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Triumph TR6 - Warmed up car won't re-start

Second time this week it has happened to me. Car starts relatively easily the first time. Drive around a few miles. Shut down. Ten minutes later it refuses to start. Battery is fine. New points, cap, rotor, coil. Any ideas?
RF Ickrath

is there spark when it happens?
Is there fuel?
DNK

Plenty of fuel. After an hour or so the car cools down and it will start right up. I did a google search and most other cars it is a heat problem with either the starter or the battery cables. wires/starter heat up and resistance increases. Engine will crank but not enough power left to fire. Just wish I knew if throwing a voltmeter on it would tell which it is. Hate to buy a new starter $$$ and have it be something else!
RF Ickrath

Coil
DNK

Coil is brand new. No ballast resistor in the system so I threw a Pertronix 3 ohm coil in. When the car wouldn't restart after driving it ten miles, I put a brand new 1.5 ohm coil back in. Still wouldn't start. Engine cooled down...started fine. So I need to put the 3 Ohm back in, since a 1.5 ohm without a ballast resistor puts out way too much power....will fry the condenser/points. I just purchased the car, and there appears to be a brand new solenoid on the starter. So I am thinking cables or the starter it self. Gues I need to take it for a drive and when I get home and it won't re-start, pull a plug and see if they are sparking.
RF Ickrath

I won't pretend to be an expert, but if the engine is turning, then surely the starter can be ruled out, unless it is turning very slowly?

You say that you recently bought the car - did it come from a cooler climate? Could you be seeing a gas vaporisation issue? When you stop the car the temperature of the engine bay actually rises for a short while before dropping, so with the exhaust manifold right under the carbs this is a real possibility. I put one of Joe Alexander's heat shields on and haven't had a problem even in the Texas summer.

I had an issue a few years ago where the car would start up from cold but was a lot harder when warm. After a while the problem got worse and the car would run rough after a couple of minutes of driving. I replaced pretty much everything except the brand new condenser. Turns out it was a dodgy condenser... That might be irrelevant here as it was only after the rough running that it failed to start completely.
A Hewitt

Car came from Maryland. Was in VA prior to that and now NC. Not a big change. I am going to warm the car up and measure to see if there is any voltage drop on the battery cable going to the starter, since that goes right by the exhaust manifold. Cable looks like it could use replacing anyway. I will look into the heat shields though. I originally thought vapor lock, since that had been my experience on my 69 Camaro thirty years ago. Thanks for the advice. At least the engine is clean!

RF Ickrath

Just ordered the heat shield. Will let you know in a week or so if it solves the problem. It would be nice to be able to cruise up to Dobson in two weeks if I can get her a bit more reliable, since it is a mere two hours away!
RF Ickrath

RJ

If it is the starter, you should be able to get it going by bump starting it (pushing car and popping clutch with ignition on and in gear). I suspect it is not the starter.

If points are not set correctly, when they heat up they may not be opening enough to allow the spark.

Bad condenser is also a good possibility.

You can maybe try a heavier weight oil in the carb dampers. A light oil when it gets warm may be not viscous enough and too much gas is let in "flooding" the engine. I found my 6 was tougher to start warm when I had a lighter oil in the damper.

Also check the tappets clearance. If not set properly, when the engine is warm, it can cause valves to be partially open when they shouldn't be - but the car usually runs rough when warm if that is the condition. Specification is 0.010 in when the valve is fully closed.

Good luck- and I hope you make your trip to Dobson with no incident.
Michael Petryschuk

Thanks for the advice Michael. I set the points by hand but I will throw my dwell meter on to see if that is the problem.

What weight "heavier" oil did you use in the damper?

On a totally different topic, I eventually have to get a one time Safety inspection in NC for the car and figured working horns might be nice. I had rebuilt the left horn already, as it was frozen, but I still need to tune it. All I get is a sick buzz out of it. Using Dan Master's book I trouble shot everything, to no avail. I was just going to pull the LH horn out and replace it, when after disconnecting the wires, on a whim, I hit the horn button. The RH horn came to life! So now I think the LH horn is so sick or out of tune that it draws all the voltage and nothing was getting to the RH horn.
RF Ickrath

I use 20W50 in my carb dampers. I used it from when I rebuilt the car in 2005 until 2 years ago when I tried 5 w20 and as I indicated found it harder to start when warm. I went back to 20W50 this year.

Something else came to mind as well. The seals around the throttle rod (where it enters and exits the carb housing must be pretty air tight as well. Too much leakage can make it hard to start. I would imagine an expanded (hot carb) might have higher leakage than cold.

Most leaks if present in the manifold/ carburettor area gets worse when warm and leaks rob the vacuum in the manifold to suck in the gas.

One other thing would be to ensure the gas mixture (needle) is adjusted to the proper level- not too lean not too rich. I guess you would have to check it after starting it cold so you can do it while its running.

In my experience, I don't think the ignition system gets too affected by temperature change (other than the points) and starting problems hot versus cold seem to be a gas delivery / carburettor issue.

I agree on the horns. the left is sucking the juice so the right isn't getting any.

Michael Petryschuk

Well, hopefully the ARE heat shield will help in the heat area for the carbs/ throttles. I threw a replacment horn in from Moss. I won't win any shows....but I will pass inspection! I am almost able to draw the electronic schematic of a TR-6 in my sleep. Not bad...but I would prefer Katy Perry or Christy Brinkley's schematic when I dream!
RF Ickrath

This thread was discussed between 24/08/2014 and 27/08/2014

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