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MG TD TF 1500 - Spitting, backfiring and cutting out

I've had a 52 TD for about 4 months. Until recently, things ran fine. My TD has Solex carbs, not the original SUs. I may want to go back to the SUs although I'm still undecided. It largely depends on whether I can solve recent occurences of a spitting, backfiring, rough running, sort of gurgling sounding engine, which I suspect is due to the carbs. The engine has also cut out completely a few times both when the engine's cold and hot (almost as though it's flooded or there's water in the fuel line) It starts again after +/- 5 minutes but still runs rough.

Hopefully it's not the carbs and there's a less expensive fix.

With the kind assistance of a knowledgable neighbour whose passionate about these cars, we have done the following to try to remedy the problem, to no avail.

We did the following..

- checked the fuel pump (aftermarket) and its putting out about 6 lbs pressure, which is about 2x what's needed (put a clamp on the fuel line to decrease the pressure - no improvement)
- checked the floats and needles in the carb and all seems fine
-cleaned the fuel line filter and the float bowl in the carbs
- adjusted the idle and mix settings
- tightened all bolts on the carb to minimize air getting in to them

Any other ideas would be greatly appreciated?
Phil Atrill

Phil - if you have owned the car 4 months and - until recently - things ran fine, you still are not looking at a long period of smooth running - or running at all for that matter.

You could have bad gas, water in tank - or rust in the fuel tank - did you check the fuel filter that is in the tank?

Since you have not owned it long, have you adjusted valves, checked compression, gone through the ignition (checked static timing, advance weights and springs, points, condensor, rotor, cap, wires)?

I would back step a bit and check all your fuel filters and check on those foat valves again. I am not very familiar with the Solex carbs - but I would still favor the SUs.

If they were good enough for Kimber, Enever, and Thornley, they are good enough for me.

Hope you get back on the road soon,

Jeff
Jeff

Phil,
I agree with Jeff, I would start with the ingnition system,,, especially the rotor, cap and wires,, look for moisture on the inside of the cap,,... As they say, "90% of carberation problems are electrical!!!!"

SPW
Steve Wincze

phil, i am curious as to why you started your troubleshooting with the carbs...did you work on the carbs lately? if not, i agree with steve. i would start my troubleshooting else where. for an engine to run you need 3 things; compression, adequate spark at the proper time, and fuel of the proper mixture. do you have a good hot spark? is it nice and blue and jumping 1/2" ? if not, what is the condition of the rotor, distributor cap, ignition wires and asssociated connectors, and points? what is the resistance of you ignition wires including coil to distributor? is the point gap correct? what is the condition of the points and their color? if you have a good spark, how do the spark plugs look? is the engine timing correct? best of luck. regards, tom
tom peterson

Seems to me, a bad condenser will do this.
Tom

Thanks for the thoughts gentlemen.

A few weeks back, we adjusted the tappets to .019 (to spec), as they were set at .012. Prior to doing this, the motor was running much more smoothly. After a little research, we determined that the cam on the car had likely been changed and the .012 setting (done by the previous owner, who has passed away) was likely as it was due to the cam not being original. We adjusted the tappets yesterday so that they are now .012 again and it has improved the problem a fair bit. (Need to have a longer drive to really size things up).

Compression is excellent, rotor (new), distributor cap (newish), ignition wires and connectors are all fine, spark plugs are fine and engine timing was just done a week ago.

Still plan to check the fuel filter near the gas tank, assuming it's easy to get at. Also will take a look at the condenser.
Phil Atrill

Phil,
Start the car in the garage at night,,, turn off the lights, and see if you have any spark jumping between the ign wires ,,,,
Steve Wincze

Just to add to Steve's comment, spraying a light mist of water around the wires may show a spark jump that may not appear without the spray.

The new rotors that have a rivet holding the top brass piece on are suspect, too. New isn't always better.

Glad you are going through what you have done to change things, and it's helping.
Tom

I agree with Tom, try the old rotor first.

Changing the tappet settings should not alter the missing problem at all, just make them quieter. I would continue to look elsewhere. It sounds like an ignition problem to me.

Cheers,

Paul.
Paul van Gool

This thread was discussed between 15/09/2008 and 18/09/2008

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