and have it rodded out.
captainde