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Triumph TR6 - A Really 'cool' problem
|Looking forward to meeting TR owners|
My name is Chip Bull, long time TR owner from Central Massachusetts. Owned a TR3 in high school, a Spitfire in College and purchased a 1976 TR6 back in 1984. Used the car as a daily driver throughout the 80’s and into the early 90’s. As life and family commitments (not to mention a recurring mechanical problem) began to increase, the TR found itself in a period of long-term hibernation (wow! Can it really be almost ten years?) in the back of the barn until just this month. In a mid-life career change that now finds me a Middle School teacher with a good portion of the summer off; I have been re-bitten by the “TR-Bug”. The barn got a long over due cleaning and is now in the process of being transformed into a restoration center/workshop for “Toby Triumph”.
The parts packages have begun to arrive on a daily basis and the FedEx and UPS guys and I are now on a first name basis.
The mechanical problem mentioned above, continues, but through trial and error I think that I am beginning to get it figured out.
As this is a Triumph forum I am eager to get some advice from the wise sages among you who might be willing to lend their expertise on this problem.
Basically it has all the telltale signs of classic “vapor lock” but there may be more to it:
Car starts up perfectly, runs fine at idle, motors well on the highway, BUT if the trip has been any longer than a quick trip to the center of town for a quart of milk, once the engine is turned off….. and the car is left with its fully warmed-up parts percolating under the hood….. any attempt to start the will meet with immediate failure and any additional attempts in anything under one and a half hours will result in nothing more than a warn down battery.
Wait the obligatory 1.5 hours, however, and it is an entirely different story…. car starts up just fine. While this technically makes the car usable… (as long as I bring along my lesson plan folder and am willing to sit and work for and hour and a half on getting ready for my new classes in the fall)…. it sort of takes the spontaneity out of the phrase “Let’s drive over to the cruise night at the Drive-in for an Ice cream.”
What I have discovered so far:
DOES NOT appear to be vapor lock in the metal fuel line. I have installed a heat shield all the way around the engine. This made no difference.
Fuel supply from the mechanical pump to the carbs is fine even after shut down.
What has worked, although this trick would be a wee bit embarrassing to do in front of all those muscle cars at the ice cream place: If after shutting down the car I place sandwich baggies full of chipped ice directly on top of both of the Stromberg carburetors and two along side of the temperature compensation unit located on the side of the carburetors the problem will not occur and the car starts with no problems.
My assumption is that the problem can now be narrowed to;
Floats in the fuel bowels that are set too high and allow for expansion of the gas reservoir once the carbs begin to heat up, (this I understand can result in a vapor lock of sorts within the carburetor itself.
Temperature Compensators (which operate off of a bi-metal strip) sticking or not set properly.
Does anyone out there in TR6 land have any suggestions regarding this problem?
Thanks in advance for your help and I look forward to meeting the members of this well constructed forum.
Have you double checked for spark when problem happens? Seems you have it narrowed down by tests but just incase?
Does the car turn at normal speed hot start or is it slower? In some cases there is not enough juice for coil and starting motor?
I can't see the compensators being that far off to not allow a start. May be wrong?
Let me know. There are some other tricks to narrow down.
Middle school huh - here's a cyber "pat on the back" for you!
When you're cranking that hot engine in the parking lot, oozing sweat and frustration and looking for discrete bags of ice, do you smell any fuel in the exhaust - like it's flooded?
I noticed on my '74 the fuel line from the tank runs really close to the dual exhaust - so close I've moved and insulated it. I wonder if that could be adding extra heat to your fuel on it's way to the carbs?
I'm thinking you need to rebuild those carbs. They've been sitting a long time and fuel has turned to varnish. Who knows what's going on in them. Also I'd adjust the temperature compensators - google them to find out how. Mine were off a good amount and made a huge difference in driveability once set - but didn't affect starting however.
Has the previous owner done weird things like moving fuel lines away from their stock position? How old is the gas in the tank?
This thread was discussed between 08/08/2004 and 09/08/2004
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