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running way too hot.

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Alright, I got a little distracted today, my friend called me and told me that there was a spitfire 1500 in the local pick and pull junkyard. So after taking some parts (door handles and tail lights)I got back to work.

I star by double cheeking the timing. I was at 8 Before.. sorry not after.
I replace the thermostat, and no difference. I then go to flush out the system. when running off straight water for a little bit to try and flush it out. the temp seems to be where I remember it being when running on just watter. I let it cool then drain, then add the 50/50. And as soon as the car warms up the anti-freeze is dis-colored and its right back up to the higher temp.

As a little test I turn on the heater fan, and the temp just drops after a few mins of running the heater fan.

What could this be? A blockage that wasn't dislodged? any idea on how to track something like this down?

What is the beat way to check the actual water temp? just let it warm up and stick the thermometer in the top of the radiator?
 
Will_Ringrose said:
What is the beat way to check the actual water temp? just let it warm up and stick the thermometer in the top of the radiator?
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That's what I do!

Did you drain just the radiator, or did you also get the drain on the block? I'm guessing you might have a lot of buildup in the back part of the block, where that drain tap is. If it's a hex plug, remove it. If it's a petcock, remove it. Then poke and prod with a stiff wire, welding rod or small screwdriver. Likely as not, you'll eventually "break through" and start to loosen a lot of crud, at which point water should gush out as well as it does from the radiator drain.
 
Andrew Mace said:
TR3driver said:
Ah, well, Will says he has a 73 GT6 and lives in the US (presumably making it a US market car), so we should probably quote the numbers applicable to his car.
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Which is exactly what I did!
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Ok, one of us is confused (probably me) ... you said the "static" spec was 6 before and I said it was 12. I don't see how it can be both!
 
Ok, let me try again, hopefully a bit more clearly this time. My factory workshop manual gives three figures for ignition timing:

"conventional -- static" 12 BTDC
"emission control vehicles -- idling speed" 4 ATDC
"emission control vehicles -- approx. static" 6 BTDC

In reading through the "Emission Control System" section on timing, it suggests (at least to me) that the 12 BTDC is a starting point if you've R&R'ed the distributor, and that the 4 ATDC at the normal idling speed of 800-850 rpm works out to approximatly 6 BTDC? I admit I'm guessing there! Does that make any sense to you, Randall?
 
Will_Ringrose said:
And as soon as the car warms up the anti-freeze is dis-colored
Click to expand...
That would suggest to me that you are not getting the system clean. Might be worth trying one of the "fast flush" products (although the good stuff has apparently been pulled from the market). But my next step would be to pull the radiator and take it to the local radiator shop to be "rodded out".
<div class="ubbcode-block"><div class="ubbcode-header">Quote:] and its right back up to the higher temp.[/QUOTE]Antifreeze is not as good a coolant as water, so it's not unusual for the engine to run hotter with 50/50. (OTOH, it takes a higher temperature to get the 50/50 to boil.) IF it is doing OK on straight water, you might try some "Water Wetter" and/or running a lower concentration of antifreeze.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]What could this be? A blockage that wasn't dislodged? any idea on how to track something like this down?[/QUOTE]One test that can be helpful is to feel the face of the radiator with the engine running (away from the fan, of course). Some variation from top to bottom is normal, but if you can feel any variation from side to side, it indicates one or more blocked tubes in the radiator.
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]What is the beat way to check the actual water temp? just let it warm up and stick the thermometer in the top of the radiator? [/QUOTE]
I've been playing with one of those infrared thermometers, it's a pretty cool gadget. TR3s have a long extension on the upper tank (to bring the filler cap out from under the fixed front apron), and the thermometer showed what I suspected, the water in the extension doesn't circulate enough to stay the same temperature as what is coming out of the engine. I can also see as much as 20F temperature drop between the radiator tanks, when the electric fan kicks on (with the engine idling).
 
Andrew Mace said:
Ok, let me try again, hopefully a bit more clearly this time. My factory workshop manual gives three figures for ignition timing:

"conventional -- static" 12 BTDC
"emission control vehicles -- idling speed" 4 ATDC
"emission control vehicles -- approx. static" 6 BTDC

In reading through the "Emission Control System" section on timing, it suggests (at least to me) that the 12 BTDC is a starting point if you've R&R'ed the distributor, and that the 4 ATDC at the normal idling speed of 800-850 rpm works out to approximatly 6 BTDC? I admit I'm guessing there! Does that make any sense to you, Randall?
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It would make perfect sense to me; except that it contradicts my 1973 Emissions Control Service Training Notes. No wonder Will is confused!

Maybe the best thing to do here is to try both, and see which one works best (without knocking under load, of course). Or just use the vacuum gauge method (which also ducks the issue of the timing marks no longer being accurate for whatever reason).
 

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The only "contradiction" I see is the odd "approx. static" 6 BTDC figure; everything else matches up just fine. Why that "approx. static" figure is even given, I really don't know!

Regardless, it apparently should be 4 ATDC at the recommended 800-850 rpm idle speed, which might or might not work in the real world. (It almost never did for me on either of my GT6s -- 1970 + and 1972 Mk3, both of which were supposed to be timed at that 4 ATDC figure!)
 
I would try draining the block one more time and and flushing again, as suggested earlier. Whereby you would disconnect the heater core and flush it on it's owm to keep the crap out of there. The heater core acts as another smaller radiator and pulls heat away from the block, so it will drop when turned on. That's a normal trick in mid summer to keep these cars from overheating in traffic, but cooking the passengers in the process.

This is what the heater core looks like on a TR6 and you will see what I mean. TR6 Heater Case Rebuild

PS YOU DO want to make sure you get all of the air out of the system, as that will cause problems as well.
 
Alright, I am starting to get frustrated. After flushing a second time and running a cleaner in it., then flushing it a 3rd time (yes i removed the block plug above the starter, it didn't seem to be clogged at all, and yes i ran a 2nd flushes for both the heater core and the main cooling system) I don't know if its a bad sender unit or gauge or what.

With no load on the motor at idle after running for about 20min it reads a little over half on the dial.

I take it out to put gas in it and its back nearly in the read by the time I get home.

So me not thinking to clearly I pop the cap off after getting it in the driveway to try and get a reading with my thermometer and it boils over when air gets in the system.. Lucky I put one the valve caps on and let it all spray on the ground. I check the temp, as soon as I stop seeing bubbles and its at 210F.

So I was thinking that isn't too bad, let me check the voltage stableness to see if I am getting a bad reading on the dial. The "I" side of the VS is reading at 10.87 volts.

I am at a loss I don't know what he problem could be at this point. Should I just add an electric fan? replace the temp sending unit? say screw it and drive it anyway?
 
Will, Without going back to see if this is noted.How old is the rad?
 
DNK said:
Will, Without going back to see if this is noted.How old is the rad?
Click to expand...

I had it cleaned and tested when I first picked up the car about 5 years ago. The cap ripped off the lip it clips to before I got the car.

I did run my hand over the front of it. The temp didn't seem to change from side to side, or not too bad from top to bottom.
 
Andrew Mace said:
The only "contradiction" I see is the odd "approx. static" 6 BTDC figure; everything else matches up just fine. Why that "approx. static" figure is even given, I really don't know!
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That's so you can know what to set the timing at, after you've thrown the vacuum retard unit in the trash where it belongs! It is also what I was talking about as a contradiction.

The "approx" is there because US regulations at the time required it.

More things for Will to check:

1) Pull the water pump, make sure the vanes are in good shape and still attached to the shaft & pulley. While not common, they have been known to fail.

2) Check for a leaking head gasket. There are various ways to do this, including a simple test that your radiator shop can perform (mine charged less than $20 last time I had them do it). The "old time" method was to remove the fan belt & thermostat housing, fill the system level full, then start the motor and "goose" the throttle while watching for air bubbles coming through the opening on the head.

3) Although it seems unlikely, wouldn't hurt to do a "plug cut" and read the plugs for mixture. We fought a severe overheating problem for years on my Dad's TR3A, that turned out to be worn jets in the carbs. Obviously they won't wear in just a day, but there might be something else causing one or both of your carbs to go lean while driving.

Is the coolant still getting immediately discolored?
 
Shouldn't it be changing top to bottom?

or side to side if the tubes go that way.
Have you timed it with Ken's method?My Wedge timing slipped this spring and it was running hotter than the dickens.
Your damper could be really fubared
 
Another thought, you might have the radiator tested for thermal efficiency. Most radiator shops don't do it unless you ask specifically. But when my TR3A started persistently overheating at freeway speeds, that was the problem. The radiator flowed just fine, and did not leak (which are the two things they normally test for), but the tubes were not in good thermal contact with the fins, so it just would not output enough heat.

When I asked at the radiator shop, they checked and said "It's junk" even though they had given it a clean bill of health just the month before. And a recore instantly solved the problem.
 
Just athought for quick check of radiator:
Drain and let cool,
Fill with hot water,and quickly check,preferably with infared gun,to see if surface fin temps are fairly uniform.A clooged row should show up as cooler spot.
Tom
 
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