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MG MGB Technical - Help start my car.

I have and MGC and have posted there with few returns. Attempting to make a long story short which was difficult.

While waiting for a new alternator I decided to do a tune up which has not been done since I got the car a couple years back. It was running fine at the time. What I had done was put new plugs in, new wires, new dist. cap, rotor, condenser, points at which time I also installed the new alternator. When starting the car, it was hard to start and when it did run, it ran poorly with a lot of backfire and cutting out. It did run better after it got warm. If the car was run a few minutes and shut down it would not start again until an 20 minutes or so later. The first thing I did attempting to make it run better was to replaced everything with what was previously there and working well but this did not make any change.

I then replaced the gas tank (knew there was rust in there), the fuel pump, the gas filters (before the pump and before the carbs). Cleaned out the gas line and rebuilt the carbs. The car started and I set the carbs. Used the SU whiskers at 3500 RPM with out a problem. Set idle and choke. Car was in the my garage at the time, it sounded strong and even. Started and shut the car off several times a few minutes to an hour or so apart that night.

Went out the next day and the car started but was again back firing and cutting out and would not restart after initial start. Rebuild the carbs. Nice slow drop of the piston when the top hole was pluged with my finger. Nice clunk when lifted a short distance and dropped. Put the carbs back on and the car started but ran poorly as before and again would not start after initial start.

Checked the timing by a strobe at 1000 RPM but the mark kept dancing. Attempted to set it by turning it until the RPM was the highest and then backed off slightly. The RPM again varied a couple hundred RPM according to my independent tach so it was hard to set but I took a shot. The next day I set the carb jets at .70 below the bottom chamber and set the static timing at 8 BTDC with a bulb. Car would not start. Days of setting the carb jets with a dial indicator where I basically went from turned completely up to completely down a flat at a time, the car still refused to start. Also attempted to vary the timing with out a change.

The distributor turned very freely when adjusting so I pulled it and noticed some of the aluminum was broken away at the clamp that tightens it from turning. I had another dist. so I removed the distributor, cleaned all parts (which were fairly clean) and put them into the other housing of the same type. Replaced with new the points, condenser, rotor and distributor connector (plastic part with the wire to the point set). Car refused to start. Thought I may have put it in 180 degrees off but discoverd that it was impossible to do that as the end is off set.

Have been charging the battery when it runs down from cranking. Engine turns freely. I do smell gas after cranking regardless if I try the choke or not and regardless of where I have the jets set. Did check the float level and it is corredt. Added washers to the gross jets to increase and decrease the settings with no change. Engine ground wire was also changed out. I check for spark with a timing light that I can watch while attempting to start the car. Generally it has spark but occasionally I do not see the light flashing. Coil has been changed out three times without a change. Did this when it started and ran poorly and when it refused to start.

I would prefer working out this bug myself with your imput, otherwise I am facing having this car towed to the nearest British garage 50 miles away. Not a pretty thought. Any suggestions would be greately appreciated.

Randy Palsgrove

Randy, Maybe you cannot get the dizzy in backwards but it can be wired wrong if you have number 6 cylinder at TDC and wire the dizzy thinking you have number one cylinder at TDC. So in short you need to go back over your ignition tune up and get the number one cylinder on TDC and base your ignition timing and dizzy wiring from there. I'm assuming you have a manual that gives instructions on how to find TDC and set your point gap. That should get the ignition close enough for the car to run. Did you adjust the valves in your checks? Not saying you need to but it may be helpful if we know.

On the carbs, did you add some oil to the dampers? They need oil to run properly. Engne oil is fine, usually same weight as used in the engine.

Since you have an MGC I don't know if anyone else will respond. Get the timing and dwell right and if it still isn't running well get back, I'll try to help. Good luck, Clifton




Clifton Gordon

Randy. Is is perfectly possible to re-assemble the distributor 180 out. The points cam will fit on two ways--correctly and 180 out. If it were me, I would pull the rocker arm cover and set the number one and two valves so they were closed, then see where the rotor arm is pointing. As to the carb jets, Peter Burgess recommends .060" below the bridge as an initial tuning point. I find .055" works better for me. The ocassional failure to flash on the timing light can indicate some form of low tension or high tension problem. But, I would make sure the dizzy is oriented correctly before starting to go through the system. Did you install the points correctly? If the C points are like the B points, the wires must make contact with the spring arm of the points, but cannot make contact with the nut or stud the nut screws to. If you do make contact, the points ground out and the car will not start. There is a plastic insulator which goes through the connectors for the wire from the coil and condensor, then the wires are attached to the spring arm with this plastic insulator keeping the wires from touching the stud or nut. It is also possible that the timing marks on the outside of the harmonic balancer are not correct. This happens when the rubber spacer between the inner hub and outer ring gets out and no longer binds the two parts together. Check out the archives on how to find top dead center without pulling the cylinder head. There are several methods. That would give you an idea if the crankshaft pulley has begun to de-laminate. First thing is to get it started again, then the troubleshooting can begin. Les
Les Bengtson

This thread was discussed on 01/09/2002

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