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TR6 TR6 Overheating after being shut down

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hondo402000 said:
you could take the thermostat housing off and pull the thermostat out and check to see if you have air in the head. pour coolant in the thermostat housing directly into the head, put the thermostat cover back on without the thermostat, run the car for a few minutes with out the radiator cap on and heater in full on, fill up the radiator if it goes down, shut the engine off, put the thermostat back in and cap on. it problem persist, there could be blockage somewhere,

did you have the radiator cleaned out by a professional shop?

that probably how I would approach the problem

Hondo
Click to expand...

If your going to all that trouble. Take an aspirin ,not gel coated, and open the thermostat. Place the aspirin there. Put it all back together and start it up and fill it. That way you get all the air out of it while it is cold.
 
Hey Gents - I'm back. Got the overheating / overflow condition resolved (I think). I believe I'd overfilled the radiator, plus it may have had air trapped. It idles at normal temp, and runs at normal temp. Now I have a second issue - it does get very hot after being shut down, so much so that if I go to turn the car over a few minutes after being shut down it won't start. It spins and spins, sputters, and dies. Seems like gas starvation. I get the impression the gas is evaporating (?) from the heat, or perhaps I have vapor lock? (I'm exposing my automotive ignorance here...) Once it has cooled off (a few hours) it starts normally. As for the ignition, I have it dead on at 35 degree dwell, dynamic timing 4 degrees ATDC, at 800 rpm. Final question - in dynamic timing, on a 1976 TR6, the distributor advance vacuum line is removed in making the setting, correct? Plugged, or unplugged? So many things, so little time...

Regards,
Jeff
 
brgrmyster said:
Now I have a second issue - it does get very hot after being shut down, so much so that if I go to turn the car over a few minutes after being shut down it won't start.
Click to expand...
A very common problem with modern fuel in old cars. The fuel literally boils in the carbs, making the mixture way, way too rich. Adding a heat shield or electric fan (that runs after shutdown) can help.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:] Final question - in dynamic timing, on a 1976 TR6, the distributor advance vacuum line is removed in making the setting, correct? Plugged, or unplugged? So many things, so little time...[/QUOTE]
The 4 ATDC figure is with the vacuum retard connected and working (not disabled by the TVS). It's confusing because many references say to disconnect and plug the vacuum line; but they are referring to the PI models with vacuum advance rather than US models with vacuum retard.

Many people opt for disabling the retard, in which case you should use the "static" timing figure (around 10 BTDC) instead of 4 ATDC. But you'll have to readjust the carbs as well.
 
Thanks Randall. I'm going to reset it dynamic at 4 ATDC with the vacuum line attached. As for the fuel issue, the carbs were set up in late October, when it was cool and brisk. I wonder if they may be set up a bit lean for summer running in very hot conditions. I hoping some other members weigh in here.

Thanks,
Jeff
 
It's not the mixture per se. It's fuel percolation in the carb's float chamber that's cauing the starting difficulty. They are just a few inches above the extremely hot exahust manifold.
When the gas is not moving it has time to sit there above the heat and eventually boil.
In the Owners Manual, instructions say to hold the accelerator pedal down (no pumping) 1/3 while using the starter if the engine is hot.

Eventually it'll start and run rough until cooler gas comes in and replaces the hot stuff.
A carb heat shield helps, too, so does spot on ignition timing.
I wouldn't depend on the degree marks on your damper to be all that accurate anymore,though.
Try this:
https://automotivemileposts.com/garage/v2n8.html
 
What do you guys use as a vacuum port for the test gauge on say a 59tr3.The only option I see is to T into the dist/front carb vacuum line.
Thanks
Tom
 
Can't use the distributor line either, as it connects to 'ported' vacuum. At idle it will read zero or nearly so.

I tapped a couple of fittings into the manifold on my TR3A, but soon realized I didn't really need a vacuum gauge. But I'll do it again if I ever try to install the water injection unit again (not likely).
 
Thanks guys. I have the timing spot on now at 4 degrees ATDC with the distributor vacuum line attached. As hot as the car was, it started, although there is no doubt the gas is percolating as it sits there while shut down. I can hear it (sounds just like the old glass pyrex coffee percolator my mom once had).

Thanks to all. I'll try the 1/3 down trick if it contonues to act up.

Jeff
 
Probably not as spot on as you think.
BTW, 1/3 down is in the owners manual; it's not a a secret or a trick.
 
Thanks. As soon as the weather cools a bit, I'll try the vacuum guage setup. I can't stand dripping on the car in 95 degree weather, 85% humidity. I'll wait for a break in the weather. Now, where would I find a vacuum source directly on the intake manidfold?
 
On your 76 there's a banjo fitting on the intake manifold,
It has 3 hoses attached to it.
One to the brake servo, another to the diverter valve over by the distributor and the 3rd goes to the Anti Run-on Valve, under the carbon Canister.
That's the one. Just unplug the ARV hose from the Banjo fitting, and plug your Vacuum Gauge hose on that nipple on the Banjo..no need to plug the ARV hose during the procedure.
As you advance the timing by turning the distributor Clockwise, the engine idle speed may increase, Just keep the rpm around 850-900, by equal adjustment of the throttle stop (idle speed) screws.
I'd loosen the dizzy clamp a bit,then hook up the Vac, Gauge, start the engine, and let it warm up before fiddling with the distributor.
Leave the dizzy retard hooked up during the process, don't exceded 19 in. Hg.
17 to 18 at sea level, minus 1in/1000 ft elevation is a rule of thumb for the TR6 carb'd engine with a stock cam.
 
Great stuff. Couldn't be more helpful. I can't wait to give it a try and see how far off it may be. I'll say this - timing it dynamic correctly made for a noticeable jump in power and pep. I'll tell you how I make out, and thanks for all your help.

Regards,
Jeff
 
Gents - all issues resolved. No more overheating after shutdown, and no more boiling of gasoline. Took first place today for the late-class TR6's in the concours judged Cars of England at Oakbourne Mansion Show, Westtown, PA. Car could not have looked or ran better!

Many thanks for your technical advice.

Jeff
 
Congrats on your award, Jeff. How did you fix the percolation issue ?
 
Hate to admit it, but the 1/3 down on the pedal before turning it over did the trick. Timing it properly with both a light and vacuum gauge couldn't have hurt. Seems to start almost immediately. No more boil over also. I think that was a combination of the radiator being overfilled, and air in the system that seems to have entirely disappeared given the driving I've given it in the past few weeks.

Any more issues I'll be calling for your help again.

Thanks,
Jeff
 
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