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MG TD TF 1500 - engine sputter
|I have a 1952 MGTD. It was a warm day in Florida and took the TD out for a spin. On cooler days when the car runs at temp of 75 degrees it runs like a champ. On warmer days the temp gets above 80 to 90 degrees and when I shut off the car I have a hard time restarting. When it does start it pops and sputters --seems like vapor lock? I did installed a shutoff switch on the electric fuel pump and I switch off and let the car run out of gas. I switch the pump on and the car starts but still get the popping and sputter until fuel seems to be flowing. Any recommendations on a fix?|
|The fuel may be boiling in the float bowls if you just shut it off, but at least it's providing some small amount of temp stabilization. I think pumping the fuel into a dry, hot float bowl would most likely vaporize the fuel and might make your problem worse. The standard practice of using the choke seems to work for most people.|
|L E D LaVerne|
|Funny, this keeps coming up....|
Some folks say that the fix involves a combination of having the exhaust manifold ceramic coated, and using stainless fuel lines.....
Some people have even added heat shields, like the ones on a "B".
I think the simple answer is what LaVerne says....Just choke the engine and feather the gas pedal, until it runs smoothly again...
My personal experience is that the stainless lines alone, are not enough.
|Edward Wesson 52TD|
|I am working on my own design of cooling the carbies when I shut the engine down for a short while,,,, but in the meantime,, I do the same as Lavern,, A little choke will do ya!!!|
|Hello Russ, My TD has always done that to some extent, but only on really hot days and after a few minutes of hot-soak. I second just using the choke. I do think ceramic coating my manifold helped my car. Are you making it to the GOF in Ocala? It sounds like a really great event. George|
|IMHO: Exhaust treatment that does "inside" is the best cure. I have not had VL for 10+ years since doing that. |
Before that ...forget it ..all the time.
|Steve - "I am working on my own design of cooling the carbies when I shut the engine down for a short while"|
What - pack them in some of that snow in your avatar? That should do it nicely.
Seriously, what is your plan for cooling the carbs when the car is stopped? I just purchased a 3" vane-axial bilge vent fan that I intend to mount under the front apron, with ducting that will direct a stream of air to the carburetors when parked. I am looking for a thermostatically on/off switch that will turn the fan on when the temperature of the carbs reach a predetermined temperature.
I got the idea of the bilge vent fan from a discussion some time ago on the MGA Bulletin Board. Apparently the MGA suffer the same problem that the T series cars do. Cheers - Dave
|Just as a preventive measure I took a piece of clear plastic aquarium hose slit it and fitted it over the fuel line for about 2 feet from the pump to toward the tank. I think that this helps insulate the line from absorbing engine compartment heat when shut down. Have not had any hot weather running issues so maybe this helps.|
|John Quilter (TD8986)|
|Russ, just choke it to restart and no modifications are needed. I have never heard of a TD having a vapor lock issue while running..even during a parade on a hot day..it happens when the under hood temp elevates when the car is shut down and sits for just a few minutes..the carbs heat soak. The fan with thermostat mod Dave is talking about is the only one that will work to prevent heat soak vapor lock of the carbs...heat shields provide NO relief when the car is parked and the entire underhood area cooks off.|
I would just pull the choke and start her up and drive off..it has worked for me for the last decade in 100 plus temps..
Drove in Chicago rush hour summer before last in stop and go..mostly stopped traffic for almost two hours..no vapor lock while the engine is running. Regards, Tom
|Tom - I have had a vapor lock/heat soak problem one time when we we were on the road. The situation arose as we were traveling south on I5 through southern Oregon on summer. As we reached the crest of one a number of ridges that we had to cross, the engine started sputtering exactly the same way as on start up on a hot day after letting the car sit for a short period of time. By downshifting and nursing the car to the top of the ridge, then started down the other side. After less than 1/4 of a mile the engine settled out and we had no other problems. |
I remember in the 50s in Southern California, seeing numerous TD running around with the side panels of the bonnet removed during the summer months - just didn't think that the Puget Sound region of Washington state would get hot enough to cause the problem. Cheers - Dave
"Seriously, what is your plan for cooling the carbs when the car is stopped? I just purchased a 3" vane-axial bilge vent fan that I intend to mount under the front apron, with ducting that will direct a stream of air to the carburetors when parked. I am looking for a thermostatically on/off switch that will turn the fan on when the temperature of the carbs reach a predetermined temperature."
I wonder if the adjustable thermostat used for electric cooling fans, used on hot rods, would work?
They have a control that allows infinite adjustment of the on/off point....
The sensors are made to go into the radiator hose connection, but I can't see why it couldn't be attached to the carb body.
I bought one from NAPA , many years ago, for my FFR roadster, and still use it.
|Edward Wesson 52TD|
|Edward, I run a Jaguar 3.8S with a Hayden electric cooling fan for the radiator. It is controlled by an adjustable thermoswitch which looks like a large aluminum nail and simply is inserted between the fins of the radiator. It works quite well and I think could be adapted to work an other type underhood fan. |
As another suggestion why not wrap the carb float bowls with some foam pipe insulation which would keep them from absorbing engine compartment heat during the heat soak hot shut down period. Insulation on the lines to the fuel pump and from the pump to the carbs could help as well.
|John Quilter (TD8986)|
|I have a small, solid state unit that I attach to the fuel pumps that I run on the test stand that I use to test the pumps. I installed this since I run a 24 hour endurance test on the pumps I restore prior to shipping them out and occasionally a pump will stall in a current on condition and overheat. I am using mineral spirits as a testing fluid and didn't want thing to get hot enough to ignite the fluid. The unit can be adjusted for the temperature that is wanted for the unit to activate to turn on or off the power source. I have not experimented with it yet to see if it will activate at a high enough temperature to be useful in the engine compartment. The nice thing about this unit is that the sensor is a very small transistor that can be attached with something like a tie wrap. I also need to see at what temperature the vapor lock occurs. I will keep everyone posted when I make any progress. Cheers - Dave|
That is exatly what I am planning on using!!!!!!!! A 3" Rule Marine In-Line Blower,, all plastic, so polarity won't matter,,,and oly $26.99 at my local Defender Marine,planning on buying it this Sunday when I'm down there,, You are getting more detailed in design trying to do a temp operaterd swith,,, I was just going to turn it on when ever I was going to be stopped for less than 20 minutes,,
Please keep me posted on what happens!!
MGTD52 AT COMCAST DOT NET
|I also am very interested in the final tested design.|
This thread was discussed between 11/03/2013 and 14/03/2013
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